Java HttpURLConnection的工具类

废话不说，直接上代码，这是一个HttpURLConnection的工具类

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.*;

public final class HttpURLUtils {
    /**
     * @Author: Lvxianqing
     * @Description: 发送字符串接收响应的post请求
     * @Date: 2018-05-23 13:36:10
     * @param reqUrl 请求地址
     * @param content 请求内容，可以是xml、json、参数（例：parm1=xxx&parm2=xxx）
     */
    public static String doPost(String reqUrl, String content) {

        HttpURLConnection urlConn = null;
        try {
            urlConn = sendPost(reqUrl, content);
            String responseContent = getResponseBody(urlConn);
            return responseContent.trim();
        } finally {
            if (urlConn != null) {
                urlConn.disconnect();
                urlConn = null;
            }
        }
    }
    /**
     * @Author: Lvxianqing
     * @Description: 发送参数接收响应的post请求
     * @Date: 2018-05-23 13:36:10
     * @param reqUrl 请求地址
     * @param parameters 参数（把map转化为parm1=xxx&parm2=xxx 发送请求）
     */
    public static String doPost(String reqUrl, Map<String, String> parameters) {
        String content = generatorParamString(parameters);
        return doPost(reqUrl, content);
    }
    /**
     * @Author: Lvxianqing
     * @Description: 获取响应体
     * @Date: 2018-05-23 13:47:07
     * @param urlConn
     */
    private static String getResponseBody(HttpURLConnection urlConn) {
        try {
            String responseContent = null;
            InputStream in = urlConn.getInputStream();
            BufferedReader rd = new BufferedReader(new InputStreamReader(in, "UTF-8"));
            String tempLine = rd.readLine();
            StringBuffer tempStr = new StringBuffer();
            String crlf = System.getProperty("line.separator");
            while (tempLine != null) {
                tempStr.append(tempLine);
                tempStr.append(crlf);
                tempLine = rd.readLine();
            }
            responseContent = tempStr.toString();
            rd.close();
            in.close();
            return responseContent;
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        }
    }
    /**
     * @Author: Lvxianqing
     * @Description: 发送字符串的post请求
     * @Date: 2018-05-23 13:38:57
     * @param reqUrl
     * @param content
     */
    private static HttpURLConnection sendPost(String reqUrl,String content) {
        HttpURLConnection urlConn = null;
        try {
            URL url = new URL(reqUrl);
            urlConn = (HttpURLConnection) url.openConnection();
            urlConn.setRequestMethod("POST");
            urlConn.setConnectTimeout(50000);// （单位：毫秒）jdk
            urlConn.setReadTimeout(50000);// （单位：毫秒）jdk 1.5换成这个,读操作超时
            urlConn.setDoOutput(true);
            byte[] b = content.getBytes();
            urlConn.getOutputStream().write(b);;
            urlConn.getOutputStream().flush();
            urlConn.getOutputStream().close();
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        }
        return urlConn;
    }

    /**
     * @Author: Lvxianqing
     * @Description: 将parameters中数据转换成用"&"链接的http请求参数形式
     * @Date: 2018-05-23 13:41:56
     * @param parameters
     */
    public static String generatorParamString(Map<String, String> parameters) {
        StringBuffer params = new StringBuffer();
        if (parameters != null) {
            for (Iterator<String> iter = parameters.keySet().iterator(); iter.hasNext();) {
                String name = iter.next();
                String value = parameters.get(name);
                params.append(name + "=");
                try {
                    // 决定是否对http的get请求参数编码
//                  params.append(URLEncoder.encode(value, "UTF-8"));
                    params.append(value);
                } 
//              catch (UnsupportedEncodingException e) {
//                  throw new RuntimeException(e.getMessage(), e);
//              }
                catch (Exception e) {
                    String message = String.format("'%s'='%s'", name, value);
                    throw new RuntimeException(message, e);
                }
                if (iter.hasNext())
                    params.append("&");
            }
        }
        return params.toString();
    }
    /**
     * @Author: Lvxianqing
     * @Description: 发送指定响应编码格式的get请求（发送前请自行把参数拼接在url后）
     * @Date: 2018-05-23 13:42:40
     * @param link
     * @param charset
     */
    public static String doGet(String link, String charset) {

        try {
            URL url = new URL(link);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("User-Agent", "Mozilla/5.0");
            // HttpURLConnection 获取输入输出流时会自动打开连接
            BufferedInputStream in = new BufferedInputStream(conn.getInputStream());
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            for (int i = 0; (i = in.read(buf)) > 0;) {
                out.write(buf, 0, i);
            }
            out.flush();
            String s = new String(out.toByteArray(), charset);
            return s;
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage(), e);
        }
    }

    /**
     * @Author: Lvxianqing
     * @Description: 发送UTF-8响应格式的get请求（发送前请自行把参数拼接在url后）
     * @Date: 2018-05-23 13:44:09
     * @param link
     */
    public static String doGet(String link) {
        return doGet(link, "UTF-8");
    }

    /**
     * @Author: Lvxianqing
     * @Description: 用于生成升序排列的请求参数字符串（支付回调常用的方法）
     * @Date: 2018-05-23 13:45:42
     * @param params
     * @param sign
     */
    public static String genParmString(Map<String, String[]> params,String sign) {

        StringBuffer content = new StringBuffer();
        List<String> keys = new ArrayList<String>(params.keySet());
        Collections.sort(keys);

        for (int i = 0; i < keys.size(); i++)
        {
            String key = (String) keys.get(i);
            if (sign.equals(key))
            {
                continue;
            }
            String value = (String) params.get(key)[0];
            if (value != null)
            {
                content.append((i == 0 ? "" : "&") + key + "=" + value);
            }
            else
            {
                content.append((i == 0 ? "" : "&") + key + "=");
            }

        }
        return content.toString();
    }

}