Json使用总结

前言：在当今互联网的企业中，大多数企业都会与其他第三方的公司有合作的项目，而现如今互联网项目之间跨平台的交互格式更多选择的是json格式，本篇是作者总结日常开发过程中一些常用的json方法。

• • • • 一、Jackson（推荐）
      • 二、谷歌的Gson
      • 三、阿里的Fastjson
      • 四、Hutool-json

1. 导入依赖

   
   	
       2.8.6
       
       2.8.6
       
       2.8.11.1
   
   
   
   
       com.fasterxml.jackson.core
       jackson-annotations
       ${jackson-annotations.version}
   
   
       com.fasterxml.jackson.core
       jackson-core
       ${jackson-core.version}
   
   
       com.fasterxml.jackson.core
       jackson-databind
       ${jackson-databind.version}
   
   
   
     org.projectlombok
     lombok
     1.18.2
   
   
   

2. 创建Java Bean

   import lombok.Data;
   
   @Data
   public class Person {
       private String name;
       private Integer age;
   }
   

3. 测试jackson

   import com.fasterxml.jackson.core.type.TypeReference;
   import com.fasterxml.jackson.databind.ObjectMapper;
   import com.test.bean.Person;
   import org.junit.Test;
   
   import java.io.IOException;
   import java.util.List;
   import java.util.Map;
   
   public class Test {
       
       @Test
       public void testJackson() throws IOException {
           String jsonStr = "{"name":"Tom","age":20}";
           // json字符串转java对象
           ObjectMapper om = new ObjectMapper();
           Person person = om.readValue(jsonStr, Person.class);
           System.out.println(person);
   
           // java对象转json字符串
           String str = om.writevalueAsString(person);
           System.out.println(str);
   
           // json字符串转java对象列表（list）
           String jsonStr2 = "[{"name":"Tom","age":20},{"name":"Tony","age":25}]";
           List persons = om.readValue(jsonStr2, new TypeReference>(){});
           System.out.println(persons);
   
           // json字符串转java map
           Map jsonMap = om.readValue(jsonStr, new TypeReference>(){});
           System.out.println(jsonMap);
       }
   }
   

4. 运行结果截图
   

1. 导入依赖

    
     com.google.code.gson  
     gson  
     2.8.6 
    
   

2. 沿用第一节的Java Bean

3. 测试gson

   import com.google.gson.Gson;
   import com.google.gson.reflect.TypeToken;
   import com.test.bean.Person;
   import org.junit.Test;
   
   import java.lang.reflect.Type;
   import java.util.List;
   import java.util.Map;
   
   public class TestGson {
       @Test
       public void test() {
           System.out.println("测试Gson...");
           Gson gson = new Gson();
           String jsonStr = "{"name":"Tom","age":20}";
           // json字符串转java对象
           Person person = gson.fromJson(jsonStr, Person.class);
           System.out.println(person);
   
           // java对象转json字符串
           String str = gson.toJson(person);
           System.out.println(str);
   
           // json字符串转java对象列表（list）
           String jsonStr2 = "[{"name":"Tom","age":20},{"name":"Tony","age":25}]";
           Type type = new TypeToken>(){}.getType();
           List persons = gson.fromJson(jsonStr2, type);
           System.out.println(persons);
   
           // json字符串转java map
           Type type2 = new TypeToken>(){}.getType();
           Map jsonMap = gson.fromJson(jsonStr, type2);
           System.out.println(jsonMap);
       }
   }
   

4. 运行结果截图
   

1. 导入依赖

   
     com.alibaba
     fastjson
     1.2.70
   
   

2. 沿用第一节的Java Bean
3. 测试fastjson

   import com.alibaba.fastjson.JSON;
   import com.alibaba.fastjson.TypeReference;
   import com.test.bean.Person;
   import org.junit.Test;
   
   import java.lang.reflect.Type;
   import java.util.List;
   import java.util.Map;
   
   public class TestFastjson {
   
       
       @Test
       public void test() {
           System.out.println("测试Fastjson...");
           String jsonStr = "{"name":"Tom","age":20}";
           // json字符串转java对象
           Person person = JSON.parseObject(jsonStr, Person.class);
           System.out.println(person);
   
           // java对象转json字符串
           String str = JSON.toJSONString(person);
           System.out.println(str);
   
           // json字符串转java对象列表（list）
           String jsonStr2 = "[{"name":"Tom","age":20},{"name":"Tony","age":25}]";
           Type type = new TypeReference>() {}.getType();
           List persons = JSON.parseObject(jsonStr2, type);
           System.out.println(persons);
   
           // json字符串转java map
           Type type2 = new TypeReference>() {}.getType();
           Map jsonMap = JSON.parseObject(jsonStr, type2);
           System.out.println(jsonMap);
       }
   }
   

4. 运行结果截图
   

1. 导入依赖

   
       cn.hutool
       hutool-all
       5.7.3
   
   

2. 沿用第一节的Java Bean
3. 测试Hutool-json

   import cn.hutool.core.lang.TypeReference;
   import cn.hutool.json.JSONUtil;
   import com.test.bean.Person;
   import org.junit.Test;
   
   import java.lang.reflect.Type;
   import java.util.List;
   import java.util.Map;
   
   public class TestHutoolJson {
       @Test
       public void test() {
           System.out.println("测试Hutool-json...");
           String jsonStr = "{"name":"Tom","age":20}";
           // json字符串转java对象
           Person person = JSONUtil.toBean(jsonStr, Person.class);
           System.out.println(person);
   
           // java对象转json字符串
           String str = JSONUtil.toJsonStr(person);
           System.out.println(str);
   
           // json字符串转java对象列表（list）
           String jsonStr2 = "[{"name":"Tom","age":20},{"name":"Tony","age":25}]";
           List persons = JSONUtil.toList(jsonStr2, Person.class);
           System.out.println(persons);
   
           // json字符串转java map
           Type type = new TypeReference>() {}.getType();
           Map jsonMap = JSONUtil.toBean(jsonStr, type, false);
           System.out.println(jsonMap);
       }
   }
   

4. 运行结果截图