求java高手編寫(xiě)一個(gè)IO流的程序，大體是關(guān)于文件拷貝的

你好，代碼如下：

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import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.Reader;

import java.io.Writer;

public class ReaderDemo02{

public static void main(String args[]) throws Exception{ // 異常拋出，不處理

File f1= new File("c:" + File.separator + "a.txt") ; // 聲明File對(duì)象

File f2= new File("c:" + File.separator + "b.txt") ; // 聲明File對(duì)象

Reader input = null ; // 準(zhǔn)備好一個(gè)輸入的對(duì)象

Writer out = null ;

input = new FileReader(f1) ; // 通過(guò)對(duì)象多態(tài)性，進(jìn)行實(shí)例化

out = new FileWriter(f2) ;

char c[] = new char[1024] ; // 所有的內(nèi)容都讀到此數(shù)組之中

int temp = 0 ; // 接收每一個(gè)內(nèi)容

int len = 0 ; // 讀取內(nèi)容

while((temp=input.read())!=-1){

out.write(temp) ;

c[len] = (char)temp ;

len++ ;

}

input.close() ; // 關(guān)閉輸出流

out.close() ;

System.out.println("內(nèi)容為：" + new String(c,0,len)) ; // 把字符數(shù)組變?yōu)樽址敵?/p>

}

};

java用io怎么對(duì)文件進(jìn)行加密？代碼！！

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.io.*;

import java.security.*;

import javax.crypto.*;

import javax.crypto.spec.*;

/**

文件名：FileEncrypter.java

JDK：1.40以上

說(shuō)明：文件加密

加密方法：三重DES加密

加密過(guò)程：對(duì)選中的文件加密后在同文件夾下生成一個(gè)增加了".tdes"

擴(kuò)展名的加密文件

解密過(guò)程：對(duì)選中的加密文件（必須有".tdes"擴(kuò)展名）進(jìn)行解密

*/

public class FileEncrypter extends JFrame{

public static final int WIDTH = 550;

public static final int HEIGHT = 200;

public static void main(String args[]) {

FileEncrypter fe = new FileEncrypter();

fe.show();

}

FileEncrypter(){

this.setSize(WIDTH,HEIGHT);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setResizable(false);

Toolkit tk = Toolkit.getDefaultToolkit();

Dimension screenSize = tk.getScreenSize();

this.setLocation((screenSize.width - WIDTH)/2,

(screenSize.height - HEIGHT)/2);

this.setTitle("文件加密器(TriDES)");

Container c = this.getContentPane();

c.setLayout( new FlowLayout());

final FilePanel fp = new FilePanel("文件選擇");

c.add(fp);

final KeyPanel pp = new KeyPanel("密碼");

c.add(pp);

JButton jbE = new JButton("加密");

c.add(jbE);

jbE.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent event){

File file = new File(fp.getFileName());

if (file.exists())

encrypt(file.getAbsoluteFile(),pp.getKey());

else

JOptionPane.showMessageDialog(

null,"請(qǐng)選擇文件！","提示",JOptionPane.OK_OPTION);

}

});

JButton jbD = new JButton("解密");

c.add(jbD);

jbD.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent event){

File file = new File(fp.getFileName());

if (file.exists())

decrypt(file.getAbsoluteFile(),pp.getKey());

else

JOptionPane.showMessageDialog(

null,"請(qǐng)選擇文件！","提示",JOptionPane.OK_OPTION);

}

});

}

/**

加密函數(shù)

輸入：

要加密的文件，密碼（由0-F組成，共48個(gè)字符，表示3個(gè)8位的密碼）如：

AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746

其中：

AD67EA2F3BE6E5AD DES密碼一

D368DFE03120B5DF DES密碼二

92A8FD8FEC2F0746 DES密碼三

輸出：

對(duì)輸入的文件加密后，保存到同一文件夾下增加了".tdes"擴(kuò)展名的文件中。

*/

private void encrypt(File fileIn,String sKey){

try{

if(sKey.length() == 48){

byte[] bytK1 = getKeyByStr(sKey.substring(0,16));

byte[] bytK2 = getKeyByStr(sKey.substring(16,32));

byte[] bytK3 = getKeyByStr(sKey.substring(32,48));

FileInputStream fis = new FileInputStream(fileIn);

byte[] bytIn = new byte[(int)fileIn.length()];

for(int i = 0;iFILEIN.LENGTH();I++){

bytIn[i] = (byte)fis.read();

}

//加密

byte[] bytOut = encryptByDES(encryptByDES(

encryptByDES(bytIn,bytK1),bytK2),bytK3);

String fileOut = fileIn.getPath() + ".tdes";

FileOutputStream fos = new FileOutputStream(fileOut);

for(int i = 0;iBYTOUT.LENGTH;I++){

fos.write((int)bytOut[i]);

}

fos.close();

JOptionPane.showMessageDialog(

this,"加密成功！","提示",JOptionPane.OK_OPTION);

}else

JOptionPane.showMessageDialog(

this,"密碼長(zhǎng)度必須等于48！","錯(cuò)誤信息",JOptionPane.ERROR_MESSAGE);

}catch(Exception e){

e.printStackTrace();

}

}

/**

解密函數(shù)

輸入：

要解密的文件，密碼（由0-F組成，共48個(gè)字符，表示3個(gè)8位的密碼）如：

AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746

其中：

AD67EA2F3BE6E5AD DES密碼一

D368DFE03120B5DF DES密碼二

92A8FD8FEC2F0746 DES密碼三

輸出：

對(duì)輸入的文件解密后，保存到用戶指定的文件中。

*/

private void decrypt(File fileIn,String sKey){

try{

if(sKey.length() == 48){

String strPath = fileIn.getPath();

if(strPath.substring(strPath.length()-5).toLowerCase().equals(".tdes"))

strPath = strPath.substring(0,strPath.length()-5);

else{

JOptionPane.showMessageDialog(

this,"不是合法的加密文件！","提示",JOptionPane.OK_OPTION);

return;

}

JFileChooser chooser = new JFileChooser();

chooser.setCurrentDirectory(new File("."));

chooser.setSelectedFile(new File(strPath));

//用戶指定要保存的文件

int ret = chooser.showSaveDialog(this);

if(ret==JFileChooser.APPROVE_OPTION){

byte[] bytK1 = getKeyByStr(sKey.substring(0,16));

byte[] bytK2 = getKeyByStr(sKey.substring(16,32));

byte[] bytK3 = getKeyByStr(sKey.substring(32,48));

FileInputStream fis = new FileInputStream(fileIn);

byte[] bytIn = new byte[(int)fileIn.length()];

for(int i = 0;iFILEIN.LENGTH();I++){

bytIn[i] = (byte)fis.read();

}

//解密

byte[] bytOut = decryptByDES(decryptByDES(

decryptByDES(bytIn,bytK3),bytK2),bytK1);

