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本文会介绍从一个最基本的java工程,到Web工程,到集成Spring、SpringMVC、SpringDataJPA+Hibernate。
平时我们可能是通过一个模板搭建一个工程,或者是直接导入一个项目,而本文选择从最基本的java工程开始,目的是为了展示更多原理。
当然,我们还是从一个最基本的Maven工程开始,其实普通的非Maven工程,搭建过程几乎是一模一样的,只是Jar包需要我们手动的添加到工程中,而Maven工程就只是修改配置文件即可。推荐几篇相关文章:
- Maven介绍及安装和在eclipse中的配置
- Eclipse中使用Maven创建基本的web项目
- Eclipse搭建Maven工程集成Spring4MVC
- Eclipse搭建Maven工程集成Spring4+MVC+Hibernate5
- JPA规范介绍及实例(Java数据持久化解决方案)
对 Spring Data JPA 更详细的介绍,请戳->Spring ORM+Hibernate?Out!换 Spring Data JPA 吧!
下面就正式开始。
新建工程,选择Maven Project,Next:
勾选为简单的工程(Create a simple project),Next:
Group id为你的域名反序,通常跟工程源码的包名对应,Artifact id为这个Group id中工程的唯一名,根据你的爱好,怎么填都行,然后Finish:
这是得到的工程目录结构是这样的:
pom.xml就是Maven的核心文件。
接下来就将工程转换为Web工程,右键打开工程属性,如图,点击左边菜单中的Project Facets,然后点击Convert to faceted from...:
在右边,我们勾选Dynamic Web Module(动态网页),然后点OK:
这时会多出一个WebContent目录:
在WEB-INF目录下,添加web.xml文件,内如如下:
- <?xml version="1.0" encoding="UTF-8"?>
- <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xmlns="http://java.sun.com/xml/ns/javaee"
- xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
- version="3.0">
- <display-name>SpringDataJPA</display-name>
- <welcome-file-list>
- <welcome-file>index.html</welcome-file>
- </welcome-file-list>
- </web-app>
然后添加一个欢迎页index.html:
- <html>
- <head>
- </head>
- <body>
- <h1>Hello Word!</h1>
- </body>
- </html>
这时目录结构如下:
这时,就可以右键工程,Run On Server了,可以看下效果:
新建包,并添加一些接口和类(具体代码后面会列出来),包结构如图:
需要添加jar包,直接修改pom文件即可,如果为普通工程,按pom.xml中的jar包,添加到工程中即可。
首先添加使用的spring版本,方便统一管理,然后再添加所有需要的jar包,下面把此处需要的所有jar包添加进来,完成后的pom.xml如下:
- <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.anxpp</groupId>
- <artifactId>SpringDataJPA</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <properties>
- <!-- spring版本号 -->
- <spring.version>4.2.5.RELEASE</spring.version>
- </properties>
- <dependencies>
- <!-- spring核心包 -->
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-core</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-web</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-orm</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-tx</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-jdbc</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-webmvc</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-aop</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-context-support</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-test</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework</groupId>
- <artifactId>spring-orm</artifactId>
- <version>${spring.version}</version>
- </dependency>
- <dependency>
- <groupId>org.springframework.data</groupId>
- <artifactId>spring-data-jpa</artifactId>
- <version>1.10.1.RELEASE</version>
- </dependency>
- </dependencies>
- </project>
在WEB-INF目录下添加Spring配置文件applicationContext.xml,并添加如下内容:
- <?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:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p"
- xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
- http://www.springframework.org/schema/context
- http://www.springframework.org/schema/context/spring-context-4.2.xsd
- http://www.springframework.org/schema/tx
- http://www.springframework.org/schema/tx/spring-tx-4.2.xsd
- http://www.springframework.org/schema/aop
- http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
- http://www.springframework.org/schema/mvc
- http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd">
- <!-- 开启IOC注解扫描 -->
- <context:component-scan base-package="com.anxpp.demo" />
- <!-- 开启MVC注解扫描 -->
- <mvc:annotation-driven />
- </beans>
修改web.xml,将spring添加进去:
- <?xml version="1.0" encoding="UTF-8"?>
- <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xmlns="http://java.sun.com/xml/ns/javaee"
- xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
- version="3.0">
- <display-name>SpringDataJPA</display-name>
- <listener>
- <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
- </listener>
- <context-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>WEB-INF/applicationContext.xml</param-value>
- </context-param>
- <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-servlet.xml</param-value>
- </init-param>
- <load-on-startup>1</load-on-startup>
- </servlet>
- <servlet-mapping>
- <servlet-name>springmvc</servlet-name>
