由于MessageDigest是Java系统类，因此您需要按照以下方式分别处理它们: https://github.com/powermock/powermock/wiki/Mock-System

As MessageDigest is a Java system class, you need to deal with them differently as per: https://github.com/powermock/powermock/wiki/Mock-System

因此，在@PrepareForTest批注中声明测试类，如下所示: @PrepareForTest({MessageDigest.class, MyTest.class})

So declare the test class in the @PrepareForTest annotation as follows: @PrepareForTest({MessageDigest.class, MyTest.class})

不确定此注释是否按照您的示例作为方法级别使用，但应在类级别使用:

Not sure if this annotation works as method level as per your example, but it should at class level:

@RunWith(PowerMockRunner.class)
@PrepareForTest({MessageDigest.class, MyTest.class})
public class MyTest {