通过URLConnection/HttpURLConnection发送HTTP请求的方法

package com.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;
import java.util.Map;

public class HttpConnectionUtil {

// post请求
public static final String HTTP_POST = "POST";

// get请求
public static final String HTTP_GET = "GET";

// utf-8字符编码
public static final String CHARSET_UTF_8 = "utf-8";

// HTTP内容类型。如果未指定ContentType，默认为TEXT/HTML
public static final String CONTENT_TYPE_TEXT_HTML = "text/xml";

// HTTP内容类型。相当于form表单的形式，提交暑假
public static final String CONTENT_TYPE_FORM_URL = "application/x-www-form-urlencoded";

// 请求超时时间
public static final int SEND_REQUEST_TIME_OUT = 50000;

// 将读超时时间
public static final int READ_TIME_OUT = 50000;

/**
*
* @param requestType
* 请求类型
* @param urlStr
* 请求地址
* @param body
* 请求发送内容
* @return 返回内容
*/
public static String requestMethod(String requestType, String urlStr, String body) {

// 是否有http正文提交
boolean isDoInput = false;
if (body != null && body.length() > 0)
isDoInput = true;
OutputStream outputStream = null;
OutputStreamWriter outputStreamWriter = null;
InputStream inputStream = null;
InputStreamReader inputStreamReader = null;
BufferedReader reader = null;
StringBuffer resultBuffer = new StringBuffer();
String tempLine = null;
try {
// 统一资源
URL url = new URL(urlStr);
// 连接类的父类，抽象类
URLConnection urlConnection = url.openConnection();
// http的连接类
HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;

// 设置是否向httpUrlConnection输出，因为这个是post请求，参数要放在
// http正文内，因此需要设为true, 默认情况下是false;
if (isDoInput) {
httpURLConnection.setDoOutput(true);
httpURLConnection.setRequestProperty("Content-Length", String.valueOf(body.length()));
}
// 设置是否从httpUrlConnection读入，默认情况下是true;
httpURLConnection.setDoInput(true);
// 设置一个指定的超时值（以毫秒为单位）
httpURLConnection.setConnectTimeout(SEND_REQUEST_TIME_OUT);
// 将读超时设置为指定的超时，以毫秒为单位。
httpURLConnection.setReadTimeout(READ_TIME_OUT);
// Post 请求不能使用缓存
httpURLConnection.setUseCaches(false);
// 设置字符编码
httpURLConnection.setRequestProperty("Accept-Charset", CHARSET_UTF_8);
// 设置内容类型
httpURLConnection.setRequestProperty("Content-Type", CONTENT_TYPE_FORM_URL);
// 设定请求的方法，默认是GET
httpURLConnection.setRequestMethod(requestType);

// 打开到此 URL 引用的资源的通信链接（如果尚未建立这样的连接）。
// 如果在已打开连接（此时 connected 字段的值为 true）的情况下调用 connect 方法，则忽略该调用。
httpURLConnection.connect();

if (isDoInput) {
outputStream = httpURLConnection.getOutputStream();
outputStreamWriter = new OutputStreamWriter(outputStream);
outputStreamWriter.write(body);
outputStreamWriter.flush();// 刷新
}
if (httpURLConnection.getResponseCode() >= 300) {
throw new Exception(
"HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
}

if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
inputStream = httpURLConnection.getInputStream();
inputStreamReader = new InputStreamReader(inputStream);
reader = new BufferedReader(inputStreamReader);

while ((tempLine = reader.readLine()) != null) {
resultBuffer.append(tempLine);
resultBuffer.append(" ");
}
}

} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {// 关闭流

try {
if (outputStreamWriter != null) {
outputStreamWriter.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (outputStream != null) {
outputStream.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (reader != null) {
reader.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (inputStreamReader != null) {
inputStreamReader.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if (inputStream != null) {
inputStream.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return resultBuffer.toString();
}

public static void main(String[] args) throws MalformedURLException {

System.out.println(requestMethod(HTTP_GET, "http://127.0.0.1:8080/test/TestHttpRequestServlet",
"username=123&password=我是谁"));

}
}

 POST

public static String post(String reqUrl, String body) throws IOException {
        URL serverUrl = new URL(reqUrl);
        HttpURLConnection conn = null;
        InputStreamReader isr = null;
        BufferedReader br = null;
        StringBuffer buffer = new StringBuffer();

        try {
            conn = (HttpURLConnection) serverUrl.openConnection();
            conn.setConnectTimeout(CONNECTION_TIMEOUT);
            conn.setReadTimeout(READ_TIMEOUT);
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            conn.connect();

            conn.getOutputStream().write(body.getBytes(CharEncoding.UTF_8));

            isr = new InputStreamReader(conn.getInputStream(), CharEncoding.UTF_8);
            br = new BufferedReader(isr);

            for (String line = ""; (line = br.readLine()) != null;) {
                buffer.append(line);
            }
        } finally {
            if (null != br) {
                br.close();
            }
            if (null != isr) {
                isr.close();
            }
            if (null != conn) {
                conn.disconnect();
            }
        }

        return buffer.toString();
    }

GET

public static String get(String url) throws IOException {
        URL reqUrl = new URL(url);
        HttpURLConnection conn = null;
        InputStream inStream = null;
        InputStreamReader isr = null;
        BufferedReader br = null;
        StringBuffer buffer = new StringBuffer(1024);

        try {
            conn = (HttpURLConnection) reqUrl.openConnection();
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setAllowUserInteraction(false);
            conn.setUseCaches(false);
            conn.setRequestMethod("GET");

            inStream = conn.getInputStream();
            isr = new InputStreamReader(inStream, CharEncoding.UTF_8);
            br = new BufferedReader(isr);

            for (String line = ""; (line = br.readLine()) != null;) {
                buffer.append(line);
            }
        } finally {
            if (null != inStream) {
                inStream.close();
            }
            if (null != br) {
                br.close();
            }
            if (null != isr) {
                isr.close();
            }
            if (null != conn) {
                conn.disconnect();
            }
        }
        return buffer.toString();
    }