Question

是否有可能在spring-data存储库中有两个方法 - 一个没有锁定T findOne(Predicate p);但同时锁定@Lock(LockModeType.PESSIMISTIC_WRITE) T findOne(Predicate p);？

我希望有像

这样的东西

public interface TransactionRepository extends JpaRepository<Transaction, String>,
    QueryDslPredicateExecutor<Transaction> {

    @Lock(LockModeType.PESSIMISTIC_WRITE)
    @AliasFor("findOne")
    Transaction findOne_withLock(Predicate p);
}

Answer 1

不，它不可能

Java不允许您使用相同的原型定义两个函数。 U可以有一个选择器，它根据一些环境变量调用函数

scala> val df = spark.read.json("data.json")

scala> df.printSchema
root
 |-- a: struct (nullable = true)
 |    |-- b: struct (nullable = true)
 |    |    |-- c: long (nullable = true)
 |-- **TimeStamp: string (nullable = true)**
 |-- id: string (nullable = true)


scala> val df1 = df.withColumn("TimeStamp", $"TimeStamp".cast(TimestampType))

scala> df1.printSchema
root
 |-- a: struct (nullable = true)
 |    |-- b: struct (nullable = true)
 |    |    |-- c: long (nullable = true)
 |-- **TimeStamp: timestamp (nullable = true)** // WORKING AS EXPECTED
 |-- id: string (nullable = true)


scala> val df2 = df.withColumn("a.b.c", $"a.b.c".cast(DoubleType))

scala> df2.printSchema
root
 |-- a: struct (nullable = true)
 |    |-- b: struct (nullable = true)
 |    |    |-- c: long (nullable = true)
 |-- TimeStamp: string (nullable = true)
 |-- id: string (nullable = true)
 |-- **a.b.c: double (nullable = true)** // DUPLICATE COLUMN ADDED

Spring数据和锁定

1 个答案: