springboot之jpa（简述）

1、maven引入jar包（jpa和mysql）

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-data-jpa</artifactId>

        </dependency>

        <dependency>

            <groupId>mysql</groupId>

            <artifactId>mysql-connector-java</artifactId>

        </dependency>

2、配置文件

spring.datasource.url=jdbc:mysql://localhost:3306/test

spring.datasource.username=root

spring.datasource.password=root

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

server.port=8080

3、创建实体类（示例）

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.Table;

import java.io.Serializable;

@Entity

@Table(name="student")

public class Student implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id

    @GeneratedValue

    private Integer sid;

    private String sname;

    private Integer sage;

    private String ssex;

    public Integer getSid() {

        return sid;

    }

    public void setSid(Integer sid) {

        this.sid = sid;

    }

    public String getSname() {

        return sname;

    }

    public void setSname(String sname) {

        this.sname = sname;

    }

    public Integer getSage() {

        return sage;

    }

    public void setSage(Integer sage) {

        this.sage = sage;

    }

    public String getSsex() {

        return ssex;

    }

    public void setSsex(String ssex) {

        this.ssex = ssex;

    }

}

4、创建对应实体的接口

import com.demo.entity.Student;

import org.springframework.data.jpa.repository.JpaRepository;


//1、这个类中自带一些简单的增删改查方法，可以直接调用

public interface StudentRepository extends JpaRepository<Student,Integer> {

  /*2、也支持执行sql语句（例如）*/
 @Query("from Student where sage = ?1")
 List<Student> getStudentsBySage(@Param("sage") Integer sage);

 /*3、支持根据方法名的查询（例如）*/
  Student findBySid(Integer sid);

}

And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstname,findByFirstnameIs,findByFirstnameEquals	… where x.firstname = ?1
Between	findByStartDateBetween	… where x.startDate between ?1 and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
LessThanEqual	findByAgeLessThanEqual	… where x.age <= ?1
GreaterThan	findByAgeGreaterThan	… where x.age > ?1
GreaterThanEqual	findByAgeGreaterThanEqual	… where x.age >= ?1
After	findByStartDateAfter	… where x.startDate > ?1
Before	findByStartDateBefore	… where x.startDate < ?1
IsNull	findByAgeIsNull	… where x.age is null
IsNotNull,NotNull	findByAge(Is)NotNull	… where x.age not null
Like	findByFirstnameLike	… where x.firstname like ?1
NotLike	findByFirstnameNotLike	… where x.firstname not like ?1
StartingWith	findByFirstnameStartingWith	… where x.firstname like ?1 (parameter bound with appended %)
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1 (parameter bound with prepended %)
Containing	findByFirstnameContaining	… where x.firstname like ?1 (parameter bound wrapped in %)
OrderBy	findByAgeOrderByLastnameDesc	… where x.age = ?1 order by x.lastname desc
Not	findByLastnameNot	… where x.lastname <> ?1
In	findByAgeIn(Collection<Age> ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection<Age> age)	… where x.age not in ?1
True	findByActiveTrue()	… where x.active = true
False	findByActiveFalse()	… where x.active = false
IgnoreCase	findByFirstnameIgnoreCase	… where UPPER(x.firstame) = UPPER(?1)

详细介绍：

https://blog.csdn.net/ityouknow/article/details/52688664