javanio完整代码 java代码例子讲解

java nio 非阻塞读写具体应该怎么操作，能否给个例子程序

package com.java.xiong.Net17;

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import java.io.IOException;

import java点虐 .InetSocketAddress;

import java.nio.ByteBuffer;

import java.nio.channels.Channel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.nio.charset.Charset;

public class NServer {

// 用于检测所有的Channel状态的selector

private Selector selector = null;

static final int PORT = 30000;

// 定义实现编码、解码的字符串集对象

private Charset charse = Charset.forName("GBK");

public void init() throws IOException {

selector = Selector.open();

// 通过open方法来打开一个未绑定的ServerSocketChannel是咧

ServerSocketChannel server = ServerSocketChannel.open();

InetSocketAddress isa = new InetSocketAddress("127.0.0.1", PORT);

// 将该ServerSocketChannel绑定到指定的IP地址

server.bind(isa);

// 设置serverSocket已非阻塞方式工作

server.configureBlocking(false);

// 将server注册到指定的selector对象

server.register(selector, SelectionKey.OP_ACCEPT);

while (selector.select()  0) {

// 一次处理selector上的每个选择的SelectionKey

for (SelectionKey sk : selector.selectedKeys()) {

// 从selector上已选择的Kye集中删除正在处理的SelectionKey

selector.selectedKeys().remove(sk);

// 如果sk对应的Channel包含客户端的连接请求

if (sk.isAcceptable()) {

// 调用accept方法接收连接，产生服务器段的SocketChennal

SocketChannel sc = server.accept();

// 设置采用非阻塞模式

sc.configureBlocking(false);

// 将该SocketChannel注册到selector

sc.register(selector, SelectionKey.OP_READ);

}

// 如果sk对应的Channel有数据需要读取

if (sk.isReadable()) {

// 获取该SelectionKey对银行的Channel，该Channel中有刻度的数据

SocketChannel sc = (SocketChannel) sk.channel();

// 定义备注执行读取数据源的ByteBuffer

ByteBuffer buff = ByteBuffer.allocate(1024);

String content = "";

// 开始读取数据

try {

while (sc.read(buff)  0) {

buff.flip();

content += charse.decode(buff);

}

System.out.println("读取的数据：" + content);

// 将sk对应的Channel设置成准备下一次读取

sk.interestOps(SelectionKey.OP_READ);

}

// 如果捕获到该sk对银行的Channel出现了异常，表明

// Channel对应的Client出现了问题，所以从Selector中取消

catch (IOException io) {

// 从Selector中删除指定的SelectionKey

sk.cancel();

if (sk.channel() != null) {

sk.channel().close();

}

}

// 如果content的长度大于0,则连天信息不为空

if (content.length()  0) {

// 遍历selector里注册的所有SelectionKey

for (SelectionKey key : selector.keys()) {

// 获取该key对应的Channel

Channel targerChannel = key.channel();

// 如果该Channel是SocketChannel对象

if (targerChannel instanceof SocketChannel) {

// 将读取到的内容写入该Channel中

SocketChannel dest = (SocketChannel) targerChannel;

dest.write(charse.encode(content));

}

}

}

}

}

}

}

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

new NServer().init();

}

}

JAVA用nio写CS程序，服务器端接收到的信息不完整，求助！SocketChannel，Bytebuffer

while(true){

buff.clear();

int len = sc.read(buff);

if(len ==-1){ break;}

buff.flip();

content += charset.decode(buff);

}

介绍一下Java NIO，NIO读取文件都有哪些方法

NIO也就是New I/O,是一组扩展Java IO操作的API集， 于Java 1.4起被引入，Java 7中NIO又提供了一些新的文件系统API，叫NIO2.

NIO2提供两种主要的文件读取方法：

使用buffer和channel类

使用Path 和 File 类

NIO读取文件有以下三种方式：

1. 旧的NIO方式，使用BufferedReader

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

public class WithoutNIOExample

{

public static void main(String[] args)

{

BufferedReader br = null;

String sCurrentLine = null;

try

{

br = new BufferedReader(

new FileReader("test.txt"));

while ((sCurrentLine = br.readLine()) != null)

{

System.out.println(sCurrentLine);

}

}

catch (IOException e)

{

e.printStackTrace();

}

finally

{

try

{

if (br != null)

br.close();

} catch (IOException ex)

{

ex.printStackTrace();

}

}

}

}

2. 使用buffer读取小文件

import java.io.IOException;

import java.io.RandomAccessFile;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

public class ReadFileWithFileSizeBuffer

{

public static void main(String args[])

{

try

{

RandomAccessFile aFile = new RandomAccessFile(

"test.txt","r");

FileChannel inChannel = aFile.getChannel();

long fileSize = inChannel.size();

ByteBuffer buffer = ByteBuffer.allocate((int) fileSize);

inChannel.read(buffer);

buffer.rewind();

buffer.flip();

for (int i = 0; i fileSize; i++)

{

System.out.print((char) buffer.get());

}

inChannel.close();

aFile.close();

}

catch (IOException exc)

{

System.out.println(exc);

System.exit(1);

}

}

}

3. 分块读取大文件

import java.io.IOException;

import java.io.RandomAccessFile;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

public class ReadFileWithFixedSizeBuffer

{

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

{

RandomAccessFile aFile = new RandomAccessFile

("test.txt", "r");

FileChannel inChannel = aFile.getChannel();

ByteBuffer buffer = ByteBuffer.allocate(1024);

while(inChannel.read(buffer) 0)

{

buffer.flip();

for (int i = 0; i buffer.limit(); i++)

{

System.out.print((char) buffer.get());

}

buffer.clear(); // do something with the data and clear/compact it.

