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；

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://192.168.1.111:8080/test.do?level=1