Java 对象不是声明 class 的实例

Question

public class SendEmailImpl 
{     
    private boolean isValidEmailAddress(String email)
    {
        boolean stricterFilter = true;
        String stricterFilterString = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}";
        String laxString = ".+@.+\.[A-Za-z]{2}[A-Za-z]*";
        String emailRegex = stricterFilter ? stricterFilterString : laxString;
        Pattern p = Pattern.compile(emailRegex);
        Matcher m = p.matcher(email);
        return m.matches();
    } 
}

我尝试使用反射调用此代码

@Test
public void testValidEmail() throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException
{
    Method method = SendEmailImpl.class.getDeclaredMethod("isValidEmailAddress", String.class);
    method.setAccessible(true);
    Boolean invoke = (Boolean) method.invoke("isValidEmailAddress", String.class);

    assertTrue(invoke);
    System.out.println("Testing E-mail validator - case example@example.com");
}

但是我得到错误

java.lang.IllegalArgumentException: object is not an instance of declaring class

你知道我的代码哪里错了吗？

我也试过这个：

@Test
public void testValidEmail() throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException
{
    Method method1 = SendEmailImpl.class.getDeclaredMethod("isValidEmailAddress", String.class);
    method1.setAccessible(true);

    Boolean invoke = (Boolean)method1.invoke(String.class);
    assertTrue(invoke);
    System.out.println("Testing E-mail validator - case example@example.com");
}

但是结果是一样的

Answer 1

您正在使用 Class<String> 参数 (String.class) 而不是 String 调用 isValidEmailAddress 方法。此外，第一个参数应该是 class 你想要调用方法的实例（因为它不是静态方法）。

引用 Method.invoke Javadoc：

Parameters:

obj - the object the underlying method is invoked from

args - the arguments used for the method call

更正后的代码：

@Test
public void testValidEmail() throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
    SendEmailImpl instance = new SendEmailImpl();
    Method method = instance.getClass().getDeclaredMethod("isValidEmailAddress", String.class);
    method.setAccessible(true);
    Boolean invoke = (Boolean) method.invoke(instance, "myStringArgument");
    // rest of code
}

Java 对象不是声明 class 的实例

Java object is not an instance of declaring class

java

reflection