springmvc注解开发

@RequestMapping定义请求规则

此注解就是来映射服务器访问的路径
此注解可加在方法上,是为此方法注册一个可以访问的名称(路径)

package com.peihj.controller;

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

@Controller // 交给Spring去创建对象
public class DemoAction2 {
    /**
     * action中所有方法的创建都是由方法来完成的
     * action方法的规范
     * 1）访问权限是public
     * 2）方法的返回值任意
     * 3）方法名称任意
     * 4）参数任意类型，方法可以没有参数
     * 5）要使用@RequestMappering注解来进行声明一个访问路径
     */
    @RequestMapping("demo.action")
    public String demo(){
        System.out.println("user服务器被访问到了.............");
        return "main";  // 可以直接跳到/admin/main.jsp页面上
    }

}


  <a href="${pageContext.request.contextPath}/demo.action">访问服务器</a>

此注解可以加在类上,相当于是包名(虚拟路径),区分不同类中相同的action的名称。

package com.peihj.controller;

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

@Controller // 交给Spring去创建对象
@RequestMapping("user")
public class DemoAction2 {
    /**
     * action中所有方法的创建都是由方法来完成的
     * action方法的规范
     * 1）访问权限是public
     * 2）方法的返回值任意
     * 3）方法名称任意
     * 4）参数任意类型，方法可以没有参数
     * 5）要使用@RequestMappering注解来进行声明一个访问路径
     */
    @RequestMapping("demo.action")
    public String demo(){
        System.out.println("user服务器被访问到了.............");
        return "main";  // 可以直接跳到/admin/main.jsp页面上
    }
}

  <a href="${pageContext.request.contextPath}/user/demo.action">访问服务器</a>

此注解可区分get请求和post请求

@Controller
	public class ReqAction {
	    @RequestMapping(value = "/req",method = RequestMethod.GET)
	    public String req(){
	        System.out.println("我是处理get请求的........");
	        return "main";
	    }
	    @RequestMapping(value = "/req" ,method = RequestMethod.POST)
	    public String req1(){
	        System.out.println("我是处理post请求的........");
	        return "main";
	    }
	}

五种数据提交方式的优化

我们首先建立一个工程文件，具体流程见：https://blog.csdn.net/weixin_45522528/article/details/124672914
在这里插入图片描述
pom文件

<?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.peihj</groupId>
  <artifactId>springmvc-002-datasubmit</artifactId>
  <version>1.0</version>
  <packaging>war</packaging>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!--添加Spring-MVC依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.18</version>
    </dependency>
    <!--添加servlet依赖-->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.2</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>1.1.2</version>
    </dependency>
  </dependencies>

  <build>
    <resources>
      <resource>
        <directory>src/main/java</directory><!--所在的目录-->
        <includes><!--包括目录下的.properties,.xml 文件都会被扫描到-->
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
      </resource>

      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
      </resource>
    </resources>

    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <port>7070</port>
          <uriEncoding>UTF-8</uriEncoding>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

Springmvc编写

<?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"
       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">


    <!--添加包扫描-->
    <context:component-scan base-package="com.peihj"></context:component-scan>
    <!--添加视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/admin/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

创建admin包文件以及main.jsp文件夹，删除重新创建index.jsp文件，删除并重新编写web.xml文件

<?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_4_0.xsd"
         version="4.0">
   
    <!--注册springmvc框架-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.action</url-pattern>
    </servlet-mapping>
</web-app>

五种数据注入

<%--
  Created by IntelliJ IDEA.
  User: peihj
  Date: 2022/5/9
  Time: 14:56
  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>
<br><br><br>
<h2>测试不同的请求提交方式</h2>
<form action="${pageContext.request.contextPath}/req.action" method="post">
    <input type="submit" value="提交">
</form><br><br><br>
<h2>1.单个数据的提交</h2>
<form action="${pageContext.request.contextPath}/one.action" method="post">
    姓名：<input name="myname"><br>
    年龄：<input name="age"><br>
    <input type="submit" value="提交">
</form>


