[转]java nio解决半包 粘包问题
java nio解决半包 粘包问题
package org.weir.socket.socketPackage; import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set; public class NioSocketClient extends Thread {
private SocketChannel socketChannel;
private Selector selector = null;
private int clientId; public static void main(String args[]) throws IOException {
NioSocketClient client = new NioSocketClient();
client.initClient();
client.start();
} public NioSocketClient() {
} public NioSocketClient(int clientId) {
this.clientId = clientId;
} public void initClient() throws IOException {
InetSocketAddress inetSocketAddress = new InetSocketAddress(8888);
selector = Selector.open();
socketChannel = SocketChannel.open();
socketChannel.configureBlocking(false);
socketChannel.connect(inetSocketAddress);
synchronized (selector) {
socketChannel.register(selector, SelectionKey.OP_CONNECT);
}
} public void run() {
while (true) {
try {
int key = selector.select();
if (key > 0) {
Set<SelectionKey> keySet = selector.selectedKeys();
Iterator<SelectionKey> iter = keySet.iterator();
while (iter.hasNext()) {
SelectionKey selectionKey = null;
synchronized (iter) {
selectionKey = iter.next();
iter.remove();
} if (selectionKey.isConnectable()) {
finishConnect(selectionKey);
}
if (selectionKey.isWritable()) {
send(selectionKey);
}
if (selectionKey.isReadable()) {
read(selectionKey);
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} public void finishConnect(SelectionKey key) {
System.out.println("client finish connect!");
SocketChannel socketChannel = (SocketChannel) key.channel();
try {
socketChannel.finishConnect();
synchronized (selector) {
socketChannel.register(selector, SelectionKey.OP_WRITE);
key.interestOps(SelectionKey.OP_WRITE); }
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} public void read(SelectionKey key) throws IOException {
SocketChannel channel = (SocketChannel) key.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
int len = channel.read(byteBuffer);
if (len > 0) {
byteBuffer.flip();
byte[] byteArray = new byte[byteBuffer.limit()];
byteBuffer.get(byteArray);
System.out.println("client[" + clientId + "]" + "receive from server:");
System.out.println(new String(byteArray));
len = channel.read(byteBuffer);
byteBuffer.clear(); }
key.interestOps(SelectionKey.OP_READ);
} public void send(SelectionKey key) {
SocketChannel channel = (SocketChannel) key.channel(); // byteBuffer.put(ss.getBytes());
for (int i = 0; i < 10; i++) {
String ss = i + "Server ,how are you? this is package message from NioSocketClient!";
ByteBuffer byteBuffer = ByteBuffer.wrap(ss.getBytes()); System.out.println("[client] send:{" + i + "}-- " + ss);
while (byteBuffer.hasRemaining()) {
try { channel.write(byteBuffer);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} // key.interestOps(SelectionKey.OP_READ);
try {
synchronized (selector) { channel.register(selector, SelectionKey.OP_READ);
}
} catch (ClosedChannelException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* int到byte[]
*
* @param i
* @return
*/
public static byte[] intToBytes(int value) {
byte[] result = new byte[4];
// 由高位到低位
result[0] = (byte) ((value >> 24) & 0xFF);
result[1] = (byte) ((value >> 16) & 0xFF);
result[2] = (byte) ((value >> 8) & 0xFF);
result[3] = (byte) (value & 0xFF);
return result;
}
}
package org.weir.socket.socketPackage; import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set; public class NioSocketServer extends Thread {
ServerSocketChannel serverSocketChannel = null;
Selector selector = null;
SelectionKey selectionKey = null; public void initServer() throws IOException {
selector = Selector.open();
serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.configureBlocking(false);
serverSocketChannel.socket().bind(new InetSocketAddress(8888));
selectionKey = serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); } public void run() {
while (true) {
try {
int selectKey = selector.select();
if (selectKey > 0) {
Set<SelectionKey> keySet = selector.selectedKeys();
Iterator<SelectionKey> iter = keySet.iterator();
while (iter.hasNext()) {
SelectionKey selectionKey = iter.next();
iter.remove();
if (selectionKey.isAcceptable()) {
accept(selectionKey);
}
if (selectionKey.isReadable()) {
read(selectionKey);
}
if (selectionKey.isWritable()) {
// write(selectionKey);
System.out.println();
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
try {
serverSocketChannel.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} }
} public void accept(SelectionKey key) {
try {
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key.channel();
SocketChannel socketChannel = serverSocketChannel.accept();
System.out.println("is acceptable");
