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）

1. 导入依赖

   <properties><!-- jackson-annotations版本号 --><jackson-annotations.version>2.8.6</jackson-annotations.version><!-- jackson-core版本号 --><jackson-core.version>2.8.6</jackson-core.version><!-- jackson-databind版本号 --><jackson-databind.version>2.8.11.1</jackson-databind.version>
   </properties><!-- Jackson框架所需要JAR包 -->
   <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>${jackson-annotations.version}</version>
   </dependency>
   <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>${jackson-core.version}</version>
   </dependency>
   <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>${jackson-databind.version}</version>
   </dependency>
   <!-- lombok -->
   <dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.2</version>
   </dependency>

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 {/*** 参考：https://developer.aliyun.com/article/696266*/@Testpublic 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<Person> persons = om.readValue(jsonStr2, new TypeReference<List<Person>>(){});System.out.println(persons);// json字符串转java mapMap<String, Object> jsonMap = om.readValue(jsonStr, new TypeReference<Map<String, Object>>(){});System.out.println(jsonMap);}
   }
   

4. 运行结果截图
   

二、谷歌的Gson

1. 导入依赖

   <dependency> <groupId>com.google.code.gson</groupId>  <artifactId>gson</artifactId>  <version>2.8.6</version> 
   </dependency> 
   

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 {@Testpublic 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<List<Person>>(){}.getType();List<Person> persons = gson.fromJson(jsonStr2, type);System.out.println(persons);// json字符串转java mapType type2 = new TypeToken<Map<String, Object>>(){}.getType();Map<String, Object> jsonMap = gson.fromJson(jsonStr, type2);System.out.println(jsonMap);}
   }
   

4. 运行结果截图
   

三、阿里的Fastjson

1. 导入依赖

   <dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.70</version>
   </dependency>
   

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 {/*** 参考：https://my.oschina.net/liuzelin/blog/2984265?hmsr=kaifa_aladdin*/@Testpublic 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<List<Person>>() {}.getType();List<Person> persons = JSON.parseObject(jsonStr2, type);System.out.println(persons);// json字符串转java mapType type2 = new TypeReference<Map<String, Object>>() {}.getType();Map<String, Object> jsonMap = JSON.parseObject(jsonStr, type2);System.out.println(jsonMap);}
   }
   

4. 运行结果截图
   

四、Hutool-json

1. 导入依赖

   <dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.7.3</version>
   </dependency>
   

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 {@Testpublic 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<Person> persons = JSONUtil.toList(jsonStr2, Person.class);System.out.println(persons);// json字符串转java mapType type = new TypeReference<Map<String, Object>>() {}.getType();Map<String, Object> jsonMap = JSONUtil.toBean(jsonStr, type, false);System.out.println(jsonMap);}
   }
   

4. 运行结果截图