Spring MVC

2023-11-11 17:43:04

文章目录

一、Spring MVC是什么？
二、Spring MVC环境配置
三、SpringMVC处理示意图
四、Spring MVC数据绑定
五、解决响应中的中文乱码
六、响应输出结果
- ModelAndView
七、SpringMVC整合Freemarker

一、Spring MVC是什么？

二、Spring MVC环境配置

1.Maven依赖spring-wevmvc

<?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.imooc</groupId>
    <artifactId>first-springmvc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
    </dependencies>
</project>

2.web.xml配置DispaerServlet

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <!--DispatchServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <!--
            DispatchServlet是spring MVC最核心的对象
            DispatchServlet用于拦截Http请求
            并根据请求对URL调用与之对应对Controller方法
            -->
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--applicationContext.xml-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <!--
            在web应用启动时自动创建Spring IOC容器，
            并初始化DispatchServlet
        -->
        <load-on-startup>0</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <!--"/" 代表拦截所有请求-->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

3.配置applicationContext.xml的mvc标记

<?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" xmlns:mv="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.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--
    context:component-scan 标签作用
    在Spring IOC初始化过程中,自动创建并管理com.imooc.springmvc及子包中
    拥有以下注解的对象.
    @Repository
    @Service
    @Controller
    @Component
    -->
    <context:component-scan base-package="com.imooc.springmvc"></context:component-scan>
    <!--启动Spring MVC注解开发模式-->
    <mvc:annotation-driven/>
    <mvc:default-servlet-handler/>
</beans>

4.开发Controller控制器

@Controller
public class TestController {
    @GetMapping("/t")
    @ResponseBody
    public String test(){
        return "hello,SUCCESS";
    }
}

三、SpringMVC处理示意图

四、Spring MVC数据绑定

1.URL Mapping

@Controller
@RequestMapping("/um")
public class URLMappingController {
    @GetMapping("/g")
    @ResponseBody
    public String getMapping(){
        return "get method";
    }

    @PostMapping("/p")
    @ResponseBody
    public String postMapping(){
        return "post method";
    }
}

2.接收请求参数

@Controller
@RequestMapping("/um")
public class URLMappingController {
    @GetMapping("/g")
    @ResponseBody
    //通过@RequestParam()完成自定义的参数对照关系
    public String getMapping(@RequestParam("manager_name") String managerName){
        return "get method";
    }

    @PostMapping("/p")
    @ResponseBody
    public String postMapping(String username,String password){
        System.out.println(username+":"+password);
        return "post method";
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <form action="/um/p" method="post">
        <input name="username"><br/>
        <input name="password"><br/>
        <input type="submit" value="提交">
    </form>
</body>
</html>

3.使用Java Bean接受请求参数

@PostMapping("p1")
    @ResponseBody
    public String postMapping(User user){
        System.out.println(user.getUsername()+":"+user.getPassword());
        return "post method";
    }

需要有对应的实体类，并且实体类中属性的名字必须要跟前端页面的name一致

public class User {
    private String username;
    private Long password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Long getPassword() {
        return password;
    }

    public void setPassword(Long password) {
        this.password = password;
    }
}

4.接收表单复合数据

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>学员调查问卷</title>
    <style>
        .container {
            position: absolute;
            border: 1px solid #cccccc;
            left: 50%;
            top: 50%;
            width: 400px;
            height: 300px;
            margin-left: -200px;
            margin-top: -150px;
            box-sizing: border-box;
            padding: 10px;
        }
        h2{
            margin: 10px 0px;
            text-align: center;
        }
        h3{
            margin: 10px  0px;
        }
    </style>
</head>
<body>
    <div class="container">
        <h2>学员调查问卷</h2>
        <form action="./apply" method="post">
        <h3>您的姓名</h3>
        <input name="name" class="text"  style="width: 150px">
        <h3>您正在学习的技术方向</h3>
        <select name="course" style="width: 150px">
            <option value="java">Java</option>
            <option value="h5">HTML5</option>
            <option value="python">Python</option>
            <option value="php">PHP</option>
        </select>
        <div>
            <h3>您的学习目的：</h3>
            <input type="checkbox" name="purpose" value="1">就业找工作
            <input type="checkbox" name="purpose" value="2">工作要求
            <input type="checkbox" name="purpose" value="3">兴趣爱好
            <input type="checkbox" name="purpose" value="4">其他
        </div>
        <div style="text-align: center;padding-top:10px" >
            <input type="submit" value="提交" style="width:100px">
        </div>
        </form>

    </div>
</body>
</html>

@Controller
public class FormController {
//    @PostMapping("/apply")
    @ResponseBody
    public String apply(@RequestParam(value = "n",defaultValue = "ANON") String name, String course, Integer[] purpose){
        System.out.println(name);
        System.out.println(course);
        for (Integer p : purpose) {
            System.out.println(p);
        }
        return "SUCCESS";
    }