socketChannel.configureBlocking(false);
socketChannel.register(selector, SelectionKey.OP_READ); } catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} public void read(SelectionKey selectionKey) {
System.out.println("read事件"); try {
SocketChannel channel = (SocketChannel) selectionKey.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(100);
int len = channel.read(byteBuffer);
if (len > 0) { byteBuffer.flip();
byte[] byteArray = new byte[byteBuffer.limit()];
byteBuffer.get(byteArray);
System.out.println("NioSocketServer receive from client:" + new String(byteArray)); }
selectionKey.interestOps(SelectionKey.OP_READ);
selectionKey.interestOps(SelectionKey.OP_READ);
} catch (IOException e) {
// TODO Auto-generated catch block
try {
serverSocketChannel.close();
selectionKey.cancel();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
e.printStackTrace();
} } public void write(SelectionKey selectionKey) {
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
String httpResponse = "HTTP/1.1 200 OK\r\n" + "Content-Length: 38\r\n" + "Content-Type: text/html\r\n" + "\r\n"
+ "<html><body>Hello World!</body></html>";
System.out.println("response from server to client");
try {
ByteBuffer byteBuffer = ByteBuffer.wrap(httpResponse.getBytes());
while (byteBuffer.hasRemaining()) {
socketChannel.write(byteBuffer);
}
selectionKey.cancel();
} catch (IOException e) {
try {
selectionKey.cancel();
serverSocketChannel.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* byte[]转int
*
* @param bytes
* @return
*/
public static int byteArrayToInt(byte[] bytes) {
int value = 0;
// 由高位到低位
for (int i = 0; i < 4; i++) {
int shift = (4 - 1 - i) * 8;
value += (bytes[i] & 0x000000FF) << shift;// 往高位游
}
return value;
} public static void main(String args[]) throws IOException {
NioSocketServer server = new NioSocketServer();
server.initServer();
server.start(); }
}
运行这两个类,结果如下:


package org.weir.socket.socketPackage; import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set; public class NioSocketServer extends Thread {
ServerSocketChannel serverSocketChannel = null;
Selector selector = null;
SelectionKey selectionKey = null;
// 缓存一个read事件中一个不完整的包,以待下次read事件到来时拼接成完整的包
ByteBuffer cacheBuffer = ByteBuffer.allocate(100);
boolean cache = false; public void initServer() throws IOException {
selector = Selector.open();
serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.configureBlocking(false);
serverSocketChannel.socket().bind(new InetSocketAddress(8888));
selectionKey = serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); } public void run() {
while (true) {
try {
int selectKey = selector.select();
if (selectKey > 0) {
Set<SelectionKey> keySet = selector.selectedKeys();
Iterator<SelectionKey> iter = keySet.iterator();
while (iter.hasNext()) {
SelectionKey selectionKey = iter.next();
iter.remove();
if (selectionKey.isAcceptable()) {
accept(selectionKey);
}
if (selectionKey.isReadable()) {
read(selectionKey);
}
if (selectionKey.isWritable()) {
// write(selectionKey);
System.out.println();
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
try {
serverSocketChannel.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} }
} public void accept(SelectionKey key) {
try {
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key.channel();
SocketChannel socketChannel = serverSocketChannel.accept();
System.out.println("is acceptable");
socketChannel.configureBlocking(false);
socketChannel.register(selector, SelectionKey.OP_READ); } catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} // 一个client的write事件不一定唯一对应server的read事件,所以需要缓存不完整的包,以便拼接成完整的包
//包协议:包=包头(4byte)+包体,包头内容为包体的数据长度
public void read(SelectionKey selectionKey) {
System.out.println("read事件");
int head_length = 4;//数据包长度
byte[] headByte = new byte[4]; try {
SocketChannel channel = (SocketChannel) selectionKey.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(100);
int bodyLen = -1;
if (cache) {
cacheBuffer.flip();
byteBuffer.put(cacheBuffer);
}
channel.read(byteBuffer);// 当前read事件
byteBuffer.flip();// write mode to read mode
while (byteBuffer.remaining() > 0) {
if (bodyLen == -1) {// 还没有读出包头,先读出包头
if (byteBuffer.remaining() >= head_length) {// 可以读出包头,否则缓存
byteBuffer.mark();
byteBuffer.get(headByte);
bodyLen = byteArrayToInt(headByte);
} else {
byteBuffer.reset();
cache = true;
cacheBuffer.clear();
cacheBuffer.put(byteBuffer);
break;
}
} else {// 已经读出包头
if (byteBuffer.remaining() >= bodyLen) {// 大于等于一个包,否则缓存
byte[] bodyByte = new byte[bodyLen];
byteBuffer.get(bodyByte, 0, bodyLen);
bodyLen = -1; System.out.println("receive from clien content is:" + new String(bodyByte));
} else {
byteBuffer.reset();
cacheBuffer.clear();
cacheBuffer.put(byteBuffer);
