为什么我可以自动装配或注入pojo但我无法自动装配或注入RestTemplate
我在这个论坛上阅读了很多关于在尝试自动加入pojo时发生的类似问题，通常修复的答案与component-scan或@Component / @Controller有关。但在我的情况下，我设法自动装配我的pojo（Mas60010）但我不能自动装配RestTemplate或ObjectMapper以及可能来自我没有编码的包中的任何其他对象。
为简单起见，我只提到RestTemplate。我做错了什么？我想问题是库或配置问题。注意：请不要仅仅通过显示与他自己的pojo相关的问题来指出此问题是重复的。您可以看到这不是我的问题，因为我能够管理它。问题出在我的项目中包含的jar中的类。
package com.ma.mhe.log.handler;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.client.RestTemplate;
@Component
public class Lo_DisplayHandler extends Lo_Handler {
@Autowired private Mas60010 _mas60010; //this work perfectly
@Autowired private RestTemplate restTemplate; //this always cause nullPointException
MVC-调度-servlet.xml中
<context:annotation-config />
<mvc:annotation-driven />
<context:component-scan base-package="com.ma.mhe.log.handle, com.ma.mhe.log.domain" />
<context:property-placeholder location="classpath:restServices.properties"/>
<mvc:resources mapping="/**" location="/" />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="jsonMessageConverter"/>
</list>
</property>
</bean>
<bean id="jsonMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
</bean>
<!-- I was expecting this line to be enouth -->
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
</bean>
// Pojo - 我可以自动装载它
package com.ma.log.domain;
import org.springframework.stereotype.Service;
@Service
public class Mas60010 {
所有图书馆
- ＆＃34;验证-API-1.0.0.GA.jar＆＃34;
- ＆＃34; aopalliance-1.0.jar＆＃34;
- ＆＃34;共享记录-1.1.1.jar＆＃34;
- ＆＃34; db2java.zip＆＃34;
- ＆＃34;冬眠-验证-4.1.0.Final.jar＆＃34;
- ＆＃34;冬眠验证器的注释处理器的4.1.0.Final.jar＆＃34;
- ＆＃34;杰克逊 - 注解-2.2.3.jar＆＃34;
- ＆＃34;杰克逊 - 芯 - 2.2.3.jar＆＃34;
- ＆＃34;杰克逊 - 数据绑定-2.2.3.jar＆＃34;
- ＆＃34; SLF4J-API-1.7.5.jar＆＃34;
- ＆＃34;弹簧AOP-4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧豆-4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧上下文4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧上下文支持-4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧芯4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧表达-4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧网络4.1.2.RELEASE.jar＆＃34;
- ＆＃34;弹簧webmvc-4.1.2.RELEASE.jar＆＃34;
- ＆＃34; upload.jar＆＃34;
//堆栈跟踪
[12/17/14 10:38:54:243 CST] 00000033 SystemErr R at com.ma.mhe.log.handler.Lo_DisplayHandler.lastPage(Lo_DisplayHandler.java:181)
[12/17/14 10:38:54:246 CST] 00000033 SystemErr R at com.ma.mhe.log.Lo_Servlet.doDisDis(Lo_Servlet.java:164)
[12/17/14 10:38:54:248 CST] 00000033 SystemErr R at com.ma.mhe.log.Lo_Servlet.doProcess(Lo_Servlet.java:51)
[12/17/14 10:38:54:250 CST] 00000033 SystemErr R at com.ma.mhe.log.Lo_Servlet.doPost(Lo_Servlet.java:24)
[12/17/14 10:38:54:253 CST] 00000033 SystemErr R at javax.servlet.http.HttpServlet.service(HttpServlet.java:595)
[12/17/14 10:38:54:255 CST] 00000033 SystemErr R at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
[12/17/14 10:38:54:257 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1274)
[12/17/14 10:38:54:260 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:767)
[12/17/14 10:38:54:261 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:469)
[12/17/14 10:38:54:262 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1060)
[12/17/14 10:38:54:263 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.dispatch(WebAppRequestDispatcher.java:1377)
[12/17/14 10:38:54:265 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:185)
[12/17/14 10:38:54:266 CST] 00000033 SystemErr R at com.ma.mhe.Mhe_ControllerServlet.doProcess(Mhe_ControllerServlet.java:83)
[12/17/14 10:38:54:267 CST] 00000033 SystemErr R at com.ma.mhe.Mhe_ControllerServlet.doPost(Mhe_ControllerServlet.java:32)
[12/17/14 10:38:54:268 CST] 00000033 SystemErr R at javax.servlet.http.HttpServlet.service(HttpServlet.java:595)
[12/17/14 10:38:54:269 CST] 00000033 SystemErr R at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
[12/17/14 10:38:54:270 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1274)
[12/17/14 10:38:54:271 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:767)
[12/17/14 10:38:54:272 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:469)
[12/17/14 10:38:54:273 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1060)
[12/17/14 10:38:54:275 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:81)
[12/17/14 10:38:54:276 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:885)
[12/17/14 10:38:54:277 CST] 00000033 SystemErr R at com.ibm.ws.webcontainer.osgi.DynamicVirtualHost$2.run(DynamicVirtualHost.java:266)
[12/17/14 10:38:54:277 CST] 00000033 SystemErr R at com.ibm.ws.http.dispatcher.internal.channel.HttpDispatcherLink$TaskWrapper.run(HttpDispatcherLink.java:776)
[12/17/14 10:38:54:278 CST] 00000033 SystemErr R at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
[12/17/14 10:38:54:279 CST] 00000033 SystemErr R at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
[12/17/14 10:38:54:280 CST] 00000033 SystemErr R at java.lang.Thread.run(Thread.java:662)
IBM WebSphere Liberty Profile启用的功能
<featureManager>
<feature>jsp-2.2</feature>
<feature>localConnector-1.0</feature>
<feature>jdbc-4.0</feature>
<feature>jaxrs-1.1</feature>
<feature>json-1.0</feature>
<feature>cdi-1.0</feature>
<feature>managedBeans-1.0</feature>
<feature>beanValidation-1.0</feature>
</featureManager>
// class Lo_DisplayHandler
@Component
public class Lo_DisplayHandler extends Lo_Handler {
public Lo_DisplayHandler() {
super();
}
@Autowired
private Mas60010 _mas60010;
@Autowired private RestTemplate restTemplate;
public Lo_DisplayHandler(HttpServletRequest request,HttpServletResponse response) {
super();
this.request = request;
this.response = response;
}
public void lastPage() {
//RestTemplate restTemplate = new RestTemplate(); //if I uncomment this line and comment the @Autowired it will work
ObjectMapper mapper = new ObjectMapper();
try{
myPojoParameters...