- <url-pattern>/*</url-pattern>
- </servlet-mapping>
- <welcome-file-list>
- <welcome-file>index.html</welcome-file>
- </welcome-file-list>
- </web-app>
下面开始编写代码,注意注解不要忘记写,在本小节开始部分已经给出了包的层次结构。
实体User:
- package com.anxpp.demo.core.entity;
- public class User {
- private Integer id;
- private String name;
- public User(Integer id, String name) {
- this.id = id;
- this.name = name;
- }
- public Integer getId() {
- return id;
- }
- public void setId(Integer id) {
- this.id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- @Override
- public String toString() {
- return "id:"+id+",name:"+name;
- }
- }
dao层接口UserDao:
- package com.anxpp.demo.core.dao;
- import com.anxpp.demo.core.entity.User;
- public interface UserDao {
- User getUser(Integer id,String name);
- }
dao层实现UserDaoImpl:
- package com.anxpp.demo.core.dao.impl;
- import org.springframework.stereotype.Repository;
- import com.anxpp.demo.core.dao.UserDao;
- import com.anxpp.demo.core.entity.User;
- @Repository
- public class UserDaoImpl implements UserDao{
- @Override
- public User getUser(Integer id, String name) {
- return new User(id, name);
- }
- }
service层接口UserService:
- package com.anxpp.demo.core.service;
- import com.anxpp.demo.core.entity.User;
- public interface UserService {
- User getUser(Integer id, String name);
- }
service层实现:
- package com.anxpp.demo.core.service.impl;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Service;
- import com.anxpp.demo.core.dao.UserDao;
- import com.anxpp.demo.core.entity.User;
- import com.anxpp.demo.core.service.UserService;
- @Service
- public class UserServiceImpl implements UserService{
- @Autowired
- UserDao userDao;
- @Override
- public User getUser(Integer id, String name) {
- return userDao.getUser(id, name);
- }
- }
controller层DemoController:
- package com.anxpp.demo.controller;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.RequestMapping;
- import org.springframework.web.bind.annotation.ResponseBody;
- import com.anxpp.demo.core.service.UserService;
- @Controller
- @RequestMapping("/")
- public class demoController {
- @Autowired
- UserService userService;
- @RequestMapping("/")
- @ResponseBody
- public String index(){
- return "index";
- }
- @RequestMapping("/getuser")
- @ResponseBody
- public String getUser(Integer id, String name){
- return userService.getUser(id, name).toString();
- }
- }
这是还不能直接Run On Server,因为jar包不会被一同发布,我们需要如下配置:
这时候就可以运行测试了,效果如下:
到这里,我们还没有操作数据库的。
现在,我们常使用json作为数据传输的格式,下面就为SpringMVC添加返回json的支持
首先添加jar包:
- <dependency>
- <groupId>com.fasterxml.jackson.core</groupId>
- <artifactId>jackson-databind</artifactId>
- <version>2.5.0</version>
- </dependency>
- <dependency>
- <groupId>com.fasterxml.jackson.core</groupId>
- <artifactId>jackson-core</artifactId>
- <version>2.5.0</version>
- </dependency>
- <dependency>
- <groupId>com.fasterxml.jackson.core</groupId>
- <artifactId>jackson-annotations</artifactId>
- <version>2.5.0</version>
- </dependency>
然后改写getUser()方法如下:
- @RequestMapping("/getuser")
- @ResponseBody
- public Map<String, Object> getUser(Integer id, String name){
- Map<String, Object> map = new HashMap<String, Object>();
- map.put("state", "success");
- map.put("data", userService.getUser(id, name));
- return map;
- }
重新运行后访问效果如下:
此时,就可以返回json数据了。
通常情况下,WEB-INF目录下的资源,我们是无法直接访问的,如果我们的网站是html+ajax构成的,那么就可以在WEB-INF之外新建html的目录,并为web.xml配置默认的过滤器,不过注意要放到SpingMVC过滤器之前:
- <servlet-mapping>
- <servlet-name>default</servlet-name>
- <url-pattern>*.html</url-pattern>
- </servlet-mapping>
如果一定要访问WEB-INF目录内的资源,通过查阅Spring官方文档,发现有两种方式:
1、手写一个资源映射器:
- @Configuration
- @EnableWebMvc
- public class WebConfig extends WebMvcConfigurerAdapter {
- @Override
- public void addResourceHandlers(ResourceHandlerRegistry registry) {
- registry.addResourceHandler("/resources/**")
- .addResourceLocations("/public-resources/")
- .setCacheControl(CacheControl.maxAge(1, TimeUnit.HOURS).cachePublic());
- }
- }
可以看到,还可以设置缓存时间的,而更简单的方式,就是xml配置:
- <mvc:resources mapping="/resources/**" location="/public-resources/">
- <mvc:cache-control max-age="3600" cache-public="true"/>
- </mvc:resources>
也可以加上下面的这个:
- <!-- 对静态资源文件的访问,将无法mapping到Controller的path交给default servlet handler处理-->
- <mvc:default-servlet-handler />
我们通常使用ajax提交请求,但也常用地址栏直接测试。请求提交分get和post。