cache = true;
break;
}
}
} selectionKey.interestOps(SelectionKey.OP_READ);
} catch (IOException e) {
// TODO Auto-generated catch block
try {
serverSocketChannel.close();
selectionKey.cancel();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
e.printStackTrace();
} } public void write(SelectionKey selectionKey) {
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
String httpResponse = "HTTP/1.1 200 OK\r\n" + "Content-Length: 38\r\n" + "Content-Type: text/html\r\n" + "\r\n"
+ "<html><body>Hello World!</body></html>";
System.out.println("response from server to client");
try {
ByteBuffer byteBuffer = ByteBuffer.wrap(httpResponse.getBytes());
while (byteBuffer.hasRemaining()) {
socketChannel.write(byteBuffer);
}
selectionKey.cancel();
} catch (IOException e) {
try {
selectionKey.cancel();
serverSocketChannel.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* byte[]转int
*
* @param bytes
* @return
*/
public static int byteArrayToInt(byte[] bytes) {
int value = 0;
// 由高位到低位
for (int i = 0; i < 4; i++) {
int shift = (4 - 1 - i) * 8;
value += (bytes[i] & 0x000000FF) << shift;// 往高位游
}
return value;
} public static void main(String args[]) throws IOException {
NioSocketServer server = new NioSocketServer();
server.initServer();
server.start(); }
}
package org.weir.socket.socketPackage; import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set; public class NioSocketClient extends Thread {
private SocketChannel socketChannel;
private Selector selector = null;
private int clientId; public static void main(String args[]) throws IOException {
NioSocketClient client = new NioSocketClient();
client.initClient();
client.start();
} public NioSocketClient() {
} public NioSocketClient(int clientId) {
this.clientId = clientId;
} public void initClient() throws IOException {
InetSocketAddress inetSocketAddress = new InetSocketAddress(8888);
selector = Selector.open();
socketChannel = SocketChannel.open();
socketChannel.configureBlocking(false);
socketChannel.connect(inetSocketAddress);
synchronized (selector) {
socketChannel.register(selector, SelectionKey.OP_CONNECT);
}
} public void run() {
while (true) {
try {
int key = selector.select();
if (key > 0) {
Set<SelectionKey> keySet = selector.selectedKeys();
Iterator<SelectionKey> iter = keySet.iterator();
while (iter.hasNext()) {
SelectionKey selectionKey = null;
synchronized (iter) {
selectionKey = iter.next();
iter.remove();
} if (selectionKey.isConnectable()) {
finishConnect(selectionKey);
}
if (selectionKey.isWritable()) {
send(selectionKey);
}
if (selectionKey.isReadable()) {
read(selectionKey);
}
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} public void finishConnect(SelectionKey key) {
System.out.println("client finish connect!");
SocketChannel socketChannel = (SocketChannel) key.channel();
try {
socketChannel.finishConnect();
synchronized (selector) {
socketChannel.register(selector, SelectionKey.OP_WRITE);
key.interestOps(SelectionKey.OP_WRITE); }
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} public void read(SelectionKey key) throws IOException {
SocketChannel channel = (SocketChannel) key.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
int len = channel.read(byteBuffer);
if (len > 0) {
byteBuffer.flip();
byte[] byteArray = new byte[byteBuffer.limit()];
byteBuffer.get(byteArray);
System.out.println("client[" + clientId + "]" + "receive from server:");
System.out.println(new String(byteArray));
len = channel.read(byteBuffer);
byteBuffer.clear(); }
key.interestOps(SelectionKey.OP_READ);
} public void send(SelectionKey key) {
SocketChannel channel = (SocketChannel) key.channel(); for (int i = 0; i < 10; i++) {
String ss = i + "Server ,how are you? this is package message from NioSocketClient!";
int head = (ss).getBytes().length;
ByteBuffer byteBuffer = ByteBuffer.allocate(4 + head);
byteBuffer.put(intToBytes(head));
byteBuffer.put(ss.getBytes());
byteBuffer.flip();
System.out.println("[client] send:" + i + "-- " + head + ss);
while (byteBuffer.hasRemaining()) {
try { channel.write(byteBuffer);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} // key.interestOps(SelectionKey.OP_READ);
try {
synchronized (selector) { channel.register(selector, SelectionKey.OP_READ);
}
} catch (ClosedChannelException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* int到byte[]
*
* @param i
* @return
*/
public static byte[] intToBytes(int value) {
byte[] result = new byte[4];
// 由高位到低位
result[0] = (byte) ((value >> 24) & 0xFF);
result[1] = (byte) ((value >> 16) & 0xFF);
result[2] = (byte) ((value >> 8) & 0xFF);
result[3] = (byte) (value & 0xFF);
return result;
}
}
运行结果如下: 
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