java如何将list<VO>中所有对象输出成json格式，并打印出来system.out，每个对象之间通过换行符隔开，用具体代码表示下

您可以使用Jackson库实现将List<VO>转换为JSON格式并打印出来。以下是示例代码：

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<VO> voList = new ArrayList<>();
        voList.add(new VO("Tom", 20));
        voList.add(new VO("Jerry", 18));
        voList.add(new VO("Lucy", 22));

        ObjectMapper mapper = new ObjectMapper();

        for (VO vo : voList) {
            try {
                String json = mapper.writeValueAsString(vo);
                System.out.println(json);
            } catch (JsonProcessingException e) {
                e.printStackTrace();
            }
        }
    }
}

class VO {
    private String name;
    private int age;

    public VO(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

输出结果为：

{"name":"Tom","age":20}
{"name":"Jerry","age":18}
{"name":"Lucy","age":22}

每个对象之间通过换行符隔开。