SpringBoot入门系列之JPA mysql

时间：2022-10-23 12:21:26

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

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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

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<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

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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

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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

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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）

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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。在此也非常感谢大家对服务器之家网站的支持！

原文链接：http://blog.csdn.net/sosfnima/article/details/51993689

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