springboot+jpa 基础框架搭建

• 创建一个spring boot 项目
• 目录结构
• 
• 添加maven 依赖
  -1.创建一个spring boot 项目.

2.添加maven 依赖

1.创建一个spring boot 项目.

2.添加maven 依赖

<dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.datagroupId>
            <artifactId>spring-data-jpaartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-data-jpaartifactId>
 dependency>
    <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.29version>
        dependency>

• application.properties 配置文件内容如下

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/zqp
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.show-sql= true
spring.jpa.hibernate.ddl-auto=update//create  //等等.就是跟着实体创建数据库表.正式环境基本不用
spring.jpa.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jackson.serialization.indent_output=false

dao 层:

 - 
public interface PersonRespository  extends JpaRepository<Person, Integer>{

}

• model层

- @Entity
public class Person {
    @Id
    @GeneratedValue
    private int id;
    private String name;
    private String age;
    private Person(int id, String name, String age) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
    }
    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 String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    private Person() {
        super();
        // TODO Auto-generated constructor stub
    }


}

• servece 层

public class PersonService {

    @Autowired
    PersonRespository personRespository;

    @Transactional(rollbackOn=IllegalArgumentException.class)
    public Person savePersonWithRollBack(Person person){
        Person p = personRespository.save(person);
            if(p.getName().equals("xxx")){
                throw new IllegalArgumentException("xx 数据库 ,已经存在");
            }
            return p;
    }

}

1. controller 层

@RestController
@SpringBootApplication
public class DataController {
    //测试事务能否回滚
    @RequestMapping("/rollBack")
    public Person rollBack(Person person){
        Person p = personService.savePersonWithRollBack(person);
        return p;
    }
}

1. 注意.spring boot 的入口要写到其他包目录的上面.不然其他bean 会扫描不到.spring boot 的入口 是从启动程序上级包开始像下扫描
2. spring data-jpa 默认开启了事务注解,可以直接使用可以看spring-data-jpa包下 simplejpaRespository.class
3. 这篇博客是基础搭建.实际上spring data-jpa 有很强大的功能.