修改字节码使方法返回 true

发布于 2024-11-11 03:26:34 字数 153 浏览 3 评论 0原文

我的类文件有一个这样的方法：

public boolean validate(String str) {}

这个验证方法中有很多代码，但我只想让它始终返回 true 或 false。有人可以指出如何修改类文件来实现此目的吗？

原文

I have class file has a method like this:

public boolean validate(String str) {}

There're lots of codes inside this validate method, but I only want to make it always return true or false. Can someone point me out how to modify a class file to achieve this?

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紫﹏色ふ单纯 2024-11-18 03:26:34

规则覆盖 rtn
福级
方法验证
如果为真
请返回 true
ENDRULE

http://www.jboss.org/byteman

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三生殊途 2024-11-18 03:26:34

您是否试图对这段代码进行单元测试并强制给出答案而不关心条件？如果是这种情况，那么您正在寻找“Mocking”框架。在Java中，我可以想到 Mockito 和 EasyMock 就在我的脑海中。

相关地，您可以使用 PowerMock（与上述任一模拟框架配合使用）动态地更改类（例如final类/方法、static方法，甚至private类片段）。 PowerMock实际上可以在必要时更改字节码。检查其类加载文件夹。

我从未考虑过它，但可能可以在非测试代码中使用它们中的任何一个，但它们可能需要欺骗以避免 JUnit 依赖项（例如 JUnit Runner）。再说一遍，我从来没有考虑过这个问题，所以我从来没有考虑过其中的含义。

至少，您可以通过 PowerMockito 来了解它们如何更改字节码。

如果您只想进行单元测试，那么这非常简单，您可能不需要担心字节代码。

public class SomeClass {
    public boolean validate(String s) {
        // tons of logic
    }
}

测试（将 Mockito 与 JUnit 4 结合使用（删除 JUnit 3 的 @Test 属性））：

private final MyClassBeingTested testClass = new MyClassBeingTested();

@Test
public void testMyCodeWithSomeClass() {
    SomeClass some = mock(SomeClass.class);

    when(some.validate(anyString())).thenReturn(eq(true));

    // whenever it uses "some.validate()", with any
    //  string, then it will return true
    testClass.useSomeClass(some);

    // assert whatever conditions you want

    // if you care to ensure that it called validate:
    //  note: times(1) is implied if not supplied, but times(0), times(2), etc.
    //  could be used ("never()" exists as a synonym for times(0))
    verify(some, times(1)).validate(anyString());
}

Are you trying to unit test this code and force an answer without caring about the conditions? If that is the case, then you are looking for "Mocking" frameworks. In Java, I can think of Mockito and EasyMock off of the top of my head.

Relatedly, you can use PowerMock (works in tandem with either of the above Mocking frameworks) to dynamically change classes (such as final classes/methods, static methods, and even private pieces of classes). PowerMock actually can change the byte code when necessary. Check under its classloading folders.

I've never considered it, but it might be possible to use any of them within non-test code, but they may require finagling to avoid JUnit dependencies (such as JUnit Runner). Again, I have never thought about it, so I never thought through the implications.

At the very least, you can probably look through PowerMockito to see how they change the byte code.

If you just want to unit test, then it's extremely easy and you probably don't need to worry about the byte code.

public class SomeClass {
    public boolean validate(String s) {
        // tons of logic
    }
}

Test (using Mockito with JUnit 4 (drop the @Test attribute for JUnit 3)):

private final MyClassBeingTested testClass = new MyClassBeingTested();

@Test
public void testMyCodeWithSomeClass() {
    SomeClass some = mock(SomeClass.class);

    when(some.validate(anyString())).thenReturn(eq(true));

    // whenever it uses "some.validate()", with any
    //  string, then it will return true
    testClass.useSomeClass(some);

    // assert whatever conditions you want

    // if you care to ensure that it called validate:
    //  note: times(1) is implied if not supplied, but times(0), times(2), etc.
    //  could be used ("never()" exists as a synonym for times(0))
    verify(some, times(1)).validate(anyString());
}

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