SpringMVC简单使用

倚-天-照-海

于 2024-11-17 22:45:04 发布

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分类专栏： java 文章标签： java 开发语言面试

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MVC模型：是一种架构的新模式，本身不引入新的功能，只是帮助我们将开发的结构组织的更加合理。使展示与模型分离，流程逻辑控制、业务逻辑调用与展示逻辑分离。

M(model模型）：数据模型，包含要展示的数据和业务。

V(View视图）：用户界面，在界面上展示模型数据。

C（Controller控制器）：起调度作用，接收用户请求，调用业务处理请求，共享数据模型并跳转界面。

使用方式有两种，现在基本上都是使用第二种方式：

1、基于XML配置与注解的方式使用Spring MVC

2、基于Java配置与注解的方式使用Spring MVC

1、基于XML配置与注解的方式使用Spring MVC

1. 在pom.xml中添加依赖

<?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>net.hw.spring</groupId>
    <artifactId>SpringMVCDemo01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <!-- spring.version -->
        <spring.version>5.3.4</spring.version>
    </properties>

    <dependencies>
        <!--Spring核心-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring Bean-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring容器-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring测试-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring Web-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring MVC-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--JSP标准标签库-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <!--Servlet -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!--日志框架-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

2. 添加项目web功能

3. 创建登录页面、登录成功页面、登录失败页面

创建views子包

登录页面login.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>用户登录</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" >
</head>
<body>
	<h3 style="text-align: center">用户登录</h3>
	<form id="frmLogin" action="login" method="post">
		<table class="tb" border="1" cellpadding="10" style="margin: 0px auto">
			<tr>
				<td align="center">账号</td>
				<td><input id="username" type="text" name="username"></td>
			</tr>
			<tr>
				<td align="center">密码</td>
				<td><input id="password" type="password" name="password"/></td>
			</tr>
			<tr align="center">
				<td colspan="2">
					<input type="submit" value="登录" onclick="check()"/>
					<input type="reset" value="重置"/>
				</td>
			</tr>
		</table>
	</form>
</body>
</html>

登录成功页面success.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
	<head>
		<title>登录成功</title>
	</head>
	<body>
		<h1>${username}，登录成功！</h1>
	</body>
</html>

登录失败页面failure.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
	<head>
		<title>登录失败</title>
	</head>
	<body>
		<h1>${username}，登录失败！</h1>
	</body>
</html>

4. 创建登录控制器loginController

package net.lj.spring.controller;

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

import javax.servlet.http.HttpSession;

/**
 * 登录控制器
 */
@Controller
public class LoginController {
    @RequestMapping("/login")
    public String login(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        HttpSession session) {
        //将从登录表单获取的用户名写入会话
        session.setAttribute("username", username);
        //判断是否登陆成功
        if (username.equals("admin") && password.equals("123456")) {
            return "success";//返回逻辑视图名
        } else {
            //返回逻辑视图名
            return "failure";
        }
    }
}

5. 创建Spring配置文件spring-config.xml

<?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
       https://www.springframework.org/schema/context/spring-context.xsd">

    <!--组件扫描-->
    <context:component-scan base-package="net.lj.spring"/>
</beans>

6. 创建Spring MVC配置文件spring-mvc-config.xml

<?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:mvc="http://www.springframework.org/schema/mvc"
       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/mvc
       https://www.springframework.org/schema/mvc/spring-mvc.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd">

    <!--采用注解驱动-->
    <mvc:annotation-driven />

    <!--扫描控制器-->
    <context:component-scan base-package="net.lj.spring.controller" />

    <!--定义内部资源视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/views/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <!--定义视图控制器-->
    <mvc:view-controller path="/" view-name="index"/>
    <mvc:view-controller path="/toLogin" view-name="login"/>

    <!--处理静态资源的请求-->
    <mvc:resources mapping="/imgs/**" location="/WEB-INF/imgs/"/>

    <mvc:resources mapping="/css/**" location="/WEB-INF/css/"/>
    <mvc:resources mapping="/js/**" location="/WEB-INF/js/"/>
</beans>

7. 通过web.xml加载配置文件

<?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">

    <!--设置启动首页-->
<!--    <welcome-file-list>-->
<!--        <welcome-file>/WEB-INF/views/login.jsp</welcome-file>-->
<!--    </welcome-file-list>-->

    <!--Spring容器加载监听器，让Spring随着Web项目启动而初始化-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!--指定Spring配置文件位置-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:mvc/spring-config.xml</param-value>
    </context-param>

    <!--配置Spring前端控制器，加载Spring MVC配置文件-->
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:mvc/spring-mvc-config.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>  <!--“/”表明拦截一切请求-->
    </servlet-mapping>

    <!--设置字符编码过滤器-->
    <filter>
        <filter-name>Character Encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>Character Encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

至此，基于XML配置文件的方式使用spring mvc的操作就完成了，下面是配置Tomcat启动服务进行验证，现在idea都内置了Tomcat，无需配置，直接启动服务，打开浏览器发起请求进行验证。