File fileOut = chooser.getSelectedFile();

fileOut.createNewFile();

FileOutputStream fos = new FileOutputStream(fileOut);

for(int i = 0;iBYTOUT.LENGTH;I++){

fos.write((int)bytOut[i]);

}

fos.close();

JOptionPane.showMessageDialog(

this,"解密成功！","提示",JOptionPane.OK_OPTION);

}

}else

JOptionPane.showMessageDialog(

this,"密碼長(zhǎng)度必須等于48！","錯(cuò)誤信息",JOptionPane.ERROR_MESSAGE);

}catch(Exception e){

JOptionPane.showMessageDialog(

this,"解密失敗，請(qǐng)核對(duì)密碼！","提示",JOptionPane.OK_OPTION);

}

}

/**

用DES方法加密輸入的字節(jié)

bytKey需為8字節(jié)長(zhǎng)，是加密的密碼

*/

private byte[] encryptByDES(byte[] bytP,byte[] bytKey) throws Exception{

DESKeySpec desKS = new DESKeySpec(bytKey);

SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");

SecretKey sk = skf.generateSecret(desKS);

Cipher cip = Cipher.getInstance("DES");

cip.init(Cipher.ENCRYPT_MODE,sk);

return cip.doFinal(bytP);

}

/**

用DES方法解密輸入的字節(jié)

bytKey需為8字節(jié)長(zhǎng)，是解密的密碼

*/

private byte[] decryptByDES(byte[] bytE,byte[] bytKey) throws Exception{

DESKeySpec desKS = new DESKeySpec(bytKey);

SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");

SecretKey sk = skf.generateSecret(desKS);

Cipher cip = Cipher.getInstance("DES");

cip.init(Cipher.DECRYPT_MODE,sk);

return cip.doFinal(bytE);

}

/**

輸入密碼的字符形式，返回字節(jié)數(shù)組形式。

如輸入字符串：AD67EA2F3BE6E5AD

返回字節(jié)數(shù)組：{173,103,234,47,59,230,229,173}

*/

private byte[] getKeyByStr(String str){

byte[] bRet = new byte[str.length()/2];

for(int i=0;iSTR.LENGTH()

Integer itg =

new Integer(16*getChrInt(str.charAt(2*i)) + getChrInt(str.charAt(2*i+1)));

bRet[i] = itg.byteValue();

}

return bRet;

}

/**

計(jì)算一個(gè)16進(jìn)制字符的10進(jìn)制值

輸入：0-F

*/

private int getChrInt(char chr){

int iRet=0;

if(chr=="0".charAt(0)) iRet = 0;

if(chr=="1".charAt(0)) iRet = 1;

if(chr=="2".charAt(0)) iRet = 2;

if(chr=="3".charAt(0)) iRet = 3;

if(chr=="4".charAt(0)) iRet = 4;

if(chr=="5".charAt(0)) iRet = 5;

if(chr=="6".charAt(0)) iRet = 6;

if(chr=="7".charAt(0)) iRet = 7;

if(chr=="8".charAt(0)) iRet = 8;

if(chr=="9".charAt(0)) iRet = 9;

if(chr=="A".charAt(0)) iRet = 10;

if(chr=="B".charAt(0)) iRet = 11;

if(chr=="C".charAt(0)) iRet = 12;

if(chr=="D".charAt(0)) iRet = 13;

if(chr=="E".charAt(0)) iRet = 14;

if(chr=="F".charAt(0)) iRet = 15;

return iRet;

}

}

/**

文件選擇組件。

*/

class FilePanel extends JPanel{

FilePanel(String str){

JLabel label = new JLabel(str);

JTextField fileText = new JTextField(35);

JButton chooseButton = new JButton("瀏覽...");

this.add(label);

this.add(fileText);

this.add(chooseButton);

clickAction ca = new clickAction(this);

chooseButton.addActionListener(ca);

}

public String getFileName(){

JTextField jtf = (JTextField)this.getComponent(1);

return jtf.getText();

}

private class clickAction implements ActionListener{

clickAction(Component c){

cmpt = c;

}

public void actionPerformed(ActionEvent event){

JFileChooser chooser = new JFileChooser();

chooser.setCurrentDirectory(new File("."));

int ret = chooser.showOpenDialog(cmpt);

if(ret==JFileChooser.APPROVE_OPTION){

JPanel jp = (JPanel)cmpt;

JTextField jtf = (JTextField)jp.getComponent(1);

jtf.setText(chooser.getSelectedFile().getPath());

}

}

private Component cmpt;

}

}

/**

密碼生成組件。

*/

class KeyPanel extends JPanel{

KeyPanel(String str){

JLabel label = new JLabel(str);

JTextField fileText = new JTextField(35);

JButton chooseButton = new JButton("隨機(jī)產(chǎn)生");

this.add(label);

this.add(fileText);

this.add(chooseButton);

clickAction ca = new clickAction(this);

chooseButton.addActionListener(ca);

}

//返回生成的密碼（48個(gè)字符長(zhǎng)度）

public String getKey(){

JTextField jtf = (JTextField)this.getComponent(1);

return jtf.getText();

}

private class clickAction implements ActionListener{

clickAction(Component c){

cmpt = c;

}

public void actionPerformed(ActionEvent event){

try{

KeyGenerator kg = KeyGenerator.getInstance("DES");

kg.init(56);

Key ke = kg.generateKey();

byte[] bytK1 = ke.getEncoded();

ke = kg.generateKey();

byte[] bytK2 = ke.getEncoded();

ke = kg.generateKey();

byte[] bytK3 = ke.getEncoded();

JPanel jp = (JPanel)cmpt;

JTextField jtf = (JTextField)jp.getComponent(1);

jtf.setText(getByteStr(bytK1)+getByteStr(bytK2)+getByteStr(bytK3));

}catch(Exception e){

e.printStackTrace();

}

}

private String getByteStr(byte[] byt){

String strRet = "";

for(int i=0;iBYT.LENGTH;I++){

//System.out.println(byt[i]);

strRet += getHexValue((byt[i]240)/16);

strRet += getHexValue(byt[i]15);

}

return strRet;

}

private String getHexValue(int s){

String sRet=null;

switch (s){

case 0: sRet = "0";break;

case 1: sRet = "1";break;

case 2: sRet = "2";break;

case 3: sRet = "3";break;

case 4: sRet = "4";break;

case 5: sRet = "5";break;

case 6: sRet = "6";break;

case 7: sRet = "7";break;

case 8: sRet = "8";break;

case 9: sRet = "9";break;

case 10: sRet = "A";break;

case 11: sRet = "B";break;

case 12: sRet = "C";break;

case 13: sRet = "D";break;

case 14: sRet = "E";break;

case 15: sRet = "F";

}

return sRet;

}

private Component cmpt;

