JSONObject、JSONArray、Map、JavaBean的相互轉換

1，JSONObject

  json對象，就是一個鍵對應一個值，使用的是大括號{ }，如：{key:value}

2，JSONArray

  json數組，使用中括號[ ],只不過數組裏面的項也是json鍵值對格式的

  Json對象中添加的是鍵值對，JSONArray中添加的是Json對象

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import org.junit.Test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

public class JsonTest {

    public static void main(String[] args) {
        //----------------JsonObject建立的方法-----------------------------------------------------------
        //建立JsonObject第一種方法
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("UserName", "kobi");
        jsonObject.put("age", "34");
        jsonObject.put("workIn", "ALI");//此處的"ALI"也能夠替換爲一個json{"sex":"男","station":"徐州","hoobey":"coding"}
        // System.out.println("jsonObject1：" + jsonObject);//jsonObject1：{"UserName":"kobi","workIn":"ALI","age":"34"}
        Iterator iterator = jsonObject.keys();//用Iterator迭代器遍歷取值，建議用反射機制解析到封裝好的對象中
        while (iterator.hasNext()) {
            String key = (String) iterator.next();
            String value = jsonObject.getString(key);
            System.out.println(value);//輸出值   kobi ALI 34
        }
        //建立JsonObject第二種方法
        HashMap<String, String> hashMap = new HashMap<String, String>();
        hashMap.put("UserName", "ZHULI");
        hashMap.put("age", "30");
        hashMap.put("workIn", "ALI");
        // System.out.println("jsonObject2：" + JSONObject.fromObject(hashMap));//jsonObject2：{"UserName":"ZHULI","workIn":"ALI","age":"30"}


        //----------------JSONArray建立的方法-----------------------------------------------------------
        //一：遍歷JsonArray
        String str = "[{name:'a',value:'aa'},{name:'b',value:'bb'},{name:'c',value:'cc'},{name:'d',value:'dd'}]";  // 一個未轉化的字符串
        JSONArray json = JSONArray.fromObject(str); // 首先把字符串轉成 JSONArray  對象
        if (json.length() > 0) {
            for (int i = 0; i < json.length(); i++) {
                JSONObject job = json.getJSONObject(i);  // 遍歷 jsonarray 數組，把每個對象轉成 json 對象
                // System.out.println(job);//{"name":"a","value":"aa"}  {"name":"b","value":"bb"} {"name":"c","value":"cc"}.....
                //  System.out.println(job.get("name"));  // a b c d

            }
        }

        //建立JsonArray方法2
        ArrayList<String> arrayList = new ArrayList<String>();
        arrayList.add("kobi");
        arrayList.add("34");
        arrayList.add("ALI");
        //System.out.println("jsonArray2：" + JSONArray.fromObject(arrayList));//jsonArray2：["kobi","34","ALI"]


    }

    @Test
    public void test0105() {
        /*
取出name4值過程步驟:  1.將以上字符串轉成JSONArray對象  2.取出對象的第一項,JSONObject 3.取出name1的值JSONObject
                      4.而後取出name2的值JSONObject對象  5.取出name4的值value2
* */
        /*  記住":"前是鍵,符號後是值  大括號成對找  一層層撥開就清楚了*/
        String str = "[{name1:{name2:{name3:'value1',name4:'value2'}}},{}]";

        JSONArray jsonArray = JSONArray.fromObject(str);//  將結果轉成JSONArray對象的形式

        JSONObject getJsonObj = jsonArray.getJSONObject(0);//獲取json數組中的第一項

        JSONObject json = getJsonObj.getJSONObject("name1").getJSONObject("name2");//{"name4":"value2","name3":"value1"}
        Object value = json.get("name4");
        System.out.println(value);//value2
    }

    @Test
    public void test01051() {
        JSONObject json = new JSONObject();
        JSONArray jsonArray = new JSONArray();

        json.put("key", "value");//JSONObject對象中添加鍵值對
        jsonArray.put(json);//將JSONObject對象添加到Json數組中


