基于Mina的Http Server以及简单的Http请求客户端

目的：
    Java平台下的内部组件之间的通信。
    1.WebService 由于感觉本身Java平台下的Web Service标准就不够统一，相互之间的调用就会有一些问题，更不用说与.net等其他平台了。而且WebService也是对HTTP请求的一次封装，效率上肯定会有损失，所以就不考虑用WebService了。
    2.Socket，包括Java原生的Socket API和nio，本身都很好，效率也会不错，它们之间的区别大概就是资源占用上了。但是使用Socket的通信，有几个比较复杂的地方是：1）协议解析，要订协议，解析及序列化2）粘包分包的处理（这个在长连接的情况下才会出现，可以不在考虑范围内）3）资源的管理，弄不好的话会导致CPU占用较高或者内存不知不觉泄露。
    3.HTTP通信。由于应用是独立的，不能依托于Web容器。Java原生的HttpServer API好像不推荐使用（藏在好深的一个包里com.sun.net.httpserver.*）。
    4.话说Mina的效率很高，是基于nio的异步通信，封装简化了好多。通过比较简单的包装就可以组成一个HTTP Server(下面例子中就是按照Mina官方提供的demo，自己改动了几点形成的)。然后HTTP的Client端也随便封装下就是了。

步骤
1.封装HTTP请求消息类和响应消息类

package com.ajita.httpserver;

import java.util.Map;
import java.util.Map.Entry;

/**
 * 使用Mina解析出的HTTP请求对象
 * 
 * @author Ajita
 * 
 */
public class HttpRequestMessage {
	/**
	 * HTTP请求的主要属性及内容
	 */
	private Map<String, String[]> headers = null;

	public Map<String, String[]> getHeaders() {
		return headers;
	}

	public void setHeaders(Map<String, String[]> headers) {
		this.headers = headers;
	}

	/**
	 * 获取HTTP请求的Context信息
	 */
	public String getContext() {
		String[] context = headers.get("Context");
		return context == null ? "" : context[0];
	}

	/**
	 * 根据属性名称获得属性值数组第一个值，用于在url中传递的参数
	 */
	public String getParameter(String name) {
		String[] param = headers.get("@".concat(name));
		return param == null ? "" : param[0];
	}

	/**
	 * 根据属性名称获得属性值，用于在url中传递的参数
	 */
	public String[] getParameters(String name) {
		String[] param = headers.get("@".concat(name));
		return param == null ? new String[] {} : param;
	}

	/**
	 * 根据属性名称获得属性值，用于请求的特征参数
	 */
	public String[] getHeader(String name) {
		return headers.get(name);
	}

	@Override
	public String toString() {
		StringBuilder str = new StringBuilder();

		for (Entry<String, String[]> e : headers.entrySet()) {
			str.append(e.getKey() + " : " + arrayToString(e.getValue(), ',')
					+ "\n");
		}
		return str.toString();
	}

	/**
	 * 静态方法，用来把一个字符串数组拼接成一个字符串
	 * 
	 * @param s要拼接的字符串数组
	 * @param sep数据元素之间的烦恼歌负
	 * @return 拼接成的字符串
	 */
	public static String arrayToString(String[] s, char sep) {
		if (s == null || s.length == 0) {
			return "";
		}
		StringBuffer buf = new StringBuffer();
		if (s != null) {
			for (int i = 0; i < s.length; i++) {
				if (i > 0) {
					buf.append(sep);
				}
				buf.append(s[i]);
			}
		}
		return buf.toString();
	}

}

package com.ajita.httpserver;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.mina.core.buffer.IoBuffer;

public class HttpResponseMessage {
	/** HTTP response codes */
	public static final int HTTP_STATUS_SUCCESS = 200;

	public static final int HTTP_STATUS_NOT_FOUND = 404;

	/** Map<String, String> */
	private final Map<String, String> headers = new HashMap<String, String>();

