是否可以在 Spring Boot 中在运行时构建自定义查询? [英] Is it possible to build customized query at run time in Spring Boot?

问题描述

这就是我想要做的，

我有一个实体，

@Entity
public class JobEntity {

    @Id
    @GeneratedValue
    private Long id;

    @Enumerated(EnumType.STRING)
    private Project project;

    @Enumerated(EnumType.STRING)
    private JobType jobType;

    @Enumerated(EnumType.STRING)
    private JobStatus jobStatus;

    private Date createTime;
}

我知道我可以在存储库中自定义一个查询，但这只是一个固定查询.我希望导出一些 RESTful api，如下所示，

I know I could customize one query in repository, but that is just one fixed query. I hope to export some RESTful api, like below,

/search?project=""&jobType=""&jobStatue=""&createTime=""

那些参数不应该是强制要求的，并且可以很容易地使用它们中的任何一个来进行查询，比如

Those params should not be forcing required, and can easily use any of them to do the query, like

/search?createTime=""...

有没有一种优雅的方式来实现这一点?

Is there an elegant way to implement this?

推荐答案

您可以使用 Spring 的规范 API，它是 JPA 标准 API 的包装器.确保您的存储库从 JpaSpecificationExecutor

You could work with the specification API of Spring, which is a wrapper to the JPA criteria API. Make sure your repository extends from JpaSpecificationExecutor<JobEntity>

一个示例规范是:

public class JobEntitySpecifications {
    public static Specification<JobEntity> withProject(Project project) {
        if (project == null) {
            return null;
        } else {
            return (root, query, cb) -> cb.equal(root.get("project"), project);
        }
    }

    public static Specification<JobEntity> withJobType() { ... }
    public static Specification<JobEntity> withJobStatus() { ... }
    public static Specification<JobEntity> withCreateTime() { ... }
}

确保在未提供项目代码/作业类型/...时返回 null，以便在查询中将其忽略.

Make sure you return null when no project code/job type/... is given so that it will be ignored in your query.

现在你可以使用这个:

repository.findAll(Specifications.where(JobEntitySpecifications.withJobType(jobType))
    .and(JobEntitySpecifications.withJobStatus(jobStatus))
    .and(JobEntitySpecifications.withProject(project))
    .and(JobEntitySpecifications.withCreateTime(createTime)));

如果你在这里使用静态导入，你可以让它看起来更好.

You can make it look even better if you use static imports here.

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