//the next line rises nullPointExcepetion if I choose Autowired instead of new RestTemplate()
LogDisplay _l = restTemplate.postForObject(myServiceUrl,myPojoParameters, LogDisplay.class);
Lo_DisplayRecord lo_DisplayRecord = new Lo_DisplayRecord();
ArrayList<Lo_DisplayRecord> displayValues = new ArrayList<Lo_DisplayRecord>();
for(int i = 0; i < _l.getDisplayValues().size(); i++){
lo_DisplayRecord = mapper.convertValue(_l.getDisplayValues().get(i), Lo_DisplayRecord.class);
displayValues.add(lo_DisplayRecord);
}
Some not relevant operations...
}catch(Exception e){
e.printStackTrace();
// Lo_Servlet
package com.ma.mhe.log;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.ma.mhe.Mhe_Servlet;
import com.ma.mhe.PageFlow;
import com.ma.mhe.log.handler.*;
public class Lo_Servlet extends Mhe_Servlet {
private String _module = "lo public void init(){}
public void doPost(
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
throws javax.servlet.ServletException, java.io.IOException {
doProcess(request,response);
}
public void doGet(
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
throws javax.servlet.ServletException, java.io.IOException {
doProcess(request,response);
}
public void doProcess(
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
throws javax.servlet.ServletException, java.io.IOException {
HttpSession session = request.getSession();
int val = setTask(session,request);
switch(val){
//FILTER PAGE
case 1:doFilRep(request,response);break;
case 2:doFilFil(request,response);break;
case 3:doFilDis(request,response);break;
case 4:doFilDef(request,response);break;
//DISPLAY PAGE
case 5:doDisRep(request,response);break;
case 6:doDisFil(request,response);break;
case 7:doDisDis(request,response);break;
private void doDisDis(HttpServletRequest request,HttpServletResponse response){
Lo_DisplayHandler display = null;
try{
display = new Lo_DisplayHandler(request,response);
display.lastPage();
}catch(Exception e){
}finally{
display = null;
}
}
// web.xml中 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> MHE
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>myservice</servlet-name>
<servlet-class>org.springframework.ws.transport.http.MessageDispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
</init-param>
</servlet>
<servlet>
<description>
</description>
<display-name>Lo_Servlet</display-name>
<servlet-name>Lo_Servlet</servlet-name>
<servlet-class>com.ma.mhe.log.Lo_Servlet</servlet-class>
</servlet>
... others servlets configuration like this
1 个答案:
答案 0 :(得分：0)
private void doDisDis(HttpServletRequest request,HttpServletResponse response){
Lo_DisplayHandler display = null;
try {
display = new Lo_DisplayHandler(request,response);
display.lastPage();
}catch(Exception e){
}finally{
display = null;
}
}
上面的代码是创建Lo_DisplayHandler类的新实例。那些实例不是由Spring管理的，所以基本上@Autowired在这里是没用的。 Spring只会将依赖注入到它知道的bean中。
假设您使用ContextLoaderListener加载弹簧配置，可以使用WebApplicationContextUtils获取ApplicationContext。您可以使用它来获取所需的bean。
private void doDisDis(HttpServletRequest request,HttpServletResponse response){
Lo_DisplayHandler display = null;
try {
ApplicationContext context = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
display = context.getBean(Lo_DisplayHandler.class, request, response);
display.lastPage();
}catch(Exception e){
}finally{
display = null;
}
}
要完成这项工作，您必须使Lo_DisplayHandler成为原型bean，这意味着每次getBean调用完成后，都会创建一个新实例。为此，将@Scope注释添加到类中。
@Component
@Scope("prototype")
public class Lo_DisplayHandler extends Lo_Handler { ... }
最后一个注释，而不是每次需要查找ApplicationContext时，您可能希望在servlet的init方法中执行一次，并将其存储为实例变量。为您节省一行代码和一些性能。
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