使用post提交请求是,一般是不会出现中文乱码的,但是如果确实出现了乱码,可以通过在web.xml添加一个编码过滤器解决:
- <filter>
- <filter-name>CharacterEncoding</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>
- <init-param>
- <param-name>forceEncoding</param-name>
- <param-value>true</param-value>
- </init-param>
- </filter>
- <filter-mapping>
- <filter-name>CharacterEncoding</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
上面只能解决post的中文乱码,对于get(含浏览器地址栏直接提交方式),我们需要修改tomcat配置,在conf目录下的server.xml中找到并如下修改:
- <Connector connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443" URIEncoding="UTF-8"/>
如果我们只是测试,项目并没有部署,可以直接在eclipse中的server下,找到server.xml,做出上面一样的改动即可:
你可以通过这篇文字了解JPA:JPA规范介绍及实例(Java数据持久化解决方案)
SpringDataJPA也正是这样一种轻量级的解决方案,而首选的Hibernate就实现了JPA。
首先还是jar包,SpringDataJPA的jar包,在之前整合Spring时已经一并加入,下面是Hibernate(和mysql驱动)的jar包:
- <!-- hibernate -->
- <dependency>
- <groupId>org.hibernate</groupId>
- <artifactId>hibernate-core</artifactId>
- <version>${hibernate.version}</version>
- </dependency>
- <dependency>
- <groupId>org.hibernate</groupId>
- <artifactId>hibernate-ehcache</artifactId>
- <version>${hibernate.version}</version>
- </dependency>
- <dependency>
- <groupId>org.hibernate</groupId>
- <artifactId>hibernate-entitymanager</artifactId>
- <version>${hibernate.version}</version>
- </dependency>
- <dependency>
- <groupId>org.hibernate</groupId>
- <artifactId>hibernate-c3p0</artifactId>
- <version>${hibernate.version}</version>
- </dependency>
- <dependency>
- <groupId>mysql</groupId>
- <artifactId>mysql-connector-java</artifactId>
- <version>5.1.9</version>
- </dependency>
统一管理的版本为:
- <!-- hibernate 版本号 -->
- <hibernate.version>5.1.0.Final</hibernate.version>
添加Jpa的配置文件persistence.xml到META-INF目录下,本文介绍时数据库使用MySQL。并添加如下内容:
- <?xml version="1.0" encoding="UTF-8"?>
- <persistence version="1.0"
- xmlns="http://java.sun.com/xml/ns/persistence"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
- <persistence-unit name="demo" transaction-type="RESOURCE_LOCAL">
- <!-- provider>org.eclipse.persistence.jpa.PersistenceProvider</provider -->
- <provider>org.hibernate.ejb.HibernatePersistence</provider>
- <class>com.ninelephas.meerkat.pojo.User</class>
- <!-- MYSql 的连接 -->
- <properties>
- <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
- <property name="hibernate.connection.url" value="jdbc:mysql://127.0.0.1:3306/demo?createDatabaseIfNotExist=true" />
- <property name="hibernate.connection.username" value="root" />
- <property name="hibernate.connection.password" value="root" />
- <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
- </properties>
- </persistence-unit>
- </persistence>
Spring配置文件applicationContext.xml中增加JPA支持后的完整内容:
- <?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:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p"
- xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc"
- xmlns:jpa="http://www.springframework.org/schema/data/jpa"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
- http://www.springframework.org/schema/context
- http://www.springframework.org/schema/context/spring-context-4.2.xsd
- http://www.springframework.org/schema/tx
- http://www.springframework.org/schema/tx/spring-tx-4.2.xsd
- http://www.springframework.org/schema/aop
- http://www.springframework.org/schema/aop/spring-aop-4.2.xsd
- http://www.springframework.org/schema/mvc
- http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd
- http://www.springframework.org/schema/data/jpa
- http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
- <!-- 开启IOC注解扫描 -->
- <context:component-scan base-package="com.anxpp.demo" />
- <bean id="entityManagerFactory"
- class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
- <property name="jpaVendorAdapter">
- <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
- <property name="generateDdl" value="true" />
- <property name="database" value="MYSQL" />
- </bean>
- </property>
- <property name="persistenceUnitName" value="demo" />
- </bean>
- <!-- 开启MVC注解扫描 -->
- <mvc:annotation-driven />
- <bean
- class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
- <property name="viewResolvers">
- <list>
- <bean
- class="org.springframework.web.servlet.view.InternalResourceViewResolver">
- <property name="prefix" value="/WEB-INF/view/" />
