Advanced JDBC Techniques

最新推荐文章于 2025-05-07 23:06:59 发布

最新推荐文章于 2025-05-07 23:06:59 发布 · 70 阅读

文章标签：

#JDBC #SQL #Servlet

本文介绍了如何使用CallableStatement调用存储过程，并说明了不同情况下返回结果的语法。此外，还探讨了处理大型文本字符串和二进制对象的方法，包括使用ResultSet的getAsciiStream()和getBinaryStream()。

1. Stored Procedures: CallableStatement

Synatax for a procedure that doesn't return a result is {call procedure_name(.., >>)}, Synatax that return a result value is {?= call procedure_name(.., ..)}. Using like below:

CallableStatment cstmt = con.prepareCall("{call p_name(.., ..)}"); // like PreparedStatement

cstmt.registerOutParameter(col_num, java.sql.Types.FLOAT); //declear that the type of the value returned if FLOAT

cstmt.setInt(col_num, value);

cstmt.execute();

cstmt.getFloat(col_num);

2.Binaries and Books: ResultSet.getAsciiStream() handles large text strings, getBinaryStream() works for large binary objects.

When reading from InputStream(from getAsciiStream()), the servlet doesn't get the value of any other columns in the result set, because calling any other getXxx() metod of ResultSet closes the InputStream.