java后台發送請求獲取數據，並解析json數據

　　先寫一個發送請求的一個工具類BackEndHttpRequest

 

package com.bs.utils;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

public class BackEndHttpRequest {
    /**
     * 向指定的URL發送GET方法的請求
     * @param url    發送請求的URL
     * @param param  請求參數，請求參數應該是 name1=value1&name2=value2 的形式 
     * @return       遠程資源的響應結果 
     */
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader bufferedReader = null;
        try {
            //1、讀取初始URL
            String urlNameString = url + "?" + param;
            //2、將url轉變為URL類對象
            URL realUrl = new URL(urlNameString);
            
            //3、打開和URL之間的連接
            URLConnection connection = realUrl.openConnection();
            //4、設置通用的請求屬性
            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("Content-Type", "application/json; charset=utf-8");
            
            //5、建立實際的連接 
            connection.connect();
            //獲取所有響應頭字段
            Map<String, List<String>> map = connection.getHeaderFields();
            //遍歷所有的響應頭字段
            for(String key : map.keySet()) {
                System.out.println(key + "---->" + map.get(key));
            }
            
            //6、定義BufferedReader輸入流來讀取URL的響應內容 ，UTF-8是后續自己加的設置編碼格式，也可以去掉這個參數
            bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream(),"UTF-8"));
            String line = "";
            while(null != (line = bufferedReader.readLine())) {
                result += line;
            }
//            int tmp;
//            while((tmp = bufferedReader.read()) != -1){
//                result += (char)tmp;
//            }
            
        }catch (Exception e) {
            // TODO: handle exception
            System.out.println("發送GET請求出現異常！！！"  + e);
            e.printStackTrace();
        }finally {        //使用finally塊來關閉輸入流 
            try {
                if(null != bufferedReader) {
                    bufferedReader.close();
                }
            }catch (Exception e2) {
                // TODO: handle exception
                e2.printStackTrace();
            }
        }
        return result;
    }
    /**
     * 向指定的URL發送POST方法的請求
     * @param url    發送請求的URL
     * @param param  請求參數，請求參數應該是 name1=value1&name2=value2 的形式 
     * @return       遠程資源的響應結果 
     */
    public static String sendPost(String url, String param) {
        String result = "";
        BufferedReader bufferedReader = null;
        PrintWriter out = null;
        try {
            //1、2、讀取並將url轉變為URL類對象
            URL realUrl = new URL(url);
            
            //3、打開和URL之間的連接
            URLConnection connection = realUrl.openConnection();
            //4、設置通用的請求屬性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        
            // 發送POST請求必須設置如下兩行  
            connection.setDoInput(true);
            connection.setDoOutput(true);
            
            //5、建立實際的連接
            //connection.connect();
            //獲取URLConnection對象對應的輸出流
            out = new PrintWriter(connection.getOutputStream());
            //發送請求參數
            out.print(param);
            //flush輸出流的緩沖
            out.flush();
            //
            
            //6、定義BufferedReader輸入流來讀取URL的響應內容
            bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream(),"UTF-8"));
            String line;
            while(null != (line = bufferedReader.readLine())) {
                result += line;
            }
        }catch (Exception e) {
            // TODO: handle exception
            System.out.println("發送POST請求出現異常！！！"  + e);
            e.printStackTrace();
        }finally {        //使用finally塊來關閉輸出流、輸入流 
            try {
                if(null != out) {
                    out.close();
                }
                if(null != bufferedReader) {
                    bufferedReader.close();
                }
            }catch (Exception e2) {
                // TODO: handle exception
                e2.printStackTrace();
            }
        }
        return result;
    }
}

 

測試：

 

package com.bs.utils;

import java.util.Timer;

public class Test {
    public static void main(String[] args) {
        
         //發送 GET 請求
        String str1=BackEndHttpRequest.sendGet("http://localhost:8080/showWaterregion", "page=1&rows=5&regionID=4");
        System.out.println(str1);
        
        //發送 POST 請求
        String str2=BackEndHttpRequest.sendPost("http://localhost:8080/waterregion/flow/year", "type=1&regionID=2");
　　　　　System.out.println(str2);

} }

 

postman請求數據

get請求的結果此處略；

post請求的結果：

 

 

 

進行解析請求回的json數據：

依賴jar包：

 fastjson-1.2.47.jar

　　　<dependency>
         <groupId>org.json</groupId>
         <artifactId>json</artifactId>
         <version>20160810</version>
     </dependency>

 

 

 測試：

 

package com.bs.utils;

import java.util.Timer;

import org.json.JSONArray;
import org.json.JSONObject;

public class Test {
    public static void main(String[] args) {
         //發送 GET 請求
        String str1=BackEndHttpRequest.sendGet("http://localhost:8080/showWaterregion", "page=1&rows=5&regionID=4");
        System.out.println(str1);
        
        //發送 POST 請求
        String str2=BackEndHttpRequest.sendPost("http://localhost:8080/waterregion/flow/year", "type=1&regionID=2");
        
        System.out.println("get請求json數據-----------------"+str1);
        
        JSONObject getjson = new JSONObject(str1);                //創建json對象(Json數據)
        System.out.println(getjson.get("total"));
        JSONArray getarray = getjson.getJSONArray("rows");        //獲取json中的數組（數組名）
        for (int i = 0; i < getarray.length(); i++) {            //遍歷數組
            JSONObject sonObject = getarray.getJSONObject(i);    //獲得數組中的第一個對象
            System.out.println(sonObject.get("id"));            //根據字段名獲得對象的每一個屬性字段
            System.out.println(sonObject.get("name"));
            System.out.println(sonObject.get("readtime"));
        }
        
        
        System.out.println("post請求json數據-----------------"+str2);
        
        JSONObject json = new JSONObject(str2);
        System.out.println(json.get("status"));
        System.out.println(json.get("msg"));
        JSONArray jsonArray = json.getJSONArray("data");
        System.out.println(jsonArray);
        for (int i = 0; i < jsonArray.length(); i++) {
            JSONObject sonObject = jsonArray.getJSONObject(i);
            String s = (String) sonObject.get("time");
            Double bigDecimal = (Double) sonObject.get("flow");
            System.out.println(s);
            System.out.println(bigDecimal);
        }
    }
}