java中Json/List/Map/Object的相互转换

╰+攻爆jí腚メ 2023-06-14 04:09 24阅读 0赞

日常开发中免不了和json格式的字符串数组，list，json，map打交道，因此这篇文章的着重点就是这四者的相互转换

1、json格式的字符串数组转list

String json = "['北京','天津','杭州']";//"[\"北京\",\"天津\",\"杭州\"]";
     
        String[] pathArr = (json.substring(1, json.length() - 1)).split(",");//string数组
     
        // 使用Arrays.asList 转换
        List<String> pathList = Arrays.asList(pathArr);
        for (String s : pathList) { 
            System.out.println(s);
        }
        //使用collections
        List list=new ArrayList();
        Collections.addAll(list,pathArr);
        for (Object o : list) { 
            System.out.println(o);
        }

2、list转json格式数组

List<String> list1=new ArrayList<String>();
            list1.add("a");
            list1.add("b");
            list1.add("vc");
     
            JSONArray jsonArray = JSONArray.fromObject(list1);
            String string=jsonArray.toString();//string
            String[] sd = (string.substring(1, string.length() - 1)).split(",");//string数组
            System.out.println(sd instanceof String[]);
            for (String s : sd) { 
                System.out.println(s);
            }

3、list转JSONArray

JSONArray jsonArray1=JSONArray.fromObject(list1);

4、JSONArray转list

List<String> list1=new ArrayList<String>();
            list1.add("a");
            list1.add("b");
            list1.add("vc");
            JSONArray jsonArray1=JSONArray.fromObject(list1);
            List<String> list=JSONArray.toList(jsonArray1);
            for (String s : list) { 
                System.out.println(s);
            }

5、Java对象、list、map转json字符串

JSONObject.toJSONString(user);
    JSONObject.toJSONString(list);
    JSONObject.toJSONString(map);

6、json字符串转java对象、list、map

Employee employee=new Employee();
            employee.setA("a");
            employee.setB("bb");
            employee.setC("cc");
     
            String s= JSONObject.toJSONString(employee);//Java对象转json字符串
            System.out.println(s);
     
            employee=JSONObject.parseObject(s,Employee.class);//json字符串转java对象
            System.out.println(employee.toString());
            
     
            public static String jsonmap = "{\"001\": {\"name\":\"xiaohong\",\"password\":\"654321\"},\"002\":[{\"$ref\":\"$.001\"},{\"name\":\"xixi\",\"password\":\"789\"}]}";
            public static String jsonuser = "{\"name\":\"xiaohong\",\"password\":\"654321\"}";
            public static String jsonlist = "[{\"name\":\"xiaohong\",\"password\":\"654321\"},{\"name\":\"xixi\",\"password\":\"789\"}]";       
     
            List list1 =  JSONObject.parseObject(jsonlist, List.class);//jsonlist转list
            Map map1 = JSONObject.parseObject(jsonmap, Map.class);//jsonmap转map