Netty实现HTTP客户端

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Netty实现HTTP客户端

这是用netty写的http客户端，没什么好说的，细节直接看代码

Http客户端

package http2;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.multipart.DefaultHttpDataFactory;
import io.netty.handler.codec.http.multipart.HttpDataFactory;
import io.netty.handler.codec.http.multipart.HttpPostRequestEncoder;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Created with IntelliJ IDEA.
 * User: ASUS
 * Date: 14-6-25
 * Time: 下午2:44
 * To change this template use File | Settings | File Templates.
 */
public class Client {

    public static HttpRequest getRequestMethod(Map<String, String> parameter, String url, String method) throws HttpPostRequestEncoder.ErrorDataEncoderException {
        URI uri;
        try {
            uri = new URI(url);
        } catch (URISyntaxException e) {
            e.printStackTrace();
            return null;
        }

        String path = uri.getRawPath();
        String host = uri.getHost();

        HttpRequest request = null;
        if ("post".equalsIgnoreCase(method)) {
            request = new DefaultFullHttpRequest(
                    HttpVersion.HTTP_1_1, HttpMethod.POST, path);

            HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE);
            // This encoder will help to encode Request for a FORM as POST.
            HttpPostRequestEncoder bodyRequestEncoder = new HttpPostRequestEncoder(factory, request, false);
            // add Form attribute
            if (parameter != null) {
                Set<Map.Entry<String, String>> entrySet = parameter.entrySet();
                for (Map.Entry<String, String> e : entrySet) {
                    String key = e.getKey();
                    String value = e.getValue();
                    bodyRequestEncoder.addBodyAttribute(key, value);
                }
                try {
                    request = bodyRequestEncoder.finalizeRequest();
                } catch (HttpPostRequestEncoder.ErrorDataEncoderException e) {
                    // if an encoding error occurs
                    e.printStackTrace();
                }
            }

            request.headers().set(HttpHeaders.Names.HOST, host);
            request.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.CLOSE);
            request.headers().set(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.GZIP);
            request.headers().set(HttpHeaders.Names.COOKIE, ClientCookieEncoder.encode(
                    new DefaultCookie("my-cookie", "foo"),
                    new DefaultCookie("another-cookie", "bar")));
        } else if ("get".equalsIgnoreCase(method)) {
            //uri.toString()没有查询参数的uri
            QueryStringEncoder encoder = new QueryStringEncoder(uri.toString());
            if (parameter != null) {
                Set<Map.Entry<String, String>> entrySet = parameter.entrySet();
                for (Map.Entry<String, String> e : entrySet) {
                    String key = e.getKey();
                    String value = e.getValue();
                    encoder.addParam(key, value);
                }
            }
            //encoder.toString()有查询参数的uri
            request = new DefaultFullHttpRequest(
                    HttpVersion.HTTP_1_1, HttpMethod.GET, encoder.toString());
            HttpHeaders headers = request.headers();
            headers.set(HttpHeaders.Names.HOST, host);
            headers.set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.CLOSE);
            headers.set(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.GZIP.toString() + ','
                    + HttpHeaders.Values.DEFLATE.toString());

            headers.set(HttpHeaders.Names.ACCEPT_CHARSET, "ISO-8859-1,utf-8;q=0.7,*;q=0.7");
            headers.set(HttpHeaders.Names.ACCEPT_LANGUAGE, "fr");
            headers.set(HttpHeaders.Names.USER_AGENT, "Netty Simple Http Client side");
            headers.set(HttpHeaders.Names.ACCEPT, "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");

            headers.set(HttpHeaders.Names.COOKIE, ClientCookieEncoder.encode(
                    new DefaultCookie("my-cookie", "foo"),
                    new DefaultCookie("another-cookie", "bar"))
            );
        } else {
            System.err.println("this method is not support!");
        }
        return request;
    }

    public void run(String url, HttpRequest request) throws HttpPostRequestEncoder.ErrorDataEncoderException, InterruptedException {
        URI uri;
        try {
            uri = new URI(url);
        } catch (URISyntaxException e) {
            e.printStackTrace();
            return;
        }

        String scheme = uri.getScheme() == null ? "http" : uri.getScheme();
        String host = uri.getHost() == null ? "localhost" : uri.getHost();
        int port = uri.getPort();
        if (port == -1) {
            if ("http".equalsIgnoreCase(scheme)) {
                port = 80;
            } else if ("https".equalsIgnoreCase(scheme)) {
                port = 443;
            }
        }

        if (!"http".equalsIgnoreCase(scheme) && !"https".equalsIgnoreCase(scheme)) {
            System.err.println("Only HTTP(S) is supported.");
        }

        boolean ssl = "https".equalsIgnoreCase(scheme);

        // Configure the client.
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new HttpClientInitializer(ssl));