}

}

Java IO 控制臺(tái)，利用字節(jié)流輸出中文 內(nèi)容（本是同根生，相煎何太急。）代碼如下

用BufferedReader就可以了

public class Test8

{

public static void main(String[] args) throws Exception

{

BufferedReader br = new BufferedReader(new InputStreamReader(

new FileInputStream(new File(

"C:/Users/Lenovo/Desktop/新建文本文檔.txt"))));

String line = br.readLine();

while (null != line)

{

System.out.print(line);

line = br.readLine();

}

br.close();

}

}

java io代碼學(xué)習(xí)

package IO;

import java.io.*;

public class FileDirectoryDemo {

public static void main(String[] args) {

// 如果沒(méi)有指定參數(shù)，則缺省為當(dāng)前目錄。

if (args.length == 0) {

args = new String[] { "." };

}

try {

// 新建指定目錄的File對(duì)象。

File currentPath = new File(args[0]);

// 在指定目錄新建temp目錄的File對(duì)象。

File tempPath = new File(currentPath, "temp");

// 用“tempPath”對(duì)象在指定目錄下創(chuàng)建temp目錄。

tempPath.mkdir();

// 在temp目錄下創(chuàng)建兩個(gè)文件。

File temp1 = new File(tempPath, "temp1.txt");

temp1.createNewFile();

File temp2 = new File(tempPath, "temp2.txt");

temp2.createNewFile();

// 遞歸顯示指定目錄的內(nèi)容。

System.out.println("顯示指定目錄的內(nèi)容");

listSubDir(currentPath);

// 更改文件名“temp1.txt”為“temp.txt”。

File temp1new = new File(tempPath, "temp.txt");

temp1.renameTo(temp1new);

// 遞歸顯示temp子目錄的內(nèi)容。

System.out.println("更改文件名后，顯示temp子目錄的內(nèi)容");

listSubDir(tempPath);

// 刪除文件“temp2.txt”。

temp2.delete();

// 遞歸顯示temp子目錄的內(nèi)容。

System.out.println("刪除文件后，顯示temp子目錄的內(nèi)容");

listSubDir(tempPath);

} catch (IOException e) {

System.err.println("IOException");

}

}

// 遞歸顯示指定目錄的內(nèi)容。

static void listSubDir(File currentPath) {

// 取得指定目錄的內(nèi)容列表。

String[] fileNames = currentPath.list();

try {

for (int i = 0; i fileNames.length; i++) {

File f = new File(currentPath.getPath(), fileNames[i]);

// 如果是目錄，則顯示目錄名后，遞歸調(diào)用，顯示子目錄的內(nèi)容。

if (f.isDirectory()) {

// 以規(guī)范的路徑格式顯示目錄。

System.out.println(f.getCanonicalPath());

// 遞歸調(diào)用，顯示子目錄。

listSubDir(f);

}

// 如果是文件，則顯示文件名，不包含路徑信息。

else {

System.out.println(f.getName());

}

}

} catch (IOException e) {

System.err.println("IOException");

}

}

}

package IO;

import java.io.*;

public class FileExample {

public FileExample() {

super();// 調(diào)用父類(lèi)的構(gòu)造函數(shù)

}

public static void main(String[] args) {

try {

String outfile = "demoout.xml";

// 定義了一個(gè)變量, 用于標(biāo)識(shí)輸出文件

String infile = "demoin.xml";

// 定義了一個(gè)變量, 用于標(biāo)識(shí)輸入文件

DataOutputStream dt = new DataOutputStream(

new BufferedOutputStream(new FileOutputStream(outfile)));

/**

* 用FileOutputStream定義一個(gè)輸入流文件，

* 然后用BuferedOutputStream調(diào)用FileOutputStream對(duì)象生成一個(gè)緩沖輸出流

* 然后用DataOutputStream調(diào)用BuferedOutputStream對(duì)象生成數(shù)據(jù)格式化輸出流

*/

BufferedWriter NewFile = new BufferedWriter(new OutputStreamWriter(

dt, "gbk"));// 對(duì)中文的處理

DataInputStream rafFile1 = new DataInputStream(

new BufferedInputStream(new FileInputStream(infile)));

/**

*用FileInputStream定義一個(gè)輸入流文件，

* 然后用BuferedInputStream調(diào)用FileInputStream對(duì)象生成一個(gè)緩沖輸出流

* ，其后用DataInputStream中調(diào)用BuferedInputStream對(duì)象生成數(shù)據(jù)格式化輸出流

*/

BufferedReader rafFile = new BufferedReader(new InputStreamReader(

rafFile1, "gbk"));// 對(duì)中文的處理

String xmlcontent = "";

char tag = 0;// 文件用字符零結(jié)束

while (tag != (char) (-1)) {

xmlcontent = xmlcontent + tag + rafFile.readLine() + '\n';

}

NewFile.write(xmlcontent);

NewFile.flush();// 清空緩沖區(qū)

NewFile.close();

rafFile.close();

System.gc();// 強(qiáng)制立即回收垃圾，即釋放內(nèi)存。

} catch (NullPointerException exc) {

exc.printStackTrace();

} catch (java.lang.IndexOutOfBoundsException outb) {

System.out.println(outb.getMessage());

outb.printStackTrace();

} catch (FileNotFoundException fex) {

System.out.println("fex" + fex.getMessage());

} catch (IOException iex) {

System.out.println("iex" + iex.getMessage());

}

}

}

package IO;

import java.io.*;

public class FileRandomRW {

// 需要輸入的person數(shù)目。

public static int NUMBER = 3;

public static void main(String[] args) {

Persons[] people = new Persons[NUMBER];

people[0] = new Persons("張峰", 26, 2000, "N");

people[1] = new Persons("艷娜", 25, 50000, "Y");

people[2] = new Persons("李朋", 50, 7000, "F");

try {

DataOutputStream out = new DataOutputStream(new FileOutputStream(

"peoplerandom.dat"));

// 將人員數(shù)據(jù)保存至“peoplerandom.dat”二進(jìn)制文件中。

writeData(people, out);

// 關(guān)閉流。

out.close();

// 從二進(jìn)制文件“peoplerandom.dat”中逆序讀取數(shù)據(jù)。

RandomAccessFile inOut = new RandomAccessFile("peoplerandom.dat",

"rw");

Persons[] inPeople = readDataReverse(inOut);

// 輸出讀入的數(shù)據(jù)。

System.out.println("原始數(shù)據(jù)：");

for (int i = 0; i inPeople.length; i++) {

System.out.println(inPeople[i]);

}

// 修改文件的第三條記錄。

inPeople[2].setSalary(4500);

// 將修改結(jié)果寫(xiě)入文件。

inPeople[2].writeData(inOut, 3);

// 關(guān)閉流。

inOut.close();

// 從文件中讀入的第三條記錄，并輸出，以驗(yàn)證修改結(jié)果。

RandomAccessFile in = new RandomAccessFile("peoplerandom.dat", "r");

