首页 > 数据库 >【问题】Unknown return value type: java.lang.Integer springboot插入数据 报错 数据也成功插入数据库

【问题】Unknown return value type: java.lang.Integer springboot插入数据 报错 数据也成功插入数据库

时间:2022-12-02 17:31:24浏览次数:43  
标签:lang core java jar 34 插入 报错 org 8.5


很诡异的事情发生了。。。。。。。

在使用springboot搭建一个springboot整合mybatis的demo时,测试插入数据的方法,数据成功插入数据库了,但是控制台却报了这个错,提示为止返回类型。

控制台打印的错误:

java.lang.IllegalArgumentException: Unknown return value type: java.lang.Integer
at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:80) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:119) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) ~[druid-1.1.9.jar:1.1.9]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]

postman返回的数据:

{
"timestamp": "2019-01-28T03:00:03.804+0000",
"status": 500,
"error": "Internal Server Error",
"message": "Unknown return value type: java.lang.Integer",
"path": "/user/insert"
}

解决办法:

在controller的方法上面添加​​@ResponseBody​​注解即可。

百度了一下之后发现好多人遇到了这个错误,但是为什么会出现这种错误的原因并没有人指出来,大家都是看到解决办法之后,直接加上此注解就可以解决这个bug了。

对于出现这种原因再查了一些博客之后,做一个简单的总结:
这里是结合springmvc为例来进行说明:

对于springMVC处理方法支持支持一系列的返回方式:

  1. ModelAndView
  2. Model
  3. ModelMap
  4. Map
  5. View
  6. String
  7. Void

一、ModelAndView:一个包含模型和视图的ModelAndView 对象。

@RequestMapping(method=RequestMethod.GET)
public ModelAndView index(){
ModelAndView modelAndView = new ModelAndView("/user/index");
modelAndView.addObject("xxx", "xxx");
return modelAndView;
}

对于ModelAndView构造函数可以指定返回页面的名称,也可以通过setViewName方法来设置所需要跳转的页面;

@RequestMapping(method=RequestMethod.GET)
public ModelAndView index(){
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("xxx", "xxx");
modelAndView.setViewName("/user/index");
return modelAndView;
}

返回的是一个包含模型和视图的ModelAndView对象;

二、Model:一个模型对象,主要包含spring封装好的model和modelMap,以及java.util.Map,当没有视图返回的时候视图名称将由requestToViewNameTranslator决定;

三、ModelMap

待续

四、Map

@RequestMapping("/demo2/show") 
public Map<String, String> getMap() {
Map<String, String> map = new HashMap<String, String>();
map.put("key1", "value-1");
map.put("key2", "value-2");
return map;
}

响应的view应该也是该请求的view。等同于void返回。

在jsp页面中可直通过${key1}获得到值, map.put()相当于request.setAttribute方法。

五、View

这个时候如果在渲染页面的过程中模型的话,就会给处理器方法定义一个模型参数,然后在方法体里面往模型中添加值。

可以返回pdf excel等,暂时没详细了解。

六、String

对于String的返回类型,笔者是配合Model来使用的。

@RequestMapping(method = RequestMethod.GET)
public String index(Model model) {
String retVal = "user/index";
List<User> users = userService.getUsers();
model.addAttribute("users", users);

return retVal;
}

指定返回的视图页面名称,结合设置的返回地址路径加上页面名称后缀即可访问到。
  注意:如果方法声明了注解@ResponseBody ,则会直接将返回值输出到页面。

@RequestMapping(value="/showdog")
public String hello1(){
return "hello";
}
@RequestMapping(value="/print")
@ResponseBody
public String print(){
String message = "Hello World, Spring MVC!";
return message;
}

或者通过配合@ResponseBody来将内容或者对象作为HTTP响应正文返回(适合做即时校验)

@RequestMapping(value = "/valid", method = RequestMethod.GET)  
public @ResponseBody
String valid(@RequestParam(value = "userId", required = false) Integer userId,
@RequestParam(value = "logName") String strLogName) {
return String.valueOf(!userService.isLogNameExist(strLogName, userId));

}

关于String.valueOf()方法的使用请见:​​javascript:void(0)​​

返回字符串表示一个视图名称,这个时候如果需要在渲染视图的过程中需要模型的话,就可以给处理器添加一个模型参数,然后在方法体往模型添加值就可以了。

如果返回的是对象则会产生一个默认的视图,然后将返回的对象直接解析成JSON,默认视图+JSON生成正文返回。

七、void

当返回类型为void的时候,则

@Controller
@RequestMapping(value="/type")
public class TypeController extends AbstractBaseController{
@RequestMapping(method=RequestMethod.GET)
public void index(){
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("xxx", "xxx");
}
}

返回的结果页面还是:/type

这个时候我们一般是将返回结果写在了HttpServletResponse 中了,如果没写的话,spring就会利用RequestToViewNameTranslator 来返回一个对应的视图名称。如果这个时候需要模型的话,处理方法和返回字符串的情况是相同的。

 

标签:lang,core,java,jar,34,插入,报错,org,8.5
From: https://blog.51cto.com/linmengmeng/5907354

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