            // Make the connection attempt.
            Channel ch = b.connect(host, port).sync().channel();
            // send request
            ch.writeAndFlush(request).sync();
            ch.closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }


    public static void main(String args[]) throws HttpPostRequestEncoder.ErrorDataEncoderException, InterruptedException {
        String url = "http://www.cnivi.com.cn/curriculum/search.html";
        Map<String, String> getData = new HashMap<String, String>();
        getData.put("tags", "806:938356;");
        getData.put("sort", "_p");

        HttpRequest get = getRequestMethod(getData, url, "get");
        new Client().run(url, get);
    }
}

package http2;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpContentDecompressor;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpRequestEncoder;
import io.netty.handler.codec.http.HttpResponseDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.SslHandler;

import javax.net.ssl.SSLEngine;

public class HttpClientInitializer extends ChannelInitializer<SocketChannel> {

    private final boolean ssl;

    public HttpClientInitializer(boolean ssl) {
        this.ssl = ssl;
    }


    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline p = ch.pipeline();

        p.addLast("log", new LoggingHandler(LogLevel.INFO));
        if (ssl) {
            SSLEngine engine = SslContextFactory.getClientContext().createSSLEngine();
            engine.setUseClientMode(true);
            p.addLast("ssl", new SslHandler(engine));
        }
        p.addLast("request-encoder", new HttpRequestEncoder());

        p.addLast("response-decoder", new HttpResponseDecoder());

        // Remove the following line if you don't want automatic content decompression.
        p.addLast("inflater", new HttpContentDecompressor());

        //HttpObjectAggregator会把多个消息转换为 一个单一的FullHttpRequest或是FullHttpResponse
        //p.addLast("aggregator", new HttpObjectAggregator(1048576));
        p.addLast("handler", new HttpClientHandler());
    }
}

package http2;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

/**
 * Created with IntelliJ IDEA.
 * User: ASUS
 * Date: 14-6-25
 * Time: 下午2:49
 * To change this template use File | Settings | File Templates.
 */
public class HttpClientHandler extends SimpleChannelInboundHandler<HttpObject> {

    public void messageReceived(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
        System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
        if (msg instanceof HttpResponse) {
            HttpResponse response = (HttpResponse) msg;

            System.out.println("STATUS: " + response.getStatus());
            System.out.println("VERSION: " + response.getProtocolVersion());
            System.out.println();

            if (!response.headers().isEmpty()) {
                for (String name : response.headers().names()) {
                    for (String value : response.headers().getAll(name)) {
                        System.out.println("HEADER: " + name + " = " + value);
                    }
                }
                System.out.println();
            }

            if (HttpHeaders.isTransferEncodingChunked(response)) {
                System.out.println("CHUNKED CONTENT {");
            } else {
                System.out.println("CONTENT {");
            }
        }
        if (msg instanceof HttpContent) {
            HttpContent content = (HttpContent) msg;

            System.out.print(content.content().toString(CharsetUtil.UTF_8));
            System.out.flush();

            if (content instanceof LastHttpContent) {
                System.out.println("} END OF CONTENT");
            }
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
        messageReceived(ctx, msg);
    }
}

这是完整的netty实现的http客户端的代码。

补充：

//HttpObjectAggregator会把多个消息转换为 一个单一的FullHttpRequest或是FullHttpResponse

//p.addLast("aggregator", new HttpObjectAggregator(1048576));

这句代码对handler的处理方式有很大不同。如果注释掉这行代码，则对应的handler应该这样处理

package http3;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

import java.nio.charset.Charset;

/**
 * Created with IntelliJ IDEA.
 * User: ASUS
 * Date: 14-6-25
 * Time: 下午2:49
 * To change this template use File | Settings | File Templates.
 */
public class HttpClientHandler extends SimpleChannelInboundHandler<HttpObject> {

    public void messageReceived(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
        System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
        DefaultFullHttpResponse fullHttpResponse = (DefaultFullHttpResponse) msg;

        System.out.println("STATUS: " + fullHttpResponse.getStatus());
        System.out.println("VERSION: " + fullHttpResponse.getProtocolVersion());
        System.out.println();

        if (!fullHttpResponse.headers().isEmpty()) {
            for (String name : fullHttpResponse.headers().names()) {
                for (String value : fullHttpResponse.headers().getAll(name)) {
                    System.out.println("HEADER: " + name + " = " + value);
                }
            }
            System.out.println();
        }

        if (HttpHeaders.isTransferEncodingChunked(fullHttpResponse)) {
            System.out.println("CHUNKED CONTENT {");
        } else {
            System.out.println("CONTENT {");
            ByteBuf content = fullHttpResponse.content();
            System.out.println(content.toString(CharsetUtil.UTF_8));
            System.out.println("} END OF CONTENT");
        }
    }


    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
        messageReceived(ctx, msg);
    }
}

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转载于:https://my.oschina.net/xinxingegeya/blog/284103