// Dan brown's first book
Book.find("from Book as b where b.author='Dan Brown'")
// with a positional parameter
Book.find("from Book as b where b.author=?", ['Dan Brown'])
// with a named parameter
Book.find("from Book as b where b.author=:author", [author: 'Dan Brown'])
// use the query cache
Book.find("from Book as b where b.author='Dan Brown'", [cache: true])
Book.find("from Book as b where b.author=:author",
[author: 'Dan Brown'],
[cache: true])
// query by example
def example = new Book(author: "Dan Brown")
Book.find(example)
// Using where criteria (since Grails 2.0)
Person p = Person.find { firstName == "Bart" }查找
目的
查找给定查询的第一个匹配结果，如果没有找到任何实例，则返回null
示例
描述
find方法允许使用Hibernate的查询语言HQL和按示例查询查询。基本语法是
Book.find(String query)
Book.find(String query, Collection positionalParams)
Book.find(String query, Collection positionalParams, Map queryParams)
Book.find(String query, Map namedParams)
Book.find(String query, Map namedParams, Map queryParams)
Book.find(Book example)
Book.find(Closure whereCriteria)参数
-
query- 一个HQL查询 -
positionalParams- 一个按位置参数化HQL查询的List -
namedParams- 一个HQL查询的命名字段 -
queryParams- 一个查询参数的Map。目前，仅支持cache -
example- 一个用于按示例查询的领域类的实例