Mina工具类v1.5

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我是靠谱客的博主明亮航空，最近开发中收集的这篇文章主要介绍Mina工具类v1.5，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

完整版见https://jadyer.github.io/2013/07/12/mina-tcp-http-server/

package com.cucpay.fundswap.util;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import java.util.concurrent.TimeUnit;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.future.ConnectFuture;
import org.apache.mina.core.future.ReadFuture;
import org.apache.mina.core.service.IoConnector;
import org.apache.mina.core.session.AttributeKey;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.ProtocolEncoderAdapter;
import org.apache.mina.filter.codec.ProtocolEncoderOutput;
import org.apache.mina.transport.socket.nio.NioSocketConnector;
/**
* 使用Mina2.x发送报文的工具类
* @see 详细说明请参阅我的博客http://blog.csdn.net/jadyer/article/details/8088068
* @version v1.5
* @history v1.1-->编码器和解码器中的字符处理,升级为Mina2.x提供的<code>putString()</code>方法来处理
* @history v1.2-->解码器采用CumulativeProtocolDecoder实现,以适应应答报文被拆分多次后发送Client的情况
* @history v1.3-->修复BUG:请求报文有误时,Server可能返回非约定报文,此时会抛java.lang.NumberFormatException
* @history v1.4-->增加全局异常捕获
* @history v1.5-->由于本工具类的作用是同步的客户端,故取消IoHandler设置,但注意必须setUseReadOperation(true)
* @update Jul 27, 2013 10:21:01 AM
* @create Oct 3, 2012 12:42:21 PM
* @author 玄玉<http://blog.csdn.net/jadyer>
*/
public class MinaUtil {
private MinaUtil(){}
/**
* 发送TCP消息
* @see 当通信发生异常时,如Fail to get session....返回<code>"MINA_SERVER_ERROR"</code>字符串
* @param message
待发送报文的中文字符串形式
* @param ipAddress 远程主机的IP地址
* @param port
远程主机的端口号
* @param charset
该方法与远程主机间通信报文为编码字符集(编码为byte[]发送到Server)
* @return 远程主机响应报文的字符串形式
*/
public static String sendTCPMessage(String message, String ipAddress, int port, String charset){
IoConnector connector = new NioSocketConnector();
connector.setConnectTimeoutMillis(1000);
connector.getSessionConfig().setUseReadOperation(true); //同步的客户端,必须设置此项,其默认为false
connector.getFilterChain().addLast("codec", new ProtocolCodecFilter(new ClientProtocolEncoder(charset), new ClientProtocolDecode(charset)));
//connector.setHandler(this); //作为同步的客户端,可以不需要IoHandler,Mina会自动添加一个默认的IoHandler实现,即AbstractIoConnector
IoSession session = null;
Object respData = null;
try{
ConnectFuture connectFuture = connector.connect(new InetSocketAddress(ipAddress, port));
connectFuture.awaitUninterruptibly();
//等待连接成功,相当于将异步执行转为同步执行
session = connectFuture.getSession();
//获取连接成功后的会话对象
session.write(message).awaitUninterruptibly(); //由于上面已经设置setUseReadOperation(true),故IoSession.read()方法才可用
ReadFuture readFuture = session.read();
//因其内部使用BlockingQueue,故Server端用之可能会内存泄漏,但Client端可适当用之
if(readFuture.awaitUninterruptibly(90, TimeUnit.SECONDS)){ //Wait until the message is received
respData = readFuture.getMessage();
//Get the received message
}else{
LogUtil.getLogger().info("读取[/" + ipAddress + ":" + port + "]超时");
}
}catch(Exception e){
LogUtil.getLogger().error("请求通信[/" + ipAddress + ":" + port + "]偶遇异常,堆栈轨迹如下", e);
}finally{
if(session != null){
//关闭IoSession,该操作是异步的,true为立即关闭,false为所有写操作都flush后关闭
//这里仅仅是关闭了TCP的连接通道,并未关闭Client端程序
session.close(true);
//客户端发起连接时,会请求系统分配相关的文件句柄,而在连接失败时记得释放资源,否则会造成文件句柄泄露
//当总的文件句柄数超过系统设置值时[ulimit -n],则抛异常"java.io.IOException: Too many open files",导致新连接无法创建,服务器挂掉
//所以,若不关闭的话,其运行一段时间后可能抛出too many open files异常,导致无法连接
session.getService().dispose();
}
}
