spring boot 整合spring data jpa

本文结构：
- 什么是springdata jpa
- springboot 整合spring data jpa

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Spring Data Repository的核心接口是Repository(好像也没什么好惊讶的)。这个接口需要领域类(Domain Class)跟领域类的ID类型作为参数。这个接口主要是让你能知道继承这个类的接口的类型。CrudRepository 供了对被管理的实体类的一些常用CRUD方法。

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2. springboot 整合spring data jpa

默认你已经构建好了spring boot 项目，关于spring boot项目的新建，请参考：
springboot Demo
springboot 整合mybatis

2.1. 首先导入jar 包

springboot 整合spring data jpa 首先要导入依赖的jar包。pom.xml 文件中新增如下依赖：

    <!-- spring-data-jpa -->        <dependency>            <groupId>org.springframework.data</groupId>            <artifactId>spring-data-jpa</artifactId>        </dependency>        <dependency>            <groupId>org.hibernate</groupId>            <artifactId>hibernate-entitymanager</artifactId>        </dependency>        <dependency>            <groupId>org.aspectj</groupId>            <artifactId>aspectjweaver</artifactId>        </dependency>    <!--data source  spring data jpa 需要用c3p0 连接池-->        <dependency>            <groupId>com.mchange</groupId>            <artifactId>c3p0</artifactId>            <version>0.9.5.2</version>            <exclusions>                <exclusion>                    <groupId>commons-logging</groupId>                    <artifactId>commons-logging</artifactId>                </exclusion>            </exclusions>        </dependency>
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2.2 配置datasource

新建DBConfig.Java 文件 配置数据源。

package com.example.config;import java.beans.PropertyVetoException;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.env.Environment;import com.mchange.v2.c3p0.ComboPooledDataSource;@Configurationpublic class DBConfig {    @Autowired    private Environment env;    @Bean(name="dataSource")    public ComboPooledDataSource dataSource() throws PropertyVetoException {        ComboPooledDataSource dataSource = new ComboPooledDataSource();        dataSource.setDriverClass(env.getProperty("ms.db.driverClassName"));        dataSource.setJdbcUrl(env.getProperty("ms.db.url"));        dataSource.setUser(env.getProperty("ms.db.username"));        dataSource.setPassword(env.getProperty("ms.db.password"));        dataSource.setMaxPoolSize(20);        dataSource.setMinPoolSize(5);        dataSource.setInitialPoolSize(10);        dataSource.setMaxIdleTime(300);        dataSource.setAcquireIncrement(5);        dataSource.setIdleConnectionTestPeriod(60);        return dataSource;    }}
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2.3. 添加数据库连接信息

在配置文件application.properties中添加数据库连接信息如下：

ms.db.driverClassName=com.mysql.jdbc.Driverms.db.url=jdbc:mysql://localhost:3306/msm?prepStmtCacheSize=517&cachePrepStmts=true&autoReconnect=true&characterEncoding=utf-8&allowMultiQueries=truems.db.username=rootms.db.password=adminms.db.maxActive=500
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2.4 配置JpaConfig

新建JpaConfig.java 文件内容如下：

package com.example.config;import java.util.HashMap;import java.util.Map;import javax.persistence.EntityManagerFactory;import javax.sql.DataSource;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.jpa.repository.config.EnableJpaRepositories;import org.springframework.orm.jpa.JpaTransactionManager;import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;import org.springframework.transaction.PlatformTransactionManager;import org.springframework.transaction.annotation.EnableTransactionManagement;@Configuration//此处是你dao文件所在的包名@EnableJpaRepositories("com.example.*.dao")@EnableTransactionManagementpublic class JpaConfig {    @Autowired    private DataSource dataSource;    @Bean    public EntityManagerFactory entityManagerFactory() {        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();        factory.setJpaVendorAdapter(vendorAdapter);        //此处com.example.*.model是你的java bean所在的包名        factory.setPackagesToScan("com.example.*.model");        factory.setDataSource(dataSource);        Map<String, Object> jpaProperties = new HashMap<String, Object>();        jpaProperties.put("hibernate.ejb.naming_strategy","org.hibernate.cfg.ImprovedNamingStrategy");        jpaProperties.put("hibernate.jdbc.batch_size",50);        factory.setJpaPropertyMap(jpaProperties);        factory.afterPropertiesSet();        return factory.getObject();    }    @Bean    public PlatformTransactionManager transactionManager() {        JpaTransactionManager txManager = new JpaTransactionManager();        txManager.setEntityManagerFactory(entityManagerFactory());        return txManager;    }}
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2.5 新建对应数据库表的实体类。（也就是java bean ）

