Android-----------HttpURLConnection的 get 请求和 post 请求 (可以下载浏览的内容)-优快云博客

本文介绍了一个使用Java实现的HTTP请求处理方法，包括GET和POST请求的处理流程，并提供了字符串MD5加密的方法。对于POST请求，文章详细展示了如何构建请求参数并发送到服务器，以及如何接收服务器返回的数据。

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public class HttpUrl {
     /**
                   * HttpURLConnection的post请求
                   * @param urlPath
                   * @param map
                   * @return
                   */
                  public static String postUrlConnect(String urlPath, Map<String,Object> map){
                     StringBuffer sbRequest =new StringBuffer();
                      if(map!=null&&map.size()>0){
                          for (String key:map.keySet()){
                              sbRequest.append(key+"="+map.get(key)+"&");
                          }
                      }
                      String request = sbRequest.substring(0,sbRequest.length()-1);
                      try {
                          //创建URL
                          URL url = new URL(urlPath);
                          //由URL的openConnection方法得到一个HttpURLConnection（需要强转）
                          HttpURLConnection httpURLConnection =
                                  (HttpURLConnection) url.openConnection();
                          //设置post提交
                          httpURLConnection.setRequestMethod("POST");
                          //设置超时时间
                          httpURLConnection.setConnectTimeout(30000);
                          httpURLConnection.setReadTimeout(30000);

                          httpURLConnection.setDoInput(true);
                          httpURLConnection.setDoOutput(true);

                          //把请求正文通过OutputStream发出去
                          OutputStream os =httpURLConnection.getOutputStream();
                          os.write(request.getBytes());
                          os.flush();

                          //判断响应码  200 代表成功
                          if(httpURLConnection.getResponseCode()==200){
                              //由HttpURLConnection拿到输入流
                              InputStream in=httpURLConnection.getInputStream();
                              StringBuffer sb=new StringBuffer();
                              //根据输入流做一些IO操作
                              byte [] buff =new byte[1024];
                              int len=-1;
                              while((len=in.read(buff))!=-1){
                                  sb.append(new String(buff,0,len,"utf-8"));
                              }

                              in.close();
                              os.close();
                              httpURLConnection.disconnect();
                              return  sb.toString();
                          }else{
                              return null;
                          }

                      }catch (Exception e){
                          Log.e("post","code:"+e.getMessage());
                          return null;
                      }
                  }

                  /**
                   * HttpURLConnection的get请求
                   * @param urlPath
                   * @return
                   */
                  public static String getUrlConnect(Context context,String urlPath){

                      try {
                          //创建URL
                          URL url = new URL(urlPath);
                          //由URL的openConnection方法得到一个HttpURLConnection（需要强转）
                          HttpURLConnection httpURLConnection =
                                  (HttpURLConnection) url.openConnection();
                          //设置连接
                          httpURLConnection.connect();
                          //判断响应码  200 代表成功
                          if(httpURLConnection.getResponseCode()==200){
                              //由HttpURLConnection拿到输入流
                              InputStream in=httpURLConnection.getInputStream();
                              StringBuffer sb=new StringBuffer();
                              //定义一个文件的保存路径
                             File file=new File(context.getExternalCacheDir(),getMD5(urlPath));
                              FileOutputStream fos=new FileOutputStream(file);

                              //根据输入流做一些IO操作
                              byte [] buff =new byte[1024];
                              int len=-1;
                              while((len=in.read(buff))!=-1){
                                  //把读到的内容写到文件中
                                  fos.write(buff,0,len);
                                  sb.append(new String(buff,0,len,"utf-8"));
                              }
                             fos.flush();
                              fos.close();
                              in.close();
                              httpURLConnection.disconnect();
                              return  sb.toString();
                          }else{
                              return null;
                          }
                      } catch (Exception e) {
                          e.printStackTrace();
                      }
                      return null;
                  }

    /**
     * 对字符串md5加密
     *
     * @param str
     * @return
     */
    public static String getMD5(String str) {
        try {
            // 生成一个MD5加密计算摘要
            MessageDigest md = MessageDigest.getInstance("MD5");
            // 计算md5函数
            md.update(str.getBytes());
            // digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
            // BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
            return new BigInteger(1, md.digest()).toString(16);
        } catch (Exception e) {
            return str;
        }
    }
}