<!-- mysql依赖 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.42</version></dependency><!-- spring-boot-jpa依赖 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency>

#mysql配置信息
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

# 下面为连接池的补充设置，应用到上面所有数据源中# 初始化大小，最小，最大#spring.datasource.initialSize=5#spring.datasource.minIdle=5#spring.datasource.maxActive=20#配置获取连接等待超时的时间#spring.datasource.maxWait=60000#配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 #spring.datasource.timeBetweenEvictionRunsMillis=60000# 配置一个连接在池中最小生存的时间，单位是毫秒 #spring.datasource.minEvictableIdleTimeMillis=300000#spring.datasource.validationQuery=SELECT 1 FROM DUAL#spring.datasource.testWhileIdle=true#spring.datasource.testOnBorrow=false#spring.datasource.testOnReturn=false# 打开PSCache，并且指定每个连接上PSCache的大小 #spring.datasource.poolPreparedStatements=true#spring.datasource.maxPoolPreparedStatementPerConnectionSize=20# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙 #spring.datasource.filters=stat,wall,log4j# 通过connectProperties属性来打开mergeSql功能；慢SQL记录#spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000# 合并多个DruidDataSource的监控数据#spring.datasource.useGlobalDataSourceStat=true 

#spring boot JPA相关配置
spring.jpa.datasource=MYSQL# Show or not log for each sql query
spring.jpa.show-sql = true# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update# Naming strategy
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy#spring.jpa.database=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

/*
* Grade类
*/
package com.wyl.bean;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;@Entity
public class Grade {@Id@GeneratedValue(strategy=GenerationType.AUTO)//设置id自增长private int id;private String gradeNm;private int teacherId;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getGradeNm() {return gradeNm;}public void setGradeNm(String gradeNm) {this.gradeNm = gradeNm;}public int getTeacherId() {return teacherId;}public void setTeacherId(int teacherId) {this.teacherId = teacherId;}
}

Grade.class

/*** GradeDAO，数据库操作类必须继承Repository类*/package com.wyl.dao;import org.springframework.data.repository.Repository;import com.wyl.bean.Grade;
/**  Spring Boot中dao最重要的就是继承 Repository类，完成数据库相应的操作 *  GradeDAO也可以继承CrudRepository类，调用Spring boot中已有的数据库操作方法更方便*  GradeDAO继承PagingAndSortingRepository类，完成分页查询和排序  *　　*/
public interface GradeDAO extends Repository<Grade, Integer>{　　　　//自定义的数据库操作方法//public Grade findByGradeNm(String gradeNm);　　　　@Query("from Grade where gradeNm=:nm")    public Grade findByGradeNm(@Param("nm")String gradeNm);
}

package com.wyl.service;import javax.annotation.Resource;import org.springframework.stereotype.Service;import com.wyl.bean.Grade;
import com.wyl.dao.GradeDAO;/*** GradeService类，调用gradeDAO中的方法* */
@Service
public class GradeService {@Resourceprivate GradeDAO gradeDAO;　　@Transactionalpublic Grade findByGradeNm(String gradeNm){return gradeDAO.findByGradeNm(gradeNm);}　　　　//分页查询　　/*@Transactional    public Iterable<Grade> getAll(){        return gradeDAO3.findAll(new PageRequest(0, 4));    }

　　//排序查询    @Transactional    public Iterable<Grade> getAll2(){        Sort sort = new Sort(Sort.Direction.DESC, "teacherId");        return gradeDAO3.findAll(sort);    }*/
}

package com.wyl.controller;import javax.annotation.Resource;import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import com.wyl.bean.Grade;
import com.wyl.service.GradeService;@RestController
public class JPAController {@Resourceprivate GradeService gradeService;@RequestMapping("/finfByGradeNm")public Grade finfByGradeNm(String gradeNm){System.out.println("finfByGradeNm");return gradeService.findByGradeNm(gradeNm);}
}