SpringBoot入门系列：第五篇 JPA mysql

最新推荐文章于 2025-02-21 07:52:43 发布

lxhjh

最新推荐文章于 2025-02-21 07:52:43 发布

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分类专栏： springboot 文章标签： springboot

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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。