一、响应数据和结果视图
1. 返回值分类
1.1搭建开发环境
坐标
XML
<!-- 版本锁定 -->
<properties>
<spring.version>5.0.2.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
前端控制器和过滤器
XML
<!-- 配置过滤器,解决中文乱码的问题 -->
<filter>
<filter-name>characterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<!-- 指定字符集 -->
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<!-- 强制使用指定字符集 -->
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!--配置前端控制器-->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--加载springmvc.xml配置文件,配置的是Spring配置-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<!--配置启动加载-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
springmvc.xml配置文件
XML
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
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/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 开启注解驱动 -->
<mvc:annotation-driven />
<!-- 扫描控制器所在的包 -->
<context:component-scan base-package="com.qcby.demo" />
<!-- 视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
返回String
Controller方法返回字符串可以指定逻辑视图的名称,根据视图解析器为物理视图的地址。
java
package com.qcby.demo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Controller
@RequestMapping("/user")
public class UserController {
/**
* 返回String
* @return
*/
@RequestMapping("/save1.do")
public String save1(){
System.out.println("执行了...");
return "suc";
}
}
返回值是void
如果控制器的方法返回值编写成void,执行程序报404的异常,默认查找JSP页面没有找到。
可以使用请求转发或者重定向跳转到指定的页面
java
package com.qcby.demo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Controller
@RequestMapping("/user")
public class UserController {
/**
* 返回void
* 默认查询 /pages/sav2.do.jsp的页面
* @return
*/
@RequestMapping("/save2.do")
public void save2(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("执行了...");
// request.getRequestDispatcher("/pages/suc.jsp").forward(request,response);
// 做出相应的操作
response.getWriter().print("hello");
return;
}
}
返回值是ModelAndView对象
ModelAndView对象是Spring提供的一个对象,可以用来调整具体的JSP视图
java
package com.qcby.demo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Controller
@RequestMapping("/user")
public class UserController {
/**
* 返回ModelAndView对象的方式
* @return
*/
@RequestMapping("/save3.do")
public ModelAndView save3(){
System.out.println("执行了...");
// 创建mv对象
ModelAndView mv = new ModelAndView();
// 把一些数据,存储到mv对象中
mv.addObject("msg","用户名或者密码已经存在");
// 设置逻辑视图的名称
mv.setViewName("suc");
return mv;
}
}
2.SpringMVC框架提供的转发和重定向
forward请求转发
controller方法返回String类型,想进行请求转发也可以编写成
java
package com.qcby.demo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Controller
@RequestMapping("/user")
public class UserController {
/**
* 返回String
* 请求转发
* @return
*/
@RequestMapping("/save4.do")
public String save4(){
System.out.println("执行了...");
return "forward:/pages/suc.jsp";
}
}
redirect重定向
java
package com.qcby.demo;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Controller
@RequestMapping("/user")
public class UserController {
/**
* 返回String
* 重定向
* @return
*/
@RequestMapping("/save5.do")
public String save5(){
System.out.println("执行了...");
return "redirect:/pages/suc.jsp";
}
}