《Dubbo 实现原理与源码解析 —— 精品合集》 《Netty 实现原理与源码解析 —— 精品合集》
《Spring 实现原理与源码解析 —— 精品合集》 《MyBatis 实现原理与源码解析 —— 精品合集》
《Spring MVC 实现原理与源码解析 —— 精品合集》 《数据库实体设计合集》
《Spring Boot 实现原理与源码解析 —— 精品合集》 《Java 面试题 + Java 学习指南》

摘要: 原创出处 blog.csdn.net/shzy1988/article/details/78841140 「双子叶」欢迎转载,保留摘要,谢谢!


🙂🙂🙂关注**微信公众号:【芋道源码】**有福利:

  1. RocketMQ / MyCAT / Sharding-JDBC 所有源码分析文章列表
  2. RocketMQ / MyCAT / Sharding-JDBC 中文注释源码 GitHub 地址
  3. 您对于源码的疑问每条留言将得到认真回复。甚至不知道如何读源码也可以请教噢
  4. 新的源码解析文章实时收到通知。每周更新一篇左右
  5. 认真的源码交流微信群。

首先,你必须要了解netty,说简单点:客户端通过TCP链接和服务器建立长连接,client和server都是通过管道(ChannelPipeline)的addLast方法的添加顺序来处理接收或者发送的数据。

这个和struts的filter的doFilter原理类似,处理完一个filter,如果后面还有其他的filter,就将数据chain.doFilter来继续处理。

然后,说说netty怎么来整合springMVC:当client和server建立连接后,我们在addLast的某个类中将client发来的请求,让DispatcherServlet来处理,然后将处理后的结果通过ChannelHandlerContext或者Channel将,结果writeAndFlush到client。

1.写一个netty sever的java代码

package com.magic.netty.server;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.DispatcherServlet;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

import com.magic.netty.HttpServerInitializer;

public class NettyHttpServer {

public NettyHttpServer(Integer port) {
this.port = port;
}
public NettyHttpServer(Integer port, DispatcherServlet servlet) {
this.port = port;
this.servlet = servlet;
}

public void start(){
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new HttpServerInitializer(servlet))
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);

System.out.println("NettyHttpServer Run successfully");
// 绑定端口,开始接收进来的连接
ChannelFuture f = b.bind(port).sync();
// 等待服务器 socket 关闭 。在这个例子中,这不会发生,但你可以优雅地关闭你的服务器。
f.channel().closeFuture().sync();
} catch (Exception e) {
log.error("NettySever start fail",e);
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
private int port;
private static Logger log = LoggerFactory.getLogger(NettyHttpServer.class);
private DispatcherServlet servlet;
}

2.初始化netty的channel管道

package com.magic.netty;

import org.springframework.web.servlet.DispatcherServlet;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpContentCompressor;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.stream.ChunkedWriteHandler;



public class HttpServerInitializer extends ChannelInitializer<SocketChannel> {

public HttpServerInitializer(DispatcherServlet servlet) {
this.servlet = servlet;
}
public HttpServerInitializer() {

}

@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("decoder", new HttpRequestDecoder());
pipeline.addLast("encoder", new HttpResponseEncoder());
pipeline.addLast("aggregator", new HttpObjectAggregator(2147483647));
pipeline.addLast("chunkedWriter", new ChunkedWriteHandler());
pipeline.addLast("deflater", new HttpContentCompressor());
pipeline.addLast("handler", new HttpRequestHandler(servlet));
}
private DispatcherServlet servlet;
}

3.在handler里面处理client发来的请求

package com.magic.netty;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.ServletContext;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.multipart.DefaultHttpDataFactory;
import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder;
import io.netty.handler.codec.http.multipart.InterfaceHttpData;
import io.netty.handler.codec.http.multipart.InterfaceHttpData.HttpDataType;
import io.netty.handler.codec.http.multipart.MemoryAttribute;
import io.netty.util.CharsetUtil;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;
import org.springframework.web.util.UriUtils;

public class HttpRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {

public HttpRequestHandler(DispatcherServlet servlet) {
this.servlet = servlet;
this.servletContext = servlet.getServletConfig().getServletContext();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable e) throws Exception {
logger.error(e.getMessage(),e);
ctx.close();
}

protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest fullHttpRequest) throws Exception {
boolean flag = HttpMethod.POST.equals(fullHttpRequest.getMethod())
|| HttpMethod.GET.equals(fullHttpRequest.getMethod());

Map<String, String> parammap = getRequestParams(ctx,fullHttpRequest);
if(flag && ctx.channel().isActive()){
//HTTP请求、GET/POST
MockHttpServletResponse servletResponse = new MockHttpServletResponse();
MockHttpServletRequest servletRequest =new MockHttpServletRequest(servletContext);
// headers
for (String name : fullHttpRequest.headers().names()) {
for (String value : fullHttpRequest.headers().getAll(name)) {
servletRequest.addHeader(name, value);
}
}
String uri = fullHttpRequest.getUri();
uri = new String(uri.getBytes("ISO8859-1"), "UTF-8");
uri = URLDecoder.decode(uri, "UTF-8");
UriComponents uriComponents = UriComponentsBuilder.fromUriString(uri).build();
String path = uriComponents.getPath();
path = URLDecoder.decode(path, "UTF-8");
servletRequest.setRequestURI(path);
servletRequest.setServletPath(path);
servletRequest.setMethod(fullHttpRequest.getMethod().name());

if (uriComponents.getScheme() != null) {
servletRequest.setScheme(uriComponents.getScheme());
}
if (uriComponents.getHost() != null) {
servletRequest.setServerName(uriComponents.getHost());
}
if (uriComponents.getPort() != -1) {
servletRequest.setServerPort(uriComponents.getPort());
}