Persons in3People = new Persons();

// 隨機(jī)讀第三條記錄。

in3People.readData(in, 3);

// 關(guān)閉流。

in.close();

System.out.println("修改后的記錄");

System.out.println(in3People);

} catch (IOException exception) {

System.err.println("IOException");

}

}

// 將數(shù)據(jù)寫(xiě)入輸出流。

static void writeData(Persons[] p, DataOutputStream out) throws IOException {

for (int i = 0; i p.length; i++) {

p[i].writeData(out);

}

}

// 將數(shù)據(jù)從輸入流中逆序讀出。

static Persons[] readDataReverse(RandomAccessFile in) throws IOException {

// 獲得記錄數(shù)目。

int record_num = (int) (in.length() / Persons.RECORD_LENGTH);

Persons[] p = new Persons[record_num];

// 逆序讀取。

for (int i = record_num - 1; i = 0; i--) {

p[i] = new Persons();

// 文件定位。

in.seek(i * Persons.RECORD_LENGTH);

p[i].readData(in, i + 1);

}

return p;

}

}

class Persons {

private String name;

private int age; // 4個(gè)字節(jié)

private double salary; // 8個(gè)字節(jié)

private String married;

public static final int NAME_LENGTH = 20; // 姓名長(zhǎng)度

public static final int MARRIED_LENGTH = 2; // 婚否長(zhǎng)度

public static final int RECORD_LENGTH = NAME_LENGTH * 2 + 4 + 8

+ MARRIED_LENGTH * 2;

public Persons() {

}

public Persons(String n, int a, double s) {

name = n;

age = a;

salary = s;

married = "F";

}

public Persons(String n, int a, double s, String m) {

name = n;

age = a;

salary = s;

married = m;

}

public String getName() {

return name;

}

public int getAge() {

return age;

}

public double getSalary() {

return salary;

}

public String getMarried() {

return married;

}

public String setName(String n) {

name = n;

return name;

}

public int setAge(int a) {

age = a;

return age;

}

public double setSalary(double s) {

salary = s;

return salary;

}

public String setMarried(String m) {

married = m;

return married;

}

// 設(shè)置輸出格式。

public String toString() {

return getClass().getName() + "[name=" + name + ",age=" + age

+ ",salary=" + salary + ",married=" + married + "]";

}

// 寫(xiě)入一條固定長(zhǎng)度的記錄，即一個(gè)人的數(shù)據(jù)到輸出流。

public void writeData(DataOutput out) throws IOException {

FixStringIO.writeFixString(name, NAME_LENGTH, out);

out.writeInt(age);

out.writeDouble(salary);

FixStringIO.writeFixString(married, MARRIED_LENGTH, out);

}

// 寫(xiě)入一條固定長(zhǎng)度的記錄到隨機(jī)讀取文件中。

private void writeData(RandomAccessFile out) throws IOException {

FixStringIO.writeFixString(name, NAME_LENGTH, out);

out.writeInt(age);

out.writeDouble(salary);

FixStringIO.writeFixString(married, MARRIED_LENGTH, out);

}

// 隨機(jī)寫(xiě)入一條固定長(zhǎng)度的記錄到輸出流的指定位置。

public void writeData(RandomAccessFile out, int n) throws IOException {

out.seek((n - 1) * RECORD_LENGTH);

writeData(out);

}

// 從輸入流隨機(jī)讀入一條記錄，即一個(gè)人的數(shù)據(jù)。

private void readData(RandomAccessFile in) throws IOException {

name = FixStringIO.readFixString(NAME_LENGTH, in);

age = in.readInt();

salary = in.readDouble();

married = FixStringIO.readFixString(MARRIED_LENGTH, in);

}

// 從輸入流隨機(jī)讀入指定位置的記錄。

public void readData(RandomAccessFile in, int n) throws IOException {

in.seek((n - 1) * RECORD_LENGTH);

readData(in);

}

}

// 對(duì)固定長(zhǎng)度字符串從文件讀出、寫(xiě)入文件

class FixStringIO {

// 讀取固定長(zhǎng)度的Unicode字符串。

public static String readFixString(int size, DataInput in)

throws IOException {

StringBuffer b = new StringBuffer(size);

int i = 0;

boolean more = true;

while (more i size) {

char ch = in.readChar();

i++;

if (ch == 0) {

more = false;

} else {

b.append(ch);

}

}

// 跳過(guò)剩余的字節(jié)。

in.skipBytes(2 * (size - i));

return b.toString();

}

// 寫(xiě)入固定長(zhǎng)度的Unicode字符串。

public static void writeFixString(String s, int size, DataOutput out)

throws IOException {

int i;

for (i = 0; i size; i++) {

char ch = 0;

if (i s.length()) {

ch = s.charAt(i);

}

out.writeChar(ch);

}

}

}

package IO;

import java.io.*;

import java.util.*;

public class FileRW {

// 需要輸入的person數(shù)目。

public static int NUMBER = 3;

public static void main(String[] args) {

Person[] people = new Person[NUMBER];

// 暫時(shí)容納輸入數(shù)據(jù)的臨時(shí)字符串?dāng)?shù)組。

String[] field = new String[4];

// 初始化field數(shù)組。

for (int i = 0; i 4; i++) {

field[i] = "";

}

// IO操作必須捕獲IO異常。

try {

// 用于對(duì)field數(shù)組進(jìn)行增加控制。

int fieldcount = 0;

// 先使用System.in構(gòu)造InputStreamReader，再構(gòu)造BufferedReader。

BufferedReader stdin = new BufferedReader(new InputStreamReader(

System.in));

for (int i = 0; i NUMBER; i++) {

fieldcount = 0;

System.out.println("The number " + (i + 1) + " person");

System.out

.println("Enter name,age,salary,married(optional),please separate fields by ':'");

// 讀取一行。

String personstr = stdin.readLine();

// 設(shè)置分隔符。

StringTokenizer st = new StringTokenizer(personstr, ":");

// 判斷是否還有分隔符可用。

while (st.hasMoreTokens()) {

field[fieldcount] = st.nextToken();

fieldcount++;

}

// 如果輸入married，則field[3]不為空，調(diào)用具有四個(gè)參數(shù)的Person構(gòu)造函數(shù)。

if (field[3] != "") {

people[i] = new Person(field[0],

Integer.parseInt(field[1]), Double

.parseDouble(field[2]), field[3]);

// 置field[3]為空，以備下次輸入使用。

field[3] = "";

}

// 如果未輸入married，則field[3]為空，調(diào)用具有三個(gè)參數(shù)的Person構(gòu)造函數(shù)。

else {

people[i] = new Person(field[0],

Integer.parseInt(field[1]), Double

.parseDouble(field[2]));

}

}

// 將輸入的數(shù)據(jù)保存至“people.dat”文本文件中。

PrintWriter out = new PrintWriter(new BufferedWriter(

new FileWriter("people.dat")));

writeData(people, out);