<%--   private String name;
    private int age;

    保证名称一致以便于自动注入
--%>
<h2>2.对象封装提交</h2>
<form action="${pageContext.request.contextPath}/two.action" method="post">
    姓名：<input name="name"><br>
    年龄：<input name="age"><br>
    <input type="submit" value="提交">
</form>
<br>
<h2>3.动态占位符提交</h2>
<a href="${pageContext.request.contextPath}/three/张三/22.action">动态提交</a>

<br><br><br>
<h2> 4.参数名称不一致解决方案></h2>
<form action="${pageContext.request.contextPath}/four.action" method="post">
    姓名：<input name="name"><br>
    年龄：<input name="age"><br>
    <input type="submit" value="提交">
</form>

<h2> 5.手工提取数据></h2>
<form action="${pageContext.request.contextPath}/five.action" method="post">
    姓名：<input name="name"><br>
    年龄：<input name="age"><br>
    <input type="submit" value="提交">
</form>
</body>
</html>

package com.peihj.controller;

import com.peihj.pojo.Users;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpServletRequest;

@Controller
public class DataSubmitAction {
    @RequestMapping("/one.action")
    public String one(String myname,int age){
        System.out.println("myname="+myname+",age="+(age+0));
        return "main";
    }

    @RequestMapping("/two.action")
    public String two(Users u){
        System.out.println(u);
        return "main";
    }

    @RequestMapping("/three/{uname}/{uage}.action")
    public String three(@PathVariable("uname") String name, @PathVariable("uage") int age){
        System.out.println("myname="+name+",age="+(age+0));
        return "main";
    }

    @RequestMapping("four.action")
    public String four(@RequestParam("name") String uname,@RequestParam("age") int uage){
        System.out.println("myname="+uname+",age="+(uage+0));
        return "main";
    }

    @RequestMapping("five.action")
    public String five(HttpServletRequest httpServletRequest){
        String name = httpServletRequest.getParameter("name");
        Integer age = Integer.parseInt(httpServletRequest.getParameter("age"));
        System.out.println(name);
        System.out.println(age);
        return "main";
    }
}

单个提交数据

在方法中声明一个和表单提交的参数名称相同的参数，由框架按照名称直接注入，只要表单name属性的值与action方法参数的名称一致就可以实现自动注入
在这里插入图片描述

对象封装注入

在提交请求中,保证请求参数的名称与实体类中成员变量的名称一致,则可以自动创建对象,则可以自动提交数据,自动类型转换,自动封装数据到对象中.

首先我们先创建对象类

package com.peihj.pojo;

public class Users {
    private String name;
    private int age;

    public Users() {
    }

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

    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;
    }

    @Override
    public String toString() {
        return "Users{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

在这里插入图片描述

动态占位符提交（仅用于超链接）

仅限于超链接或地址拦提交数据.它是一杠一值,一杠一大括号,使用注解@PathVariable来解析.
在这里插入图片描述

请求参数名称与形参名称不一致

请求与形参中的名字不对应，可以使用
@RequestParam(value=“name1”,required=true)String namea来进行参数名称绑定
在这里插入图片描述

手工提取数据

在这里插入图片描述

中文乱码解决方案

配置过滤器

过滤器代码

<!--配置中文编码过滤器的配置-->
    <!--配置字符集编码过滤器-->
    <filter>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <!--设置字符集编码-->
        <!--配置参数
        private String encoding;
        private boolean forceRequestEncoding;
        private boolean forceResponseEncoding;
        -->
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceRequestEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

完整

<?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_4_0.xsd"
         version="4.0">
    <!--配置中文编码过滤器的配置-->
    <!--配置字符集编码过滤器-->
    <filter>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <!--设置字符集编码-->
        <!--配置参数
        private String encoding;
        private boolean forceRequestEncoding;
        private boolean forceResponseEncoding;
        -->
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceRequestEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


    <!--注册springmvc框架-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.action</url-pattern>
    </servlet-mapping>
</web-app>