java代码实现访问网络外部接口并获取数据的工具类

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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();
	}
}