java - 如何将 java 类字段转换为字符串值数组

Question

我正在寻找一种干净优雅的方法来根据变量值将对象变量转换为数组。

例子:

public class Subject {

    public Subject(boolean music, boolean food, boolean sport, boolean business, boolean art) {
        this.music = music;
        this.food = food;
        this.sport = sport;
        this.business = business;
        this.art = art;
    }

    private final Long id;
    private final boolean music;
    private final boolean food;
    private final boolean sport;
    private final boolean business;
    private final boolean art;

}

根据每个字段的值，我想将字段名称作为字符串添加到数组中。

例子:新主题(真，真，真，假，假)

预期结果:["音乐", "食物", "运动"]

Answer 1

假设没有 setter/getter ，你可以使用反射:

Subject subject = new Subject(true, true, true, false, false);

Field[] fields = Subject.class.getDeclaredFields();   // Get the object's fields
List<String> result = new ArrayList<>();
Object value;

for(Field field : fields) {                           // Iterate over the object's fields

    field.setAccessible(true);                        // Ignore the private modifier
    value = field.get(subject);                       // Get the value stored in the field

    if(value instanceof Boolean && (Boolean)value) {  // If this field contains a boolean object and the boolean is set to true
        result.add(field.getName());                  // Add the field name to the list
    }
}
System.out.println(result); // ["music", "food", "sport"]

Working example