springmvc怎么添加依赖 springmvc依赖注入

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代码匠人之心 2024-03-28 15:21:32

文章标签 springmvc怎么添加依赖 SpringMVC spring mvc User 文章分类 架构后端开发

概述

可以通过org.springframework.beans.factory.annotation.Autowired注解类型将依赖注入到一个属性或方法中。

如：

// 将服务依赖注入到属性userService
    @Autowired
    public UserService userService;

在Spring MVC中，为了能够被作为依赖注入，类必须使用org.springframework.stereotype.Service注解类型注明为@Service。

即创建service包，包下有两个类UserService.java和UserServiceImpl.java。

UserService接口如下：

package springmvcdemo.service;

import springmvcdemo.pojo.User;

public interface UserService {
    /**
     * 用户登录
     *
     * @param user 用户实体类对象
     * @return 返回是否登录成功
     */
    boolean login(User user);

    /**
     * 用户注册
     *
     * @param user 用户实体类对象
     * @return 返回是否注册成功
     */
    boolean register(User user);
}

UserServiceImpl实现类代码如下：

package springmvcdemo.service;

import org.springframework.stereotype.Service;
import springmvcdemo.pojo.User;

@Service
public class UserServiceImpl implements UserService {

    @Override
    public boolean login(User user) {
        if ("hello".equals(user.getUsername()) && "world".equals(user.getPassword())) {
            return true;
        }
        return false;
    }

    @Override
    public boolean register(User user) {
        if ("hello".equals(user.getUsername()) && "world".equals(user.getPassword())) {
            return true;
        }
        return false;
    }
}

除此之外，还需要在配置文件中使用<context:component-scan base-package="服务类所在的包"/>元素来扫描依赖基本包。

故配置文件中的需要配置的代码如下：

<!--使用扫描机制扫描服务类，服务类都在service包及其子包下-->
    <context:component-scan base-package="springmvcdemo.service"/>

修改UserController控制器代码如下：

package springmvcdemo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import springmvcdemo.pojo.User;
import springmvcdemo.service.UserService;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class UserController {

    // 将服务依赖注入到属性userService
    @Autowired
    public UserService userService;

    @RequestMapping("/login")
    public String login(User user, HttpSession session, Model model) {
        if (userService.login(user)) {
            System.out.println("登录成功");
            session.setAttribute("user", user);
            // 跳转到/WEB-INF/jsp/下的main.jsp
            return "main";
        } else {
            System.out.println("登录失败");
            model.addAttribute("messageError", "用户名或密码错误");
            // 登录失败跳转到login.jsp
            return "login";
        }
    }

    @RequestMapping("/register")
    public String register(User user, Model model) {
        if (userService.register(user)) {
            System.out.println("注册成功");
            // 注册成功，跳转到login.jsp
            return "login";
        } else {
            System.out.println("注册失败");
            model.addAttribute("username", user.getUsername());
            // 注册失败，跳转到register.jsp
            return "register";
        }
    }
}

实例

在本实例中将login和register的业务逻辑单独分离出来，交给了service去处理。

创建spring mvc项目并且按照下图创建文件夹及文件：

springmvc怎么添加依赖 springmvc依赖注入_SpringMVC

各文件代码如下：

IndexController.java

package springmvcdemo.controller;


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

@Controller
@RequestMapping("/index")
public class IndexController {

    @RequestMapping("/register")
    public String register() {
        return "register";
    }

    @RequestMapping("/login")
    public String login() {
        return "login";
    }
}

UserController.java

package springmvcdemo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import springmvcdemo.pojo.User;
import springmvcdemo.service.UserService;

import javax.servlet.http.HttpSession;

@Controller
@RequestMapping("/user")
public class UserController {

    // 将服务依赖注入到属性userService
    @Autowired
    public UserService userService;

    @RequestMapping("/login")
    public String login(User user, HttpSession session, Model model) {
        if (userService.login(user)) {
            System.out.println("登录成功");
            session.setAttribute("user", user);
            // 跳转到/WEB-INF/jsp/下的main.jsp
            return "main";
        } else {
            System.out.println("登录失败");
            model.addAttribute("messageError", "用户名或密码错误");
            // 登录失败跳转到login.jsp
            return "login";
        }
    }

    @RequestMapping("/register")
    public String register(User user, Model model) {
        if (userService.register(user)) {
            System.out.println("注册成功");
            // 注册成功，跳转到login.jsp
            return "login";
        } else {
            System.out.println("注册失败");
            model.addAttribute("username", user.getUsername());
            // 注册失败，跳转到register.jsp
            return "register";
        }
    }
}

User.java

package springmvcdemo.pojo;

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

    public String getUsername() {
        return username;
    }

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

    public String getPassword() {
        return password;
    }

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

}

UserService.java

package springmvcdemo.service;

import springmvcdemo.pojo.User;

public interface UserService {
    /**
     * 用户登录
     *
     * @param user 用户实体类对象
     * @return 返回是否登录成功
     */
    boolean login(User user);

    /**
     * 用户注册
     *
     * @param user 用户实体类对象
     * @return 返回是否注册成功
     */
    boolean register(User user);
}

UserServiceImpl.java

package springmvcdemo.service;

import org.springframework.stereotype.Service;
import springmvcdemo.pojo.User;

@Service
public class UserServiceImpl implements UserService {

    @Override
    public boolean login(User user) {
        if ("hello".equals(user.getUsername()) && "world".equals(user.getPassword())) {
            return true;
        }
        return false;
    }

    @Override
    public boolean register(User user) {
        if ("hello".equals(user.getUsername()) && "world".equals(user.getPassword())) {
            return true;
        }
        return false;
    }
}

springmvc-servlet.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"
       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">

    <!--使用扫描机制扫描控制器类，控制器类都在controller包及其子包下-->
    <context:component-scan base-package="springmvcdemo.controller"/>

    <!--使用扫描机制扫描服务类，服务类都在service包及其子包下-->
    <context:component-scan base-package="springmvcdemo.service"/>

    <!--配置视图解析器-->
    <!--配置视图解析器成功后，RegisterController和LoginController控制器类的视图路径仅需提供register和login，视图解析器将会自动添加前缀和后缀-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录</title>
</head>
<body>
<form action="/user/login" method="post">
    姓名：<input type="text" name="username"><br>
    密码：<input type="password" name="password"><br>
    <input type="submit" value="登录">
    <span style="color:red"><%=request.getAttribute("messageError")%></span>
</form>
</body>
</html>

main.jsp

<%@ page import="springmvcdemo.pojo.User" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>主页</title>
</head>
<body>
    <%
        User user = (User)session.getAttribute("user");
    %>
    欢迎<%=user.getUsername()%>，访问本页面！
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>注册</title>
</head>
<body>
<form action="/user/register" method="post">
    姓名：<input type="text" name="username"><br>
    密码：<input type="password" name="password"><br>
    <input type="submit" value="注册">
</form>
</body>
</html>

web.xml

<?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">
    <!--部署DispatcherServlet-->
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--加载Spring MVC的配置文件，配置文件可以放在项目目录的任意位置，使用init-param元素加载配置文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--配置文件的位置-->
            <param-value>/WEB-INF/config/springmvc-config/springmvc-servlet.xml</param-value>
        </init-param>
        <!--表示容器在启动时立即加载servlet-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <!--处理所有URL-->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>首页</title>
</head>
<body>
未注册的用户，请<a href="/index/register">注册</a>！<br>
已注册的用户，去<a href="/index/login">登录</a>！<br>
</body>
</html>

运行效果如下：

springmvc怎么添加依赖 springmvc依赖注入_mvc_02