Spring的<context:property-placeholder.../>在junit中不起作用，失效，解决方法
大家都知道，我们使用spring框架的时候喜欢把可以配置的变量放入一个properties配置文件中，然后在spring的applicationContext.xml配置文件中加入配置：
<context:property-placeholder location="classpath:*.properties" ignore-unresolvable="true"/>
最后就可以在applicationContext.xml中愉快的使用${attributeName}来获取properties中的值了，屡试不爽。获取方式如下：
这种配置在正常启动项目的时候工作的很好，并且很简洁，我肥肠的稀饭，然而，我今天做练习junit测试的时候，居然报错！如下：
java.lang.IllegalStateException: Failed to load ApplicationContext at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:183) at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:123) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [context-mybatis.xml]: Invocation of init method failed; nested exception is java.sql.SQLException: ${driverClassName} at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1583) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:778) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:843) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) at org.springframework.test.context.web.AbstractGenericWebContextLoader.loadContext(AbstractGenericWebContextLoader.java:133) at org.springframework.test.context.web.AbstractGenericWebContextLoader.loadContext(AbstractGenericWebContextLoader.java:60) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) ... 29 more Caused by: java.sql.SQLException: ${driverClassName} at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:570) at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:697) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeCustomInitMethod(AbstractAutowireCapableBeanFactory.java:1713) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1650) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1579) ... 44 more Caused by: java.lang.ClassNotFoundException: ${driverClassName} at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:264) at com.alibaba.druid.util.JdbcUtils.createDriver(JdbcUtils.java:568) ... 52 more
诸如此类吧，反正就是找不到我properties中配置的变量。
我的配置文件：
driverClassName=com.mysql.jdbc.Driver jdbc_url=jdbc:mysql://localhost:3306/***-demo?useUnicode=true&characterEncoding=UTF-8 jdbc_username=root jdbc_password=root
经过各种挣扎，各种调换位置，铩羽而归！but 楼主不抛弃，不放弃，最后还是完美的解决了问题。方案如下：
- 直接写死（废话），这种方式肯定可以解决，但是这不符合我广大程序猿的传统美德。
- 采用如下配置替换<context:property-placeholder...
<bean id="propertyPlaceHolderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations"> <list> <value>classpath:dbconfig.properties</value> <value>classpath:system-config.properties</value> </list> </property> </bean>
最后重新启动junit测试，诱人的小绿条蠢蠢欲动。至此问题解决，特此记下，下面送上junit的测试代码样子：
/** * 测试使用SqlSessionTemplate * Created by ascend on 2017/6/7 14:27. */ @RunWith(SpringJUnit4ClassRunner.class) @WebAppConfiguration //配置了@ContextConfiguration注解并使用该注解的locations属性指明spring和配置文件 @ContextConfiguration(locations = {"classpath:context-mybatis.xml", "classpath:context-spring.xml", "classpath:context-springmvc.xml"}) //也可以用“classpath:context-*.xml”取代 public class SqlSessionTest { @Autowired private SqlSession sqlSession; @Test public void testSqlSession(){ System.out.println("sqlSession = " + sqlSession); TestStudentPO studentPO = sqlSession.selectOne("com.***.manage.gen.dao.mapper.TestStudentPOMapper.selectByPrimaryKey", 1L); System.out.println("studentPO = " + studentPO); } }
结果：
studentPO = TestStudentPO [Hash = 1934908288, id=1, name=张三, age=24]
作者原创，转载请注明：http://www.cnblogs.com/adeng/p/6957463.html
