spring mvc


在https://mvnrepository.com/查找maven库里spring的包.

围绕DispatchServlet来设计,所有web请求都会到这个类.

从spring 2.5,java5或以上的用户就可以使用基于注解的control声明方式.

老的方式:

1. 在pom.xml里导入Spring依赖

<dependencies>

    <dependency>
        <groupId>org.springframeworkgroupId>
        <artifactId>spring-webartifactId>
        <version>5.3.14version>
    dependency>

    <dependency>
        <groupId>org.springframeworkgroupId>
        <artifactId>spring-webmvcartifactId>
        <version>5.3.14version>
    dependency>
    <dependency>
        <groupId>commons-logginggroupId>
        <artifactId>commons-loggingartifactId>
        <version>1.2version>
    dependency>
    <dependency>
        <groupId>javax.servlet.jspgroupId>
        <artifactId>javax.servlet.jsp-apiartifactId>
        <version>2.3.3version>
        <scope>providedscope>
    dependency>
    <dependency>
        <groupId>javax.servletgroupId>
        <artifactId>javax.servlet-apiartifactId>
        <version>4.0.1version>
        <scope>providedscope>
    dependency>
dependencies>

2. 在web.xml中配置DispatchServelet,MVC的配置文件,以及DispatchServlet的mapping.

<servlet>
   <servlet-name>springDispatcherServletservlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
    
    <init-param>
        <param-name>contextConfigLocationparam-name>
        <param-value>classpath:springmvc.xmlparam-value>
    init-param>
    
    <load-on-startup>1load-on-startup>
servlet>


<servlet-mapping>
    <servlet-name>springDispatcherServletservlet-name>
    <url-pattern>/url-pattern>
servlet-mapping>

3. 在resources下添加文件springmvc.xml,并添加

<?xml version="1.0" encoding="UTF-8"?>
    <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 http://www.springframework.org/schema/context/spring-context-4.0.xsd
             http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.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">
            <property name = "prefix" value="/WEB-INF/views/">property>
            <property name = "suffix" value = ".jsp">property>
        bean>
        
        <bean id="/hello" class="com.ptc.springmvc.handler.HelloWorld"/>
    beans>

 4.创建controller

package com.ptc.springmvc.handler;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

public class HelloWorld implements Controller {

     public ModelAndView handleRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws Exception {
          //模型和视图
          ModelAndView mv = new ModelAndView();
          //封装对象,放在ModelAndView中,Model
          mv.addObject("msg","HelloSpringMVC!");
          //封装要跳转的视图,放在ModelAndView中
          mv.setViewName("hello"); //: /WEB-INF/jsp/hello.jsp
          return mv;
     }
}


5. 在WEB-INF/jsp下创建hello.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    Title


    ${msg}

新的方式:

1. 在pom.xml里导入Spring依赖

<dependencies>

    <dependency>
        <groupId>org.springframeworkgroupId>
        <artifactId>spring-webartifactId>
        <version>5.3.14version>
    dependency>

    <dependency>
        <groupId>org.springframeworkgroupId>
        <artifactId>spring-webmvcartifactId>
        <version>5.3.14version>
    dependency>
    <dependency>
        <groupId>commons-logginggroupId>
        <artifactId>commons-loggingartifactId>
        <version>1.2version>
    dependency>
    <dependency>
        <groupId>javax.servlet.jspgroupId>
        <artifactId>javax.servlet.jsp-apiartifactId>
        <version>2.3.3version>
        <scope>providedscope>
    dependency>
    <dependency>
        <groupId>javax.servletgroupId>
        <artifactId>javax.servlet-apiartifactId>
        <version>4.0.1version>
        <scope>providedscope>
    dependency>
dependencies>

2. 在web.xml中配置DispatchServelet,MVC的配置文件,以及DispatchServlet的mapping.

<servlet>
   <servlet-name>springDispatcherServletservlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
    
    <init-param>
        <param-name>contextConfigLocationparam-name>
        <param-value>classpath:springmvc.xmlparam-value>
    init-param>
    
    <load-on-startup>1load-on-startup>
servlet>


<servlet-mapping>
    <servlet-name>springDispatcherServletservlet-name>
    <url-pattern>/url-pattern>
servlet-mapping>

3.在resources下添加文件springmvc.xml,并添加

<?xml version="1.0" encoding="UTF-8"?>
    <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 http://www.springframework.org/schema/context/spring-context-4.0.xsd
             http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

        
        <context:component-scan base-package="com.ptc.springmvc">context:component-scan>
        
        <mvc:default-servlet-handler/>
        
        <mvc:annotation-driven/>
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name = "prefix" value="/WEB-INF/views/">property>
            <property name = "suffix" value = ".jsp">property>
        bean>
    beans>

 

