java中常用的反射

java中常用的反射

public class User {

    private String name;
    public String getName() {
        return name;
    }

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

1、根据属性名称，利用反射射设置private属性的值

    //根据属性名称，利用反射射设置private属性的值
    public static void setPrivateValue(User user, String privateName, String privateValue) {
        try {
            Field privateStringField = user.getClass().getDeclaredField(privateName);
            privateStringField.setAccessible(true);
            privateStringField.set(user, privateValue);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

        User user = new User();
        setPrivateValue(user, "name", "hellworld");
         System.out.println(user.getName());//输出 hellworld

2、获取根据函数名调用函数，无参数

   //获取根据函数名调用函数，无参数
    public static Object callingMethod(User user, String methodName) {
        try {
            Method method = user.getClass().getDeclaredMethod(methodName);
            return method.invoke(user);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

  User user = new User();
  setPrivateValue(user, "name", "hellworld");
   System.out.println(callingMethod(user, "getName"));//输出 hellworld

3、获取根据函数名调用函数，带参数

  //获取根据函数名调用函数，有参数
    public static Object callingMethod(User user, String methodName, Class<?>[] cls, Object[] objs) {
        try {
            Method method = user.getClass().getDeclaredMethod(methodName, cls);
            return method.invoke(user, objs);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    User user = new User();
    callingMethod(user, "setName", new Class[]{String.class}, new Object[]{"hellowrld"});
     System.out.println(callingMethod(user, "getName"));//输出 hellworld