SpringMVC学习笔记（二）-阿里云开发者社区

视图解析器概述

将Controller的返回值进行解析，到浏览器。

在SpringMVC中也有很多视图解析器

这时通过视图解析器解析handler返回的值（逻辑视图，转发数据）

InternalResourceViewResolver会将逻辑视图与prefix和suffix组合成物理视图名，
如果逻辑视图返回值中包含redirect:,则进行重定向操作，如果是forward：或者没有前缀，则转发操作。

编写一个视图

package cn.cqie.controller.a_view;
import org.springframework.web.servlet.View;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Map;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/25 15:02
 */
public class MyView implements View {
    @Override
    public String getContentType() {
        return null;
    }
    @Override
    public void render(Map<String, ?> map, HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        //map就是model中添加的数据
        for (Map.Entry<String, ?> entry : map.entrySet()) {
            httpServletRequest.setAttribute(entry.getKey(), entry.getValue());
            System.out.println("  "+entry.getKey()+" :  " +entry.getValue());
        }
        System.out.println("MyView.render");
        httpServletRequest.getRequestDispatcher("abc.jsp").forward(httpServletRequest, httpServletResponse);
    }
}

<?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.xsd
        http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">
   <context:component-scan base-package="cn.cqie.controller.a_view"/>
    <mvc:annotation-driven/>
    <!--
      BeanNameViewResolver是当前项目的中视图解析器
      MyView声明了跳转的方式和数据转发
  -->
    <bean class="org.springframework.web.servlet.view.BeanNameViewResolver"></bean>
    <bean id="myView" class="cn.cqie.controller.a_view.MyView"></bean>
</beans>

package cn.cqie.controller.a_view;
import cn.cqie.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/23 21:30
 */
@Controller
public class UserController {
   @RequestMapping("save")
    public String save(Model model){
       System.out.println("UserController.save");
       User xy = new User("xy", 30);
       model.addAttribute("a",xy);
       return "myView";
    }
}

请求映射

1、RequestMapping可以声明在类和方法上

RequestMapping

可以声明在类上，如果要访问方法，需要将类的RequestMapping的值与方法上的RequestMapping的值组合访问。

http://localhost:8080/项目名称/类上注解/方法上注解

为了防止直接通过浏览器访问jsp页面，将所有页面放到WEB-INF下。只能通过控制器跳转。在视图解析器中的前缀添加WEB-INF。

2、可以根据不同的请求方式来控制哪种请求可以访问

//method = RequestMethod.POST只有页面通过post传参，才可以访问到这个方法
@RequestMapping(value = "save",method = RequestMethod.POST)
public String save(){
    System.out.println("UserController.save");
    return "b";
}

浏览器地址栏访问都是Get请求

3、在RequestMapping中添加params

//页面需要传递params中声明的参数，且值必须相等，这时才可以访问该方法
@RequestMapping(value = "login",params = {"uname=admin","pwd=123"})
public String login(String uname,String pwd){//这里要和 地址栏里面的参数一致才行  uname与uname对应  要对应
    System.out.println("UserController.save2");
    System.out.println(uname+"  "+pwd);
    return "b";
}

4、在RequestMapping中添加Headers

//可以在RequestMapping中声明headers,获得页面传递的请求头，从请求头中获得对应的信息，如果该信息相等，允许访问该方法
@RequestMapping(value = "list",headers = "host=localhost:8080")
//headers = "host=localhost:8080"只允许本机访问 。 【注意】 127.0.0.1 也不行必须 localhost
public String list(){
    System.out.println("UserController.list");
    return "b";
}

5、在RequestMapping中添加占位符

@RequestMapping(value = "login2/{uname}/{pwd}")
//需要使用注解
public String login2(@PathVariable("uname") String uname,@PathVariable("pwd") String pwd){
    System.out.println("UserController.save2");
    System.out.println(uname+"  "+pwd);
    return "b";
}

相应的配置文件

<?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.xsd
        http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">
   <context:component-scan base-package="cn.cqie.controller.b_request_mapping"/>
    <mvc:annotation-driven/>
   <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
       <property name="prefix" value="/WEB-INF/"></property>
       <property name="suffix" value=".jsp"></property>
   </bean>
</beans>