return respData==null ? "MINA_SERVER_ERROR" : respData.toString();
}
/**
* 客户端编码器
* @see 将Client的报文编码后发送到Server
*/
private static class ClientProtocolEncoder extends ProtocolEncoderAdapter {
private final String charset;
public ClientProtocolEncoder(String charset){
this.charset = charset;
}
@Override
public void encode(IoSession session, Object message, ProtocolEncoderOutput out) throws Exception {
IoBuffer buffer = IoBuffer.allocate(100).setAutoExpand(true);
//二者等效--><code>buffer.put(message.toString().getBytes(charset))</code>
buffer.putString(message.toString(), Charset.forName(charset).newEncoder());
buffer.flip();
out.write(buffer);
}
}
/**
* 客户端解码器
* @see 解码Server的响应报文给Client
* @see 样例报文[000064100030010000120121101210419100000000000028`18622233125`10`]
*/
private static class ClientProtocolDecode extends CumulativeProtocolDecoder {
private final String charset;
//注意这里使用了Mina自带的AttributeKey类来定义保存在IoSession中对象的键值,其可有效防止键值重复
//通过查询AttributeKey类源码发现,它的构造方法采用的是"类名+键名+AttributeKey的hashCode"的方式
private final AttributeKey CONTEXT = new AttributeKey(getClass(), "context");
public ClientProtocolDecode(String charset){
this.charset = charset;
}
private Context getContext(IoSession session){
Context context = (Context)session.getAttribute(CONTEXT);
if(null == context){
context = new Context();
session.setAttribute(CONTEXT, context);
}
return context;
}
@Override
protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
Context ctx = this.getContext(session);
IoBuffer buffer = ctx.innerBuffer;
int messageCount = ctx.getMessageCount();
while(in.hasRemaining()){
//判断position和limit之间是否有元素
buffer.put(in.get());
//get()读取buffer的position的字节,然后position+1
if(messageCount++ == 5){ //约定:报文的前6个字符串表示报文总长度,不足6位则左侧补0
buffer.flip();
//Set limit=position and position=0 and mark=-1
//当Server的响应报文中含0x00时,Mina2.x的buffer.getString(fieldSize, decoder)方法会break
//该方法的处理细节,详见org.apache.mina.core.buffer.AbstractIoBuffer类的第1718行源码,其说明如下
//Reads a NUL-terminated string from this buffer using the specified decoder and returns it
//ctx.setMessageLength(Integer.parseInt(buffer.getString(6, decoder)));
byte[] messageLength = new byte[6];
buffer.get(messageLength);
try{
//请求报文有误时,Server可能返回非约定报文,此时会抛java.lang.NumberFormatException
ctx.setMessageLength(Integer.parseInt(new String(messageLength, charset)));
}catch(NumberFormatException e){
ctx.setMessageLength(in.limit());
}
buffer.limit(in.limit()); //让两个IoBuffer的limit相等
}
}
ctx.setMessageCount(messageCount);
if(ctx.getMessageLength() == buffer.position()){
buffer.flip();
byte[] message = new byte[buffer.limit()];
buffer.get(message);
out.write(new String(message, charset));
ctx.reset();
return true;
}else{
return false;
}
}
private class Context{
private final IoBuffer innerBuffer; //用于累积数据的IoBuffer
private int messageCount;
//记录已读取的报文字节数
private int messageLength;
//记录已读取的报文头标识的报文长度
public Context(){
innerBuffer = IoBuffer.allocate(100).setAutoExpand(true);
}
public int getMessageCount() {
return messageCount;
}
public void setMessageCount(int messageCount) {
this.messageCount = messageCount;
}
public int getMessageLength() {
return messageLength;
}
public void setMessageLength(int messageLength) {
this.messageLength = messageLength;
}
public void reset(){
this.innerBuffer.clear(); //Set limit=capacity and position=0 and mark=-1
this.messageCount = 0;
this.messageLength = 0;
}
}
}
}