现在市面上有许多流行的http框架，其实到底层还是利用了socket。大家都学过TCP/IP的四层协议吧。其实http属于应用层，而socket则在网络层。所以http最后肯定要调用socket的。哈哈哈
TCP/IP.png
。下面例子展示了最简单的http框架，看http是怎么调用到socket的。
package com.example.sockethttp;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.OutputStreamWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private Button getbt;
private TextView resulttv;
private Lihttpclent mclient;
private static final String TAG ="wenfeng";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getbt=(Button)findViewById(R.id.Getbt);
resulttv=(TextView)findViewById(R.id.Result);
getbt.setOnClickListener(this);
}
@Override
public void onClick(View v) {
mclient=new Lihttpclent("www.youku.com");
String response=mclient.excute();
resulttv.setText(response);
}
class Lihttpclent{
private String innersite;
private StringBuilder mbuild = new StringBuilder("");
public Lihttpclent(String site){
this.innersite=site;
}
public String excute() {
Thread getthread = new Thread(new Runnable() {
@Override
public void run() {
try {
Log.i(TAG,"start run");
Socket mSocket=new Socket(
InetAddress.getByName(innersite),
80);
BufferedReader br = new BufferedReader(new
InputStreamReader(
mSocket.getInputStream(),"utf-8"));
BufferedWriter bf = new BufferedWriter((new OutputStreamWriter(
mSocket.getOutputStream())));
StringBuffer requestHeader = new StringBuffer();
requestHeader
.append("GET " + "/"
+ " HTTP/1.1\n")
.append("HOST:" + innersite + "\n")
//.append("Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\n")
.append("Accept-Encoding:gzip, deflate, sdch\n")
.append("Accept-Language:zh-CN,zh;q=0.8\n")
.append("Cache-Control:no-cache\n")
.append("User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36\n")
.append("Encoding:UTF-8\n")
.append("Connection:keep-alive" + "\n")
.append("\n");
bf.write(requestHeader.toString());
bf.flush();
String line = "";
Log.i(TAG,"start read response");
while((line=br.readLine())!=null)
{
mbuild.append(line);
mbuild.append("\r\n");
}
Log.i(TAG,mbuild.toString());
}catch (Exception e){
Log.i(TAG,"excetion = "+e.toString());
}
}
});
getthread.start();
try {
getthread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.i(TAG,"outbuilder="+mbuild.toString());
return mbuild.toString();
}
}
}
一般的框架给程序员的接口都很简单，输入参数一般是个网址就可以了，上面的例子也是这样，上面例子的框架类是Lihttpclent，为了简单说明原理，输入参数就一个String类型的网址，是不是很简单呢？
mclient=new Lihttpclent("www.youku.com");
String response=mclient.excute();
他是怎么跟socket联系在一起的呢？
1.socket构建需要ip地址和端口，所以可以通过InetAddress将网址转换为ip，端口写死80就好。
Socket mSocket=new Socket(
InetAddress.getByName(innersite),
80);
2.那现在socket通道构建起来，该给服务器发些啥呢？那就参照http协议罗，协议要啥就发啥，发一个符合http协议的字符串过去就行了，信息包含编码，缓存，语言等，那服务器就会响应你了。
StringBuffer requestHeader = new StringBuffer();
requestHeader
.append("GET " + "/"
+ " HTTP/1.1\n")
.append("HOST:" + innersite + "\n")
.append("Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\n")
.append("Accept-Encoding:gzip, deflate, sdch\n")
.append("Accept-Language:zh-CN,zh;q=0.8\n")
.append("Cache-Control:no-cache\n")
.append("User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36\n")
.append("Encoding:UTF-8\n")
.append("Connection:keep-alive" + "\n")
.append("\n");
3.开启一个线程跟服务器通信，然后获取服务器的响应，将响应的字符串显示在界面
@Override
public void onClick(View v) {
mclient=new Lihttpclent("www.youku.com");
String response=mclient.excute();
resulttv.setText(response);
}
点击get按钮后，等待一下，界面上显示如下
返回值.jpg
例子的源码路径是下面链接，大家可以体会下，其实http框架的基本原理就是这样。当然缓存机制，连接池机制等都是修饰这个大框架的，而衡量框架是否优秀就是看这些修饰了O(∩_∩)O~~。
https://github.com/wenfengtou/SocketHttpDemo