Spring Data JDBC@modificing with PostgreSQL返回从修改的行返回数据

Question

PostgreSQL提供了从DML语句返回数据的简洁方法，请参见https://www.PostgreSQL L.org/docs/current/DML-returning.html

我试图实现的是类似以下片段的东西

@Modifying
@Query("DELETE FROM Book b WHERE b.title = :title RETURNING *")
Book deleteReturning(@Param("title") String title);

若要检索已删除的行，请执行以下操作。但是，这会导致以下异常

org.springframework.dao.DataIntegrityViolationException: PreparedStatementCallback; SQL [DELETE FROM Book b WHERE b.title = ? RETURNING *]; A result was returned when none was expected.; nested exception is org.postgresql.util.PSQLException: A result was returned when none was expected.
    at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:104)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
    at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1443)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:633)
    at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:862)
    at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:883)
    at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.update(NamedParameterJdbcTemplate.java:321)
    at org.springframework.data.jdbc.repository.query.AbstractJdbcQuery.lambda$createModifyingQueryExecutor$0(AbstractJdbcQuery.java:103)
    at org.springframework.data.jdbc.repository.query.StringBasedJdbcQuery.execute(StringBasedJdbcQuery.java:85)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor$QueryMethodInvoker.invoke(QueryExecutorMethodInterceptor.java:195)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:152)
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130)
    ...
Caused by: org.postgresql.util.PSQLException: A result was returned when none was expected.
    at org.postgresql.jdbc.PgStatement.checkNoResultUpdate(PgStatement.java:269)
    at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:131)
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
    at org.springframework.jdbc.core.JdbcTemplate.lambda$update$0(JdbcTemplate.java:867)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:617)
    ... 95 more

Spring Data JDBC声明修改查询只能返回void、int和boolean，请参见https://docs.Spring.io/Spring-Data/JDBC/docs/current/reference/html/#JDBC.query-methods.at-query.modifiing

添加自定义RowMapper会导致相同的异常。

    public class BookRowMapper<T> implements RowMapper<Book> {
        @Override
        public Book mapRow(final ResultSet rs, final int rowNum) throws SQLException {
            return new Book(rs.getString(1), ...);
        }
    }

    @Modifying
    @Query(value = "delete from Book b where b.title = :title returning *", rowMapperClass = BookRowMapper.class)
    Book deleteReturning(@Param("title") String title);

编辑：我知道普通的JDBC https://stackoverflow.com/a/40787385/1239904，但我想使用Spring方式。

Answer 1

当您用@modifiing注释该方法时，它将作为一个DML语句执行，该语句除了更新的行数之外不返回任何值。

如果语句返回resultset，则不应使用@modifiing，因此Spring Data JDBC尝试提取resultset并从中为方法创建返回值。