JDBC操作mysql编写及遇到的问题_MySQL

import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class MultiResultSet {	public static void main(String[] args) {	Connection conn = null;	Statement stmt = null;	// TODO Auto-generated method stub	try {	//装载JDBC驱动	Class.forName("com.mysql.jdbc.Driver");	//连接字符串：包括数据库服务器名、端口号（省略）、数据库名、	String conStr = "jdbc:mysql://localhost/mydb?characterEncoding=UTF8&allowMultiQueries=true";	//获得Connection对象，进行连接数据库：数据库连接字符串，用户名，密码	conn = DriverManager.getConnection(conStr, "root", "123456");	//获得Statement对象：用来操作sql语句	stmt = conn.createStatement();	//建立一个图书销售表t_booksale	String createDB = "create database if not exists mydb default character set utf8";	String dropTable = "drop table if exists mydb.t_booksale";//如果存在则删除重建	String createTable = "create table mydb.t_booksale(" +	"id int unsigned not null auto_increment,"+	"bookid int unsigned not null,"+	"amount int unsigned not null,"+	"saledate datetime not null,"+	"primary key(id)) engine=innodb default charset=utf8";	String insertData1 = "insert into mydb.t_booksale(bookid,amount,saledate) values(1,23,'1988-3-23')";	String insertData2 = "insert into mydb.t_booksale(bookid,amount,saledate) values(1,120,'2008-5-11')";	String insertData3 = "insert into mydb.t_booksale(bookid,amount,saledate) values(2,218,'2011-2-09')";	stmt.execute(createDB);	stmt.execute(dropTable);	stmt.execute(createTable);	stmt.execute(insertData1);	stmt.execute(insertData2);	stmt.execute(insertData3);	//返回多个结果集ResultSet，使用do while处理	String selectData = "select id,name,author from t_books" +";"+	"select bookid,amount,saledate from t_booksale";	if(stmt.execute(selectData)){	ResultSet rs = null;	do{	rs = stmt.getResultSet();	//显示查询结果	while(rs.next()){	System.out.println(rs.getString(1));//获得id号	System.out.println(rs.getString(2));//作者名	System.out.println(rs.getString(3));	}	}while(stmt.getMoreResults());	}	} catch (Exception e) {	// TODO Auto-generated catch block	e.printStackTrace();	}finally{	try {	if(stmt!=null){	stmt.close();	}	if(conn!=null){	conn.close();	}	} catch (SQLException e) {	// TODO Auto-generated catch block	e.printStackTrace();	}	}	}}