您可以通过标记注解和 BeforeEachCallback 分机。
创建一个特殊的标记注解，例如。

@Documented
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface MyField {
}

使用注解从扩展名中查找和设置值：

import org.junit.jupiter.api.extension.BeforeEachCallback;

public class MyExtension implements BeforeEachCallback {

    @Override
    public void beforeEach(final ExtensionContext context) throws Exception {
        // Get the list of test instances (instances of test classes) 
        final List<Object> testInstances = 
            context.getRequiredTestInstances().getAllInstances();

        // Find all fields annotated with @MyField
        // in all testInstances objects.
        // You may use a utility library of your choice for this task. 
        // See for example, https://github.com/ronmamo/reflections 
        // I've omitted this boilerplate code here. 

        // Assign the annotated field's value via reflection. 
        // I've omitted this boilerplate code here. 
    }

}

然后，在测试中，对目标字段进行注解，并使用扩展名扩展测试：

@ExtendWith(MyExtension.class)
public class MyTestClass {

    @MyField
    int myField;

    @Test
    public void test() {
        // use myField which has been assigned by the extension before test execution
    }

}

注意：您也可以扩展 BeforeAllCallback 它在类的所有测试方法之前执行一次，具体取决于您的实际需求。