Use_Jackson

• Use_Jackson
  • pom.xml
  • 基本
    • json -> Model
      • input.json
      • Model.java
      • App.java
    • Model -> json
      • Model.java
      • App.java

pom.xml

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>${jackson.version}</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>${jackson.version}</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
    </dependency>

基本

json -> Model

input.json

[
    { "key":1 , "value":"hoge" , "value2" : "hogehoge" } , 
    { "key":2 , "value":"piyo" , "value2" : "piyopiyo" }
]

Model.java

package sample.json.model;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.AllArgsConstructor;
import com.fasterxml.jackson.annotation.JsonProperty;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Model {
    private int key;
    private String value;

    @JsonProperty("value2")
    private String otherName;
}

App.java

import java.util.List;
import sample.json.model.Model;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.type.TypeReference;


ObjectMapper mapper = new ObjectMapper();
List<Model> list
    = mapper.readValue(
        json,
        new TypeReference<List<Model>>(){}
);

Model -> json

Model.java

package sample.json.model;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.AllArgsConstructor;
import com.fasterxml.jackson.annotation.JsonProperty;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Model {
    private int key;
    private String value;

    @JsonProperty("value2")
    private String otherName;
}

App.java

package sample.json;

import java.util.List;
import java.util.ArrayList;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.JsonProcessingException;

import sample.json.model.Model;

public class ModelToJson {
    public static void main( String[] args ) throws JsonProcessingException {
        List<Model> list = new ArrayList<Model>();
        list.add(new Model(1,"hoge","hogehoge"));
        list.add(new Model(2,"piyo","piyopiyo"));
        
        ObjectMapper mapper = new ObjectMapper();
        System.out.println(mapper.writeValueAsString(list));
    }
}