//    @PostMapping("/apply")
    @ResponseBody
    public String apply(String name, String course, @RequestParam List<Integer> purpose){
        System.out.println(name);
        System.out.println(course);
        for (Integer p : purpose) {
            System.out.println(p);
        }
        return "SUCCESS";
    }

//    @PostMapping("/apply")
    @ResponseBody
    public String apply(Form form){
        return "SUCCESS";
    }
    @PostMapping("/apply")
    @ResponseBody
    public String apply(@RequestParam Map map){
        System.out.println(map); //如果存在复合数据，map是无法接收的
        return "SUCCESS";
    }
}

5.关联对象赋值

6.日期类型转换

方法1

如果前端传来了日期类型的字符串，并且后端想要转化为Date类型，可以在参数类型前加上

@DateTimeFormat(pattern = "yyyy-MM-dd")

具体如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/um/p1" method="post">
        <input name="username"><br/>
        <input name="password"><br/>
        <input name="createTime"><br/>
        <input type="submit" value="提交">
    </form>
</body>
</html>

@PostMapping("/p1")
    @ResponseBody
    public String postMapping1(User user , String username ,@DateTimeFormat(pattern = "yyyy-MM-dd") Date createTime){
        System.out.println(user.getUsername() + ":" + user.getPassword());
        return "<h1>这是Post响应</h1>";
    }

public class User {

    private String username;
    private Long password;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date createTime;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Long getPassword() {
        return password;
    }

    public void setPassword(Long password) {
        this.password = password;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
}

方法2

也可以自己写一个转换器,则不需要加注解：

public class MyDateConverter implements Converter<String, Date> {
    public Date convert(String s) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date d = sdf.parse(s);
            return d;
        } catch (ParseException e) {
            return null;
        }
    }
}

在applicationContext.xml注册，加入这句话

<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="com.imooc.springmvc.converter.MyDateConverter"/>
            </set>
        </property>
</bean>


<mvc:annotation-driven conversion-service="conversionService">

五、解决响应中的中文乱码

解决方法：在applicationContext.xml增加这一段

<mvc:annotation-driven conversion-service="conversionService">
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <property name="supportedMediaTypes">
                    <list>
                        <!-- response.setContentType("text/html;charset=utf-8") -->
                        <value>text/plain;charset=utf-8</value>
                        <value>text/html;charset=utf-8</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

六、响应输出结果

ModelAndView

最简单的情况：

@GetMapping("/view")
    public ModelAndView showView(){
        ModelAndView mav = new ModelAndView("/view.jsp");
        return mav;
    }

但是如果数据是由controller动态地查询产生，如：

@GetMapping("/view")
    public ModelAndView showView(Integer userId){
//        ModelAndView mav = new ModelAndView("redirect:/view.jsp");
        ModelAndView mav = new ModelAndView();
        mav.setViewName("/um/view.jsp");
        User user = new User();
        if(userId == 1){
            user.setUsername("lily");
        }else if(userId == 2){
            user.setUsername("smith");
        }else if(userId == 3){
            user.setUsername("lina");
        }
        mav.addObject("u" , user);
        return mav;
    }

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h1>I'm view page(/um/view.jsp)</h1>
    <hr>
    <h3>Username:${u.username}</h3>
</body>
</html>

    @GetMapping("/view")
    public ModelAndView showView(Integer userId){
//        ModelAndView mav = new ModelAndView("redirect:/view.jsp");
        ModelAndView mav = new ModelAndView();
        mav.setViewName("/um/view.jsp");
        User user = new User();
        if(userId == 1){
            user.setUsername("lily");
        }else if(userId == 2){
            user.setUsername("smith");
        }else if(userId == 3){
            user.setUsername("lina");
        }
        mav.addObject("u" , user);
        return mav;
    }
    //String与ModelMap
    //Controller方法返回String的情况
    //1. 方法被@ResponseBody描述，SpringMVC直接响应String字符串本身
    //2. 方法不存在@ResponseBody，则SpringMVC处理String指代的视图（页面）
    @GetMapping("/xxxx")
//    @ResponseBody
    public String showView1(Integer userId , ModelMap modelMap){
        String view = "/um/view.jsp";
        User user = new User();
        if(userId == 1){
            user.setUsername("lily");
        }else if(userId == 2){
            user.setUsername("smith");
        }else if(userId == 3){
            user.setUsername("lina");
        }
        modelMap.addAttribute("u", user);
        return view;
    }

七、SpringMVC整合Freemarker

		<dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.28</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>

<bean id="ViewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
        <property name="contentType" value="text/html;charset=utf-8"/>
        <property name="suffix" value=".ftl"/>
</bean>

<bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
        <property name="templateLoaderPath" value="/WEB-INF/ftl"/>
        <property name="freemarkerSettings">
            <props>
                <prop key="defaultEncoding">UTF-8</prop>
            </props>
        </property>
</bean>

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