Question

我有以下测试：

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest

@TestPropertySource(value = "classpath:testApplication.properties")
public class ESJavaAPITests {

    @Resource
    private Environment environment;

    private final String    CLUSTER_NAME    = environment.getProperty("ES.cluster.name");
}

这些属性位于test/java/resources/testApplication.properties，看起来就像这样：

ES.host = localhost
ES.port = 9300
ES.cluster.name = 2m3d

但是我一直得到NullPointerException第25行，这正是CLUSTER_NAME初始化的行：

java.lang.NullPointerException at com.example.estrans.ESJavaAPITests。（ESJavaAPITests.java:25）at sun.reflect.NativeConstructorAccessorImpl.newInstance0（本机方法）在 sun.reflect.NativeConstructorAccessorImpl.newInstance（NativeConstructorAccessorImpl.java:62）在 sun.reflect.DelegatingConstructorAccessorImpl.newInstance（DelegatingConstructorAccessorImpl.java:45） at java.lang.reflect.Constructor.newInstance（Constructor.java:423）在 org.junit.runners.BlockJUnit4ClassRunner.createTest（BlockJUnit4ClassRunner.java:217）在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest（SpringJUnit4ClassRunner.java:227）at org.springframework.test.context.junit4.SpringJUnit4ClassRunner $ 1.runReflectiveCall（SpringJUnit4ClassRunner.java:287）在 org.junit.internal.runners.model.ReflectiveCallable.run（ReflectiveCallable.java:12）在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock（SpringJUnit4ClassRunner.java:289）在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild（SpringJUnit4ClassRunner.java:247）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:117）在 com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart（JUnitStarter.java:234）在 com.intellij.rt.execution.junit.JUnitStarter.main（JUnitStarter.java:74） 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 com.intellij.rt.execution.application.AppMain.main（AppMain.java:144）

为什么选择NPE？

Answer 1

您获得了NPE，因为目前您的CLUSTER_NAME字段已初始化，因此环境为null，因为Spring还没有时间自动加入课程 - CLUSTER_NAME是在创建测试类实例时初始化。您应该使用@Value("${ES.cluster.name}")代替：

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
@TestPropertySource(value = "classpath:testApplication.properties")
public class ESJavaAPITests {

    @Value("${ES.cluster.name}")
    private String CLUSTER_NAME;
}

使用@TestPropertySource属性中的属性会导致NullPointerException

1 个答案: