SpringBoot+Spring-data-jpa

最近使用了spring data jpa来完成数据访问层的实现。感觉比较强大，也比较复杂，中间还有不少限制。个人还只学了一点皮毛。对于一般应用中各类简单的增删查改，spring data提供了根据名字直接查询的代理方法，啥都不需要做，唯一需要编写接口，命名方法，这部分实在是太方便了，而且简单查询解决了差不多80%的问题。

步骤：

1.配置pom.xml

a.配置Spring-data-jpa

<dependency>  
    <groupId>org.springframework.data</groupId>  
    <artifactId>spring-data-jpa</artifactId>  
    <version>1.10.2.RELEASE</version>  
</dependency>  
<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-starter-data-jpa</artifactId>  
</dependency>  

b.配置mysql连接

<dependency>  
         <groupId>mysql</groupId>  
         <artifactId>mysql-connector-java</artifactId>  
         <version>5.1.39</version>  
</dependency>  

2.配置application.properties

# 数据源配置  
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8  
spring.datasource.username=test  
spring.datasource.password=123123  
spring.datasource.driver-class-name=com.mysql.jdbc.Driver  

#JPA (JpaBaseConfiguration, HibernateJpaAutoConfiguration) 
spring.data.jpa.repositories.enabled=true
spring.jpa.database-platform=org.hibernate.dialect.MySQL5Dialect
spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.DefaultNamingStrategy
spring.jpa.generate-ddl=false
spring.jpa.show-sql=true
spring.jpa.hibernate.naming_strategy=org.hibernate.cfg.DefaultNamingStrategy
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

3.实体类

@Entity
@Table(name = "bos_customer", schema = "dbo", catalog = "userdb")
public class BosCustomerModel {
    private int id;
    private String cname;
    private String openId;

    @Id
    @Column(name = "id")
    @GeneratedValue
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "cname")
    public String getCname() {
        return cname;
    }

    public void setCname(String cname) {
        this.cname = cname;
    }

    @Basic
    @Column(name = "openId")
    public String getOpenId() {
        return openId;
    }

    public void setOpenId(String openId) {
        this.openId = openId;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        BosCustomerModel that = (BosCustomerModel) o;
        return id == that.id &&
                Objects.equals(cname, that.cname) &&
                Objects.equals(openId, that.openId);
    }

    @Override
    public int hashCode() {

        return Objects.hash(id, cname, openId);
    }
}

4. CustomerJPARespository类

public interface CustomerJPARepository extends JpaRepository<BosCustomerModel, Integer>, JpaSpecificationExecutor<BosCustomerModel> {
    @Query("select count(*) from BosCustomerModel where openId=?1")
    int findBosCustomerModelByOpenId(String openId);
}

5.WeiService

public interface WeiService {
  
    void insertCustomer(String openId,String cname);
    BosCustomerModel findBosCustomerModelByOpenId(String openId);
}

6.WeiServiceImpl

  @Service("weiServiceImpl")
public class WeiServiceImpl implements WeiService {
  
    @Autowired
    private CustomerJPARepository customerJPARepository;
    @Transactional
    @Override
    public void insertCustomer(String openId,String cname){
        BosCustomerModel model=new BosCustomerModel();
        model.setCname(cname);
        model.setOpenId(openId);
        int row=customerJPARepository.findBosCustomerModelByOpenId(openId);
        if(row==0){
            customerJPARepository.saveAndFlush(model);
        }   

}

7.WeiController

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   @RequestMapping(value="/insertData",method = RequestMethod.POST)
    public String insertCustomer(@RequestParam("cname") String cname){
        //第一次输入的时候将名字和openId保存到客户表中
        weiService.insertCustomer(WeiXinController.OPENID,cname);
        return "sucess";
    }

8.补充一下springJPA的用法：

1.增加：

                 Bos_customerModel  customer=new Bos_customerModel();

                                                    customer.setId(1);

                                                     customer.setCname("小王");

保存单个：   customerJPARespository.save(customerModel);

保存或更新：customerJPARespository.saveAndFlush(customerModel);

保存多个：   List<customerModel> customers=new ArrayList<customerModel>();

                                                             customers.add(customer);

                                                              customerJPARespository.save(customers);

2.删除

删除都是按照主键来删除的，区别是多条sql和单条sql

删除单条:          customerJPARespository.delete(1);

删除全部(删除全部,先findALL查找出来,再一条一条删除,最后提交事务)：                                  customerJPARespository.deleteAll();

删除全部，一条sql

                          customerJPARespository.deleteAllInBatch();

删除集合，一条一条删除

                           List<customerModel> customers=new ArrayList<customerModel>();

                            CustomerModel  customer=new CustomerModel();

                            customer.setId(1);

                            customer.setCname("gag);

                            customers.add(customer);

                            customerJPARespository.delete(customers);

删除集合，一条sql,拼接or

                            customerJPARespository.deleteInBatch(customers);

3.修改 (更新也是按照主键来更新)                         

                             CustomerModel  customer=new CustomerModel();

                                                          customer.setId(1);

                                                           customer.setCname("gag);

                               customerJPARespository.saveAndFlush(customer);