JDBC之Statement与preparedStatement

用Statement执行数据库语句比较麻烦。

例如，向数据库中插入整型， 字符串等数据。

String JDriver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String connectDB="jdbc:sqlserver://ABYSS-
                PC\\MYABYSS:64160;DatabaseName=master";
        //实例化驱动
        Class.forName(JDriver);
        String user ="sa";
        String possword = "";
        //连接数据库
        Connection conn = 
DriverManager.getConnection(connectDB, user, possword);
        //创建语句对象
        Statement stmt = conn.createStatement();
        int Number = 189;
        String City = "北京";
        String Job = "服务业";
        String sql = "insert into dept2 values (" +
                     Number+",'" + City +"','"+ Job+"')";
        stmt.executeUpdate(sql);

在sql变量中又是单引号 又是逗号的很麻烦，而且一不小心容易写错。

换成preparedStatement就简单许多了

        String JDriver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String connectDB="jdbc:sqlserver://ABYSS-
PC\\MYABYSS:64160;DatabaseName=master";
        //实例化驱动
        Class.forName(JDriver);
        String user ="sa";
        String possword = "";
        //连接数据库
        Connection conn = 
DriverManager.getConnection(connectDB, user, possword);
        //创建语句对象
        int Number = 189;
        String City = "北京";
        String Job = "服务业";
        PreparedStatement pstmt =
        conn.prepareStatement( "insert into dept2 values (?, ?, ?)");
        pstmt.setInt(1, Number);
        pstmt.setString(2, City);
        pstmt.setString(3, Job);
        pstmt.executeUpdate();