	/** Storage for body of HTTP response. */
	private final ByteArrayOutputStream body = new ByteArrayOutputStream(1024);

	private int responseCode = HTTP_STATUS_SUCCESS;

	public HttpResponseMessage() {
		// headers.put("Server", "HttpServer (" + Server.VERSION_STRING + ')');
		headers.put("Server", "HttpServer (" + "Mina 2.0" + ')');
		headers.put("Cache-Control", "private");
		headers.put("Content-Type", "text/html; charset=iso-8859-1");
		headers.put("Connection", "keep-alive");
		headers.put("Keep-Alive", "200");
		headers.put("Date", new SimpleDateFormat(
				"EEE, dd MMM yyyy HH:mm:ss zzz").format(new Date()));
		headers.put("Last-Modified", new SimpleDateFormat(
				"EEE, dd MMM yyyy HH:mm:ss zzz").format(new Date()));
	}

	public Map<String, String> getHeaders() {
		return headers;
	}

	public void setContentType(String contentType) {
		headers.put("Content-Type", contentType);
	}

	public void setResponseCode(int responseCode) {
		this.responseCode = responseCode;
	}

	public int getResponseCode() {
		return this.responseCode;
	}

	public void appendBody(byte[] b) {
		try {
			body.write(b);
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}

	public void appendBody(String s) {
		try {
			body.write(s.getBytes());
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}

	public IoBuffer getBody() {
		return IoBuffer.wrap(body.toByteArray());
	}

	public int getBodyLength() {
		return body.size();
	}

}

2.封装Mina的解析HTTP请求和发送HTTP响应的编码类和解码类

package com.ajita.httpserver;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.HashMap;
import java.util.Map;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.apache.mina.filter.codec.demux.MessageDecoderAdapter;
import org.apache.mina.filter.codec.demux.MessageDecoderResult;

public class HttpRequestDecoder extends MessageDecoderAdapter {
	private static final byte[] CONTENT_LENGTH = new String("Content-Length:")
			.getBytes();
	static String defaultEncoding;
	private CharsetDecoder decoder;

	public CharsetDecoder getDecoder() {
		return decoder;
	}

	public void setEncoder(CharsetDecoder decoder) {
		this.decoder = decoder;
	}

	private HttpRequestMessage request = null;

	public HttpRequestDecoder() {
		decoder = Charset.forName(defaultEncoding).newDecoder();
	}

	public MessageDecoderResult decodable(IoSession session, IoBuffer in) {
		try {
			return messageComplete(in) ? MessageDecoderResult.OK
					: MessageDecoderResult.NEED_DATA;
		} catch (Exception ex) {
			ex.printStackTrace();
		}

		return MessageDecoderResult.NOT_OK;
	}

	public MessageDecoderResult decode(IoSession session, IoBuffer in,
			ProtocolDecoderOutput out) throws Exception {
		HttpRequestMessage m = decodeBody(in);

		// Return NEED_DATA if the body is not fully read.
		if (m == null) {
			return MessageDecoderResult.NEED_DATA;
		}

		out.write(m);

		return MessageDecoderResult.OK;

	}

	/*
	 * 判断HTTP请求是否完整，若格式有错误直接抛出异常
	 */
	private boolean messageComplete(IoBuffer in) {
		int last = in.remaining() - 1;
		if (in.remaining() < 4) {
			return false;
		}

		// to speed up things we check if the Http request is a GET or POST
		if (in.get(0) == (byte) 'G' && in.get(1) == (byte) 'E'
				&& in.get(2) == (byte) 'T') {
			// Http GET request therefore the last 4 bytes should be 0x0D 0x0A
			// 0x0D 0x0A
			return in.get(last) == (byte) 0x0A
					&& in.get(last - 1) == (byte) 0x0D
					&& in.get(last - 2) == (byte) 0x0A
					&& in.get(last - 3) == (byte) 0x0D;
		} else if (in.get(0) == (byte) 'P' && in.get(1) == (byte) 'O'
				&& in.get(2) == (byte) 'S' && in.get(3) == (byte) 'T') {
			// Http POST request
			// first the position of the 0x0D 0x0A 0x0D 0x0A bytes
			int eoh = -1;
			for (int i = last; i > 2; i--) {
				if (in.get(i) == (byte) 0x0A && in.get(i - 1) == (byte) 0x0D
						&& in.get(i - 2) == (byte) 0x0A
						&& in.get(i - 3) == (byte) 0x0D) {
					eoh = i + 1;
					break;
				}
			}
			if (eoh == -1) {
				return false;
			}
			for (int i = 0; i < last; i++) {
				boolean found = false;
				for (int j = 0; j < CONTENT_LENGTH.length; j++) {
					if (in.get(i + j) != CONTENT_LENGTH[j]) {
						found = false;
						break;
					}
					found = true;
				}
				if (found) {
					// retrieve value from this position till next 0x0D 0x0A
					StringBuilder contentLength = new StringBuilder();
					for (int j = i + CONTENT_LENGTH.length; j < last; j++) {
						if (in.get(j) == 0x0D) {
							break;
						}
						contentLength.append(new String(
								new byte[] { in.get(j) }));
					}
					// if content-length worth of data has been received then
					// the message is complete
					return Integer.parseInt(contentLength.toString().trim())
							+ eoh == in.remaining();
				}
			}
		}

