Java 反射：给指定字段赋值

public class Student {

    private Integer id;
    private String shortId;
    private String name;

    public Student(){

    }

    public Student(Integer id, String shortId, String name) {
        this.id = id;
        this.shortId = shortId;
        this.name = name;

    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getShortId() {
        return shortId;
    }

    public void setShortId(String shortId) {
        this.shortId = shortId;
    }

    public String getName() {
        return name;
    }

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

• getDeclaredField
  包含public, protected, default范围权限的字段，不包含父类的字段
• getField
  包含public权限的字段，包含父类的public权限的字段

public class TestSetObjectFieldValue {
    public static void main(String[] args) throws Exception {
        String[] fieldStrs = new String[]{"id", "name", "shortId"};
        Class<Student> clazz = Student.class;
        Student student = clazz.newInstance();
        for (String fieldStr : fieldStrs) {
            /**
             * Returns an array containing {@code Method} objects reflecting all the
             * declared methods of the class or interface represented by this {@code
             * Class} object, including public, protected, default (package)
             * access, and private methods, but excluding inherited methods.
             */
            Field field = clazz.getDeclaredField(fieldStr);
            /**
             * Returns a Field object that reflects the specified public member field of the class or interface
             * represented by this Class object.
             */
            // clazz.getField(fieldStr);
            // 注意
            field.setAccessible(true);
            if (field.getType().equals(Integer.class)) {
                field.set(student, 111);
            } else {
                field.set(student, "111");
            }
        }
        System.out.println(JSON.toJSONString(student));
    }
}