Java利用Http 模拟POST、GET请求

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;


public class HttpTry {


/**
* 向指向的url发送POST请求
* 
* @param url
*            发送的URL
* @param param
*            请求参数，格式 param1=value1&param2=value2
* @return
*/
public static String sendPost(String url, String param) {

PrintWriter out = null;
BufferedReader in = null;
String result = "";
try {

URL realUrl = new URL(url);

// 打开和url之间的连接

URLConnection conn = realUrl.openConnection();

// 设置通用的请求属性

conn.setRequestProperty("accept", "*/*");

conn.setRequestProperty("connection", "Keep-Alive");

conn.setRequestProperty("user-agent",

"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

// 发送POST请求必须设置如下两行

conn.setDoInput(true);

conn.setDoOutput(true);

// 获取URLConnection对象对应的输出流

out = new PrintWriter(conn.getOutputStream());

// 发送参数

out.print(param);

// flush输出流的缓冲

out.flush();

// 定义BufferedReader输入流来读取URL的响应

in = new BufferedReader(

new InputStreamReader(conn.getInputStream()));

// 读取请求响应的数据

String line;

while ((line = in.readLine()) != null) {

result += line;

}

} catch (Exception e) {

System.out.println("发送 POST 请求出现异常," + e);

e.printStackTrace();

}
// 最后关闭输入、输出流
finally {

try {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

} catch (IOException ex) {

ex.printStackTrace();

}

}
return result;
}


/**
* 向指定URL发送GET 方法的请求
* 
* @param url
*            发送请求的URL
* @param param
*            请求参数，格式 param1=value1&param2=value2
* @return
*/
public static String sendGet(String url, String param) {

String result = "";

BufferedReader in = null;

try {

String urlName = url + "?" + param;

URL realUrl = new URL(urlName);

// 打开与url的连接

URLConnection conn = realUrl.openConnection();

// 设置通用的属性

conn.setRequestProperty("accept", "*/*");

conn.setRequestProperty("connection", "Keep-Alive");

conn.setRequestProperty("user-agent",

"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

// 建立实际的连接

conn.connect();

// 获取所有相应头字段

Map<String, List<String>> map = conn.getHeaderFields();

for (String key : map.keySet()) {

System.out.println(key + "------>" + map.get(key));

}

// 定义BufferedReader输入流来读取URL的响应

in = new BufferedReader(

new InputStreamReader(conn.getInputStream()));

String line;

while ((line = in.readLine()) != null) {

result += line;

}

} catch (Exception e) {

System.out.println("发送GET请求异常，" + e);

e.printStackTrace();

}

// 关闭流

finally {

try {

if (in != null) {

in.close();

}

} catch (IOException e) {

e.printStackTrace();

}

}

return result;

}

public static void main(String[] args) {
// 发送 GET 请求
String s = HttpTry.sendGet("http://localhost:6144/Home/RequestString","key=123&v=456");
System.out.println(s);


// 发送 POST 请求
String sr = HttpTry.sendPost("http://localhost:6144/Home/RequestPostString","key=123&v=456");
System.out.println(sr);
}
}