我最近知道了@Resource注解和@Autowired注解之间的区别,但在spring-framework发明之前,我不知道@Resource注解将用于什么场景。
我已经在google和stackoverflow上搜索过任何提示,但没有得到任何合理的解释。然后,我尝试创建一个Java Web项目(使用J2EE1.4、jdk1.7、tomcat7),并使用@Resource注释创建一个servlet来模拟Spring的自动布线行为,但是我们遇到了一个错误。
下面是我使用的代码:
public class TestServlet extends HttpServlet {
public void init() throws ServletException {
Student student=new Student("1");
}
public void service(ServletRequest arg0, ServletResponse arg1)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("111111111111");
}
}public class TestServlet2 extends HttpServlet {
@Resource
Student student;
public void service(ServletRequest arg0, ServletResponse arg1)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println(student);
}
}首先,我访问TestServlet以创建学生java bean,然后访问TestServlet2以将学生对象注入到学生属性中。但我遇到如下错误:
javax.naming.NamingException: Cannot create resource instance
at org.apache.naming.factory.ResourceEnvFactory.getObjectInstance(ResourceEnvFactory.java:115)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:321)
at org.apache.naming.NamingContext.lookup(NamingContext.java:848)
at org.apache.naming.NamingContext.lookup(NamingContext.java:159)
at org.apache.naming.NamingContext.lookup(NamingContext.java:836)
at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
at org.apache.catalina.core.DefaultInstanceManager.lookupFieldResource(DefaultInstanceManager.java:538)
at org.apache.catalina.core.DefaultInstanceManager.processAnnotations(DefaultInstanceManager.java:440)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:133)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:114)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1133)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:853)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2549)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2538)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)发布于 2019-05-25 16:22:56
我的解决方案是:我在WebRoot/ perfectly.This -INF中创建了一个文件Context.xml
<?xml version="1.0" encoding="UTF-8"?>
<Context>
<Resource name="student" auth="Container"
type="com.test.Student" factory="org.apache.naming.factory.BeanFactory" id="5">
</Resource>
</Context>public class TestServlet2 extends HttpServlet {
@Resource(name="student")
Student student;
public void service(ServletRequest arg0, ServletResponse arg1)
throws ServletException, IOException {
System.out.println(student.getId());
}
}https://stackoverflow.com/questions/56302487
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