Json之java-Jackson

他山之石

Maven依赖

 1 <!--Jackson 2.x ,有三个jar,jackson-core-2.x.x.jar（核心jar包）,
 2                                    jackson-annotations-2.x.x.jar（该包提供Json注解支持）
 3                                    jackson-databind-2.x.x.jar
 4                                    annotations依赖core,databind依赖annotations，所以pom中只需要加databind的依赖即可
 5                                    -->
 6 
 7         <dependency>
 8             <groupId>com.fasterxml.jackson.core</groupId>
 9             <artifactId>jackson-databind</artifactId>
10             <version>2.9.3</version>
11         </dependency>

实践代码

 1 import cn.mamp.Json.User;
 2 import com.fasterxml.jackson.core.JsonProcessingException;
 3 import com.fasterxml.jackson.databind.ObjectMapper;
 4 import org.junit.Test;
 5 
 6 import java.io.IOException;
 7 
 8 public class JacksonUse {
 9     @Test
10     public void objectMapperUser() {
11         ObjectMapper objectMapper = new ObjectMapper();
12         User user = new User();
13         user.setAge(123);
14         try {
15             // Obj -> String
16             String userJsonStr = objectMapper.writeValueAsString(user);
17             System.out.println(userJsonStr); // 默认序列化null值：{"name":null,"age":123}
18 
19             // String -> obj
20             User u = objectMapper.readValue(userJsonStr, User.class);
21             System.out.println(u);
22 
23         } catch (JsonProcessingException e) {
24             e.printStackTrace();
25         } catch (IOException e) {
26             e.printStackTrace();
27         }
28     }
29 }