注意 @Entity@Table(name = "sec_user")标签的使用，@Entity表示这个是一个实体类，@Table(name = "sec_user") 中sec_user 是数据库中对应的表名@Id@GeneratedValue 对应ID @Column(name = "name") 对应数据库中该列对应的列名，也就是属性名

package com.example.base.model;import java.util.Date;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.Table;import com.fasterxml.jackson.annotation.JsonIgnore;@Entity@Table(name = "sec_user")public class User {    @Id    @GeneratedValue    private Integer id;    @Column(name = "name")    private String name;    @Column(name = "password")    private String password;    @Column(name = "username")    private String username;    @Column(name = "division_id")    private Integer divisionId;    @Column(name = "email")    private String email;    @Column(name = "gender")    private String gender;    @Column(name = "mobilephone")    private String mobilephone;    @Column(name = "telephone")    private String telephone;    @Column(name = "user_type")    private Integer userType;    @Column(name = "create_by")    private String createBy;    @Column(name = "create_time")    private Date createTime;    @Column(name = "update_by")    private String updateBy;    @Column(name = "update_time")    private Date updateTime;    @Column(name = "disabled")    private Integer disabled;    @Column(name = "theme")    private String theme;    @Column(name = "is_ldap")    private Integer isLdap;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @JsonIgnore    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public Integer getDivisionId() {        return divisionId;    }    public void setDivisionId(Integer divisionId) {        this.divisionId = divisionId;    }    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    public String getGender() {        return gender;    }    public void setGender(String gender) {        this.gender = gender;    }    public String getMobilephone() {        return mobilephone;    }    public void setMobilephone(String mobilephone) {        this.mobilephone = mobilephone;    }    public String getTelephone() {        return telephone;    }    public void setTelephone(String telephone) {        this.telephone = telephone;    }    public Integer getUserType() {        return userType;    }    public void setUserType(Integer userType) {        this.userType = userType;    }    public String getCreateBy() {        return createBy;    }    public void setCreateBy(String createBy) {        this.createBy = createBy;    }    public Date getCreateTime() {        return createTime;    }    public void setCreateTime(Date createTime) {        this.createTime = createTime;    }    public String getUpdateBy() {        return updateBy;    }    public void setUpdateBy(String updateBy) {        this.updateBy = updateBy;    }    public Date getUpdateTime() {        return updateTime;    }    public void setUpdateTime(Date updateTime) {        this.updateTime = updateTime;    }    public Integer getDisabled() {        return disabled;    }    public void setDisabled(Integer disabled) {        this.disabled = disabled;    }    public String getTheme() {        return theme;    }    public void setTheme(String theme) {        this.theme = theme;    }    public Integer getIsLdap() {        return isLdap;    }    public void setIsLdap(Integer isLdap) {        this.isLdap = isLdap;    }    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }}
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2.5 编写spring data jpa 的dao层（重头戏哦）

首先我们先了解一下 spring data jpa 的命名规范，然后再开始编写一个简单的测试例子。

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例子：
新建UserJpaDao类继承 JpaRepository

package com.example.base.dao;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.jpa.repository.Query;import org.springframework.data.repository.query.Param;import com.example.base.model.User;/** * The Interface UserJpaDao. * @author abel */public interface UserJpaDao extends JpaRepository<User, Long> {    /**     * Find by name.     *     * @param name the name     * @return the user     */    User findByName(String name);    /**     * Find by name and user name.     * 如果参数名为多个字母组成，请首字母大写。勿使用驼峰命名，jpa不识别驼峰     * @param name the name     * @param age the age     * @return the user     */    User findByNameAndUsername(String name, Integer age);    /**     * Find user.     * User为@Entity 的名字     * @param name the name     * @return the user     */    @Query("from User u where u.name=:name")    User findUser(@Param("name") String name);}
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2.6 service 层的编写（这一步和Spring mvc 已经没有什么差别的了。）

service 代码如下。（此处我就仅仅写了dao的一个方法）

package com.example.base.service;import com.example.base.model.User;/** * The Interface UserService. */public interface UserService {    /**     * Gets the user by name.     *     * @param username the user name     * @return the user by name     */    public User getUserByName(String username);}
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实现如下：

package com.example.base.service.Impl;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.example.base.dao.UserJpaDao;import com.example.base.model.User;import com.example.base.service.UserService;/** *  * @ClassName UserServiceImpl * @author abel * @date 2016年11月10日 */@Servicepublic class UserServiceImpl implements UserService {    @Autowired    private UserJpaDao userJpaDao;    /**     *      * @param UserName     * @return     */    @Override    public User getUserByName(String username) {        return userJpaDao.findByName(username);    }}
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2.7 controller 编写

package com.example.base.controller;import javax.servlet.http.HttpServletRequest;import java.util.Map;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.HttpStatus;import org.springframework.http.ResponseEntity;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.ResponseBody;import com.example.base.service.UserService;import com.example.base.util.CommonUtil;/** *  * @ClassName UserController * @author abel * @date 2016年11月10日 */@Controller@RequestMapping(value = "/users")public class UserController {    @Autowired    private UserService userService;    /**     * 通过spring data jpa 调用方法 api :localhost:8099/users/byname?username=xxx     *      * @param request     * @return     */    @RequestMapping(value = "/byname", method = RequestMethod.GET)    @ResponseBody    public ResponseEntity<Object> getUser(HttpServletRequest request) {        Map<String, Object> map = CommonUtil.getParameterMap(request);        String username = (String) map.get("username");        return new ResponseEntity<>(userService.getUserByName(username), HttpStatus.OK);    }}
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到此代码编写结束。可以运行一下查看效果。
赠上本文源代码一份：
代码地址：https://git.oschina.net/Abelyang/springbootfirst.git

https://github.com/wolf909867753/springboot.git