spring boot中使用spring-data-jpa

spring boot POM文件中加入依赖：

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

application.yml配置：

spring:
  datasource:
    url: jdbc:oracle:thin:@127.0.0.1:1521:orcl
    username: system
    password: 123456
  jta:
    enabled: true
  jpa:
    show-sql: true
    database-platform: org.hibernate.dialect.Oracle12cDialect
    hibernate:
      ddl-auto: none

实体类：(@Table和@Column注解中name的值全部小写或全部大写，否则映射会出错)

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import java.io.Serializable;
import java.util.Date;

@Entity
@Table(name = "templatetable")
public class TemplateDto implements Serializable {

    private static final long serialVersionUID = -7409827055841916106L;

    @Id
    private String id;

    @Column(name = "PRODUCTCODE")
    private String productCode;

    @Column(name = "PRODUCTNAME")
    private String productName;

    @Column(name = "CREATETIME")
    private Date createTime;

    public String getId() {
        return id;
    }

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

    public String getProductCode() {
        return productCode;
    }

    public void setProductCode(String productCode) {
        this.productCode = productCode;
    }

    public String getProductName() {
        return productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
}

dao层：

import com.linkus.dto.TemplateDto;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

public interface TemplateDao extends JpaRepository<TemplateDto,String> {
    public TemplateDto findByProductCode(String productCode);
}

JpaRepository接口中有一些基本的增删改查方法，findByProductCode方法是我们自定义的，框架会帮我们根据方法名称生成查询sql，
findByProductCode这个方法就会生成根据productCode字段查询的sql（select * from templatetable where productcode = ''）,
详细使用说明可查看官方文档：https://docs.spring.io/spring-data/jpa/docs/2.7.15/reference/html/#jpa.query-methods
service层使用dao:

import com.linkus.dao.TemplateDao;
import com.linkus.dto.TemplateDto;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;

@Service
public class TemplateService{
    private static final Logger LOGGER = LoggerFactory.getLogger(TemplateService.class);

    @Autowired
    TemplateDao templateDao;

    public List<TemplateDto> findList(){
        List<TemplateDto> templateDtos = templateDao.findAll();
        return templateDtos;
    }
    public TemplateDto findByCode(String code){
        TemplateDto templateDto = templateDao.findByProductCode(code);
        return templateDto;
    }
}