java使用socket实现http简单get请求

Java代码







package com.hs;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class SimpleHttpGet {

public static
final String SEQUENCE = "\r\n";

public static
void main(String[] args) throws UnknownHostException,

IOException {
String host = "www.baidu.com";
Socket socket = new Socket(host,
80);
OutputStream os = socket.getOutputStream();
StringBuffer head = new StringBuffer();
// 这些是必须的
head.append("GET / HTTP/1.1" + SEQUENCE);
head.append("Host:" + host + SEQUENCE + SEQUENCE);

// 这些是可选的
head.append("Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");

head.append("Accept-Language:zh-CN,zh;q=0.8");
head.append("User-Agent:Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");

os.write(head.toString().getBytes());
os.flush();
InputStream is = socket.getInputStream();
LineNumberReader lnr = new LineNumberReader(new InputStreamReader(is));

StringBuffer headRes = new StringBuffer();
String line = null;
int contentLength = 0;

do {
line = lnr.readLine();
headRes.append(line + SEQUENCE);
if (line.startsWith("Content-Length")) {

contentLength = Integer.parseInt(line.split(":")[1].trim());

}
// 由于LineNumberReader会把\r\n替换掉，所以如果读到一行为""证明http head结束

} while (!line.equals(""));

int totalCount = 0;
byte[] buff = new
byte[256];
StringBuffer contentRes = new StringBuffer();
while (totalCount < contentLength) {
int len = is.read(buff);
totalCount += len;
contentRes.append(new String(buff,
0, len, "gbk"));
}
System.out.println(headRes.toString());
System.out.println(contentRes.toString());
socket.close();
}
}

package com.hs;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class SimpleHttpGet {
public static final String SEQUENCE = "\r\n";

public static void main(String[] args) throws UnknownHostException,
IOException {
String host = "www.baidu.com";
Socket socket = new Socket(host, 80);
OutputStream os = socket.getOutputStream();
StringBuffer head = new StringBuffer();
// 这些是必须的
head.append("GET / HTTP/1.1" + SEQUENCE);
head.append("Host:" + host + SEQUENCE + SEQUENCE);
// 这些是可选的
head.append("Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
head.append("Accept-Language:zh-CN,zh;q=0.8");
head.append("User-Agent:Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
os.write(head.toString().getBytes());
os.flush();
InputStream is = socket.getInputStream();
LineNumberReader lnr = new LineNumberReader(new InputStreamReader(is));
StringBuffer headRes = new StringBuffer();
String line = null;
int contentLength = 0;
do {
line = lnr.readLine();
headRes.append(line + SEQUENCE);
if (line.startsWith("Content-Length")) {
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 由于LineNumberReader会把\r\n替换掉，所以如果读到一行为""证明http head结束
} while (!line.equals(""));

int totalCount = 0;
byte[] buff = new byte[256];
StringBuffer contentRes = new StringBuffer();
while (totalCount < contentLength) {
int len = is.read(buff);
totalCount += len;
contentRes.append(new String(buff, 0, len, "gbk"));
}
System.out.println(headRes.toString());
System.out.println(contentRes.toString());
socket.close();
}
}

只实现了get请求，而且如果http head中没有 content-length也会有问题， 比如有的网站头中有

Transfer-Encoding:

chunked ，这样就会没有content-length信息， 这个我也没解决， 如果谁有兴趣可以以深入了解下http协议头中的

Transfer-Encoding:

chunked代表什么意思。