【应用】通过反射写一个通用的设置某个对象的某个属性为指定的值

public class Tool {
    public void setProperty(Object obj, String propertyName, Object value)
            throws NoSuchFieldException, SecurityException,
            IllegalArgumentException, IllegalAccessException {
        // 根据对象获取字节码文件对象

        Class c = obj.getClass();
        // 获取该对象的propertyName成员变量

        Field field = c.getDeclaredField(propertyName);
        // 取消访问检查

        field.setAccessible(true);
        // 给对象的成员变量赋值为指定的值

        field.set(obj, value);
    }
}

public class ToolDemo {
    public static void main(String[] args) throws NoSuchFieldException,
            SecurityException, IllegalArgumentException, IllegalAccessException {
        Person p = new Person();
        Tool t = new Tool();
        t.setProperty(p, "name", "林青霞");
        t.setProperty(p, "age", 27);
        System.out.println(p);
        System.out.println("-----------");

        Dog d = new Dog();

        t.setProperty(d, "sex", '男');
        t.setProperty(d, "price", 12.34f);

        System.out.println(d);
    }
}

class Dog {
    char sex;
    float price;

    @Override
    public String toString() {
        return sex + "---" + price;
    }
}

class Person {
    private String name;
    public int age;

    @Override
    public String toString() {
        return name + "---" + age;
    }
}