使用@TestPropertySource属性中的属性将导致NullPointerException

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");
}

属性位于测试/Java/resources/testapplication.properties中，看起来如下：

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

但是，我一直得到NullPointerException第25行，这正是具有cluster_name初始化的行：

Java.lang.NullPointerException位于com.example.estrans.esjavaapitests.(esjavaapitests.Java:25)位于sun.reflect.nativeConstructorAccessorImpl.newInstance0（原生方法）位于sun.reflect.nativeConstructorAccessorImpl.newInstance（原生方法）位于sun.reflect.nativeConstructorAccessorImpl.newInstance（原生方法）位于sun.reflect.nativeConstructorAccessorImpl.newInstance（RingJunit4ClassRunner.RunChild(SpringJunit4ClassRunner.:247）在org.springFramework.test.context.junit4.SpringJunit4ClassRunner.Runchild(SpringJunit4ClassRunner.Runner.:94）在org.junit.runners.ParentRunner$3。Run（ParentRunner.Java:290)在org.junit.runners.ParentRunner$1。Schedule（ParentRunner.Java:71)在nit4.junit4ideatestrunner.startrunnerWithargs(junit4ideatestrunner.:117）在com.intellij.rt.execution.junit.junitstarter.preparestreamsandstart(junitstarter.Java:234)在com.intellij.rt.execution.junit.junit.junit.main(junitstarter.Java:74)在com.intellij.rt.execution.junit.junit.main(junitstarter.Java:74)在

为什么是NPE？

Answer 1

您得到一个NPE，因为在cluster_name字段初始化时，环境为null，因为spring还没有时间自动连接类-cluster_name是在创建测试类实例时初始化的。您应该改用@value（“${es.cluster.name}”）:

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

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