// 關(guān)閉流。

out.close();

// 從文件“people.dat”讀取數(shù)據(jù)。

BufferedReader in = new BufferedReader(new FileReader("people.dat"));

Person[] inPeople = readData(in);

// 關(guān)閉流。

in.close();

// 輸出從文件中讀入的數(shù)據(jù)。

for (int i = 0; i inPeople.length; i++) {

System.out.println(inPeople[i]);

}

} catch (IOException exception) {

System.err.println("IOException");

}

}

// 將所有數(shù)據(jù)寫(xiě)入輸出流。

static void writeData(Person[] p, PrintWriter out) throws IOException {

// 寫(xiě)入記錄條數(shù)，即人數(shù)。

out.println(p.length);

for (int i = 0; i p.length; i++) {

p[i].writeData(out);

}

}

// 將所有數(shù)據(jù)從輸入流中讀出。

static Person[] readData(BufferedReader in) throws IOException {

// 獲取記錄條數(shù)，即人數(shù)。

int n = Integer.parseInt(in.readLine());

Person[] p = new Person[n];

for (int i = 0; i n; i++) {

p[i] = new Person();

p[i].readData(in);

}

return p;

}

}

class Person {

private String name;

private int age;

private double salary;

private String married;

public Person() {

}

public Person(String n, int a, double s) {

name = n;

age = a;

salary = s;

married = "F";

}

public Person(String n, int a, double s, String m) {

name = n;

age = a;

salary = s;

married = m;

}

public String getName() {

return name;

}

public int getAge() {

return age;

}

public double getSalary() {

return salary;

}

public String getMarried() {

return married;

}

// 設(shè)置輸出格式。

public String toString() {

return getClass().getName() + "[name=" + name + ",age=" + age

+ ",salary=" + salary + ",married=" + married + "]";

}

// 寫(xiě)入一條記錄，即一個(gè)人的數(shù)據(jù)到輸出流。

public void writeData(PrintWriter out) throws IOException {

// 格式化輸出。

out.println(name + ":" + age + ":" + salary + ":" + married);

}

// 從輸入流讀入一條記錄，即一個(gè)人的數(shù)據(jù)。

public void readData(BufferedReader in) throws IOException {

String s = in.readLine();

StringTokenizer t = new StringTokenizer(s, ":");

name = t.nextToken();

age = Integer.parseInt(t.nextToken());

salary = Double.parseDouble(t.nextToken());

married = t.nextToken();

}

}

package IO;

import java.io.IOException;

public class FileStdRead {

public static void main(String[] args) throws IOException {

int b = 0;

char c = ' ';

System.out.println("請(qǐng)輸入：");

while (c != 'q') {

int a = System.in.read();

c = (char) a;

b++;

System.out.println((char) a);

}

System.err.print("counted\t" + b + "\ttotalbytes.");

}

}

//讀取輸入的數(shù)據(jù),直到數(shù)據(jù)中有Q這個(gè)字母然

package IO;

import java.io.*;

public class IOStreamExample {

public static void main(String[] args) throws IOException {

// 1. 讀入一行數(shù)據(jù):

BufferedReader in = new BufferedReader(new FileReader(

"FileStdRead.java"));

String s, s2 = new String();

while ((s = in.readLine()) != null) {

s2 += s + "\n";

}

in.close();

BufferedReader stdin = new BufferedReader(new InputStreamReader(

System.in));

System.out.print("Enter a line:");

System.out.println(stdin.readLine());

// 2. 從內(nèi)存中讀入

StringReader in2 = new StringReader(s2);

int c;

while ((c = in2.read()) != -1) {

System.out.print((char) c);

}

// 3. 格式化內(nèi)存輸入

try {

DataInputStream in3 = new DataInputStream(new ByteArrayInputStream(

s2.getBytes()));

while (true) {

System.out.print((char) in3.readByte());

}

} catch (EOFException e) {

System.err.println("End of stream");

}

// 4. 文件輸入

try {

BufferedReader in4 = new BufferedReader(new StringReader(s2));

PrintWriter out1 = new PrintWriter(new BufferedWriter(

new FileWriter("IODemo.out")));

int lineCount = 1;

while ((s = in4.readLine()) != null) {

out1.println(lineCount++ + ": " + s);

}

out1.close();

} catch (EOFException e) {

System.err.println("End of stream");

}

// 5. 接收和保存數(shù)據(jù)

try {

DataOutputStream out2 = new DataOutputStream(

new BufferedOutputStream(new FileOutputStream("Data.txt")));

out2.writeDouble(3.14159);

out2.writeUTF("That was pi");

out2.writeDouble(1.41413);

out2.writeUTF("Square root of 2");

out2.close();

DataInputStream in5 = new DataInputStream(new BufferedInputStream(

new FileInputStream("Data.txt")));

System.out.println(in5.readDouble());

System.out.println(in5.readUTF());

System.out.println(in5.readDouble());

System.out.println(in5.readUTF());

} catch (EOFException e) {

throw new RuntimeException(e);

}

// 6. 隨機(jī)讀取文件內(nèi)容

RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw");

for (int i = 0; i 10; i++) {

rf.writeDouble(i * 1.414);

}

rf.close();

rf = new RandomAccessFile("rtest.dat", "rw");

rf.seek(5 * 8);

rf.writeDouble(47.0001);

rf.close();

rf = new RandomAccessFile("rtest.dat", "r");

for (int i = 0; i 10; i++) {

System.out.println("Value " + i + ": " + rf.readDouble());

}

rf.close();

}

}

package IO;

import java.io.*;

/**

* p

* Title: JAVA進(jìn)階訣竅

* /p

*

* @author 張峰

* @version 1.0

*/

public class MakeDirectoriesExample {

private static void fileattrib(File f) {

System.out.println("絕對(duì)路徑: " + f.getAbsolutePath() + "\n 可讀屬性: "

+ f.canRead() + "\n 可定屬性: " + f.canWrite() + "\n 文件名: "

+ f.getName() + "\n 父目錄: " + f.getParent() + "\n 當(dāng)前路徑: "

+ f.getPath() + "\n 文件長(zhǎng)度: " + f.length() + "\n 最后更新日期: "

+ f.lastModified());

if (f.isFile()) {

System.out.println("輸入的是一個(gè)文件");

} else if (f.isDirectory()) {

System.out.println("輸入的是一個(gè)目錄");

}

}

public static void main(String[] args) {

if (args.length 1) {

args = new String[3];

}

args[0] = "d";

args[1] = "test1.txt";

args[2] = "test2.txt";

File old = new File(args[1]), rname = new File(args[2]);

old.renameTo(rname);

fileattrib(old);

fileattrib(rname);

int count = 0;

boolean del = false;

if (args[0].equals("d")) {

count++;

del = true;

