java - 使用单个 JDBC Statement 对象执行多个查询

Question

在 JDBC 中，我可以使用单个 Statement 对象多次调用 executeQuery("") 吗？安全吗？或者我应该在每次查询后关闭语句对象，并创建新对象来执行另一个查询。

例如:

Connection con;
Statement s;
ResultSet rs;
ResultSet rs2;
try
{
    con = getConnection();
    // Initially I was creating the Statement object in an
    // incorrect way. It was just intended to be a pseudocode.
    // But too many answerers misinterpretted it wrongly. Sorry 
    // for that. I corrected the question now. Following is the 
    // wrong way, commented out now. 
    // s = con.prepareStatement();
    
    // Following is the way which is correct and fits for my question.
    s = con.createStatement();

    try
    {
        rs = s.executeQuery(".......................");

        // process the result set rs
    }
    finally
    {
        close(rs);
    }

    // I know what to do to rs here
    // But I am asking, should I close the Statement s here? Or can I use it again for the next query?

    try
    {
        rs2 = s.executeQuery(".......................");

        // process the result set rs2
    }
    finally
    {
        close(rs2);
    }
}
finally
{
    close(s);
    close(con);
}

Answer 1

是的，您可以重复使用 Statement(特别是 PreparedStatement)并且通常应该使用 JDBC 这样做。如果您不重新使用您的语句并立即创建另一个相同的 Statement 对象，那将是低效和糟糕的风格。至于关闭它，最好在 finally block 中关闭它，就像您在此代码段中一样。

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