不使用@Autowired注入JobLauncherTestUtils进行Spring Batch单元测试遇空指针

你的核心问题是直接Mockito模拟了JobLauncherTestUtils，而Mockito默认会让所有mock对象的方法返回null，所以launchJob()调用自然返回null，触发空指针异常。而且当前测试逻辑没有关联到MyjobConfiguration的实际代码，完全偏离了测试目标。

下面分两种场景给出修正方案：

场景1：测试myJob Bean的构建逻辑 #

如果你的目标是验证MyjobConfiguration中myJob方法是否正确构建了Job（比如设置正确的作业名、步骤、监听器等），不需要用到JobLauncherTestUtils，直接mock依赖并调用方法验证即可：

class MyjobConfigurationTest {

    // 实例化配置类，不要mock它（我们要测它的方法逻辑）
    private final MyjobConfiguration myjobConfiguration = new MyjobConfiguration();

    // mock配置类的依赖
    private final Step convertStep = Mockito.mock(Step.class);
    private final Step writeStep = Mockito.mock(Step.class);
    private final JobBuilderFactory jobBuilderFactory = Mockito.mock(JobBuilderFactory.class);
    private final JobListener jobListener = Mockito.mock(JobListener.class);

    @Test
    void myJob_ShouldBuildWithCorrectConfig() {
        // 模拟JobBuilderFactory的链式调用行为
        JobBuilder jobBuilder = Mockito.mock(JobBuilder.class);
        SimpleJobBuilder simpleJobBuilder = Mockito.mock(SimpleJobBuilder.class);
        Job mockJob = Mockito.mock(Job.class);
        JobInstance mockJobInstance = Mockito.mock(JobInstance.class);

        // 预设mock的返回值
        Mockito.when(jobBuilderFactory.get("myJob")).thenReturn(jobBuilder);
        Mockito.when(jobBuilder.incrementer(Mockito.any(RunIdIncrementer.class))).thenReturn(jobBuilder);
        Mockito.when(jobBuilder.start(convertStep)).thenReturn(simpleJobBuilder);
        Mockito.when(simpleJobBuilder.next(writeStep)).thenReturn(simpleJobBuilder);
        Mockito.when(simpleJobBuilder.listener(jobListener)).thenReturn(simpleJobBuilder);
        Mockito.when(simpleJobBuilder.build()).thenReturn(mockJob);
        Mockito.when(mockJob.getJobInstance()).thenReturn(mockJobInstance);
        Mockito.when(mockJobInstance.getJobName()).thenReturn("myJob");

        // 测试带监听器的情况
        Job jobWithListener = myjobConfiguration.myJob(convertStep, writeStep, Optional.of(jobListener), jobBuilderFactory);
        org.assertj.core.api.Assertions.assertThat(jobWithListener.getJobInstance().getJobName()).isEqualTo("myJob");

        // 测试不带监听器的情况
        Job jobWithoutListener = myjobConfiguration.myJob(convertStep, writeStep, Optional.empty(), jobBuilderFactory);
        org.assertj.core.api.Assertions.assertThat(jobWithoutListener.getJobInstance().getJobName()).isEqualTo("myJob");
    }
}

场景2：模拟作业执行流程 #

如果需要测试作业执行的结果验证逻辑，不能mockJobLauncherTestUtils，而是要手动配置它，给它传入mock的Job和JobLauncher来模拟执行结果：

class MyjobConfigurationTest {

    private final MyjobConfiguration myjobConfiguration = new MyjobConfiguration();

    private final Step convertStep = Mockito.mock(Step.class);
    private final Step writeStep = Mockito.mock(Step.class);
    private final JobBuilderFactory jobBuilderFactory = Mockito.mock(JobBuilderFactory.class);
    private final JobLauncher jobLauncher = Mockito.mock(JobLauncher.class);
    private final JobLauncherTestUtils jobLauncherTestUtils = new JobLauncherTestUtils();

    @org.junit.jupiter.api.BeforeEach
    void setUp() throws Exception {
        // 构建mock的Job对象
        Job mockJob = Mockito.mock(Job.class);
        JobExecution mockJobExecution = Mockito.mock(JobExecution.class);
        JobInstance mockJobInstance = Mockito.mock(JobInstance.class);
        ExitStatus successExitStatus = new ExitStatus("COMPLETED");

        // 预设Job构建逻辑的返回值
        Mockito.when(jobBuilderFactory.get("myJob")).thenReturn(Mockito.mock(JobBuilder.class));
        Mockito.when(myjobConfiguration.myJob(convertStep, writeStep, Optional.empty(), jobBuilderFactory)).thenReturn(mockJob);

        // 模拟JobLauncher执行成功的场景
        Mockito.when(jobLauncher.run(Mockito.eq(mockJob), Mockito.any(JobParameters.class))).thenReturn(mockJobExecution);
        Mockito.when(mockJobExecution.getJobInstance()).thenReturn(mockJobInstance);
        Mockito.when(mockJobInstance.getJobName()).thenReturn("myJob");
        Mockito.when(mockJobExecution.getExitStatus()).thenReturn(successExitStatus);

        // 配置JobLauncherTestUtils
        jobLauncherTestUtils.setJob(mockJob);
        jobLauncherTestUtils.setJobLauncher(jobLauncher);
    }

    @org.junit.jupiter.api.Test
    void whenJobExecuted_thenSuccess() throws Exception {
        JobExecution jobExecution = jobLauncherTestUtils.launchJob(
                new JobParametersBuilder().addString("timestamp", java.time.LocalDateTime.now().toString())
                        .toJobParameters());

        org.assertj.core.api.Assertions.assertThat(jobExecution.getJobInstance().getJobName()).isEqualTo("myJob");
        org.assertj.core.api.Assertions.assertThat(jobExecution.getExitStatus().getExitCode()).isEqualTo("COMPLETED");
    }
}

关键注意点 #

1. 不要mock测试工具类：JobLauncherTestUtils是用来辅助测试的工具，需要给它提供真实或mock的依赖（Job、JobLauncher）才能正常工作，直接mock它没有意义。
2. 区分测试目标：如果是测Bean构建，就直接调用配置类的方法验证；如果是测执行逻辑，就模拟JobLauncher的返回结果，配置到测试工具中。

内容的提问来源于stack exchange，提问作者Nick