程序包 org.springframework.jdbc.object

类 SqlFunction<T>

  • 所有已实现的接口:
    InitializingBean
    public class SqlFunction<T>
extends MappingSqlQuery<T>
    SQL "function" wrapper for a query that returns a single row of results. The default behavior is to return an int, but that can be overridden by using the constructor with an extra return type parameter.

    Intended to use to call SQL functions that return a single result using a query like "select user()" or "select sysdate from dual". It is not intended for calling more complex stored functions or for using a CallableStatement to invoke a stored procedure or stored function. Use StoredProcedure or SqlCall for this type of processing.

    This is a concrete class, which there is often no need to subclass. Code using this package can create an object of this type, declaring SQL and parameters, and then invoke the appropriate run method repeatedly to execute the function. Subclasses are only supposed to add specialized run methods for specific parameter and return types.

    Like all RdbmsOperation objects, SqlFunction objects are thread-safe.

    作者:
    Rod Johnson, Juergen Hoeller, Jean-Pierre Pawlak
    另请参阅:
    StoredProcedure

    • 构造器详细资料

      • SqlFunction

        public SqlFunction​(DataSource ds,
                   String sql)
        Create a new SqlFunction object with SQL, but without parameters. Must add parameters or settle with none.
        参数:
        ds - DataSource to obtain connections from
        sql - SQL to execute

      • SqlFunction

        public SqlFunction​(DataSource ds,
                   String sql,
                   int[] types)
        Create a new SqlFunction object with SQL and parameters.
        参数:
        ds - DataSource to obtain connections from
        sql - SQL to execute
        types - SQL types of the parameters, as defined in the java.sql.Types class
        另请参阅:
        Types

      • SqlFunction

        public SqlFunction​(DataSource ds,
                   String sql,
                   int[] types,
                   Class<T> resultType)
        Create a new SqlFunction object with SQL, parameters and a result type.
        参数:
        ds - DataSource to obtain connections from
        sql - SQL to execute
        types - SQL types of the parameters, as defined in the java.sql.Types class
        resultType - the type that the result object is required to match
        另请参阅:
        setResultType(Class), Types

    • 方法详细资料

      • setResultType

        public void setResultType​(Class<T> resultType)
        Specify the type that the result object is required to match.

        If not specified, the result value will be exposed as returned by the JDBC driver.

      • mapRow

        protected T mapRow​(ResultSet rs,
                   int rowNum)
            throws SQLException
        This implementation of this method extracts a single value from the single row returned by the function. If there are a different number of rows returned, this is treated as an error.
        指定者:
        mapRow 在类中 MappingSqlQuery<T>
        参数:
        rs - ResultSet we're working through
        rowNum - row number (from 0) we're up to
        返回:
        an object of the result type
        抛出:
        SQLException - if there's an error extracting data. Subclasses can simply not catch SQLExceptions, relying on the framework to clean up.

      • run

        public int run()
        Convenient method to run the function without arguments.
        返回:
        the value of the function

      • run

        public int run​(int parameter)
        Convenient method to run the function with a single int argument.
        参数:
        parameter - single int parameter
        返回:
        the value of the function

      • run

        public int run​(Object... parameters)
        Analogous to the SqlQuery.execute([]) method. This is a generic method to execute a query, taken a number of arguments.
        参数:
        parameters - array of parameters. These will be objects or object wrapper types for primitives.
        返回:
        the value of the function

      • runGeneric

        public Object runGeneric()
        Convenient method to run the function without arguments, returning the value as an object.
        返回:
        the value of the function

      • runGeneric

        public Object runGeneric​(int parameter)
        Convenient method to run the function with a single int argument.
        参数:
        parameter - single int parameter
        返回:
        the value of the function as an Object

      • runGeneric

        public Object runGeneric​(Object[] parameters)
        Analogous to the SqlQuery.findObject(Object[]) method. This is a generic method to execute a query, taken a number of arguments.
        参数:
        parameters - array of parameters. These will be objects or object wrapper types for primitives.
        返回:
        the value of the function, as an Object
        另请参阅:
        SqlQuery.execute(Object[])