8. 配置Tomcat服务器

9. 添加Tomcat依赖

10. 启动Tomcat服务器，测试登录功能

11. 设置首页

注释web.xml中的首页设置

在views下创建index.jsp并编写问候语

在LoginController.java控制器里设置主页面

启动服务器

12. 实现主页跳转到登录页面功能

在index.jsp页面增加跳转到登录页面功能

在LoginController.java中增加跳转到登录页面方法

启动服务，进入首页，进行用户登录。

13. 利用SpringMVC配置文件的视图控制器元素实现从主页跳转到登录页面

将LoginController.java中的index方法和toLogin方法都注释掉，在spring-mvc-config.xml定义负责跳转的视图控制器，也可以实现从主页跳转到登录页面的功能。

2、基于Java配置与注解的方式使用Spring MVC

1. 在pom.xml里添加依赖

<?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>nei.lj.spring</groupId>
    <artifactId>SpringMVCDemo02</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <!-- spring.version -->
        <spring.version>5.3.4</spring.version>
    </properties>

    <dependencies>
        <!--Spring核心-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring Bean-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring容器-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring测试-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring Web-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring MVC-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--JSP标准标签库-->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <!--Servlet -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!--日志框架-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>
        <!--对json的支持-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.7</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.7</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.7</version>
        </dependency>
        <!--对xml的支持-->
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-xml</artifactId>
            <version>2.5.3</version>
        </dependency>
    </dependencies>
</project>

2. 创建日志属性文件 log4j.properties

log4j.rootLogger=WARN, stdout, logfile
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

3. 创建index.jsp

4. 创建配置类SpringMvcConfig

package net.lj.spring;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
/**
 * Spring MVC配置类
 */
@Configuration
@EnableWebMvc
@ComponentScan("net.lj.spring")
public class SpringMvcConfig implements WebMvcConfigurer {
    @Bean
    public InternalResourceViewResolver viewResolver () {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/classes/templates/");//路径
        viewResolver.setSuffix(".jsp"); //文件后缀
        viewResolver.setViewClass(JstlView.class);
        return viewResolver;
    }
}

5. 创建Web配置类 MyWebInitializer

所涉及的WebApplicationInitializer接口功能类似于web.xml

package net.lj.spring;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

/**
 * Web应用初始化配置类
 */
public class MyWebInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        // 创建Web应用容器
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        // 注册配置类（配置类对应以前的spring-mvc-config.xml文件）
        context.register(SpringMvcConfig.class);
        // 与当前ServletContext关联
        context.setServletContext(servletContext);
        // 注册Spring MVC的前端控制器（DispatcherServlet）
        ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(context));
        // 过滤一切资源请求
        servlet.addMapping("/");
        // 设置启动加载顺序
        servlet.setLoadOnStartup(1);
    }
}

6. 创建控制器 HelloController

package net.lj.spring.controller;

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

/**
 * 控制器
 */
@Controller
public class HelloController {
    @RequestMapping("/")
    public String hello() {
        return "index";
    }
}

7. 配置Tomcat服务器

8.启动服务进行测试

实现登录功能

1. 创建登录、登录成功、登录失败三个界面

登录页面Login.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>用户登录</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" >
</head>
<body>
	<h3 style="text-align: center">用户登录</h3>
	<form id="frmLogin" action="login" method="post">
		<table class="tb" border="1" cellpadding="10" style="margin: 0px auto">
			<tr>
				<td align="center">账号</td>
				<td><input id="username" type="text" name="username"/></td>
			</tr>
			<tr>
				<td align="center">密码</td>
				<td><input id="password" type="password" name="password"/></td>
			</tr>
			<tr align="center">
				<td colspan="2">
					<input type="submit" value="登录"/>
					<input type="reset" value="重置"/>
				</td>
			</tr>
		</table>
	</form>
</body>
</html>

登录成功页面success.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
	<head>
		<title>登录成功</title>
	</head>
	<body>
		<h1>${username}，登录成功！</h1>
	</body>
</html>

登录失败页面failure.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
	<head>
		<title>登录失败</title>
	</head>
	<body>
		<h1>${username}，登录失败！</h1>
	</body>
</html>

2. 在首页增加跳转登录功能

首页增加跳转链接

定义视图控制器，打开SpringMVC配置类

/**
 * 添加视图控制器
 */
@Override
public void addViewControllers(ViewControllerRegistry registry) {
    registry.addViewController("/toLogin").setViewName("login");
}

创建登录控制器 LoginController

package net.lj.spring.controller;

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

import javax.servlet.http.HttpSession;

/**
 * 登录控制器
 */
@Controller
public class LoginController {
    @RequestMapping("/login")
    public String login(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        HttpSession session) {
        session.setAttribute("username", username);
        if (username.equals("admin") && password.equals("123456")) {
            return "success"; // 逻辑视图名
        } else {
            return "failure"; // 逻辑视图名
        }
    }
}

启动服务进行测试：