		// the message is not complete and we need more data
		return false;

	}

	private HttpRequestMessage decodeBody(IoBuffer in) {
		request = new HttpRequestMessage();
		try {
			request.setHeaders(parseRequest(new StringReader(in
					.getString(decoder))));
			return request;
		} catch (CharacterCodingException ex) {
			ex.printStackTrace();
		}

		return null;

	}

	private Map<String, String[]> parseRequest(StringReader is) {
		Map<String, String[]> map = new HashMap<String, String[]>();
		BufferedReader rdr = new BufferedReader(is);

		try {
			// Get request URL.
			String line = rdr.readLine();
			String[] url = line.split(" ");
			if (url.length < 3) {
				return map;
			}

			map.put("URI", new String[] { line });
			map.put("Method", new String[] { url[0].toUpperCase() });
			map.put("Context", new String[] { url[1].substring(1) });
			map.put("Protocol", new String[] { url[2] });
			// Read header
			while ((line = rdr.readLine()) != null && line.length() > 0) {
				String[] tokens = line.split(": ");
				map.put(tokens[0], new String[] { tokens[1] });
			}

			// If method 'POST' then read Content-Length worth of data
			if (url[0].equalsIgnoreCase("POST")) {
				int len = Integer.parseInt(map.get("Content-Length")[0]);
				char[] buf = new char[len];
				if (rdr.read(buf) == len) {
					line = String.copyValueOf(buf);
				}
			} else if (url[0].equalsIgnoreCase("GET")) {
				int idx = url[1].indexOf('?');
				if (idx != -1) {
					map.put("Context",
							new String[] { url[1].substring(1, idx) });
					line = url[1].substring(idx + 1);
				} else {
					line = null;
				}
			}
			if (line != null) {
				String[] match = line.split("\\&");
				for (String element : match) {
					String[] params = new String[1];
					String[] tokens = element.split("=");
					switch (tokens.length) {
					case 0:
						map.put("@".concat(element), new String[] {});
						break;
					case 1:
						map.put("@".concat(tokens[0]), new String[] {});
						break;
					default:
						String name = "@".concat(tokens[0]);
						if (map.containsKey(name)) {
							params = map.get(name);
							String[] tmp = new String[params.length + 1];
							for (int j = 0; j < params.length; j++) {
								tmp[j] = params[j];
							}
							params = null;
							params = tmp;
						}
						params[params.length - 1] = tokens[1].trim();
						map.put(name, params);
					}
				}
			}
		} catch (IOException ex) {
			ex.printStackTrace();
		}

		return map;
	}

}
package com.ajita.httpserver;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.mina.core.buffer.IoBuffer;

public class HttpResponseMessage {
	/** HTTP response codes */
	public static final int HTTP_STATUS_SUCCESS = 200;

	public static final int HTTP_STATUS_NOT_FOUND = 404;

	/** Map<String, String> */
	private final Map<String, String> headers = new HashMap<String, String>();

