java - 如何显示 ArrayList 中包含重复值的所有项目？

Question

我有一个包含姓名、年龄和汽车的人员列表。我能够打印出一组好的字符串值。但是，当我将另一个姓名、年龄、汽车添加到列表中时，仅显示最后一个项目/列表。如何打印两组人员数据？

    List<People> peopleInfo = getInfo(ppl);
    String peopleResults = mapper.writeValueAsString(peopleInfo);
    for(People model : peopleInfo) {          
        People people = new People(model.getName(), model.getAge(), model.getCar());
        ToJSON peop = new ToJSON(people);

         ObjectMapper mapper2 = new ObjectMapper();
         ObjectWriter writer = mapper2.writer(new DefaultPrettyPrinter());
         writer.writeValue(new File("file.json"), peop);

getInfo方法

private List<People> getInfo(String ppl) {
    List<People> peopleList = new ArrayList<People>();
    People people = new People();

    //1st Person
    people.setName("Tim");
    people.setAge("22");
    people.setCar("Ford");

    //Second Person
    people.setName("Susan");
    people.setAge("42");
    people.setCar("Toyota");

    peopleList.add(people);

    return peopleList;
}

Answer 1

您在创建第二个人时重新定义人员，因此仅将第二个人添加到列表中

//1st Person
people.setName("Tim");
people.setAge("22");
people.setCar("Ford");

//Second Person
people.setName("Susan");
people.setAge("42");
people.setCar("Toyota");

peopleList.add(people);

修复方法是创建多个人员对象或在定义人员后立即添加人员

People people = new People();
People people2 = new People();

People.setName("Time");
People2.setName("Susan");

peopleList.add(people);
peopleList.add(people2);

或者后者

people.setName("Tim");
people.setAge("22");
people.setCar("Ford");

peopleList.add(people);

people.setName("Susan");
people.setAge("42");
people.setCar("Toyota");

peopleList.add(people);