- <property name="suffix" value=".html" />
- </bean>
- </list>
- </property>
- <!-- 用于将对象转换为 JSON -->
- <property name="defaultViews">
- <list>
- <bean
- class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" />
- </list>
- </property>
- </bean>
- <!-- 对静态资源文件的访问,将无法mapping到Controller的path交给default servlet handler处理 -->
- <mvc:default-servlet-handler />
- <!-- 配置事务管理器 -->
- <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
- <property name="entityManagerFactory" ref="entityManagerFactory" />
- </bean>
- <!-- 启用 annotation事务 -->
- <tx:annotation-driven transaction-manager="transactionManager" />
- <!-- 配置Spring Data JPA扫描目录 -->
- <jpa:repositories base-package="com.anxpp.demo" />
- </beans>
修改实体:
- package com.anxpp.demo.core.entity;
- import javax.persistence.Entity;
- import javax.persistence.GeneratedValue;
- import javax.persistence.GenerationType;
- import javax.persistence.Id;
- import javax.persistence.Table;
- @Entity
- @Table
- public class User {
- @Id
- @GeneratedValue(strategy = GenerationType.AUTO)
- private Integer id;
- private String name;
- public User() {
- }
- public User(String name) {
- this.name = name;
- }
- public Integer getId() {
- return id;
- }
- public void setId(Integer id) {
- this.id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- @Override
- public String toString() {
- return "id:"+id+",name:"+name;
- }
- }
可以删掉dao层实现了,我们记住将dao层接口继承自强大的JpaRepository:
- public interface UserDao extends JpaRepository<User, Serializable>{
- User findById(Integer id);
- }
是不是看上去特别简洁,而且都不需要写实现的,SpringDataJPA会自动帮我们完成。
修改service层接口:
- package com.anxpp.demo.core.service;
- import java.util.List;
- import com.anxpp.demo.core.entity.User;
- public interface UserService {
- User findById(Integer id);
- User save(String name);
- List<User> findAll();
- }
修改service层实现:
- package com.anxpp.demo.core.service.impl;
- import java.util.List;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Service;
- import com.anxpp.demo.core.dao.UserDao;
- import com.anxpp.demo.core.entity.User;
- import com.anxpp.demo.core.service.UserService;
- @Service
- public class UserServiceImpl implements UserService{
- @Autowired
- UserDao userDao;
- @Override
- public User findById(Integer id) {
- return userDao.findById(id);
- }
- @Override
- public User save(String name) {
- return userDao.save(new User(name));
- }
- @Override
- public List<User> findAll() {
- return userDao.findAll();
- }
- }
修改controller,提供多个测试接口:
- package com.anxpp.demo.controller;
- import java.util.HashMap;
- import java.util.Map;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Controller;
- import org.springframework.web.bind.annotation.RequestMapping;
- import org.springframework.web.bind.annotation.ResponseBody;
- import com.anxpp.demo.core.service.UserService;
- @Controller
- @RequestMapping("/")
- public class demoController {
- @Autowired
- UserService userService;
- @RequestMapping("/")
- @ResponseBody
- public String index(){
- return "index";
- }
- @RequestMapping("/info")
- public String info(){
- return "info";
- }
- @RequestMapping("/findall")
- @ResponseBody
- public Map<String, Object> getUser(){
- Map<String, Object> map = new HashMap<String, Object>();
- map.put("state", "success");
- map.put("data", userService.findAll());
- return map;
- }
- @RequestMapping("/findbyid")
- @ResponseBody
- public Map<String, Object> findById(Integer id){
- Map<String, Object> map = new HashMap<String, Object>();
- map.put("state", "success");
- map.put("data", userService.findById(id));
- return map;
- }
- @RequestMapping("/add")
- @ResponseBody
- public Map<String, Object> save(String name){
- Map<String, Object> map = new HashMap<String, Object>();
- map.put("state", "success");
- map.put("data", userService.save(name));
- return map;
- }
- }
运行效果:
那么,如果需要添加一个查找id大于指定值的指定姓氏的数据呢?
如果是SQL,我们会这样写(?表示参数):
- SELECT * FROM user WHERE id>? AND name like '?%';
但是这里,我们连SQL(或者HQL)都可以不用写,直接在dao层接口添加一个方法即可:
- List<User> findByIdGreaterThanAndNameLike(Integer id,String name);
你不需要怀疑,上面的方法执行偏偏就是能成功(注意:service实现的使用,调用该方法记得name+"%")!
github地址:https://github.com/anxpp/SpringMVC-SpringDataJpa-Hibernate-Demo
本地下载:SpringMVC + Spring Data JPA + Hibernate
CSDN下载(不需要积分):http://download.csdn.net/download/anxpp/9520498