	/** Storage for body of HTTP response. */
	private final ByteArrayOutputStream body = new ByteArrayOutputStream(1024);

	private int responseCode = HTTP_STATUS_SUCCESS;

	public HttpResponseMessage() {
		// headers.put("Server", "HttpServer (" + Server.VERSION_STRING + ')');
		headers.put("Server", "HttpServer (" + "Mina 2.0" + ')');
		headers.put("Cache-Control", "private");
		headers.put("Content-Type", "text/html; charset=iso-8859-1");
		headers.put("Connection", "keep-alive");
		headers.put("Keep-Alive", "200");
		headers.put("Date", new SimpleDateFormat(
				"EEE, dd MMM yyyy HH:mm:ss zzz").format(new Date()));
		headers.put("Last-Modified", new SimpleDateFormat(
				"EEE, dd MMM yyyy HH:mm:ss zzz").format(new Date()));
	}

	public Map<String, String> getHeaders() {
		return headers;
	}

	public void setContentType(String contentType) {
		headers.put("Content-Type", contentType);
	}

	public void setResponseCode(int responseCode) {
		this.responseCode = responseCode;
	}

	public int getResponseCode() {
		return this.responseCode;
	}

	public void appendBody(byte[] b) {
		try {
			body.write(b);
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}

	public void appendBody(String s) {
		try {
			body.write(s.getBytes());
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}

	public IoBuffer getBody() {
		return IoBuffer.wrap(body.toByteArray());
	}

	public int getBodyLength() {
		return body.size();
	}

}

3.封装HTTP的Server类及HTTP的Handler处理接口，其中HttpHandler接口是要暴露给外部就行自定义处理的。

package com.ajita.httpserver;

import java.io.IOException;
import java.net.InetSocketAddress;

import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.logging.LoggingFilter;
import org.apache.mina.transport.socket.nio.NioSocketAcceptor;

public class HttpServer {
	/** Default HTTP port */
	private static final int DEFAULT_PORT = 8080;
	private NioSocketAcceptor acceptor;
	private boolean isRunning;

	private String encoding;
	private HttpHandler httpHandler;

	public String getEncoding() {
		return encoding;
	}

	public void setEncoding(String encoding) {
		this.encoding = encoding;
		HttpRequestDecoder.defaultEncoding = encoding;
		HttpResponseEncoder.defaultEncoding = encoding;
	}

	public HttpHandler getHttpHandler() {
		return httpHandler;
	}

	public void setHttpHandler(HttpHandler httpHandler) {
		this.httpHandler = httpHandler;
	}

	/**
	 * 启动HTTP服务端箭筒HTTP请求
	 * 
	 * @param port要监听的端口号
	 * @throws IOException
	 */
	public void run(int port) throws IOException {
		synchronized (this) {
			if (isRunning) {
				System.out.println("Server is already running.");
				return;
			}
			acceptor = new NioSocketAcceptor();
			acceptor.getFilterChain().addLast(
					"protocolFilter",
					new ProtocolCodecFilter(
							new HttpServerProtocolCodecFactory()));
			// acceptor.getFilterChain().addLast("logger", new LoggingFilter());
			ServerHandler handler = new ServerHandler();
			handler.setHandler(httpHandler);
			acceptor.setHandler(handler);
			acceptor.bind(new InetSocketAddress(port));
			isRunning = true;
			System.out.println("Server now listening on port " + port);
		}
	}

	/**
	 * 使用默认端口8080
	 * 
	 * @throws IOException
	 */
	public void run() throws IOException {
		run(DEFAULT_PORT);
	}

	/**
	 * 停止监听HTTP服务
	 */
	public void stop() {
		synchronized (this) {
			if (!isRunning) {
				System.out.println("Server is already stoped.");
				return;
			}
			isRunning = false;
			try {
				acceptor.unbind();
				acceptor.dispose();
				System.out.println("Server is stoped.");
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

	public static void main(String[] args) {
		int port = DEFAULT_PORT;

		for (int i = 0; i < args.length; i++) {
			if (args[i].equals("-port")) {
				port = Integer.parseInt(args[i + 1]);
			}
		}

		try {
			// Create an acceptor
			NioSocketAcceptor acceptor = new NioSocketAcceptor();

			// Create a service configuration
			acceptor.getFilterChain().addLast(
					"protocolFilter",
					new ProtocolCodecFilter(
							new HttpServerProtocolCodecFactory()));
			acceptor.getFilterChain().addLast("logger", new LoggingFilter());
			acceptor.setHandler(new ServerHandler());
			acceptor.bind(new InetSocketAddress(port));

