目标

本文章主要介绍级联中的「插入」「查询」「删除」操作。

环境搭建

• Project.java

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@SuperBuilder
@TableName("p_project")
public class Project extends BaseComponentEntity {

    private String title;

    private String description;

    private Long ownerId;

    private String coverUrl;

    @ManyToOne(value = "project_group_id", parentTable = "p_project_group")
    private ProjectGroup projectGroup;
}

@ManyToOne 是子表注解，它有2个属性，value 表示引用外键的字段名，parentTable 引用的父表名。

• ProjectGroup.java

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@SuperBuilder
@TableName("p_project_group")
public class ProjectGroup extends BaseComponentEntity {

    private String title;

    @OneToMany(subTable = "p_project", reversePropertyName = "projectGroup", cascadeSaveOrUpdate = true)
    private List<Project> projectList;

}

@OneToMany 是父表注解，属性是 List 集合。它有2个属性，reversePropertyName 表示子对象中该对象的属性名，subTable 关联的子表名。cascadeSaveOrUpdate 开启级联更新。

测试

级联插入

@Test
public void save() {
    ProjectGroup projectGroup = ProjectGroup.builder().title("我的组").projectList(Lists.newArrayList(Project.builder().title("我的项目").ownerId(11L).build())).build();
    projectGroupService.save(projectGroup);

    Project project = Project.builder().title("我的项目-2").ownerId(11L).build();
    project.setProjectGroup(projectGroup);
    projectService.save(project);
}

projectGroupService.save 可以级联插入；projectService.save单个插入，但是属性需要关联对象 ProjectGroup，需要对象中的 id 信息。

级联查询

@Test
public void select() {
    ProjectGroup projectGroup = projectGroupService.getByTitle("我的组").get(0);
    Assert.assertEquals("我的项目", projectGroup.getProjectList().get(0).getTitle());
    Assert.assertEquals("我的项目-2", projectGroup.getProjectList().get(1).getTitle());

    Project project = projectService.findById(486880981274755072L).get();
    Assert.assertEquals("我的组", project.getProjectGroup().getTitle());
}

级联删除

@Test
public void deleteLogically() {
    projectGroupService.deleteLogically(486678250836623360L);
    Assert.assertEquals(false, projectService.findById(486678250924703744L).isPresent());
}

@Test
public void deleteHardly() {
    projectGroupService.delete(486678250836623360L);
}