控制器方法入参

1、基本数据类型的自动转化

2、自动封装数据

package cn.cqie.controller.c_param;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import java.util.Arrays;
import java.util.List;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/23 21:30
 */
@Controller
public class UserController {
    /**
     * 在SpringMVC的Controller中不再需要request.getParameter(),直接在方法的参数中声明即可，要求参数名与表单控件的name一致
     * 如果非要不一致，则需要添加注解@RequestParam("表单的name值")
     */
    @RequestMapping("save1")
    public String save1(String name,@RequestParam("pwd") String password){
        System.out.println("UserController.save1:"+name+" : "+password);
        return null;
    }
    //SpringMVC的Controller，可以对数据进行自动转换
    @RequestMapping("save2")
    public String save2(Integer age){
        System.out.println("UserController.save2: "+(2021-age));//输出年份
        return null;
    }
    //可以将表单的数据自动封装成对象(参数中指定的类型)
    @RequestMapping("save3")
    public String save3(User user){
        System.out.println("UserController.save3: "+user);
        return  null;
    }
    //复选框的值可以直接获得为字符串数据,整型数组,如果需要List<Integer>类型,则需要添加注解@RequestParam
//    @RequestMapping("save4")
//    public String save4(String[] ids){
//        System.out.println("UserController.save4: ");
//        System.out.println(Arrays.toString(ids));
//        return null;
//    }
    @RequestMapping("save4")
    public String save4(@RequestParam List<Integer> ids){
        System.out.println("UserController.save4: ");
        System.out.println(ids);
        return null;
    }
}

<%--
  Created by IntelliJ IDEA.
  User: admin
  Date: 2021/11/25
  Time: 17:18
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" isELIgnored="false" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h3>传递参数到Controller</h3>
    <form action="save1" method="post">
        <input name="name">
        <input name="pwd">
        <button>submit</button>
    </form>
    <hr>
    <h3>传递整型数据</h3>
    <form action="save2">
        <input name="age">
        <button>submit</button>
    </form>
    <hr>
    <h3>传递对象数据</h3>
    <form action="save3">
        <input name="name">
        <input name="age">
        <button>submit</button>
    </form>
    <hr>
    <h3>传递复选框数据</h3>
    <form action="save4">
        <input type="checkbox" name="ids" value="1">
        <input type="checkbox" name="ids" value="2">
        <input type="checkbox" name="ids" value="3">
        <button>submit</button>
    </form>
</body>
</html>

时间类型参数

SpringMVC中默认识别日期格式为yyyy/MM/dd

其他格式需要自己编写转换类

package cn.cqie.controller.d_convert;
import org.springframework.core.convert.converter.Converter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/25 21:31
 */
public class DateConverter implements Converter<String, Date> {
    @Override
    public Date convert(String s) {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        //还可以转换其他的，  比如 yyyy.MM.dd
        Date date = null;
        try {
            //将日期转换成字符串
            date= simpleDateFormat.parse(s);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return date;
    }
}

将转换类配置到SpringMVC框架中

<?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.xsd
        http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">
   <context:component-scan base-package="cn.cqie.controller.d_convert"/>
    <mvc:annotation-driven conversion-service="conversionService"/>
   <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
       <property name="prefix" value="/"/>
       <property name="suffix" value=".jsp"/>
   </bean>
    <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="cn.cqie.controller.d_convert.DateConverter"></bean>
            </set>
        </property>
    </bean>
</beans>

Controller里面的代码

package cn.cqie.controller.d_convert;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import java.util.Date;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/23 21:30
 */
@Controller
public class UserController {
    @RequestMapping("save1")
    public String save(Date date){
        System.out.println(date);
        return null;
    }
}

使用ServletAPI

HttpServletRequest

HttpServletResponse

HttpSession

ServletContext

HttpServletRequest，HttpServletResponse，HttpSession对象都可以从方法参数中获取

@RequestMapping("login")
public String login(HttpServletRequest req, HttpServletResponse resp, HttpSession session){
    System.out.println("HttpServletRequest"+req);
    System.out.println("HttpServletResponse"+resp);
    System.out.println("HttpSession"+session);
    return  null;
}

SpringMVC数据校验

正则表达式

电话号码格式

邮箱格式

身份证格式等等

前端数据校验（可以减轻服务器压力）

后端数据校验

1、添加依赖

<dependency>
  <groupId>org.hibernate.validator</groupId>
  <artifactId>hibernate-validator</artifactId>
  <version>6.0.20.Final</version>
</dependency>

2、定义校验规则

在封装类上定义校验规则，JSR303

package cn.cqie.controller.e_validator;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.io.Serializable;
/**
 * Description：
 * Author: tiancx
 * Date: Created in 2021/11/24 21:04
 */
public class User implements Serializable {
    //null ""
//    在封装类上定义校验规则，JSR303
//    @NotBlank(message = "uname 不能为空!")
    @NotBlank(message = "name 不能为空")
    private String name;
    @NotNull(message = "age 不能为空")
    private Integer age;
    public User() {
    }
    public User(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

SpringMVC学习笔记（二）