Spring Data Jpa开发学习笔记(四)_springdata jpa学习笔记-优快云博客

本文介绍了一个使用Spring MVC和JPA实现的简单应用案例，包括项目的依赖配置、核心配置文件设置、控制器编写及视图展示等内容。

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本次在http://blog.youkuaiyun.com/xyc_csdn/article/details/52564149的基础上添加了Controller层并添加了显示页面用于输出列表。

修改pom.xml

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.xyc</groupId>
    <artifactId>chat</artifactId>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>chat Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <dependencies>

        <!-- 使用jstl 1.2时注意无需引用standard -->
        <!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.2.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.10.1.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-entitymanager -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.1.0.Final</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.38</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <finalName>chat</finalName>
    </build>
</project>

修改applicationContext.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:jpa="http://www.springframework.org/schema/data/jpa" xmlns:tx="http://www.springframework.org/schema/tx"
       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-4.1.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- 开启spring注解 -->
    <!-- 不过在使用了component-scan之后，annotation-config就不需要了 -->
    <context:annotation-config/>

    <!-- 在指定的package下扫描以及注册javabean -->
    <context:component-scan base-package="com.xyc.jpa">
        <context:exclude-filter type="regex" expression="com.xyc.jpa.controller"/>
    </context:component-scan>

    <!-- 实体管理工厂 -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="chatUnit"></property>
        <property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml"></property>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="true"></property>
                <property name="database" value="MYSQL"></property>
            </bean>
        </property>
    </bean>

    <!-- 配置事务管理器 -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <!-- 基于注解的方式使用事务配置声明 -->
    <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="false"/>

    <!-- 自动扫描并注入Spring Data JPA 需要在 <beans> 标签中增加对 jpa 命名空间的引用 -->
    <jpa:repositories base-package="com.xyc.jpa.dao"
                      entity-manager-factory-ref="entityManagerFactory"
                      transaction-manager-ref="transactionManager"/>

</beans>

修改spring-servlet.xml.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">
    <!-- 设置使用注解的类所在的包 -->
    <context:component-scan base-package="com.xyc.jpa.controller"/>

    <!-- 启用 spring mvc 注解 -->
    <!-- 注意这里使用的并不是<context:annotation-config />，<context:annotation-config />是启用 spring 注解的 -->
    <mvc:annotation-driven/>

    <!-- 对转向页面的路径解析。prefix：前缀， suffix：后缀 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/view/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

创建UserController

package com.xyc.jpa.controller;

import com.xyc.jpa.pojo.User;
import com.xyc.jpa.service.UserService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.annotation.Resource;
import java.util.Collection;
import java.util.Map;

/**
 * Created by xyc on 2016/9/17 0017.
 */
@Controller
@RequestMapping("/api/users")
public class UserController {
    @Resource
    private UserService userService;

    @RequestMapping(method = RequestMethod.GET)
    public String list(Map<String, Object> model) {
        System.out.println("list");
        Collection<User> users = this.userService.queryAll();
        model.put("users", users);
        return "list";
    }
}

修改web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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_2_5.xsd">
    <!-- 使用jstl 1.2时注意web-app头部需要如上所示为2.5或2.5版本以上 -->
    <display-name>JPA</display-name>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!-- Spring MVC配置 -->
    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 可以自定义servlet.xml配置文件的位置和名称，默认为WEB-INF目录下，名称为[<servlet-name>]-servlet.xml，如spring-servlet.xml-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-servlet.xml</param-value>
        </init-param>
        <!--
          指定当Web应用启动时，装载Servlet的次序。
          当值为正数或零时：Servlet容器先加载数值小的servlet，再依次加载其他数值大的servlet.
          当值为负或未定义：Servlet容器将在Web客户首次访问这个servlet时加载它
        -->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

创建list.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--注意应该使用如上引用<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>--%>
<%--
  Created by IntelliJ IDEA.
  User: xyc
  Date: 2016/9/17 0017
  Time: 18:18
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>列表</title>
</head>
<body>
<c:forEach items="${users}" var="user">
    <div>${user.username}</div>
</c:forEach>
</body>
</html>