}

inChannel.close();

aFile.close();

}

}

4. 使用MappedByteBuffer读取文件

import java.io.RandomAccessFile;

import java.nio.MappedByteBuffer;

import java.nio.channels.FileChannel;

public class ReadFileWithMappedByteBuffer

{

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

{

RandomAccessFile aFile = new RandomAccessFile

("test.txt", "r");

FileChannel inChannel = aFile.getChannel();

MappedByteBuffer buffer = inChannel.map(FileChannel.MapMode.READ_ONLY, 0, inChannel.size());

buffer.load();?

for (int i = 0; i buffer.limit(); i++)

{

System.out.print((char) buffer.get());

}

buffer.clear(); // do something with the data and clear/compact it.

inChannel.close();

aFile.close();

}

}

求java nio网络编程的小例子，要求客户端一直与服务器保持连接

import java.awt.*;

import java.awt.event.*;

import java.io.IOException;

import java点虐 .*;

import java.io.*;

public class chatClient extends Frame {

/**

* @param args

*/

TextField tfTxT=new TextField();

TextArea taContent=new TextArea();

Socket s=null;

DataOutputStream dos=null;

DataInputStream dis=null;

private boolean bConnected =false;

public static void main(String[] args) {

new chatClient().lunachFrame();

}

private class RecvThread implements Runnable{

public void run() {

try{

while(bConnected){

String str=dis.readUTF();

taContent.setText(taContent.getText()+str+'\n');

}

}catch(IOException e){

e.printStackTrace();

}

}

}

public void lunachFrame(){

this.setLocation(400, 300);

this.setSize(300,300);

//this.setLayout(new FlowLayout());

this.add(tfTxT,"South");

this.add(taContent,"North");

pack();

tfTxT.addActionListener(new TFListener());

this.addWindowListener(new WindowClose());

this.setVisible(true);

connect();

new Thread(new RecvThread()).start();

}

public void connect(){

try {

s= new Socket("127.0.0.1",8888);

dos =new DataOutputStream(s.getOutputStream());

dis =new DataInputStream(s.getInputStream());

System.out.println("connected!");

bConnected=true;

} catch (UnknownHostException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

public void disconnect(){

try {

dos.close();

s.close();

} catch (Exception e) {

// TODO 自动生成 catch 块

e.printStackTrace();

}

}

class WindowClose extends WindowAdapter{

@Override

public void windowClosing(WindowEvent e) {

// TODO 自动生成方法存根

System.exit(0);

disconnect();

}

}

private class TFListener implements ActionListener{

public void actionPerformed(ActionEvent e) {

String str=tfTxT.getText().trim();//trim去掉两边空格

//taContent.setText(str);

tfTxT.setText("");

try {

dos.writeUTF(str);

dos.flush();

//dos.close();

} catch (IOException e1) {

e1.printStackTrace();

}

}

}

}

======================================

import java.io.IOException;

import java点虐 .*;

import java.io.*;

import java.util.*;

public class ChatServer {

ListClient clients=new ArrayListClient();

Client c=null;

public static void main(String[] args){

new ChatServer().start();

}

public void start(){

boolean started=false;

ServerSocket ss=null;

DataInputStream dis=null;

try{

ss=new ServerSocket(8888);

started =true;

}catch(Exception e)

{

e.printStackTrace();

}

try{

while(started){

Socket s=ss.accept();

c=new Client(s);//启动线程,实行run()方法

System.out.println("a client connected!");

new Thread(c).start();//启动start方法,循环.start是Thread中的方法与这上面的start无关

clients.add(c);

//dis.close();

}

} catch (Exception e) {

//e.printStackTrace();

}

finally{

try {

ss.close();

} catch (IOException e) {

// TODO 自动生成 catch 块

e.printStackTrace();

}

}

}

class Client implements Runnable{

private Socket s;

private DataInputStream dis =null;

private boolean bConnected =false;

private DataOutputStream dos=null;

public Client(Socket s){

this.s=s;

try {

dis=new DataInputStream(s.getInputStream());

dos =new DataOutputStream(s.getOutputStream());

bConnected =true;

} catch (IOException e) {

// TODO 自动生成 catch 块

e.printStackTrace();

}

}

public void send(String str)throws Exception{

dos.writeUTF(str);

}

public void run() {

try{

while(bConnected){

String str = dis.readUTF();

System.out.println(str);

for(int i=0;iclients.size();i++){

c=clients.get(i);

c.send(str);

}

/*for(IteratorClient it=clients.iterator();it.hasNext();){

Client c=it.next();

c.send(str);

}*/

}

}catch(SocketException e){

clients.remove(this);

System.out.println("客户下线了");

}

catch(EOFException e){

System.out.println("Client closed");

}

catch (Exception e){

//e.printStackTrace();

}

finally{

try {

if(dis !=null) dis.close();

if(dos !=null) dos.close();

if(s!=null) s.close();

} catch (Exception e1) {

// TODO 自动生成 catch 块

//e1.printStackTrace();

}

}

}

}

}

第一个是客户端,

第二个是server端