自己动手利用Socket 实现HTTP与HTTPS

大致分了几个步骤

一:当然是要知道HTTP协议,知道常用的HTTP请求头,比如Host, Accept, Content-Type

    知道HTTP协议支持的方法,常用有GET/POST/PUT/DELETE等

    如果不知道,也不用担心,我保证你读完这篇文章,你就知道一些啦,当然有个最好的参考

    文档就是HTTP相关的RFC文档,认真读一下肯定解决你自己心中的HTTP那些疑惑

二: 知道发送HTTP GET与POST格式很重要, 固定的格式如下:

    [REQUEST][HTTP VERSION]

    [REQUEST HEADER: ][VALUE]

    可以有多个请求头

    最后

    发送完HTTP请求头部以后, 针对不同请求如POST要发送内容部分,发送完成以后同样

    以结尾.

    解释: 表示空格, 表示回车换行Java中表示为”\r\n”

    REQUEST表示HTTP请求命令,可以为POST, GET, PUT, DELETE等之一

    HTTP VERSION的常见可能值为HTTP/1.1或者HTTP/1.0

三: 如果1与2的知识你都具备了,下面就来介绍一下JAVA Socket的相关知识

    如何创建一个JAVA客户端套接字Socket s = new Socket()如此即可,简单吧!

    如何连接到远程的主机与端口, 当提供URL字符串时候,可以这么做

   URL url = new URL(“http://blog.csdn.NET/jia20003”);

   String host = url.getHost;

   int port = url.getDefaultPort();

  SocketAddress dest = new InetSocketAddress(this.host, this.port);

   s.connect(dest);

   即可连接到远程主机,下面就可以请求文章内容了, 也很容易的

String path = "/jia20003/article/details/16908661";
SocketAddress dest = new InetSocketAddress(this.host, this.port);
socket.connect(dest);
OutputStreamWriter streamWriter = new OutputStreamWriter(socket.getOutputStream());
bufferedWriter = new BufferedWriter(streamWriter);
bufferedWriter.write("GET " + path + " HTTP/1.1\r\n");
bufferedWriter.write("Host: " + this.host + "\r\n");
bufferedWriter.write("\r\n");
bufferedWriter.flush();

最后也是最重要的一点,字符编码,尽量都用同一种字符编码来发

送请求数据,推荐使用utf-8测试程序, 我写两个简单的PHP文件放

在wamp server上,完成对全部代码的测试

四:关于HTTP与HTTPS

HTTP协议是位于第四层协议TCP之上完成的应用层协议, 端到端都是明文传送,别人一

旦网络抓包以后都可以看到你的提交与请求数据,这个好像不太安全. HTTP协议的默认

端口是80这个是RFC文档声明的,属于官方标准,没什么道理可以讲.

HTTPS是基于SSL加密传输的,这样别人截获你的数据包破解的概率要小一点,比HTTP安

全一点,其默认端口是443, 好像QQ邮箱与谷歌的WEB Mail邮箱都是基于HTTPS. 但是

HTTPS通信方式只是传输数据加密,都客户端来说是透明的,它还是一样要遵守HTTP协

议规范来发送POST与GET请求等.

完整的测试程序如下:

package com.gloomyfish.http.client;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.URLEncoder;

public class TestDemo {
    private int port;
    private String host;
    private Socket socket;
    private BufferedReader bufferedReader;
    private BufferedWriter bufferedWriter;
    public TestDemo(String host, int port) {
        socket = new Socket();
        this.host = host;
        this.port = port;
    }

    public void sendGet() throws IOException
    {
        String path = "/zhigang/getDemo.php";
        SocketAddress dest = new InetSocketAddress(this.host, this.port);
        socket.connect(dest);
        OutputStreamWriter streamWriter = new OutputStreamWriter(socket.getOutputStream());
        bufferedWriter = new BufferedWriter(streamWriter);

        bufferedWriter.write("GET " + path + " HTTP/1.1\r\n");
        bufferedWriter.write("Host: " + this.host + "\r\n");
        bufferedWriter.write("\r\n");
        bufferedWriter.flush();

        BufferedInputStream streamReader = new BufferedInputStream(socket.getInputStream());
        bufferedReader = new BufferedReader(new InputStreamReader(streamReader, "utf-8"));
        String line = null;
        while((line = bufferedReader.readLine())!= null)
        {
            System.out.println(line);
        }
        bufferedReader.close();
        bufferedWriter.close();
        socket.close();
    }

    public void sendPost() throws IOException
    {
        String path = "/zhigang/postDemo.php";
        String data = URLEncoder.encode("name", "utf-8") + "=" + URLEncoder.encode("gloomyfish", "utf-8") + "&" +
                        URLEncoder.encode("age", "utf-8") + "=" + URLEncoder.encode("32", "utf-8");
        // String data = "name=zhigang_jia";
        SocketAddress dest = new InetSocketAddress(this.host, this.port);
        socket.connect(dest);
        OutputStreamWriter streamWriter = new OutputStreamWriter(socket.getOutputStream(), "utf-8");
        bufferedWriter = new BufferedWriter(streamWriter);

        bufferedWriter.write("POST " + path + " HTTP/1.1\r\n");
        bufferedWriter.write("Host: " + this.host + "\r\n");
        bufferedWriter.write("Content-Length: " + data.length() + "\r\n");
        bufferedWriter.write("Content-Type: application/x-www-form-urlencoded\r\n");
        bufferedWriter.write("\r\n");
        bufferedWriter.write(data);
        bufferedWriter.flush();
        bufferedWriter.write("\r\n");
        bufferedWriter.flush();

        BufferedInputStream streamReader = new BufferedInputStream(socket.getInputStream());
        bufferedReader = new BufferedReader(new InputStreamReader(streamReader, "utf-8"));
        String line = null;
        while((line = bufferedReader.readLine())!= null)
        {
            System.out.println(line);
        }
        bufferedReader.close();
        bufferedWriter.close();
        socket.close();
    }

    public static void main(String[] args)
    {
        TestDemo td = new TestDemo("127.0.0.1",8099);
        try {
            // td.sendGet(); //send HTTP GET Request

            td.sendPost(); // send HTTP POST Request
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

想要成为支持HTTPS客户端, 只要在创建Socket的时候如下:

socket = (SSLSocket)((SSLSocketFactory)SSLSocketFactory.getDefault()).createSocket(this.host, port);