java调用第三方接口代码，返回json/xml数据并可以输出到页面（含pom）

pom文件

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.2</version>
    </dependency>

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient-cache</artifactId>
      <version>4.5</version>
    </dependency>

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpmime</artifactId>
      <version>4.3.2</version>
    </dependency>

一、使用get方式调用（返回json）

     protected void service(HttpServletRequest request, HttpServletResponse response){
	         response.setCharacterEncoding("utf-8");
	         response.setContentType("application/json; charset=utf-8");
	         String urlStr= "第三方url接口";
	         String jsonString = null;
             try {
		            URL url = new URL(urlStr);
		            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
		            conn.setRequestMethod("GET");
		            conn.connect();
		            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
		            String line = "";
		            StringBuffer buffer = new StringBuffer();
		            while ((line = reader.readLine() )!= null){
		                buffer.append(line);
		            }
		            reader.close();
		            conn.disconnect();
		             jsonString = buffer.toString();
	        } catch (Exception e) {
	            e.printStackTrace();
	        }
         PrintWriter printWriter = null;
         try {
             printWriter = response.getWriter();
         } catch (IOException e) {
             e.printStackTrace();
         }
         printWriter.print(jsonString );
    }
    

二、使用post方式调用

//以后更新

三、第三方返回的是一个xml文件（get方式）

protected void service(HttpServletRequest request, HttpServletResponse response){
    response.setCharacterEncoding("utf-8");
    String urlStr = "第三方url接口";
    String result = getInfoByHttp(urlStr);
    PrintWriter printWriter = null;
    try {
        printWriter = response.getWriter();
    } catch (IOException e) {
        e.printStackTrace();
    }
    printWriter.print(result);
}
    public static String getInfoByHttp(String url) {
        HttpGet httpGet = new HttpGet(url);
        HttpClient httpClient = new DefaultHttpClient();
        String result = "";
        try {
            HttpResponse httpResponse = httpClient.execute(httpGet);
            result = getJsonStringFromGZIP(httpResponse);
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    private static String getJsonStringFromGZIP(HttpResponse response) {
        String jsonString = null;
        try {
            InputStream is = response.getEntity().getContent();
            BufferedInputStream bis = new BufferedInputStream(is);
            bis.mark(2);
            // 取前两个字节
            byte[] header = new byte[2];
            int result = bis.read(header);
            // reset输入流到开始位置
            bis.reset();
            // 判断是否是GZIP格式
            int headerData = getShort(header);
            if (result != -1 && headerData == 0x1f8b) {
                is = new GZIPInputStream(bis);
            } else {
                is = bis;
            }
            InputStreamReader reader = new InputStreamReader(is, "utf-8");
            char[] data = new char[100];
            int readSize;
            StringBuffer sb = new StringBuffer();
            while ((readSize = reader.read(data)) > 0) {
                sb.append(data, 0, readSize);
            }
            jsonString = sb.toString();
            bis.close();
            reader.close();
        } catch (Exception e) {
        }
        return jsonString;
    }
    private static int getShort(byte[] data) {
        return (int) ((data[0] << 8) | data[1] & 0xFF);
    }