        System.out.println(json);
        System.out.println(jsonArray);
    }

}

相互轉換的方法以下,能夠運用到平常的工做中去：

package com.suning.crawler.util;

import net.sf.json.JSONObject;
import sun.security.util.Password;

import java.lang.reflect.Method;
import java.text.ParseException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * @Author: hoobey
 * @Description:
 * @Date: Created in 9:12 2018/1/6
 * @Modified By:
 * *轉換器
 * 1:將JavaBean 轉換成Map、JSONObject
 * 2:將JSONObject 轉換成Map
 */
public class BeanConverter {
    /**
     * 將javaBean轉換成Map
     *
     * @param javaBean javaBean
     * @return Map對象
     */
    public static Map<String, String> BeantoMap(Object javaBean) {
        Map<String, String> result = new HashMap<String, String>();
        Method[] methods = javaBean.getClass().getDeclaredMethods();

        for (Method method : methods) {
            try {
                if (method.getName().startsWith("get")) {
                    String field = method.getName();//getName  getPassword
                    field = field.substring(field.indexOf("get") + 3);//Name  Password
                    field = field.toLowerCase().charAt(0) + field.substring(1);//name password
                    Object value = method.invoke(javaBean, (Object[]) null);
                    result.put(field, null == value ? "" : value.toString());
                }
            } catch (Exception e) {
            }
        }

        return result;
    }

    /**
     * 將json對象轉換成Map
     *
     * @param jsonObject json對象
     * @return Map對象
     */
    @SuppressWarnings("unchecked")
    public static Map<String, String> JsontoMap(JSONObject jsonObject) {
        Map<String, String> result = new HashMap<String, String>();
        Iterator<String> iterator = jsonObject.keys();
        String key = null;
        String value = null;
        while (iterator.hasNext()) {
            key = iterator.next();
            value = jsonObject.getString(key);
            result.put(key, value);
        }
        return result;
    }

    /**
     * 將javaBean轉換成JSONObject
     *
     * @param bean javaBean
     * @return json對象
     */
    public static JSONObject toJSON(Object bean) {
        return new JSONObject(BeantoMap(bean));
    }

    /**
     * 將map轉換成Javabean
     *
     * @param javabean javaBean
     * @param data     map數據
     */
    public static Object toJavaBean(Object javabean, Map<String, String> data) {
        Method[] methods = javabean.getClass().getDeclaredMethods();
        for (Method method : methods) {
            try {
                if (method.getName().startsWith("set")) {
                    String field = method.getName(); //setName   setPassword
                    field = field.substring(field.indexOf("set") + 3);//Name  Password
                    field = field.toLowerCase().charAt(0) + field.substring(1);//name  password
                    method.invoke(javabean, new Object[]
                            {
                                    data.get(field)
                            });
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        return javabean;
    }

    /**
     * 將javaBean轉換成JSONObject
     *
     * @param data javaBean
     * @return json對象
     * @throws ParseException json解析異常
     */
    public static void toJavaBean(Object javabean, String data) throws ParseException {
        JSONObject jsonObject = new JSONObject(data);
        Map<String, String> datas = BeantoMap(jsonObject);
        toJavaBean(javabean, datas);
    }
}

方法調用：

package com.suning.crawler.util;
import net.sf.json.JSONObject;
import org.junit.Test;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * @Author: hoobey
 * @Description:
 * @Date: Created in 9:16 2018/1/6
 * @Modified By:
 */
public class Test0106 {
    /*javaBean轉換成Map*/
    @Test
    public void test1(){
        Map<String, String> map = BeanConverter.BeantoMap(new Stu("hoobey","123"));
       // Map<String, String> map = BeanConverter.toMap(new Stu("hoobey", "213"));
      //  Set<Map.Entry<String, String>> entry = map.entrySet(); //Set集合中存儲的是Map.Entry<String, String> entry
        //推薦使用這種map遍歷 尤爲是容量大的時候  map.entrySet()返回此映射中包含的映射關係的 Set視圖
        for(Map.Entry<String, String> entry : map.entrySet()){
            System.out.println("key="+entry.getKey()+"，value="+entry.getValue());
        }
    }

    /*  * 將json對象轉換成Map*/
    @Test
    public void test2(){

        JSONObject json =new JSONObject();
        json.put("hoobey","123");          //{"hoobey":"123"}
        Map<String, String> toMap = BeanConverter.JsontoMap(json);
        for(Map.Entry<String, String> entry : toMap.entrySet()){
            System.out.println("key="+entry.getKey()+"，value="+entry.getValue());
        }
    }

    /*將javaBean轉換成JSONObject*/
    @Test
    public void test3(){
        JSONObject toJSON = BeanConverter.toJSON(new Stu("hoobey", "123"));
        System.out.println(toJSON);//{"password":"123","name":"hoobey"}
    }

    /*將map轉換成Javabean   map中存放的鍵值必定和bean相對應*/
    @Test
    public void test4(){
        Map<String, String> map = new HashMap<String, String>();
        map.put("name","hoobey");
        map.put("password","123");
        Object o = BeanConverter.toJavaBean(new Stu(), map);
        System.out.println(o);//Stu{name='hoobey', password='123'}
    }
}