java连接外部接口获取数据工具类

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();
}
}