java后台访问外网接口获取数据并封装成json

方法类

@ResponseBody	
public AjaxJson getAjaxJson(HttpServletRequest request, HttpServletResponse response){
		AjaxJson j = new AjaxJson();
		String url = "http://外网接口";//调用sendPost方法时传入的外网接口地址
		Map<String, String> params = new HashMap<String, String>();//调用sendPost方法时传入外网接口地址携带的参数
		params.put("access_token","xxxxxxxxxx");
		params.put("itemId","xxxxxxxx");
		try {
			String orgInfo = sendPost(url,params);
			JSONObject obj = JSONObject.fromObject(orgInfo);  
			Map<String,Object> m = new HashMap<String, Object>();
			m.put("state", obj.get("state"));//从接口的数据中取出state值并传入json中
			m.put("data", obj.get("data"));
			j.setSuccess(true);
			j.setAttributes(m);
			j.setMsg("查询成功");
		} catch (Exception e) {
			j.setSuccess(false);
			j.setMsg("查询失败");
		}
		return j;
	}
	/**
     * 向指定 URL 发送POST方法的请求     
     * @param url 发送请求的 URL    
     * @param params 请求的参数集合     
     * @return 远程资源的响应结果
     */
	private String sendPost(String url, Map<String, String> params) {
        OutputStreamWriter out = null;
        BufferedReader in = null;        
        StringBuilder result = new StringBuilder(); 
        try {
            URL realUrl = new URL(url);
            HttpURLConnection conn =(HttpURLConnection) realUrl.openConnection();
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // POST方法
            conn.setRequestMethod("POST");
            // 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("Content-Type", "application/x-www-form-urlencoded");
            conn.connect();
            // 获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            // 发送请求参数            
            if (params != null) {
		          StringBuilder param = new StringBuilder(); 
		          for (Map.Entry<String, String> entry : params.entrySet()) {
		        	  if(param.length()>0){
		        		  param.append("&");
		        	  }	        	  
		        	  param.append(entry.getKey());
		        	  param.append("=");
		        	  param.append(entry.getValue());		        	  
		        	  System.out.println(entry.getKey()+":"+entry.getValue());
		          }
		          System.out.println("param:"+param.toString());
		          out.write(param.toString());
            }
            // 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(), "UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {            
            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();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result.toString();
    }

实体类：

public class AjaxJson {


	private boolean success = true;// 是否成功
	private String msg = "操作成功";// 提示信息
	private Object obj = null;// 其他信息
	private Map<String, Object> attributes;// 其他参数
	public Map<String, Object> getAttributes() {
		return attributes;
	}


	public void setAttributes(Map<String, Object> attributes) {
		this.attributes = attributes;
	}


	public String getMsg() {
		return msg;
	}


	public void setMsg(String msg) {
		this.msg = msg;
	}


	public Object getObj() {
		return obj;
	}


	public void setObj(Object obj) {
		this.obj = obj;
	}


	public boolean isSuccess() {
		return success;
	}


	public void setSuccess(boolean success) {
		this.success = success;
	}
	public String getJsonStr(){
		JSONObject obj = new JSONObject();
		obj.put("success", this.isSuccess());
		obj.put("msg", this.getMsg());
		obj.put("obj", this.obj);
		obj.put("attributes", this.attributes);
		return obj.toJSONString();
	}
}