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。

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>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.21</version>
</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>

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;

@Configuration

public 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;

    }

}

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.Driver

ms.db.url=jdbc:mysql://localhost:3306/msm?prepStmtCacheSize=517&cachePrepStmts=true&autoReconnect=true&characterEncoding=utf-8&allowMultiQueries=true

ms.db.username=root

ms.db.password=admin

ms.db.maxActive=500

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")

@EnableTransactionManagement

public 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;

    }

}

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(strategy=GenerationType.IDENTITY)

    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;

    }

}

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。

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 findByNameAndAge(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);

}

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);

}

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

 */

@Service

public class UserServiceImpl implements UserService {

    @Autowired

    private UserJpaDao userJpaDao;

    /**

     *

     * @param UserName

     * @return

     */

    @Override

    public User getUserByName(String username) {

        return userJpaDao.findByName(username);

    }

}

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);

    }

}

巴特西

spring boot + spring data jpa