我一直在看一些关于Spring Framework入门的教程,并且遇到了this one.在完成后,我遇到了以下错误. (我已经更新为使用spring框架的第3版,我仍然遇到同样的错误.
简而言之,我得到一个NullPointerException,我在AutoWired类上调用一个方法.
我的班级是SayHello：
public class SayHello {
private String name;
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void greet() {
System.out.println("Hello " + getName());
}
}
然后,我在/src/test/resources/applicationContext.xml中设置以下内容.
最后我有AppTest类,我尝试自动测试SayHello对象进行测试.
public class AppTest {
@Autowired
private SayHello hello;
@Test
public void testApp()
{
hello.greet();
Assert.assertTrue( true );
}
}
当我尝试运行AppTest时,我收到以下错误：
java.lang.NullPointerException
at package.AppTest.testApp(AppTest.java:19)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
我已经看过有关stackoverflow的各种文章和问题但是在尝试了几个并没有到达任何地方后,我想我会创建一个新帖子.
干杯.
如果它有帮助,那就是我正在使用的依赖项(Spring v3.2.1)：
更新
我也尝试在主应用程序中使用@Autowired注释,如下所示.并且仍然会收到NullPointerException错误.
public class App
{
@Autowired
private static SayHello hello;
public static void main( String[] args )
{
hello.greet();
}
}
您需要在AppTest上添加一些注释：
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:/applicationContext.xml")
这些注释是在spring-test中定义的,所以也要添加这个依赖：