}

count--;

while (++count args.length) {

File f = new File(args[count]);

if (f.exists()) {

System.out.println(f + " 文件己經(jīng)存在");

if (del) {

System.out.println("刪除文件" + f);

f.delete();

}

} else { // 如果文件不存在

if (!del) {

f.mkdirs();

System.out.println("創(chuàng)建文件： " + f);

}

}

fileattrib(f);

}

}

}

java多線程/磁盤(pán)IO過(guò)程詳解：為什么說(shuō)多線程

磁盤(pán)IO的速度在那里了，就算你再多的線程，也繞不過(guò)IO瓶頸。不是說(shuō)多線程不能提高效率，這個(gè)要看你項(xiàng)目的性能瓶頸在哪里。 IO密集型，沒(méi)必要多線程，容易弄巧成拙。建議Cache，某些文件系統(tǒng)在順序讀或?qū)懘疟P(pán)時(shí)速度相當(dāng)快，如果恰好文件是順序存儲(chǔ)在磁盤(pán)上的，建議先盡量讀進(jìn)內(nèi)存，再一次性寫(xiě)出去。其他什么磁盤(pán)內(nèi)存通道之類(lèi)的底層技術(shù)就不是Java能左右的了。

有什么io方面的java經(jīng)典代碼

package IO;

import java.io.*;

public class FileDirectoryDemo {

public static void main(String[] args) {

// 如果沒(méi)有指定參數(shù)，則缺省為當(dāng)前目錄。

if (args.length == 0) {

args = new String[] { "." };

}

try {

// 新建指定目錄的File對(duì)象。

File currentPath = new File(args[0]);

// 在指定目錄新建temp目錄的File對(duì)象。

File tempPath = new File(currentPath, "temp");

// 用“tempPath”對(duì)象在指定目錄下創(chuàng)建temp目錄。

tempPath.mkdir();

// 在temp目錄下創(chuàng)建兩個(gè)文件。

File temp1 = new File(tempPath, "temp1.txt");

temp1.createNewFile();

File temp2 = new File(tempPath, "temp2.txt");

temp2.createNewFile();

// 遞歸顯示指定目錄的內(nèi)容。

System.out.println("顯示指定目錄的內(nèi)容");

listSubDir(currentPath);

// 更改文件名“temp1.txt”為“temp.txt”。

File temp1new = new File(tempPath, "temp.txt");

temp1.renameTo(temp1new);

// 遞歸顯示temp子目錄的內(nèi)容。

System.out.println("更改文件名后，顯示temp子目錄的內(nèi)容");

listSubDir(tempPath);

// 刪除文件“temp2.txt”。

temp2.delete();

// 遞歸顯示temp子目錄的內(nèi)容。

System.out.println("刪除文件后，顯示temp子目錄的內(nèi)容");

listSubDir(tempPath);

} catch (IOException e) {

System.err.println("IOException");

}

}

// 遞歸顯示指定目錄的內(nèi)容。

static void listSubDir(File currentPath) {

// 取得指定目錄的內(nèi)容列表。

String[] fileNames = currentPath.list();

try {

for (int i = 0; i fileNames.length; i++) {

File f = new File(currentPath.getPath(), fileNames[i]);

// 如果是目錄，則顯示目錄名后，遞歸調(diào)用，顯示子目錄的內(nèi)容。

if (f.isDirectory()) {

// 以規(guī)范的路徑格式顯示目錄。

System.out.println(f.getCanonicalPath());

// 遞歸調(diào)用，顯示子目錄。

listSubDir(f);

}

// 如果是文件，則顯示文件名，不包含路徑信息。

else {

System.out.println(f.getName());

}

}

} catch (IOException e) {

System.err.println("IOException");

}

}

}

package IO;

import java.io.*;

public class FileExample {

public FileExample() {

super();

}

public static void main(String[] args) {

try {

String outfile = "demoout.xml";

String infile = "demoin.xml";

/**

* 用FileOutputStream定義一個(gè)輸入流文件，然后用BuferedOutputStream調(diào)用FileOutputStream對(duì)象生成一個(gè)緩沖輸出流

然后用DataOutputStream調(diào)用BuferedOutputStream對(duì)象生成數(shù)據(jù)格式化輸出流

*/

DataOutputStream dt=new DataOutputStream(new BufferedOutputStream(new FileOutputStream(outfile)));

BufferedWriter NewFile = new BufferedWriter(new OutputStreamWriter(dt, "GBK"));

// 對(duì)中文的處理

// 定義一個(gè)輸入流

DataInputStream rafFile1 = new DataInputStream(new BufferedInputStream(new FileInputStream(infile)));

// 定義一個(gè)輸入緩沖

BufferedReader rafFile = new BufferedReader(new InputStreamReader(rafFile1, "GBK"));

String xmlcontent = "";

char tag = 0;// 文件友字符0結(jié)束

while (tag != (char) (-1)) {

xmlcontent = xmlcontent + tag + rafFile.readLine() + '\n';

tag = (char) rafFile.read();

}

NewFile.write(xmlcontent);

NewFile.flush();

NewFile.close();

rafFile.close();

System.gc();

} catch (NullPointerException exc) {

exc.printStackTrace();

} catch (java.lang.IndexOutOfBoundsException outb) {

System.out.println(outb.getMessage());

outb.printStackTrace();

} catch (FileNotFoundException fex) {

System.out.println("fex" + fex.getMessage());

} catch (IOException iex) {

System.out.println("iex" + iex.getMessage());

}

}

}

package IO;

import java.io.*;

public class FileRandomRW {

// 需要輸入的person數(shù)目。

public static int NUMBER = 3;

public static void main(String[] args) {

Persons[] people = new Persons[NUMBER];

people[0] = new Persons("張峰", 26, 2000, "N");

people[1] = new Persons("艷娜", 25, 50000, "Y");

people[2] = new Persons("李朋", 50, 7000, "F");

try {

DataOutputStream out = new DataOutputStream(new FileOutputStream(

"peoplerandom.dat"));

// 將人員數(shù)據(jù)保存至“peoplerandom.dat”二進(jìn)制文件中。

writeData(people, out);

// 關(guān)閉流。

out.close();

// 從二進(jìn)制文件“peoplerandom.dat”中逆序讀取數(shù)據(jù)。

RandomAccessFile inOut = new RandomAccessFile("peoplerandom.dat",

"rw");

Persons[] inPeople = readDataReverse(inOut);

// 輸出讀入的數(shù)據(jù)。

System.out.println("原始數(shù)據(jù)：");

for (int i = 0; i inPeople.length; i++) {

System.out.println(inPeople[i]);

}

// 修改文件的第三條記錄。

inPeople[2].setSalary(4500);

// 將修改結(jié)果寫(xiě)入文件。

inPeople[2].writeData(inOut, 3);

// 關(guān)閉流。

inOut.close();

// 從文件中讀入的第三條記錄，并輸出，以驗(yàn)證修改結(jié)果。

RandomAccessFile in = new RandomAccessFile("peoplerandom.dat", "r");