4.创建controller

package com.ptc.springmvc.handler;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloWorld {
        /**
        *1. 使用RequestMapping注解来映射请求的URL
        * 2. 返回值会通过视图解析器解析为实际的物理视图, 对于InternalResourceViewResolver视图解析器,会做如下解析
        * 通过prefix+returnVal+suffix 这样的方式得到实际的物理视图,然后会转发操作
        * "/WEB-INF/views/success.jsp"
        * @return
        * */
     @RequestMapping("/helloworld")
     public String hello(Model model){
          //封装数据
          model.addAttribute("msg","hello springmvc!");
          return "success";
     }
}


5.创建success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    Title
    ${msg}




转发和重定向
1. 使用HttpServletResponse来实现转发和重定向

package com.ptc.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.RegEx;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Controller
public class Redirection {
    @RequestMapping("/test1")
    public void test1(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.getWriter().println("test1.....");
    }
    @RequestMapping("/test2")
    public void test2(HttpServletRequest request,HttpServletResponse response) throws IOException {
        response.sendRedirect("/springmvc-04-redirection/views/test2.jsp");
    }
    @RequestMapping("/test3")
    public void test3(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
        request.setAttribute("msg","test3.....");
        request.getRequestDispatcher("/WEB-INF/views/test3.jsp").forward(request,response);

    }
}

 2. 使用Springmvc来转发和重定向 -无需视图解析器

要去掉springmvc.xml里配置的视图解析器

这里可以看到forward可以使用WEB-INF下面的jsp,而redirect不能.

WEB-INF是Java的WEB应用的安全目录。所谓安全就是客户端无法访问,只有服务端可以访问的目录。
页面放在WEB-INF目录下面,这样可以限制访问,提高安全性.如JSP,html

既然WEB-INF是安全目录,客户端无法访问,而重定向就相当于用户直接从客户端访问了的路径,自然就不可以啦,只有程序内部转发的时候才能转发到WEB-INF下的JSP。

package com.ptc.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class RedirectionMVC {
    @RequestMapping("/rm/t1")
    public String test1(){
        //转发
        return "/views/test2.jsp";
    }
    @RequestMapping("rm/t2")
    public String test2(Model model){
        model.addAttribute("msg","test3...");
        //转发2
        return "forward:/WEB-INF/views/test3.jsp";
    }
    @RequestMapping("rm/t3")
    public String test3(){
        //重定向
        return "redirect:/views/test2.jsp";
    }
}

 处理提交数据

1. 提交的域名称和处理方法的参数名称一致

提交数据:http://localhost:8080//springmvc_05_receivedata/hello?name=roger

package com.ptc.receivedata;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class ReceiveData {
    @RequestMapping("/hello")
    public String hello(String name) {
        System.out.println("name>>>>>>>>>>>" + name);
        return "hello";
    }
}

后台打印

2. 提交的域名称和处理方法的参数名称不一致

提交数据:http://localhost:8080//springmvc_05_receivedata/hello?username=roger

使用@RequestParam("username")来指定name对应的域名称.

@Controller
public class ReceiveData {
    //@RequestParam("username")
    @RequestMapping("/hello2")
    public String hello2(@RequestParam("username") String name) {
        System.out.println("name2>>>>>>>>>>>" + name);
        return "hello";
    }
}

 3. 提交一个对象

    提交数据:http://localhost:8080//springmvc_05_receivedata/test?id=1&name=roger&age=36

     创建一个实体类

     

package com.ptc.dojo;

public class User {
    private int id;
    private String name;
    private int age;

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

UserController.java 使用User对象参数,传过来的参数的跟它的属性名字一一对应.

package com.ptc.receivedata;

import com.ptc.dojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class UserController {
    @RequestMapping("/test")
    public String test(User user) {
        System.out.println("id:" + user.getId() + "|name:"
                + user.getName() + "|age:" + user.getAge());
        return "hello";
    }

}

结果

 数据显示到前端

1. 通过ModelAndView

public class TestController {
    @RequestMapping("/test")
    public ModelAndView test() {
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","test!!!");
        mv.setViewName("test");
        return mv;
    }
    @RequestMapping("/test1")
    public ModelAndView test1() {
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","redirect test!!!");
        mv.setViewName("redirect:/views/test.jsp");
        return mv;
    }
}

2. 通过ModelMap

 @RequestMapping("/test2")
public String test2(@RequestParam("username") String name, ModelMap modelMap) {
        modelMap.addAttribute("name",name);
        return "test2";

}

3. 通过Model

 @RequestMapping("/helloworld")
     public String hello(Model model){
          //封装数据
          model.addAttribute("msg","hello springmvc!");
          return "success";
     }

 乱码问题

1.重现乱码

  form.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    Title


    

EncodingController.java

package com.ptc.receivedata;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PostMapping;

@Controller
public class EncodingController {
    @PostMapping("/e/t1")
    public String test1(String name,Model model){
        model.addAttribute("name",name);
        return "test2";
    }
}

输入url:http://localhost:8080//springmvc_05_receivedata/form.jsp

提交之后出现乱码: