java代码实现访问网络外部接口并获取数据的工具类

工具类代码，可以直接copy使用

package com.yqzj.util;

import org.apache.log4j.LogManager;

import org.apache.log4j.Logger;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.URL;

import java.net.URLConnection;

public class HttpRequestUtil {

/** 日志 */

private static Logger log = LogManager.getLogger(HttpRequestUtil.class);

/**

* 向指定URL发送GET方法的请求

* 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。

* @param url

* 发送请求的URL

* @return URL 所代表远程资源的响应结果

*/

public static String sendGet(String url) {

StringBuilder result = new StringBuilder();

BufferedReader in = null;

try {

URL realUrl = new URL(url);

// 打开和URL之间的连接

URLConnection connection = realUrl.openConnection();

// 设置通用的请求属性

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

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

connection.setRequestProperty("user-agent",

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

connection.setRequestProperty("Accept-Charset", "UTF-8");

connection.setRequestProperty("contentType", "UTF-8");

// 建立实际的连接

connection.connect();

// 遍历所有的响应头字段

// 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(

connection.getInputStream(), "utf-8"));

String line;

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

result.append(line);

}

} catch (Exception e) {

//System.out.println("发送GET请求出现异常！" + e);

result = new StringBuilder("{\"resCode\":\"1\",\"errCode\":\"1001\",\"resData\":\"\"}");

e.printStackTrace();

log.error("远程服务未开启", e);

}

// 使用finally块来关闭输入流

finally {

try {

if (in != null) {

in.close();

}

} catch (Exception e2) {

e2.printStackTrace();

}

}

return result.toString();

}

/**

* 向指定 URL 发送POST方法的请求

*

* @param url

* 发送请求的 URL

* @param param

* 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。

* @return 所代表远程资源的响应结果

*/

public static String sendPost(String url, String param) {

PrintWriter out = null;

BufferedReader in = null;

StringBuilder result = new StringBuilder();

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)");

conn.setRequestProperty("Accept-Charset", "UTF-8");

conn.setRequestProperty("contentType", "UTF-8");

// 发送POST请求必须设置如下两行

conn.setDoOutput(true);

conn.setDoInput(true);

// 获取URLConnection对象对应的输出流

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

// 发送请求参数

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()));

String line;

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

result.append(line);

}

} catch (Exception e) {

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

result = new StringBuilder("{\"resCode\":\"1\",\"errCode\":\"1001\",\"resData\":\"\"}");

e.printStackTrace();

log.error("远程服务未开启", e);

}

// 使用finally块来关闭输出流、输入流

finally {

try {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

} catch (IOException ex) {

ex.printStackTrace();

}

}

return result.toString();

}

/**

* 向指定 URL 发送POST方法的请求

*

* @param url

* 发送请求的 URL

* @param param

* 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。

* @return 所代表远程资源的响应结果

*/

public static String sendFile(String url, String param,

BufferedInputStream bInputStream) {

BufferedOutputStream out = null;

BufferedReader in = null;

StringBuilder result = new StringBuilder();

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)");

conn.setRequestProperty("Accept-Charset", "UTF-8");

conn.setRequestProperty("contentType", "multipart/form-data");

// 发送POST请求必须设置如下两行

conn.setDoOutput(true);

conn.setDoInput(true);

// 发送参数

StringBuffer sb = new StringBuffer();

sb = sb.append(param);

byte[] paramData = sb.toString().getBytes();

//System.out.println(paramData.length);

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

out.write(paramData);

if (bInputStream != null) {

byte[] data = new byte[2048];

while (bInputStream.read(data) != -1) {

out.write(data);

}

}

out.flush();

// flush输出流的缓冲

// 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.append(line);

}

} catch (Exception e) {

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

result = new StringBuilder("{\"resCode\":\"1\",\"errCode\":\"1001\",\"resData\":\"\"}");

e.printStackTrace();

}

// 使用finally块来关闭输出流、输入流

finally {

try {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

if (bInputStream != null) {

bInputStream.close();

}

} catch (IOException ex) {

ex.printStackTrace();

}

}

return result.toString();

}

}