关于junit对DAO类中数据库操作的测试

Question

头一次用JUNIT，有些不明白的地方，请各位大侠多多指教
我是通过JDBCTemplate来连接数据库的，通过JUNIT对UserDAOImpl中的getUserById()进行测试。该方法如下：
public UserInfo getUserById(String userId) {
String sql = "select * from userinfo where userid='" + userId + "'";
System.out.println(sql);
UserInfo userInfo = (UserInfo) jt.queryForObject(sql, new UserMapper());
return userInfo;
}
我编写的测试用例如下：
private UserInfo user;
private UserDAO userDAO;
@Test
public void testGetUserById() {
user = userDAO.getUserById("admin");
assertEquals("admin",user.getUserId());
}
数据库的配置是在applicationContext.xml中配置的，通过网页调取都很顺利，但测试用例报告java.lang.NullPointerException
at css.user.dao.UserDAOImplTest.testGetUserById(UserDAOImplTest.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
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)

  求指点迷津，谢谢！ 

Answer 1

由于你的bean定义在两个配置文件中，在测试的时候需要把这些配置文件都加载:

[code="java"]private UserInfo user;

private UserDAO userDAO;

@Before  
public void initialize() {
   String[] configList = {"applicationContext.xml", "userContext.xml"},
   ApplicationContext ctx = new ClassPathXmlApplicationContext(  
            configList);  
   UserDAOImpl = (UserDAOImpl) ctx  
            .getBean("userDAO");  

}

@Test

public void testGetUserById() {

user = userDAO.getUserById("admin");

assertEquals("admin",user.getUserId());

} [/code]