ByteBuf content = fullHttpRequest.content();
content.readerIndex(0);
byte[] data = new byte[content.readableBytes()];
content.readBytes(data);
servletRequest.setContent(data);

try {
if (uriComponents.getQuery() != null) {
String query = UriUtils.decode(uriComponents.getQuery(),"UTF-8");
servletRequest.setQueryString(query);
}
if(parammap!=null&&parammap.size()>0){
for (String key : parammap.keySet()) {
servletRequest.addParameter(UriUtils.decode(key,"UTF-8"), UriUtils.decode(parammap.get(key) == null ? "": parammap.get(key), "UTF-8"));
}
}

} catch (UnsupportedEncodingException ex) {
ex.printStackTrace();
}
this.servlet.service(servletRequest,servletResponse);

HttpResponseStatus status = HttpResponseStatus.valueOf(servletResponse.getStatus());
String result = servletResponse.getContentAsString();
result = StringUtils.isEmpty(result)?"":result;
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, status,Unpooled.copiedBuffer(result,CharsetUtil.UTF_8));
response.headers().set("Content-Type", "text/json;charset=UTF-8");
response.headers().set("Access-Control-Allow-Origin", "*");
response.headers().set("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With,X-File-Name");
response.headers().set("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
response.headers().set("Content-Length", Integer.valueOf(response.content().readableBytes()));
response.headers().set("Connection", "keep-alive");
ChannelFuture writeFuture = ctx.writeAndFlush(response);
writeFuture.addListener(ChannelFutureListener.CLOSE);
}
}

/**
* 获取post请求、get请求的参数保存到map中
*/
private Map<String, String> getRequestParams(ChannelHandlerContext ctx, HttpRequest req){
Map<String, String>requestParams=new HashMap<String, String>();
// 处理get请求
if (req.getMethod() == HttpMethod.GET) {
QueryStringDecoder decoder = new QueryStringDecoder(req.getUri());
Map<String, List<String>> parame = decoder.parameters();
Iterator<Entry<String, List<String>>> iterator = parame.entrySet().iterator();
while(iterator.hasNext()){
Entry<String, List<String>> next = iterator.next();
requestParams.put(next.getKey(), next.getValue().get(0));
}
}
// 处理POST请求
if (req.getMethod() == HttpMethod.POST) {
HttpPostRequestDecoder decoder = new HttpPostRequestDecoder(
new DefaultHttpDataFactory(false), req);
List<InterfaceHttpData> postData = decoder.getBodyHttpDatas(); //
for(InterfaceHttpData data:postData){
if (data.getHttpDataType() == HttpDataType.Attribute) {
MemoryAttribute attribute = (MemoryAttribute) data;
requestParams.put(attribute.getName(), attribute.getValue());
}
}
}
return requestParams;
}

private static final Logger logger = LoggerFactory.getLogger(HttpRequestHandler.class);
private final DispatcherServlet servlet;
private final ServletContext servletContext;
}

4.初始化servlet并启动netty server

package com.magic;

import javax.servlet.ServletException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.mock.web.MockServletConfig;
import org.springframework.web.context.support.XmlWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

import com.magic.common.config.PropConfig;
import com.magic.netty.server.NettyHttpServer;

public class MagicWebServer {

private static Logger logger = LoggerFactory.getLogger(MagicWebServer.class);

public static void main(String[] args) {
ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
Integer port = 6001;
DispatcherServlet servlet = getDispatcherServlet(ctx);
NettyHttpServer server = new NettyHttpServer(port,servlet);
server.start();

}

public static DispatcherServlet getDispatcherServlet(ApplicationContext ctx){

XmlWebApplicationContext mvcContext = new XmlWebApplicationContext();
mvcContext.setConfigLocation("classpath:spring-servlet.xml");
mvcContext.setParent(ctx);
MockServletConfig servletConfig = new MockServletConfig(mvcContext.getServletContext(), "dispatcherServlet");
DispatcherServlet dispatcherServlet = new DispatcherServlet(mvcContext);
try {
dispatcherServlet.init(servletConfig);
} catch (ServletException e) {
e.printStackTrace();
}
return dispatcherServlet;
}
}

5.写一个controller,并测试一波http://127.0.0.1:6001/user/login

package com.magic.controller;

import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.alibaba.fastjson.JSONObject;

@Controller
@RequestMapping(value="/user",produces = "text/json;charset=utf-8")
public class UserController extends BaseController{

@RequestMapping("/login")
@ResponseBody
public String login(String username,String pwd){
JSONObject resultJson = new JSONObject();
Map<String, String> loginResult = new HashMap<String, String>();
loginResult.put("username", username);
loginResult.put("age", "20");
loginResult.put("sex", "boy");

resultJson.put("code", 200);
resultJson.put("msg", "登录成功");
resultJson.put("result", loginResult);

return JSONObject.toJSONString(resultJson);
}
}

Mark一下,说明在coding的时候遇到的问题

  • 代码中的applicationContext.xmlspring-servlet.xml的按照springMVC的正常配置就行
  • 如果返回到client端的代码有中文乱码,那么在requestMapping里面添加produces = “text/json;charset=utf-8”
文章目录
  1. 1. 1.写一个netty sever的java代码
  2. 2. 2.初始化netty的channel管道
  3. 3. 3.在handler里面处理client发来的请求
  4. 4. 4.初始化servlet并启动netty server
  5. 5. 5.写一个controller,并测试一波http://127.0.0.1:6001/user/login
  6. 6. Mark一下,说明在coding的时候遇到的问题