Spring工程，在Controller的方法上加@ResponseBody注解，报异常
刚学SpringMVC，学习到Spring的数据响应，在测试@ResponseBody注解的时候，报错，出错的部分用粗体标注出来了，很简单的代码
@Controller
@RequestMapping(value = "/user")
public class UserController {
@RequestMapping(value = "/quick1",method = RequestMethod.GET)
public String save1() {
/*
使用内部资源视图解析器拼接字符串后返回，实际返回的是/jsp/success.jsp页面
*/
return "success";
}
@RequestMapping(value = "/quick2")
public ModelAndView save2() {
WebApplicationContext app = ContextLoader.getCurrentWebApplicationContext();
UserService userService = app.getBean(UserService.class);
userService.save();
/*
Mode:模型 用来封装数据
View:视图 用来展示数据
*/
ModelAndView modelAndView = new ModelAndView();
//设置模型数据 这句话相当于把下面的数据放到reuqest域中
modelAndView.addObject("username","huangxin");
//设置视图名称
modelAndView.setViewName("success");
return modelAndView;
}
@RequestMapping(value = "/quick3")
public ModelAndView save3(ModelAndView modelAndView) {
//设置模型数据 这句话相当于把下面的数据放到reuqest域中
modelAndView.addObject("username","itdehong");
//设置视图名称
modelAndView.setViewName("success");
return modelAndView;
}
@RequestMapping(value = "/quick4")
public String save4(Model model) {
model.addAttribute("username","德宏师范高等专科学校");
return "success";
}
@RequestMapping(value = "/quick5")
public String save5(HttpServletRequest request) {
request.setAttribute("username","苦丁虞");
return "success";
}
@RequestMapping(value = "/quick6")
public void save6(HttpServletResponse response) throws IOException {
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write("SpringMVC的数据响应之回写数据");
}
@RequestMapping(value = "/quick7")
@ResponseBody //使用后出现异常
public String save7() throws IOException {
return "hello world!";
}
@RequestMapping(value = "/quick8")
@ResponseBody //使用后出现异常
public String save8() throws IOException {
return "{\"username\":\"zhangsan\",\"age\":18}";
}
}
porm.xml文件为：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.dhsz</groupId>
<artifactId>spring_demo3</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>spring_demo3 Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.22</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.2.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>5.3.7</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.16.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.3.7</version>
</dependency>
</dependencies>
<build>
<finalName>spring_demo3</finalName>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<port>80</port>
<path>/</path>
</configuration>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
</plugins>
</build>
</project>
报的异常为：
详细信息如下：
HTTP Status 500 - Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: javax.servlet.http.HttpServletResponse.setContentLengthLong(J)V
type Exception report
message Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: javax.servlet.http.HttpServletResponse.setContentLengthLong(J)V
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: javax.servlet.http.HttpServletResponse.setContentLengthLong(J)V
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1055)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
root cause
java.lang.NoSuchMethodError: javax.servlet.http.HttpServletResponse.setContentLengthLong(J)V
org.springframework.http.server.ServletServerHttpResponse.writeHeaders(ServletServerHttpResponse.java:130)
org.springframework.http.server.ServletServerHttpResponse.getBody(ServletServerHttpResponse.java:96)
org.springframework.http.converter.StringHttpMessageConverter.writeInternal(StringHttpMessageConverter.java:126)
org.springframework.http.converter.StringHttpMessageConverter.writeInternal(StringHttpMessageConverter.java:44)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:227)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:280)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:181)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:78)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:123)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.47 logs.
@ResponseBody
注解去掉，这个注解就是来把javabean或者map等序列化json字符串的。而你返回的数据不能转化为json字符串，肯定报错了
你要是return返回值是对象或者集合都可以
你报的这个错是没有找到对应的映射方法，有没有开启注解扫描，web配置有没有添加前端控制器
你好，你截图请求的是quick1这个方法呀
@Controller这个是返回视图
你加@ResponseBody是将数据封装成json返回，这样应该是不行的吧；
这是明显是Servlet版本问题导致的问题，你实际运行时的Servlet版本过低。低于Servlet 3.1。应该是这个插件版本低了 tomcat7-maven-plugin， 你可以考虑换一下。换成高版本的插件。（或者其他的Servlet容器）
tomcat9
<!-- https://mvnrepository.com/artifact/org.apache.tomcat.maven/tomcat9-maven-plugin -->
<dependency>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat9-maven-plugin</artifactId>
<version>2.2</version>
</dependency>
jetty
<!-- https://mvnrepository.com/artifact/org.eclipse.jetty/jetty-maven-plugin -->
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>11.0.6</version>
</dependency>
详细用法， 你可以看看这个 https://springboot.io/t/topic/1045 https://springboot.io/t/topic/1045