javax.el.PropertyNotFoundException:在 java.lang.String 类型上找不到

Question

我已经包含了所有必要的，但没有为什么有错误原因请帮助我

我的模型是：

Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String username;
private String mobileno;
private String password;
private String passwordConfirm;

并且所有吸气器设置器都包括在内

我的控制器：

@Controller
public class AdminController {
@Autowired
private UserValidator userValidator;
@Autowired
private UserService userService;
@Autowired
private SecurityService securityService;
@RequestMapping(value = "/list-user", method = RequestMethod.GET)
public ModelAndView DisplayUser(ModelAndView mv) {
mv.addObject("userlist",userService.getallUsers());
mv.setViewName("list-user");
return mv;
}
}

我的 JSP 页面

<div class="row">
<!-- main contain here -->
<h1>List of Users</h1>
<table>
<thead>
<tr>
<th>Name</th>
<th>Phone no</th>
<th>Password</th>               
</tr>
</thead>
<c:forEach items="${userlist} " var="user">
<tbody>                        
<td><c:out value=${user.username }></c:out></td>
<td>${user.mobileno }</td>
<td>${user.password }</td>
</tbody>
</c:forEach>             

</table>


<!-- Content Row -->

<!-- /.container-fluid -->
</div>

我得到的错误是

ERROR 13620 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [An exception occurred processing JSP page /list-user.jsp at line 58
null

堆栈跟踪：] 与根本原因

javax.el.PropertyNotFoundException: Property 'username' not found on type java.lang.String
at javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:268) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at javax.el.BeanELResolver$BeanProperties.access$300(BeanELResolver.java:221) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at javax.el.BeanELResolver.property(BeanELResolver.java:355) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at javax.el.BeanELResolver.getValue(BeanELResolver.java:95) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at org.apache.jasper.el.JasperELResolver.getValue(JasperELResolver.java:110) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at org.apache.el.parser.AstValue.getValue(AstValue.java:169) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184) ~[tomcat-embed-el-8.0.33.jar:8.0.33]
at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:943) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at org.apache.jsp.list_002duser_jsp._jspx_meth_c_005fforEach_005f0(list_002duser_jsp.java:478) ~[na:na]
at org.apache.jsp.list_002duser_jsp._jspService(list_002duser_jsp.java:355) ~[na:na]
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) ~[tomcat-embed-jasper-8.0.33.jar:8.0.33]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:69) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:169) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:205) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:68) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:184) ~[spring-security-web-4.0.4.RELEASE.jar:4.0.4.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) ~[spring-web-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application

Answer 1

您能否检查以下方法是否返回任何值。

userService.getallUsers((

然后，尝试使用addAttribute()而不是addObject()

mv.addAttribute("userlist",userService.getallUsers());

如果仍然有任何问题，请尝试使用以下代码替换控制器方法。

public String DisplayUser(ModelMap map) {
map.addObject("userlist",userService.getallUsers());
return "list-user";
}

如果仍然有任何问题，请参阅此链接