springboot-jpa的使用

springboot-jpa的使用

1. 创建entity包,代码如下:

    import lombok.Getter;
    import lombok.Setter;
   
    import javax.persistence.*;
    import java.util.ArrayList;
    import java.util.List;
   
    @Entity
    @Table(name = "role_info")
    public class RoleEntity {
   
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long roleId;
   
    // 生成之后的role_name表中的列名,唯一,不为空,varchar(50)
    @Column(name = "role_name", unique = true, nullable = false, length = 50)
    private String roleName;
   
    private Integer deleteFlag;
   
    @Setter
    @Getter
    @ManyToMany // 多对多关系
    @JoinTable(
        // 中间表的表名.
        name = "role_module",
        // 对应中间表的一个列名,和当前表的主键roleId关联的.
        joinColumns = @JoinColumn(name = "temp_role_id"),
        // 中间表的另一个列名,和另一张表的主键相关联.
        inverseJoinColumns = @JoinColumn(name = "temp_module_id")
     )
   
    private List<ModuleEntity> moduleEntityList = new ArrayList<>();
   
    public Integer getDeleteFlag() {
    	return deleteFlag;
    }
   
    public void setDeleteFlag(Integer deleteFlag) {
    	this.deleteFlag = deleteFlag;
    }
   
    public Long getRoleId() {
    	return roleId;
    }
   
    public void setRoleId(Long roleId) {
    	this.roleId = roleId;
    }
   
    public String getRoleName() {
    	return roleName;
    }
   
    public void setRoleName(String roleName) {
    	this.roleName = roleName;
    }
   

   }

关联表的实体类

import com.fasterxml.jackson.annotation.JsonBackReference;
import lombok.*;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "module_info")
// data 包含set/get/toString/equals
@Data
@NoArgsConstructor
@AllArgsConstructor
public class ModuleEntity {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long moduleId;

@Column(name = "module_name", unique = true, nullable = false, length = 50)
private String moduleName;


}

2. 创建repository包,代码如下:

    import com.lanou3g.springjpademo.entity.RoleEntity;
    import org.springframework.data.jpa.repository.JpaRepository;
    import org.springframework.data.jpa.repository.Query;
   
    import java.util.List;
   
    public interface RoleRepository extends JpaRepository<RoleEntity, Long> {
   
    // 自定义查询(没有使用)
    @Query(value = "select * from role_info", nativeQuery = true)
    List<RoleEntity> roles();
   
    }
   

3. 创建controller层,代码如下:

    import com.lanou3g.springjpademo.entity.RoleEntity;
    import com.lanou3g.springjpademo.repository.RoleRepository;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
   
    import javax.annotation.Resource;
    import java.util.List;
   
    @RestController
    public class RoleInfroController {
   
    @Resource
    private RoleRepository roleRepository;
   
    @RequestMapping("/list")
    public List<RoleEntity> list() {
    	return roleRepository.findAll();
    }
   

   }