Question

我正在使用以下预备声明：

 Class.forName("com.mysql.jdbc.Driver");
     con=DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql","root","root");
            String query="select ename from ? ";
            st=con.prepareStatement(query);
            st.setString(1,"emp");

这里我想从UI提供表名，在上面的代码我有硬编码的表名值。当我尝试执行此代码时，我得到以下例外。

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''emp' where intensive='1000'' at line 1
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
        at com.mysql.jdbc.Util.getInstance(Util.java:381)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3515)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3447)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1951)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2554)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1761)
        at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1912)
        at xmlbulkinsertoperation.getConnection.<init>(getConnection.java:42)
        at xmlbulkinsertoperation.getConnection.main(getConnection.java:70)
Mar 26, 2012 12:04:30 PM xmlbulkinsertoperation.getConnection <init>

我无法解决这个问题，请帮助我？

由于

Answer 1

您不能将带有表名的预准备语句作为参数之一。实体（表名/数据库名称/函数名等）无法在预准备语句中进行参数化。

您必须对表名进行硬编码或将其连接到查询中。

执行预准备语句时获得异常？

1 个答案: