fastJson中string与map的装换

package com.yinhai.bigdata.etl;


import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

import java.util.*;

public class demo {

    public static void main(String[] args){
        Map data_test_1=new HashMap();
        data_test_1.put("k1", "kaaa");
        data_test_1.put("k2", "kbbb");

        Map data_test_2=new HashMap();
        data_test_2.put("k3", "kccc");
        data_test_2.put("k4", "kddd");

        List list_test_1=new ArrayList();
        list_test_1.add(data_test_1);
        list_test_1.add(data_test_2);

        Map data_test_3=new HashMap();
        data_test_3.put("m1", list_test_1);
        data_test_3.put("m2", 1);
        System.out.println(data_test_3);
        //{m1=[{k1=kaaa, k2=kbbb}, {k3=kccc, k4=kddd}], m2=1}

        String str1=JSON.toJSONString(data_test_3);
        System.out.println(str1);
        //{"m1":[{"k1":"kaaa","k2":"kbbb"},{"k3":"kccc","k4":"kddd"}],"m2":1}

        JSONObject obj=JSON.parseObject(str1);
        System.out.println(obj);
        //{"m1":[{"k1":"kaaa","k2":"kbbb"},{"k3":"kccc","k4":"kddd"}],"m2":1}

        List list_1= (List) obj.get("m1");
        System.out.println(list_1);
        //[{"k1":"kaaa","k2":"kbbb"},{"k3":"kccc","k4":"kddd"}]

        Map data_map_4= (Map) list_1.get(1);
        System.out.println(data_map_4);
        //{"k3":"kccc","k4":"kddd"}
        System.out.println(data_map_4.get("k3"));
        //kccc

     	//这种也可以
	Map param = JSON.parseObject(str1, HashMap.class);
	System.out.println(param);
	//{m1=[{"k1":"kaaa","k2":"kbbb"},{"k3":"kccc","k4":"kddd"}], m2=1}
	List list_2= (List) param.get("m1");
	System.out.println(((Map)list_2.get(0)).get("k1"));
	//kaaa


        //其实上面生成的已经完全够用了,
        //这里我用java把上面的obj遍历了一下,其实没必要
        //这里用递归 就可以解决全部的嵌套 这里里面全是map
        Map res=new HashMap();//用来盛放解析的map
        Set<Map.Entry<String,Object>> entrySet=obj.entrySet();
        for(Map.Entry<String,Object> e:entrySet){
            String key=e.getKey().toString();
            Object value= e.getValue();
            if(value instanceof List){
                List li= (List) value;
                List<Map> newArr=new ArrayList<Map>();
                for (int i=0;i<li.size();i++){
                    Map li_map=new HashMap();
                    String str2=JSON.toJSONString(li.get(i));
                    JSONObject ja=JSON.parseObject(str2);
                    Set<Map.Entry<String,Object>> entrySet1=ja.entrySet();
                    for(Map.Entry<String,Object> e1:entrySet1) {
                        String key1 = e1.getKey().toString();
                        Object value1 = e1.getValue();
                        li_map.put(key1, value1);
                    }
                    newArr.add(li_map);
                }
                res.put(key,newArr);
                continue;
            }

           res.put(key, value);
        }

        System.out.println(res);
        //{m1=[{k1=kaaa, k2=kbbb}, {k3=kccc, k4=kddd}], m2=1}

    }


}