Persons in3People = new Persons();

// 隨機(jī)讀第三條記錄。

in3People.readData(in, 3);

// 關(guān)閉流。

in.close();

System.out.println("修改后的記錄");

System.out.println(in3People);

} catch (IOException exception) {

System.err.println("IOException");

}

}

// 將數(shù)據(jù)寫(xiě)入輸出流。

static void writeData(Persons[] p, DataOutputStream out) throws IOException {

for (int i = 0; i p.length; i++) {

p[i].writeData(out);

}

}

// 將數(shù)據(jù)從輸入流中逆序讀出。

static Persons[] readDataReverse(RandomAccessFile in) throws IOException {

// 獲得記錄數(shù)目。

int record_num = (int) (in.length() / Persons.RECORD_LENGTH);

Persons[] p = new Persons[record_num];

// 逆序讀取。

for (int i = record_num - 1; i = 0; i--) {

p[i] = new Persons();

// 文件定位。

in.seek(i * Persons.RECORD_LENGTH);

p[i].readData(in, i + 1);

}

return p;

}

}

class Persons {

private String name;

private int age; // 4個(gè)字節(jié)

private double salary; // 8個(gè)字節(jié)

private String married;

public static final int NAME_LENGTH = 20; // 姓名長(zhǎng)度

public static final int MARRIED_LENGTH = 2; // 婚否長(zhǎng)度

public static final int RECORD_LENGTH = NAME_LENGTH * 2 + 4 + 8

+ MARRIED_LENGTH * 2;

public Persons() {

}

public Persons(String n, int a, double s) {

name = n;

age = a;

salary = s;

married = "F";

}

public Persons(String n, int a, double s, String m) {

name = n;

age = a;

salary = s;

married = m;

}

public String getName() {

return name;

}

public int getAge() {

return age;

}

public double getSalary() {

return salary;

}

public String getMarried() {

return married;

}

public String setName(String n) {

name = n;

return name;

}

public int setAge(int a) {

age = a;

return age;

}

public double setSalary(double s) {

salary = s;

return salary;

}

public String setMarried(String m) {

married = m;

return married;

}

// 設(shè)置輸出格式。

public String toString() {

return getClass().getName() + "[name=" + name + ",age=" + age

+ ",salary=" + salary + ",married=" + married + "]";

}

// 寫(xiě)入一條固定長(zhǎng)度的記錄，即一個(gè)人的數(shù)據(jù)到輸出流。

public void writeData(DataOutput out) throws IOException {

FixStringIO.writeFixString(name, NAME_LENGTH, out);

out.writeInt(age);

out.writeDouble(salary);

FixStringIO.writeFixString(married, MARRIED_LENGTH, out);

}

// 寫(xiě)入一條固定長(zhǎng)度的記錄到隨機(jī)讀取文件中。

private void writeData(RandomAccessFile out) throws IOException {

FixStringIO.writeFixString(name, NAME_LENGTH, out);

out.writeInt(age);

out.writeDouble(salary);

FixStringIO.writeFixString(married, MARRIED_LENGTH, out);

}

// 隨機(jī)寫(xiě)入一條固定長(zhǎng)度的記錄到輸出流的指定位置。

public void writeData(RandomAccessFile out, int n) throws IOException {

out.seek((n - 1) * RECORD_LENGTH);

writeData(out);

}

// 從輸入流隨機(jī)讀入一條記錄，即一個(gè)人的數(shù)據(jù)。

private void readData(RandomAccessFile in) throws IOException {

name = FixStringIO.readFixString(NAME_LENGTH, in);

age = in.readInt();

salary = in.readDouble();

married = FixStringIO.readFixString(MARRIED_LENGTH, in);

}

// 從輸入流隨機(jī)讀入指定位置的記錄。

public void readData(RandomAccessFile in, int n) throws IOException {

in.seek((n - 1) * RECORD_LENGTH);

readData(in);

}

}

// 對(duì)固定長(zhǎng)度字符串從文件讀出、寫(xiě)入文件

class FixStringIO {

// 讀取固定長(zhǎng)度的Unicode字符串。

public static String readFixString(int size, DataInput in)

throws IOException {

StringBuffer b = new StringBuffer(size);

int i = 0;

boolean more = true;

while (more i size) {

char ch = in.readChar();

i++;

if (ch == 0) {

more = false;

} else {

b.append(ch);

}

}

// 跳過(guò)剩余的字節(jié)。

in.skipBytes(2 * (size - i));

return b.toString();

}

// 寫(xiě)入固定長(zhǎng)度的Unicode字符串。

public static void writeFixString(String s, int size, DataOutput out)

throws IOException {

int i;

for (i = 0; i size; i++) {

char ch = 0;

if (i s.length()) {

ch = s.charAt(i);

}

out.writeChar(ch);

}

}

}

package IO;

import java.io.*;

import java.util.*;

public class FileRW {

// 需要輸入的person數(shù)目。

public static int NUMBER = 3;

public static void main(String[] args) {

Person[] people = new Person[NUMBER];

// 暫時(shí)容納輸入數(shù)據(jù)的臨時(shí)字符串?dāng)?shù)組。

String[] field = new String[4];

// 初始化field數(shù)組。

for (int i = 0; i 4; i++) {

field[i] = "";

}

// IO操作必須捕獲IO異常。

try {

// 用于對(duì)field數(shù)組進(jìn)行增加控制。

int fieldcount = 0;

// 先使用System.in構(gòu)造InputStreamReader，再構(gòu)造BufferedReader。

BufferedReader stdin = new BufferedReader(new InputStreamReader(

System.in));

for (int i = 0; i NUMBER; i++) {

fieldcount = 0;

System.out.println("The number " + (i + 1) + " person");

System.out

.println("Enter name,age,salary,married(optional),please separate fields by ':'");

// 讀取一行。

String personstr = stdin.readLine();

// 設(shè)置分隔符。

StringTokenizer st = new StringTokenizer(personstr, ":");

// 判斷是否還有分隔符可用。

while (st.hasMoreTokens()) {

field[fieldcount] = st.nextToken();

fieldcount++;

}

// 如果輸入married，則field[3]不為空，調(diào)用具有四個(gè)參數(shù)的Person構(gòu)造函數(shù)。

if (field[3] != "") {

people[i] = new Person(field[0],

Integer.parseInt(field[1]), Double

.parseDouble(field[2]), field[3]);

// 置field[3]為空，以備下次輸入使用。

field[3] = "";

}

// 如果未輸入married，則field[3]為空，調(diào)用具有三個(gè)參數(shù)的Person構(gòu)造函數(shù)。

else {

people[i] = new Person(field[0],

Integer.parseInt(field[1]), Double

.parseDouble(field[2]));

