本文简单介绍一下spring boot+JPA实现简单的增删改查功能
一、项目结构简述
二、搭建spring boot+jap环境
三、代码示例
四、spring boot的启动方式
一、项目结构简述
1、项目的目录结构注意点
问题说明：
①使用内置服务器启动springboot项目时，会从@SpringBootApplication修饰类所在的包开始，加载当前包和所有子包下的类，将由@Component @Repository @Service @Controller修饰的类交由spring进行管理；
②如上图，项目中的启动类为ApplacationController，他与其他层代码的处于同一个包下面，项目启动时会扫描到其他层的代码，就不会报如下错误（如果启动类所在的包与其它层代码所在的包处于平级目录中，即使启动类使用了@ComponentScan注解一样会报下面的错误）：
Action: Consider defining a bean of type 'cn.oschina.dao.PersonRespority' in your configuration.
二、搭建spring boot+jap环境
1、pom.xml文件
4.0.0 cn.oschaina simple-spring-boot 0.0.1-SNAPSHOT org.springframework.boot spring-boot-starter-parent 1.5.9.RELEASE org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-data-jpa mysql mysql-connector-java 5.1.45 org.apache.maven.plugins maven-compiler-plugin 3.7.0 1.7 1.7
2、application.properites(或者是application.yml)
server.port=8081
server.context-path=/girl
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driverClassName=com.mysql.jdbc.Driver
# Specify the DBMS
#spring.jpa.database=MYSQL
# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto=update
# Show or not log for each sql query
spring.jpa.show-sql=true
# Naming strategy
#spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.ImprovedNamingStrategy
# stripped before adding them to the entity manager)
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
三、代码示例
1、代码示例
(1)启动类
package cn.oschina;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
/**
* 应用启动类 自动扫描：
*
* 使用内置服务器启动springboot项目时，会从@SpringBootApplication修饰类所在的包开始，加载当前包和所有子包下的类，
*
* 将由@Component @Repository @Service @Controller修饰的类交由spring进行管理
*
* @author Freedom
*
*/
@SpringBootApplication
public class ApplacationController {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(
ApplacationController.class, args);
String[] profiles = context.getEnvironment().getActiveProfiles();
if (profiles != null) {
for (String profile : profiles) {
System.out.println("------------start with profile : "
+ profile);
}
}
}
}
（2）控制层
package cn.oschina.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import cn.oschina.entity.Person;
import cn.oschina.service.IPersonService;
@RestController
public class PersonController {
@Autowired
private IPersonService personService;
@GetMapping(value = "/persons")
public List persons() {
return personService.findAll();
}
@GetMapping("/person/{id}")
public Person getPersonById(@PathVariable("id") Integer id) {
return personService.findOne(id);
}
@PostMapping("/save")
public Person savaPerson(@RequestParam("name") String name,
@RequestParam("age") Integer age) {
Person p = new Person();
p.setAge(age);
p.setName(name);
return personService.insert(p);
}
@PutMapping("/update/{id}")
public Person updatePerson(@PathVariable("id") Integer id,
@RequestParam("name") String name) {
Person p = new Person();
p.setId(id);
p.setName(name);
return personService.update(p);
}
@DeleteMapping("/delete/{id}")
public void deletePerson(@PathVariable("id") Integer id) {
personService.delete(id);
}
}
（3）业务层
package cn.oschina.service;
import java.util.List;
import cn.oschina.entity.Person;
/**
* 对表tbl_person的增删改查
*
* @author Freedom
*
*/
public interface IPersonService {
List findAll();
Person findOne(Integer id);
Person insert(Person p);
Person update(Person p);
void delete(Integer id);
}
package cn.oschina.service;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import cn.oschina.dao.PersonRespority;
import cn.oschina.entity.Person;
/**
* 对表tbl_person的增删改查
*
* @author Freedom
*
*/
@Service
public class PersonService implements IPersonService {
@Resource
private PersonRespority personRespority;
@Override
public List findAll() {
return personRespority.findAll();
}
@Override
public Person findOne(Integer id) {
return personRespority.findOne(id);
}
@Override
public Person insert(Person p) {
return personRespority.save(p);
}
/**
* 更新也是使用save()方法
*/
@Override
public Person update(Person p) {
return personRespority.save(p);
}
@Override
public void delete(Integer id) {
personRespority.delete(id);
}
}
（4）数据访问层
package cn.oschina.dao;
import org.springframework.data.jpa.repository.JpaRepository;
import cn.oschina.entity.Person;
public interface PersonRespority extends JpaRepository {
}
（5）实体
package cn.oschina.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "tbl_person")
public class Person {
@Id
@GeneratedValue
private int id;
private String name;
private int age;
public Person() {
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
2、运行分析
（1）POST请求时
（2）PUT方式请求说明
四、spring boot的启动方式
1、@SpringBootApplication注解的类，并且main函数中执行SpringApplication.run方法
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(
ApplacationController.class, args);
String[] profiles = context.getEnvironment().getActiveProfiles();
if (profiles != null) {
for (String profile : profiles) {
System.out.println("------------start with profile : "
+ profile);
}
}
}
2、使用maven指令方式
①找到项目所在的根目录；
②执行mvn spring-boot:run指令；