new typeReference使用

最新推荐文章于 2022-10-20 10:34:23 发布

原创最新推荐文章于 2022-10-20 10:34:23 发布 · 6.5k 阅读

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本文介绍使用Fastjson库将Java对象转换为JSON字符串的方法，并演示如何将各种类型的数据结构（如JavaBean对象、List、Map等）进行JSON序列化与反序列化。

//这个new typeReference导入的包是package com.alibaba.fastjson;
//它还有一个包是package com.fasterxml.jackson.core.type;
/**
*这是转成list的例子,转成对象还是map大体上差不多
**/
String provinces = readJsonFile(".//areaCode//provinces.json");
List<NationalCityCode> provinceList = jsonObject.parseObject(provinces, new TypeReference<List<NationalCityCode>>() {});
for (NationalCityCode province : provinceList) {
redisTemplate.opsForValue().set(province.getCode(), province.getName());
}

/**
*转成对象
**/
String provinces = readJsonFile(".//areaCode//provinces.json");
NationalCityCode province = jsonObject.parseObject(provinces, new TypeReference<NationalCityCode>() {});
for (NationalCityCode province : provinceList) {
redisTemplate.opsForValue().set(province.getCode(), province.getName());
}

 static void method1(){  
            System.out.println("javabean转化示例开始----------");  
            Person person = new Person("1","fastjson",1);  
              
            //这里将javabean转化成json字符串  
            String jsonString = JSON.toJSONString(person);  
            System.out.println(jsonString);  
            //这里将json字符串转化成javabean对象,  
            person =JSON.parseObject(jsonString,Person.class);  
            System.out.println(person.toString());  
              
            System.out.println("javabean转化示例结束----------");  
        }  
          
        static void method2(){  
            System.out.println("List<javabean>转化示例开始----------");  
              
            Person person1 = new Person("1","fastjson1",1);  
            Person person2 = new Person("2","fastjson2",2);  
            List<Person> persons = new ArrayList<Person>();  
            persons.add(person1);  
            persons.add(person2);  
            String jsonString = JSON.toJSONString(persons);  
            System.out.println("json字符串:"+jsonString);  
              
            //解析json字符串  
            List<Person> persons2 = JSON.parseArray(jsonString,Person.class);  
            //输出解析后的person对象，也可以通过调试模式查看persons2的结构  
            System.out.println("person1对象："+persons2.get(0).toString());  
            System.out.println("person2对象："+persons2.get(1).toString());  
              
            System.out.println("List<javabean>转化示例结束----------");  
        }  
          
        static void method3(){  
            System.out.println("List<String>转化示例开始----------");  
            List<String> list = new ArrayList<String>();  
            list.add("fastjson1");  
            list.add("fastjson2");  
            list.add("fastjson3");  
            String jsonString = JSON.toJSONString(list);  
            System.out.println("json字符串:"+jsonString);  
              
            //解析json字符串  
            List<String> list2 = JSON.parseObject(jsonString,new TypeReference<List<String>>(){});   
            System.out.println(list2.get(0)+"::"+list2.get(1)+"::"+list2.get(2));  
            System.out.println("List<String>转化示例结束----------");  
      
        }  
          
        static void method4(){  
            System.out.println(" List<Map<String,Object>>转化示例开始 ----------");  
            Map<String,Object> map = new HashMap<String,Object>();  
            map.put("key1", "value1");  
            map.put("key2", "value2");  
            Map<String,Object> map2 = new HashMap<String,Object>();  
            map2.put("key1", 1);  
            map2.put("key2", 2);  
            List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();  
            list.add(map);  
            list.add(map2);  
            String jsonString = JSON.toJSONString(list);  
            System.out.println("json字符串:"+jsonString);  
            //解析json字符串  
            List<Map<String,Object>> list2 = JSON.parseObject(jsonString,new TypeReference<List<Map<String,Object>>>(){});  
              
            System.out.println("map的key1值"+list2.get(0).get("key1"));  
            System.out.println("map的key2值"+list2.get(0).get("key2"));  
            System.out.println("ma2p的key1值"+list2.get(1).get("key1"));  
            System.out.println("map2的key2值"+list2.get(1).get("key2"));  
        }