java 操作mysql表

        今天要根据动态的数据库名字创建和删除表，结果一直提示sql语句显示错误，搞了很久。下面直接上正确代码：

public void dropTable(String DB){

try {

//判断数据库中是否存在表

pstmt =conn.prepareStatement("SELECT table_name FROM information_schema.TABLES WHERE table_name =?");

pstmt.setString(1, DB);

rs =pstmt.executeQuery();

if(rs.next()){//如果存在则删除

pstmt =conn.prepareStatement("drop table  "+DB);

pstmt.execute();

}

} catch (SQLException e) {

//TODO Auto-generated catch block

e.printStackTrace();

}

}

publicvoid updateTable(String DB) {

try {

pstmt =conn.prepareStatement("SELECT table_name FROM information_schema.TABLES WHERE table_name =?");

pstmt.setString(1, DB);

rs =pstmt.executeQuery();

if(rs.next()==false){

pstmt =conn.prepareStatement("CREATE TABLE "+DB+" ( id int ,productName varchar(45) ,pageNum int  ,locationH varchar(25) ,locationV varchar(25),detailMsg varchar(100) ) ");

pstmt.execute();

}

} catch (SQLException e) {

//TODO Auto-generated catch block

e.printStackTrace();

}

}

    产生错误的原因是：我在红色的地方是用占位符的，改成上面的那样才正确。