SpringMVC
一日一句：没有笨人，只有懒人！
简介：“springmvc是一种web层mvc框架，它是spring的一个模块，拥有spring的特性。springmvc分离了控制器、模型对象、分派器以及处理程序对象的角色。”
ssm: mybatis+spring+SpringMVC MVC三层结构
SSM=javaweb做项目；
spring： IOC和AOP
SpringMVC：SpringMVC的执行流程！
SpringMVC: SSM框架整合！
MVC:模型（dao，service） 视图（jsp） 控制器（servlet）
jsp：本质就是一个servlet
pom.xml依赖
<?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.liang</groupId>
<artifactId>springMVC</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<!--导入依赖-->
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.1.9.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp.jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
</dependencies>
</project>
再新建一个maven普通项目，建立子项目
子类导入依赖
<?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">
<parent>
<artifactId>springMVC</artifactId>
<groupId>com.liang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>springmvc-01-serlvet</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
</dependencies>
</project>
配置tomcat
什么是springmvc？
spring：大杂烩，我们可以将springmvc中所有要用到的bean，注册到spring中！
只要实现了HttpServlet本质上来说都是属于servlet
springMVC的执行流程
1.用户发送请求
2.请求到了dispatcherServlet，执行以下代码
3.委托请求给处理器handlermapping和handlerAdapter适配器
4.处理器返回model and view
5. model渲染视图，然后返回给前端控制器
虚线就是我们做的，实线springmvc已经帮我们做了
编辑controller
package com.liang.controller;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloController implements Controller {
@Override
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
ModelAndView mv = new ModelAndView();
//业务代码
String result = "HelloSpringMVC";
mv.addObject("msg",result);
//视图跳转
mv.setViewName("test");
return mv;
}
}
在resources下创建springmvc-servlet.xml配置文件
<beans xmlns="http://www.springframework.org/schema/beans"
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">
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
bean>
<bean id="/hello" class="com.liang.controller.HelloController"/>
beans>
在web下的WEB-INF下创建一个jsp目录，存放jsp文件，在里面创建test.jsp文件
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2021/1/3
Time: 18:20
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
${msg}
写好web.xml配置文件
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
version="5.0">
<servlet>
<servlet-name>springmvcservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springmvc-servlet.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>springmvcservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
web-app>
Maven可能存在资源过滤问题，我们将配置完善
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties
**/ *.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties
**/ *.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
springmvc-servlet.xml配置文件,以下文件中除了
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.kuang.controller"/>
<mvc:default-servlet-handler />
<mvc:annotation-driven />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
bean>
beans>
controller控制层
package com.kuang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@Controller
//@RestController 返回json字符串
//@RequestMapping("/hello")
public class HelloController {
//localhost:8080/hello/h1
@RequestMapping("/h1")
public String hello(Model model){
//封装数据
model.addAttribute("msg","hello,springmvcAnnotation!");
return "hello";//会被视图解释器处理
}
}
完整步骤
controller
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller //代表这个类会被spring接管，被注解的类，中的所有方法
//如果返回值是string，并且有具体页面可以跳转，那么就会被试图解释器解析；
public class ControllerTest2 {
@RequestMapping("/t2")
public String test1(Model model){
model.addAttribute("msg","hello,controller2");
return "test";//return是view //WEB-INF/jsp/test.jsp
}
}
RestFul风格
请求地址一样，可以通过不同的请求方式来实现不同的效果！
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class RestFulController {
@RequestMapping("/add")
public String test1(int a, int b, Model model){
//model是传数据的
int res = a+b;
model.addAttribute("msg","结果为"+res);
return "/test.jsp";
}
}
使用@PathVariable注解，让方法参数的值对应绑定到一个url模板变量上
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class RestFulController {
//原来的：http://localhost:8080/add?a=1&b=2
//RestFul： http://localhost:8080/add/a/b
@RequestMapping("/add/{a}/{b}")
public String test1(@PathVariable int a,@PathVariable int b, Model model){
//model是传数据的
int res = a+b;
model.addAttribute("msg","结果为"+res);
return "test";
}
}
400请求出问题，500代码有问题
狂神牛逼！！！
创建一个post风格提交的表单
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2021/1/4
Time: 13:41
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form action="/add/" method="post">
<input type="text" name="a">
<input type="text" name="b">
<input type="submit">
</form>
</body>
