org.springframework.data.repository.query.parser.Part有什么用？

Question

正如你在标题中看到的，如果有人能告诉我这个类的用法，我将不胜感激。

有一个内部枚举类型，如何使用它？

public static enum Type {
BETWEEN(2, "IsBetween", "Between"), IS_NOT_NULL(0, "IsNotNull", "NotNull"), IS_NULL(0, "IsNull", "Null"), LESS_THAN(
"IsLessThan", "LessThan"), LESS_THAN_EQUAL("IsLessThanEqual", "LessThanEqual"), GREATER_THAN("IsGreaterThan",
"GreaterThan"), GREATER_THAN_EQUAL("IsGreaterThanEqual", "GreaterThanEqual"), BEFORE("IsBefore", "Before"), AFTER(
"IsAfter", "After"), NOT_LIKE("IsNotLike", "NotLike"), LIKE("IsLike", "Like"), STARTING_WITH("IsStartingWith",
"StartingWith", "StartsWith"), ENDING_WITH("IsEndingWith", "EndingWith", "EndsWith"), NOT_CONTAINING(
"IsNotContaining", "NotContaining", "NotContains"), CONTAINING("IsContaining", "Containing", "Contains"), NOT_IN(
"IsNotIn", "NotIn"), IN("IsIn", "In"), NEAR("IsNear", "Near"), WITHIN("IsWithin", "Within"), REGEX(
"MatchesRegex", "Matches", "Regex"), EXISTS(0, "Exists"), TRUE(0, "IsTrue", "True"), FALSE(0, "IsFalse",
"False"), NEGATING_SIMPLE_PROPERTY("IsNot", "Not"), SIMPLE_PROPERTY("Is", "Equals");
// Need to list them again explicitly as the order is important
// (esp. for IS_NULL, IS_NOT_NULL)
private static final List<Part.Type> ALL = Arrays.asList(IS_NOT_NULL, IS_NULL, BETWEEN, LESS_THAN, LESS_THAN_EQUAL,
GREATER_THAN, GREATER_THAN_EQUAL, BEFORE, AFTER, NOT_LIKE, LIKE, STARTING_WITH, ENDING_WITH, NOT_CONTAINING,
CONTAINING, NOT_IN, IN, NEAR, WITHIN, REGEX, EXISTS, TRUE, FALSE, NEGATING_SIMPLE_PROPERTY, SIMPLE_PROPERTY);
...}

Answer 1

Part是Spring Data的内部。客户端代码不打算使用它。因此，如果你不实现你自己的Spring数据模块，你就不应该使用它，也不应该使用里面的任何东西

Part基本上是AST的一个元素，根据使用的存储，它可能会导致where子句或等效子句的元素。

例如，如果您有一个方法findByNameAndDobBetween(String, Date, Date)，则解析方法名称将导致两部分。一个用于名称条件，另一个用于之间的DOB条件。

类型枚举列出了所有可能的不同类型的条件。元素的参数是所需的方法参数的数量，以及(可能是多个(在方法名称中标识此类型的String。