SpringBoot入门系列之JPA mysql

作者: Mars符号
来源: 51数据库
2020-08-07

这篇文章主要介绍了SpringBoot入门系列之JPA mysql的相关资料,需要的朋友可以参考下

一，准备工作，建立spring-boot-sample-mysql工程

1、http://start.spring.io/

     A、Artifact中输入spring-boot-sample-MySQL
     B、勾选Web下的web
     C、勾选SQL下的JPA MYSQL

2、Eclips中导入工程spring-boot-sample-mysql

A、解压快捷工程spring-boot-sample-mysql到某文件夹

B、eclips中file->import->Import Existing Maven Projects-->Select Maven projects-->finish导入工程

3、工程导入之后，文件结构如下图

4、在包com.example下建立web文件夹

5、便于测试，引入spring-boot-sample-helloworld的HelloController及配置文件logback.xml

HelloController代码为

package com.example.web; 
import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.web.bind.annotation.PathVariable; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RestController; 
@RestController 
public class HelloController { 
  protected static Logger logger=LoggerFactory.getLogger(HelloController.class); 
  @RequestMapping("/") 
  public String helloworld(){ 
    logger.debug("访问hello"); 
    return "Hello world!"; 
  } 
  @RequestMapping("/hello/{name}") 
  public String helloName(@PathVariable String name){ 
    logger.debug("访问helloName,Name={}",name); 
    return "Hello "+name; 
  } 
}

logback.xml配置为

<configuration>  
  <!-- %m输出的信息,%p日志级别,%t线程名,%d日期,%c类的全名,,,, -->  
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">  
    <encoder>  
      <pattern>%d %p (%file:%line\)- %m%n</pattern> 
      <charset>GBK</charset>  
    </encoder>  
  </appender>  
  <appender name="baselog"  
    class="ch.qos.logback.core.rolling.RollingFileAppender">  
    <File>log/base.log</File>  
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">  
      <fileNamePattern>log/base.log.%d.i%</fileNamePattern>  
      <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">  
        <!-- or whenever the file size reaches 64 MB -->  
        <maxFileSize>64 MB</maxFileSize>  
      </timeBasedFileNamingAndTriggeringPolicy>  
    </rollingPolicy>  
    <encoder>  
      <pattern>  
        %d %p (%file:%line\)- %m%n 
      </pattern>  
      <charset>UTF-8</charset> <!-- 此处设置字符集 -->  
    </encoder>  
  </appender>  
  <root level="info">  
    <appender-ref ref="STDOUT" />  
  </root>  
  <logger name="com.example" level="DEBUG">  
    <appender-ref ref="baselog" />  
  </logger>  
</configuration>

注：logback.xml文件位于src/main/resources下

6、启动工程，通过浏览器查看正确性

http://localhost:8080/

http://localhost:8080/hello/上帝

二，使用JPA,构建业务对象及访问库

1、在包com.example下建立domain文件夹

2、在domain中建立类Person

package com.example.domain; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.Id; 
@Entity 
public class Person { 
  @Id 
  @GeneratedValue 
  private Long id; 
  private String name; 
  private Integer age; 
  private String address; 
  public Person() { 
    super(); 
  } 
  public Person(Long id, String name, Integer age, String address) { 
    super(); 
    this.id = id; 
    this.name = name; 
    this.age = age; 
    this.address = address; 
  } 
  public Long getId() { 
    return id; 
  } 
  public void setId(Long id) { 
    this.id = id; 
  } 
  public String getName() { 
    return name; 
  } 
  public void setName(String name) { 
    this.name = name; 
  } 
  public Integer getAge() { 
    return age; 
  } 
  public void setAge(Integer age) { 
    this.age = age; 
  } 
  public String getAddress() { 
    return address; 
  } 
  public void setAddress(String address) { 
    this.address = address; 
  } 
}

注意：构造函数

3、在包com.example下建立repository文件夹

4、在repository中建立接口PersonRepository

package com.example.repository; 
import java.util.List; 
import org.springframework.data.jpa.repository.JpaRepository; 
import org.springframework.data.jpa.repository.Query; 
import org.springframework.data.repository.query.Param; 
import org.springframework.stereotype.Repository; 
import com.example.domain.Person; 
@Repository 
public interface PersonRepository extends JpaRepository<Person,Long> { 
  List<Person> findByName(String name); 
  List<Person> findByAddress(String address); 
  List<Person> findByNameAndAddress(String name,String address); 
  @Query("select p from Person p where p.name=:name and p.address=:address") 
  List<Person> withNameAndAddressQuery(@Param("name")String Name,@Param("address")String address); 
}

5、在web中建立DataController

package com.example.web; 
import java.util.List; 
import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.data.domain.Page; 
import org.springframework.data.domain.PageRequest; 
import org.springframework.data.domain.Sort; 
import org.springframework.data.domain.Sort.Direction; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RestController; 
import com.example.domain.Person; 
import com.example.repository.PersonRepository; 
@RestController 
public class DataController { 
  protected static Logger logger=LoggerFactory.getLogger(DataController.class); 
  @Autowired 
  PersonRepository personRepository; 
  @RequestMapping("/save") 
  public Person save(String name,String address,Integer age){ 
    logger.debug("save 开始"); 
    Person p=personRepository.save(new Person(null,name,age,address)); 
    logger.debug("save 结束"); 
    return p; 
  } 
  @RequestMapping("/q1") 
  public List<Person> q1(String address){ 
    logger.debug("q1 开始"); 
    logger.debug("q1 接收参数address={}",address); 
    List<Person> people=personRepository.findByAddress(address); 
    return people; 
  } 
  @RequestMapping("/q2") 
  public List<Person> q2(String name,String address){ 
    logger.debug("q2 开始"); 
    logger.debug("q2接收参数name={},address={}",name,address); 
    return personRepository.findByNameAndAddress(name, address); 
  } 
  @RequestMapping("/q3") 
  public List<Person> q3(String name,String address){ 
    logger.debug("q3 开始"); 
    logger.debug("q3接收参数name={},address={}",name,address); 
    return personRepository.withNameAndAddressQuery(name, address); 
  } 
  @RequestMapping("/sort") 
  public List<Person> sort(){ 
    logger.debug("sort 开始"); 
    List<Person> people=personRepository.findAll(new Sort(Direction.ASC,"age")); 
    return people; 
  } 
  @RequestMapping("/page") 
  public Page<Person> page(){ 
    logger.debug("page 开始"); 
    Page<Person> people=personRepository.findAll(new PageRequest(1,2)); 
    return people; 
  } 
}

6、配置数据库连接，在application.properties（src/main/resources下）

spring.datasource.url=jdbc:mysql://192.168.56.201:3306/bootsample?useUnicode=true&characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jackson.serialization.indent_output=true

7、运行测试

A、先保存数据

http://localhost:8080/save?name=aa&&address=北京&&age=1
http://localhost:8080/save?name=ab&&address=北京&&age=2
http://localhost:8080/save?name=cq1&&address=重庆&&age=50
http://localhost:8080/save?name=cq2&&address=重庆&&age=51

B、查询q1

http://localhost:8080/q1?address=北京

C、查询q2

http://localhost:8080/q2?address=北京&&name=aa

D、查询q3

http://localhost:8080/q3?address=北京&&name=aa

E、排序

http://localhost:8080/sort

F、分页

http://localhost:8080/page

运用hibernate访问mysql，基本也是老技术，只是用JPA简化了dao层代码，对于业务对象基本没有变化。

以上所述是小编给大家介绍的SpringBoot入门系列之JPA mysql，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。