</html>
转发和重定向
首先把resources下xml中配置的视图解释器注释掉，以下是测试不配置试图解释器的情况
转发，默认的情况下是转发
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@Controller
public class ModelTest1 {
@RequestMapping("/m1/t1")
public String test(Model model){
//转发
model.addAttribute("msg","helloModelTest1");
return "forward:/WEB-INF/jsp/test.jsp";//通过添加关键字forward来说明他是转发
}
}
重定向，需要重定向的时候加个关键字redirect
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@Controller
public class ModelTest1 {
@RequestMapping("/m1/t1")
public String test(Model model){
//重定向
model.addAttribute("msg","helloModelTest1");
return "redirect:/index.jsp";//通过添加关键字redirect来说明他是重定向
}
}
总结：springmvc中的xml中配置的视图解释器的作用是，把访问转发或者重定向的前后缀写好，返回的时候直接写个路径即可，如果没有配置视图解释器就要自己写前后缀这样就比较麻烦，其中转发是默认的一般通过添加关键字forward来说明他是转发，重定向就是回到指定的首页加个关键字redirect
接受请求参数及数据回显
要使用lombok注解data，记得首先要去xml导入相对应的包，还要下载插件
package com.liang.controller;
import com.liang.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller
@RequestMapping("/user")
public class UserController {
//localhost：8080/user/t1？name=xxxx
@GetMapping("/t1")//@RequestParam("username") 这个无论用不用，前端都要加上，说明这个需要从前端接收数据
public String test1(@RequestParam("username") String name, Model model){
//1.接受前端参数
System.out.println("接收到前端的参数是"+name);
//2.将返回的结果传递给前端,传给前端就用model
model.addAttribute("msg",name);
//3.视图跳转
return "test";
}
//前端接受的是一个对象：id， name ，age
/*
1.接受前端用户传递的参数，判断参数的名字，假设名字直接在方法上，可以直接使用
2.假设传递的是一个对象User，匹配User对象中的字段名：如果名字一致则ok，否则，匹配不到
*/
@GetMapping("t2")
public String test2(User user){
System.out.println(user);
return "test";
}
}
创建一个pojo包建个User实体类
package com.liang.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor //有参
@NoArgsConstructor //无参
public class User {
private int id;
private String name;
private int age;
}
传对象用的几种方式
Model、ModelMap、LinkedHashMap
@RequestParam(“username”) 这个无论用不用，前端都要加上，说明这个需要从前端接收数据
使用Model接收前端参数
package com.liang.controller;
import com.liang.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller
@RequestMapping("/user")
public class UserController {
//localhost：8080/user/t1？name=xxxx
@GetMapping("/t1")//@RequestParam("username") 这个无论用不用，前端都要加上，说明这个需要从前端接收数据
public String test1(@RequestParam("username") String name, Model model){
//1.接受前端参数
System.out.println("接收到前端的参数是"+name);
//2.将返回的结果传递给前端,传给前端就用model
model.addAttribute("msg",name);
//3.视图跳转
return "test";
}
//前端接受的是一个对象：id， name ，age
/*
1.接受前端用户传递的参数，判断参数的名字，假设名字直接在方法上，可以直接使用
2.假设传递的是一个对象User，匹配User对象中的字段名：如果名字一致则ok，否则，匹配不到
3.一一匹配太麻烦了，直接传对象
*/
@GetMapping("t2")
public String test2(User user){
System.out.println(user);
return "test";
}
}
404乱码问题
如何配置过滤器解决乱码
首先建一个filter包
package com.liang.filter;
import javax.servlet.*;
import java.io.IOException;
public class EncodingFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
写完后，在web.xml添加配置
<filter>
<filter-name>encodingfilter-name>
<filter-class>com.liang.filter.EncodingFilterfilter-class>
filter>
<filter-mapping>
<filter-name>encodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
设置tomcat
get请求不会乱码，因为已经自动配置了过滤器，但是post会中文乱码喔
不得不说，乱码问题是在我们开发中十分常见的问题，也是让我们程序猿比较头大的问题！
以前乱码问题通过过滤器解决 , 而SpringMVC给我们提供了一个过滤器 , 可以在web.xml中配置 .
修改了xml文件需要重启服务器！
<filter>
<filter-name>encodingfilter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
controller代码
package com.liang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.Mapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class EncodingController {
@PostMapping("/e/t")
public String test(Model model,String name){
System.out.println(name);
model.addAttribute("msg",name); //获取表单提交的值
return "test"; //跳转到test页面显示输入的值
}
}
web.xml配置文件
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
version="5.0">
<servlet>
<servlet-name>springmvcservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springmvc-servlet.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>springmvcservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
<filter>
<filter-name>encodingfilter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
web-app>
form.jsp在web目录下，别放WEB-INF下面，可能会访问不到
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form action="/e/t" method="post">
<input type="text" name="name">
<input type="submit">
</form>
</body>
</html>
web-inf下的jsp目录中的test.jsp文件
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
${
msg}
</body>
</html>
resources下的springmvc-servlet.xml配置文件
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.liang.controller"/>
<mvc:default-servlet-handler />
<mvc:annotation-driven />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
bean>
beans>