复制的代码可以在here (Github)找到。

对不起，我的英语不好。

我正在使用Spring Boot Web、JPA、MySQL来创建一个简单的REST风格的端点。

• Spring Boot父版本：2.7.0
• Java版本：11 Oracle

我的回购：

public interface TestRepository extends JpaRepository<Test, Long> {

    @Query("SELECT t FROM Test t WHERE (?1 IS NULL OR t.name LIKE %?1%)")
    Page<Test> findAll(String keyword, Pageable pageable);
}

我的接口：

@GetMapping("/ab")
public Page<Test> ab(CustomPageable pageable) {
    //INSERT INTO test VALUES(1, 'aa', 1);
    //INSERT INTO test VALUES(2, 'a', 2);
    //INSERT INTO test VALUES(3, 'b', 3);
    return testRepository.findAll(pageable.getKeyword(), pageable);
}

可自定义分页模式：

public static class CustomPageable extends PageRequest {

    @Getter
    private final String keyword;

    protected CustomPageable(int page, int size, Sort sort) {
        super(page, size, sort);
        keyword = null;
    }

    public CustomPageable(int page, int size, Sort sort, String keyword) {
        super(page, size, sort);
        this.keyword = keyword;
    }
}

我的问题是，如果pageable.getKeyword()为空(http://localhost:8181/ab?size=3&sort=name，DESC&PAGE=0)，我预计它将返回一个包含3个元素的页面。实际上，它返回一个空页。

日志：

2022-10-02 15:40:00.967  INFO 6560 --- [nio-8181-exec-6] p6spy                                    : #1664700000967 | took 2ms | statement | connection 4| url jdbc:mysql://localhost:3306/test
select test0_.id as id1_0_, test0_.name as name2_0_, test0_.status as status3_0_ from test test0_ where ? is null or test0_.name like ? order by test0_.name desc limit ?
select test0_.id as id1_0_, test0_.name as name2_0_, test0_.status as status3_0_ from test test0_ where '%org.hibernate.jpa.TypedParameterValue@d41192d%' is null or test0_.name like '%org.hibernate.jpa.TypedParameterValue@d41192d%' order by test0_.name desc limit 3;

请看查询...where '%org.hibernate.jpa.TypedParameterValue@d41192d%' is null or test0_.name like '%org.hibernate.jpa.TypedParameterValue@d41192d%'...。我对‘%org.hibernate.jpa.TypedParameterValue@d41192d%’.一无所知

请向我解释为什么我的HQL在关键字为空的情况下不起作用？是我的错误还是JPA的错误？我如何解决这个问题？

====================================================================================

注：

如果我发送关键字(http://localhost:8181/ab?size=3&sort=name，DESC&PAGE=0&Keyword=a)，那么它将正确返回。

日志：

2022-10-02 15:42:00.659  INFO 6560 --- [io-8181-exec-10] p6spy                                    : #1664700120658 | took 3ms | statement | connection 6| url jdbc:mysql://localhost:3306/test
select test0_.id as id1_0_, test0_.name as name2_0_, test0_.status as status3_0_ from test test0_ where ? is null or test0_.name like ? order by test0_.name desc limit ?
select test0_.id as id1_0_, test0_.name as name2_0_, test0_.status as status3_0_ from test test0_ where '%a%' is null or test0_.name like '%a%' order by test0_.name desc limit 3;
2022-10-02 15:42:00.665  INFO 6560 --- [io-8181-exec-10] p6spy                                    : #1664700120665 | took 4ms | statement | connection 6| url jdbc:mysql://localhost:3306/test
select count(test0_.id) as col_0_0_ from test test0_ where ? is null or test0_.name like ?
select count(test0_.id) as col_0_0_ from test test0_ where '%a%' is null or test0_.name like '%a%';

在HQL中使用@Query是必须的，请不要建议使用其他方式，如CriteriaBuilder等