			System.out.println("Server now listening on port " + port);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}
}

package com.ajita.httpserver;

import org.apache.mina.filter.codec.demux.DemuxingProtocolCodecFactory;

public class HttpServerProtocolCodecFactory extends
		DemuxingProtocolCodecFactory {
	public HttpServerProtocolCodecFactory() {
		super.addMessageDecoder(HttpRequestDecoder.class);
		super.addMessageEncoder(HttpResponseMessage.class,
				HttpResponseEncoder.class);
	}

}

package com.ajita.httpserver;

import org.apache.mina.core.future.IoFutureListener;
import org.apache.mina.core.service.IoHandlerAdapter;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;

public class ServerHandler extends IoHandlerAdapter {
	private HttpHandler handler;

	public HttpHandler getHandler() {
		return handler;
	}

	public void setHandler(HttpHandler handler) {
		this.handler = handler;
	}

	@Override
	public void sessionOpened(IoSession session) {
		// set idle time to 60 seconds
		session.getConfig().setIdleTime(IdleStatus.BOTH_IDLE, 60);
	}

	@Override
	public void messageReceived(IoSession session, Object message) {
		// Check that we can service the request context
		HttpRequestMessage request = (HttpRequestMessage) message;
		HttpResponseMessage response = handler.handle(request);
		// HttpResponseMessage response = new HttpResponseMessage();
		// response.setContentType("text/plain");
		// response.setResponseCode(HttpResponseMessage.HTTP_STATUS_SUCCESS);
		// response.appendBody("CONNECTED");

		// msg.setResponseCode(HttpResponseMessage.HTTP_STATUS_SUCCESS);
		// byte[] b = new byte[ta.buffer.limit()];
		// ta.buffer.rewind().get(b);
		// msg.appendBody(b);
		// System.out.println("####################");
		// System.out.println("  GET_TILE RESPONSE SENT - ATTACHMENT GOOD DIAMOND.SI="+d.si+
		// ", "+new
		// java.text.SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss.SSS").format(new
		// java.util.Date()));
		// System.out.println("#################### - status="+ta.state+", index="+message.getIndex());

		// // Unknown request
		// response = new HttpResponseMessage();
		// response.setResponseCode(HttpResponseMessage.HTTP_STATUS_NOT_FOUND);
		// response.appendBody(String.format(
		// "<html><body><h1>UNKNOWN REQUEST %d</h1></body></html>",
		// HttpResponseMessage.HTTP_STATUS_NOT_FOUND));

		if (response != null) {
			session.write(response).addListener(IoFutureListener.CLOSE);
		}
	}

	@Override
	public void sessionIdle(IoSession session, IdleStatus status) {
		session.close(false);
	}

	@Override
	public void exceptionCaught(IoSession session, Throwable cause) {
		session.close(false);
	}
}

package com.ajita.httpserver;

/**
 * HTTP请求的处理接口
 * 
 * @author Ajita
 * 
 */
public interface HttpHandler {
	/**
	 * 自定义HTTP请求处理需要实现的方法
	 * @param request 一个HTTP请求对象
	 * @return HTTP请求处理后的返回结果
	 */
	HttpResponseMessage handle(HttpRequestMessage request);
}

4.HTTP Client端，网上一抓一大把，就不说了

5.测试
建立测试类如下

package com.jita;

import java.io.IOException;

import com.ajita.httpserver.HttpHandler;
import com.ajita.httpserver.HttpRequestMessage;
import com.ajita.httpserver.HttpResponseMessage;
import com.ajita.httpserver.HttpServer;

public class TestHttpServer {
	public static void main(String[] args) throws IOException,
			InterruptedException {
		HttpServer server = new HttpServer();
		server.setEncoding("GB2312");
		server.setHttpHandler(new HttpHandler() {
			public HttpResponseMessage handle(HttpRequestMessage request) {
				String level = request.getParameter("level");
				System.out.println(request.getParameter("level"));
				System.out.println(request.getContext());
				HttpResponseMessage response = new HttpResponseMessage();
				response.setContentType("text/plain");
				response.setResponseCode(HttpResponseMessage.HTTP_STATUS_SUCCESS);
				response.appendBody("CONNECTED\n");
				response.appendBody(level);
				return response;
			}
		});
		server.run();

		//Thread.sleep(10000);
		// server.stop();
	}
}

启动，在浏览器中输入HTTP请求如：http://192.168.13.242:8080/test.do?level=aaa


附件是完整的代码。