}

}

// 將輸入的數(shù)據(jù)保存至“people.dat”文本文件中。

PrintWriter out = new PrintWriter(new BufferedWriter(

new FileWriter("people.dat")));

writeData(people, out);

// 關(guān)閉流。

out.close();

// 從文件“people.dat”讀取數(shù)據(jù)。

BufferedReader in = new BufferedReader(new FileReader("people.dat"));

Person[] inPeople = readData(in);

// 關(guān)閉流。

in.close();

// 輸出從文件中讀入的數(shù)據(jù)。

for (int i = 0; i inPeople.length; i++) {

System.out.println(inPeople[i]);

}

} catch (IOException exception) {

System.err.println("IOException");

}

}

// 將所有數(shù)據(jù)寫(xiě)入輸出流。

static void writeData(Person[] p, PrintWriter out) throws IOException {

// 寫(xiě)入記錄條數(shù)，即人數(shù)。

out.println(p.length);

for (int i = 0; i p.length; i++) {

p[i].writeData(out);

}

}

// 將所有數(shù)據(jù)從輸入流中讀出。

static Person[] readData(BufferedReader in) throws IOException {

// 獲取記錄條數(shù)，即人數(shù)。

int n = Integer.parseInt(in.readLine());

Person[] p = new Person[n];

for (int i = 0; i n; i++) {

p[i] = new Person();

p[i].readData(in);

}

return p;

}

}

class Person {

private String name;

private int age;

private double salary;

private String married;

public Person() {

}

public Person(String n, int a, double s) {

name = n;

age = a;

salary = s;

married = "F";

}

public Person(String n, int a, double s, String m) {

name = n;

age = a;

salary = s;

married = m;

}

public String getName() {

return name;

}

public int getAge() {

return age;

}

public double getSalary() {

return salary;

}

public String getMarried() {

return married;

}

// 設(shè)置輸出格式。

public String toString() {

return getClass().getName() + "[name=" + name + ",age=" + age

+ ",salary=" + salary + ",married=" + married + "]";

}

// 寫(xiě)入一條記錄，即一個(gè)人的數(shù)據(jù)到輸出流。

public void writeData(PrintWriter out) throws IOException {

// 格式化輸出。

out.println(name + ":" + age + ":" + salary + ":" + married);

}

// 從輸入流讀入一條記錄，即一個(gè)人的數(shù)據(jù)。

public void readData(BufferedReader in) throws IOException {

String s = in.readLine();

StringTokenizer t = new StringTokenizer(s, ":");

name = t.nextToken();

age = Integer.parseInt(t.nextToken());

salary = Double.parseDouble(t.nextToken());

married = t.nextToken();

}

}

package IO;

import java.io.*;

public class IOStreamExample {

public static void main(String[] args) throws IOException {

// 1. 讀入一行數(shù)據(jù):

BufferedReader in = new BufferedReader(new FileReader(

"FileStdRead.java"));

String s, s2 = new String();

while ((s = in.readLine()) != null) {

s2 += s + "\n";

}

in.close();

BufferedReader stdin = new BufferedReader(new InputStreamReader(

System.in));

System.out.print("Enter a line:");

System.out.println(stdin.readLine());

// 2. 從內(nèi)存中讀入

StringReader in2 = new StringReader(s2);

int c;

while ((c = in2.read()) != -1) {

System.out.print((char) c);

}

// 3. 格式化內(nèi)存輸入

try {

DataInputStream in3 = new DataInputStream(new ByteArrayInputStream(

s2.getBytes()));

while (true) {

System.out.print((char) in3.readByte());

}

} catch (EOFException e) {

System.err.println("End of stream");

}

// 4. 文件輸入

try {

BufferedReader in4 = new BufferedReader(new StringReader(s2));

PrintWriter out1 = new PrintWriter(new BufferedWriter(

new FileWriter("IODemo.out")));

int lineCount = 1;

while ((s = in4.readLine()) != null) {

out1.println(lineCount++ + ": " + s);

}

out1.close();

} catch (EOFException e) {

System.err.println("End of stream");

}

// 5. 接收和保存數(shù)據(jù)

try {

DataOutputStream out2 = new DataOutputStream(

new BufferedOutputStream(new FileOutputStream("Data.txt")));

out2.writeDouble(3.14159);

out2.writeUTF("That was pi");

out2.writeDouble(1.41413);

out2.writeUTF("Square root of 2");

out2.close();

DataInputStream in5 = new DataInputStream(new BufferedInputStream(

new FileInputStream("Data.txt")));

System.out.println(in5.readDouble());

System.out.println(in5.readUTF());

System.out.println(in5.readDouble());

System.out.println(in5.readUTF());

} catch (EOFException e) {

throw new RuntimeException(e);

}

// 6. 隨機(jī)讀取文件內(nèi)容

RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw");

for (int i = 0; i 10; i++) {

rf.writeDouble(i * 1.414);

}

rf.close();

rf = new RandomAccessFile("rtest.dat", "rw");

rf.seek(5 * 8);

rf.writeDouble(47.0001);

rf.close();

rf = new RandomAccessFile("rtest.dat", "r");

for (int i = 0; i 10; i++) {

System.out.println("Value " + i + ": " + rf.readDouble());

}

rf.close();

}

}

package IO;

import java.io.*;

/**

* p

* Title: JAVA進(jìn)階訣竅

* /p

*

* @author 張峰

* @version 1.0

*/

public class MakeDirectoriesExample {

private static void fileattrib(File f) {

System.out.println("絕對(duì)路徑: " + f.getAbsolutePath() + "\n 可讀屬性: "

+ f.canRead() + "\n 可定屬性: " + f.canWrite() + "\n 文件名: "

+ f.getName() + "\n 父目錄: " + f.getParent() + "\n 當(dāng)前路徑: "

+ f.getPath() + "\n 文件長(zhǎng)度: " + f.length() + "\n 最后更新日期: "

+ f.lastModified());

if (f.isFile()) {

System.out.println("輸入的是一個(gè)文件");

} else if (f.isDirectory()) {

System.out.println("輸入的是一個(gè)目錄");

}

}

public static void main(String[] args) {

if (args.length 1) {

args = new String[3];

}

args[0] = "d";

args[1] = "test1.txt";

args[2] = "test2.txt";

File old = new File(args[1]), rname = new File(args[2]);

old.renameTo(rname);

fileattrib(old);

fileattrib(rname);

int count = 0;

boolean del = false;

if (args[0].equals("d")) {

count++;

del = true;

}

count--;

while (++count args.length) {

File f = new File(args[count]);

if (f.exists()) {

System.out.println(f + " 文件己經(jīng)存在");

if (del) {

System.out.println("刪除文件" + f);

f.delete();

}

} else { // 如果文件不存在

if (!del) {

f.mkdirs();

System.out.println("創(chuàng)建文件： " + f);

}

}

fileattrib(f);

}

}

}

文章標(biāo)題：javaio密集代碼,javaio流代碼
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