springMVC跳转和传值
接上一篇：SpringMVC接收请求参数
1. 跳转
1.1 pom.xml中导入依赖：jstl，jsp-api,servlet-api
<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>4.0.0modelVersion>
<groupId>org.examplegroupId>
<artifactId>springMVC03artifactId>
<version>1.0-SNAPSHOTversion>
<packaging>warpackaging>
<dependencies>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>5.3.16version>
dependency>
<dependency>
<groupId>javax.servlet.jsp.jstlgroupId>
<artifactId>jstlartifactId>
<version>1.2version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>javax.servlet-apiartifactId>
<version>3.1.0version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>jsp-apiartifactId>
<version>2.0version>
dependency>
dependencies>
<build>
<resources>
<resource>
<directory>src/main/javadirectory>
<includes>
<include>*.xmlinclude>
<include>**/*.xmlinclude>
includes>
<filtering>truefiltering>
resource>
resources>
build>
project>
1.2 视图解析器ViewResolver
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
">
<context:component-scan base-package="com.lyx"/>
<mvc:annotation-driven>mvc:annotation-driven>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"/>
<property name="suffix" value=".jsp"/>
bean>
beans>
1.3 代码
后端控制器，跳转：forword，重定向：redirect
package com.lyx.web;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
@RequestMapping("/jump")
public class ForwardController {
@RequestMapping("/test1")
public String test1(){
System.out.println("test1");
return "forward:/hello.jsp";
}
@RequestMapping("/test2")
public String test2(){
System.out.println("test2");
//return "forward:/hello/test1";//绝对路径。跨类跳转到hello的test1方法
return "forward:test1";//相对路径，当前本类的test1
}
@RequestMapping("/test3")
public String test3(){
System.out.println("test3");
return "redirect:/hello.jsp";//重定向到hello.jsp
}
@RequestMapping("/test4")
public String test4(){
System.out.println("test4");
//return "redirect:/hello/test1";//绝对路径。跨类跳转到hello的test1方法
return "redirect:test3";//相对路径，重定向到当前本类的test1
}
}
1.4 细节
- 在增删改之后，为了防止请求重复提交，要用重定向redirect跳转，如果用forward，每次刷新页面都会重新提交一次数据
- 在查询之后，我们希望的就是每次跳转都重新刷新数据，所以用forward
2. 传值
2.1 request作用域与session作用域
2.1.1 request作用域
- 后端控制器
@Controller
@RequestMapping("/data")
public class DataController {
@RequestMapping("/test1")
public String test1(HttpServletRequest request){
System.out.println("test1");
request.setAttribute("name","张三");
request.setAttribute("age",22);
return "data";
}
}
- data.jsp页面,JSP取值
<body>
name:${name}<br/>
age:${age}
body>
- Tomcat运行，访问http://locahost:8080/data/test1
2.1.2 session作用域
@Controller
@RequestMapping("/data")
public class DataController {
@RequestMapping("/test1")
public String test1(HttpServletRequest request, HttpSession session){
session.setAttribute("birth",new Date());
System.out.println("test1");
request.setAttribute("name","张三");
request.setAttribute("age",22);
return "index";
}
}
- JSP取值
<body>
birth:<fmt:formatDate value="${sessionScope.birth}" pattern="yyyy-MM-dd"/><br/>
name : ${requestScope.name}<br/>
age : ${requestScope.age}<br/>
body>
- Tomcat运行，访问路径http://localhost:8080/data/test1
2.2 Model
2.2.1 model–>request作用域
当我们把数据存在model中的时候呢，model会把这个数据复制到request作用域
- 后端控制器
@Controller
@RequestMapping("/data")
public class DataController {
@RequestMapping("/test2")
public String test2(Model model){
model.addAttribute("gender",true);
return "data";
}
}
- 当我们把数据存在model中的时候呢，model把这个数据复制到request作用域，所以所有model中的数据都可以通过以下方式调用
- data.jsp页面
<body>
gender:${requestScope.gender}
body>
- Tomcat运行，访问http://locahost:8080/data/test2
2.2.2 @SessionAttributes
通过注解设置key值，model向session作用域中存数据
- 后端控制器
@Controller
@RequestMapping("/data")
@SessionAttributes(names = {"city","hobby"})
public class DataController {
@RequestMapping("/sss")
public String test(Model model){
model.addAttribute("city","北京");
model.addAttribute("hobby","football");
return "index";
}
}
- JSP取值
<body>
city:${sessionScope.city}<br/>
hobby:${sessionScope.hobby}
body>
- Tomcat运行，访问路径：http://localhost:8080/data/sss
2.2.3 清除所有通过model存入session的数据
@Controller
@RequestMapping("/data")
public class DataController {
@RequestMapping("ds")
public String clean(SessionStatus sessionStatus){
sessionStatus.setComplete();
return "index";
}
}
2.2.4 ModelAndView集中管理跳转和传值
ModelAndView是一个用来做数据整合的类
，Model就是数据，View就是视图（.jsp文件）
- 后端控制器
@Controller
@RequestMapping("/data")
@SessionAttributes(names = {"city","hobby"})
public class DataController {
@RequestMapping("/aaa")
public ModelAndView test(){
//新建ModelAndView对象
ModelAndView modelAndView = new ModelAndView();
//设置视图名，即跳转的路径
modelAndView.setViewName("forward:/index.jsp");
//增加数据
modelAndView.addObject("Singer","刘雨昕");
return modelAndView;
}
- JSP取值，用EL表达式即可
<body>
Singer:${requestScope.Singer}
body>
- Tomcat运行，访问http:/localhost:8080/data/aaa
