java - 如何使用 Spring MVC 框架为 Spring Boot 应用程序加载 jsp 页面？我得到空指针异常

Question

当我的代码尝试查找和加载 jsp 页面时，我总是遇到空指针异常。这是一个 Spring Boot 应用程序，我正在尝试使用最新的 Spring MVC 框架。请注意，我将应用程序部署在 jar 中，而不是作为 war 文件。因此，我的项目中没有 WEB-APP 文件夹或 web.xml 等。
我在 src/main/resources 下有文件夹“templates”，其中放置了 ViewName.jsp 页面。
以下是我的 Controller java 文件中的代码片段，供您引用:

    @RequestMapping(value = "/x")
public String launch(@RequestParam("inputFile") String inputFile, @RequestParam("instance") int instance) {

    try {
        launcher.launch(inputFile, instance);
        LOGGER.info("launch completed, trying to set and load the view now");

    } catch (Exception ex) {
        LOGGER.error("Failed to launch job successfully.", ex);
    }

    ModelAndView mav = new ModelAndView();

    Map<String, String> parameters = new HashMap<>();

    parameters.put("inputFile", inputFile);
    parameters.put("instance", Integer.toString(instance));
    mav.addObject("parameters", parameters);

    LOGGER.info("Before setting mav.setViewname");

    mav.setViewName("ViewName");

    LOGGER.info("After setting mav.setViewname, that means setViewName is good"); //this gets printed in the log

    return "ViewName.jsp";


}

下面是抛出的空指针异常:

ERROR: org.springframework.boot.web.support.ErrorPageFilter - Forwarding to error page from request [/x] due to exception [null] java.lang.NullPointerException: null at weblogic.servlet.internal.ServletResponseImpl.sendContentError(ServletResponseImpl.java:713) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.ServletResponseImpl.sendError(ServletResponseImpl.java:761) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.ServletResponseImpl.sendError(ServletResponseImpl.java:693) ~[weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.boot.web.support.ErrorPageFilter$ErrorWrapperResponse.flushBuffer(ErrorPageFilter.java:315) ~[spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:321) ~[weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) ~[weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:844) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:346) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:25) ~[weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) ~[weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:115) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.boot.web.support.ErrorPageFilter.access$000(ErrorPageFilter.java:59) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.boot.web.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:90) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.boot.web.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:108) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:106) [spring-boot-actuator-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:110) [spring-boot-actuator-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55) [spring-boot-1.5.9.RELEASE.jar:1.5.9.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE] at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3451) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3417) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120) [com.oracle.css.weblogic.security.wls_7.1.0.0.jar:CSS 7.1 0.0] at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:57) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2280) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2196) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2174) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1632) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:256) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.work.ExecuteThread.execute(ExecuteThread.java:311) [weblogic.server.merged.jar:12.1.3.0.0] at weblogic.work.ExecuteThread.run(ExecuteThread.java:263) [weblogic.server.merged.jar:12.1.3.0.0]

Answer 1

默认情况下，Spring Boot不支持类路径中的任何jsp文件。有两种解决方案，1.您可以将Thymeleaf模板放入类路径中。 Spring boot 会自动配置它。2. 如果要加载JSP模板，则应将jsp文件放在src/main/webapp下。 InternalResourceViewResolver 将对其进行配置。