SpringBoot入门系列：第五篇 JPA mysql（转）

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。
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原文链接：https://blog.csdn.net/lxhjh/article/details/51755035