spring jedis客户端集成

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mob64ca13fe62db 2024-10-28 12:53:25

文章标签 spring jedis客户端集成 spring xml java 监听器 文章分类 架构后端开发

基本三层架构环境搭建

准备好Dao和Service层

Dao层

UserDao接口

package com.dao;

public interface UserDao {
    public void save();
}

UserDaoImpl类, 实现UserDao接口

package com.dao.impl;
import com.dao.UserDao;

public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("save running...");
    }
}

Service层

UserService 接口

package com.service;

public interface UserService {
    public void save();
}

UserServiceImpl实现类

package com.service.impl;

import com.dao.UserDao;
import com.service.UserService;

public class UserServiceImpl implements UserService {

    private UserDao userDao;

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public void save() {
        userDao.save();
    }
}

配置文件

配置Dao和Service

<!--配置Dao-->
    <bean id="userDao" class="com.dao.impl.UserDaoImpl"></bean>

    <!--配置Service-->
    <bean id="userService" class="com.service.impl.UserServiceImpl">
        <property name="userDao" ref="userDao"/>
    </bean>

创建web层

在pom.xml文件导入servlet的坐标

<dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.2.1</version>
            <scope>provided</scope>
        </dependency>

创建UserServlet类

public class UserServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = app.getBean(UserService.class);
        userService.save();
    }
}

UserServlet 想要被使用, 需要进行配置
web.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    
    <servlet>
        <servlet-name>UserServlet</servlet-name>
        <servlet-class>com.web.UserServlet</servlet-class>
    </servlet>
    <!--映射-->
    <servlet-mapping>
        <servlet-name>UserServlet</servlet-name>
        <url-pattern>/userServlet</url-pattern>
    </servlet-mapping>
</web-app>

配置tomcat : 通过maven配置tomcat并且在配置中引入

<!--构建-->
    <build>
        <!--设置插件-->
        <plugins>
            <!--具体的插件配置-->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.1</version>
                <configuration>
                    <port>80</port>
                    <path></path>
                </configuration>
            </plugin>
        </plugins>
    </build>

启动服务器.测试结果如下

spring jedis客户端集成_spring jedis客户端集成

spring jedis客户端集成_java_02

测试成功~

监听器的分析

ApplicationContext应用上下文获取方式

应用上下文对象是通过new ClasspathXmlAplicationContext(Spring 配置文件)方式获取的
但是每次从容器中获得Bean时都要编写new ClasspathXmlApplicationContext(Spring 配置文件)
这样的弊端的配置文件加载多次, 应用上下文对象创建多次

在Web项目中, 可以使用ServletContextListener监听Web应用的启动, 我们可以在Web应用启动时, 就加载Spring文件, 创建应用上下文对象ApplicationContext, 在将其存储到最大的域servletContext域中, 这样就可以在任意位置从域中获得应用上下文ApplicationContext对象了

创建一个监听器的类

public class ContextLoaderListener implements ServletContextListener {
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
        //将Spring的应用上下文对象存储到ServletContext域中
        ServletContext servletContext = servletContextEvent.getServletContext();
        servletContext.setAttribute("app", app);
        System.out.println("spring 容器创建完毕");
    }

    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

在web.xml配置监听器

<!--配置监听器-->
    <listener>
        <listener-class>com.listener.ContextLoaderListener</listener-class>
    </listener>

修改测试类UserServlet

public class UserServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        ServletContext servletContext = this.getServletContext();
        ApplicationContext app = (ApplicationContext) servletContext.getAttribute("app");
        UserService userService =app.getBean(UserService.class);
        userService.save();

    }
}

spring jedis客户端集成_java_03

对加载监听器进行代码优化

在Web.xml中的配置全局参数

<!--全局初始化参数-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>applicationContext.xml</param-value>
    </context-param>

在ContextLoaderListene读取全局参数, 目的是解耦

public class ContextLoaderListener implements ServletContextListener {
    public void contextInitialized(ServletContextEvent servletContextEvent) {

        ServletContext servletContext = servletContextEvent.getServletContext();

        //读取Web.xml中的全局参数
        String contextConfigLocation = servletContext.getInitParameter("contextConfigLocation");

        ApplicationContext app = new ClassPathXmlApplicationContext(contextConfigLocation);
        //将Spring的应用上下文对象存储到ServletContext域中

        servletContext.setAttribute("app", app);
        System.out.println("spring 容器创建完毕");
    }

    public void contextDestroyed(ServletContextEvent servletContextEvent) {

    }
}

创建一个工具类WebApplicationContextUtils

public class WebApplicationContextUtils {

    public static ApplicationContext getWebApplicationContext(ServletContext servletContext) {
        return (ApplicationContext) servletContext.getAttribute("app");

    }
}

优化web层UserServlet 类的代码

public class UserServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        ServletContext servletContext = this.getServletContext();
        ApplicationContext app = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        UserService userService =app.getBean(UserService.class);
        userService.save();

    }
}

Spring提供应用获取上下文的工具

上面的分析不用手动实现, Spring提供一个监听器ContextLoaderListener就是对上述功能的封装, 该监听器内部加载Spring配置文件, 创建应用上下文对象, 并存储到ServletConrext域中, 提供一个客户端工具WebApplicationContextUtils供使用者获得应用上下文对象

步骤

在web.xml配置ContextLoaderListener监听器(导入spring-web坐标)
使用WebApplicationContextUtils获得应用上下文对象ApplicationContext

导入spring-web坐标

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>

在web.xml配置ContextLoaderListener监听器

<!--全局初始化参数-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <!--配置监听器-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoader</listener-class>
    </listener>

UserServlet 类

public class UserServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        ServletContext servletContext = this.getServletContext();

        ApplicationContext app = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        UserService userService = app.getBean(UserService.class);
        userService.save();
    }
}

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