使用Jackson将Java对象转换为JSON

Question

我希望我的JSON看起来像这样：

{

    "information": [{

        "timestamp": "xxxx",

        "feature": "xxxx",

        "ean": 1234,

        "data": "xxxx"

    }, {

        "timestamp": "yyy",

        "feature": "yyy",

        "ean": 12345,

        "data": "yyy"

    }]

}

代码到目前为止：

import java.util.List;

public class ValueData {

    private List<ValueItems> information;

    public ValueData(){

    }

    public List<ValueItems> getInformation() {

        return information;

    }

    public void setInformation(List<ValueItems> information) {

        this.information = information;

    }

    @Override

    public String toString() {

        return String.format("{information:%s}", information);

    }

}

和

public class ValueItems {

    private String timestamp;

    private String feature;

    private int ean;

    private String data;

    public ValueItems(){

    }

    public ValueItems(String timestamp, String feature, int ean, String data){

        this.timestamp = timestamp;

        this.feature = feature;

        this.ean = ean;

        this.data = data;

    }

    public String getTimestamp() {

        return timestamp;

    }

    public void setTimestamp(String timestamp) {

        this.timestamp = timestamp;

    }

    public String getFeature() {

        return feature;

    }

    public void setFeature(String feature) {

        this.feature = feature;

    }

    public int getEan() {

        return ean;

    }

    public void setEan(int ean) {

        this.ean = ean;

    }

    public String getData() {

        return data;

    }

    public void setData(String data) {

        this.data = data;

    }

    @Override

    public String toString() {

        return String.format("{timestamp:%s,feature:%s,ean:%s,data:%s}", timestamp, feature, ean, data);

    }

}

我只是错过了如何用Jackson将Java对象转换为JSON的部分：

public static void main(String[] args) {

   // CONVERT THE JAVA OBJECT TO JSON HERE

    System.out.println(json);

}

我的问题是：我的课程是否正确？我必须调用哪个实例以及如何实现此JSON输出？

Answer 1

object要用杰克逊转换你的JSON：ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();String json = ow.writeValueAsString(object);

Answer 2

这可能很有用：objectMapper.writeValue(new File("c:\\employee.json"), employee);// display to consoleObject json = objectMapper.readValue(&nbsp; &nbsp; &nbsp;objectMapper.writeValueAsString(employee), Object.class);System.out.println(objectMapper.writerWithDefaultPrettyPrinter()&nbsp; &nbsp; &nbsp;.writeValueAsString(json));