Question

当我使用JUnit时，我遇到了这个错误：

java.lang.NullPointerException at com.mpdidb.mapper.TbUserServiceTest.selectByPrimaryKeyTest（TbUserServiceTest.java:27） at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在 sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）at org.junit.runners.model.FrameworkMethod $ 1.runReflectiveCall（FrameworkMethod.java:50）在 org.junit.internal.runners.model.ReflectiveCallable.run（ReflectiveCallable.java:12）在 org.junit.runners.model.FrameworkMethod.invokeExplosively（FrameworkMethod.java:47）在 org.junit.internal.runners.statements.InvokeMethod.evaluate（InvokeMethod.java:17）在 org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate（RunBeforeTestMethodCallbacks.java:75）在 org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate（RunAfterTestMethodCallbacks.java:86）在 org.springframework.test.context.junit4.statements.SpringRepeat.evaluate（SpringRepeat.java:84）在org.junit.runners.ParentRunner.runLeaf（ParentRunner.java:325）at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild（SpringJUnit4ClassRunner.java:252）在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild（SpringJUnit4ClassRunner.java:94）在org.junit.runners.ParentRunner $ 3.run（ParentRunner.java:290）at at org.junit.runners.ParentRunner $ 1.schedule（ParentRunner.java:71）at at org.junit.runners.ParentRunner.runChildren（ParentRunner.java:288）at at org.junit.runners.ParentRunner.access $ 000（ParentRunner.java:58）at at org.junit.runners.ParentRunner $ 2.evaluate（ParentRunner.java:268）at at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate（RunBeforeTestClassCallbacks.java:61）在 org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate（RunAfterTestClassCallbacks.java:70）在org.junit.runners.ParentRunner.run（ParentRunner.java:363）at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run（SpringJUnit4ClassRunner.java:191）在org.junit.runner.JUnitCore.run（JUnitCore.java:137）at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs（JUnit4IdeaTestRunner.java:68）在 com.intellij.rt.execution.junit.IdeaTestRunner $ Repeater.startRunnerWithArgs（IdeaTestRunner.java:47）在 com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart（JUnitStarter.java:242）在 com.intellij.rt.execution.junit.JUnitStarter.main（JUnitStarter.java:70）

这是我的JUnit代码：

@WebAppConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {RootConfig.class})
public class TbUserServiceTest
{
    @Autowired
    private static TbUserService tbUserService;

    @Test
    public void selectByPrimaryKeyTest()
    {
        String userId = "wusuodai";
        TbUser tbUser = tbUserService.selectByPrimaryKey(userId);
        System.out.println(tbUser.getUserName());
    }
}

如何解决此错误？

Answer 1

静态字段无法通过字段注入自动装配。考虑使用setter注入。

Signature

当我使用JUnit时，会出现此错误。如何解决此错误？

1 个答案: