高分求救(access数据迁移到mysql问题)
需要把access数据迁移到mysql，这个功能已经基本ＯＫ，但是要加个判断（如果mysql中已经存在该记录，则不添加，否则添加），可我的判断却不管用，因为我的添加语句是写在access中的循环读数据的while(rs１.next())中的，我是这样来通过插入所有的数据，可是这个判断该怎么改呢？


　ConnectMysql 类如下，这个用来连接mysql

package myclass;

import java.sql.*;

public class ConnectMysql {

Connection conn = null;
Statement stmt = null;
ResultSet r = null;
String url = "";

public ConnectMysql() {
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
url = "jdbc:mysql://192.168.1.229:3306/goodstart?user=root&password=root&useUnicode=true&characterEncoding=UTF-8";
conn = DriverManager.getConnection(url);
stmt = conn.createStatement();

} catch (Exception e) {
System.out.print("连接数据库发生错误：" + e.getMessage());
}

}

public void createDb(){
if (null == conn) {
try {
System.out.print("创建conn");
conn = DriverManager.getConnection(url);
} catch (Exception e) {
System.out.print("连接数据库发生错误：" + e.getMessage());
}
}

if(null==stmt){
try {
System.out.print("创建stmt");
stmt = conn.createStatement();
} catch (Exception e) {
System.out.print("连接数据库发生错误：" + e.getMessage());
}
}
}

public void closeDb(){

if(null!=stmt){
try {
System.out.print("关闭stmt");
stmt.close();
} catch (Exception e) {
System.out.print("连接数据库发生错误：" + e.getMessage());
}
}

if (null != conn) {
try {
System.out.print("关闭conn");
conn.close();
} catch (Exception e) {
System.out.print("连接数据库发生错误：" + e.getMessage());
}
}

}





// ResultSet Query
public ResultSet executeQuery(String sql) {
try {
r = stmt.executeQuery(sql);
} catch (Exception ex) {
System.out.print("查询发生错误：" + ex.getMessage());
}
return r;
}

// executeUpdate
public void executeUpdate(String sql) {
try {
stmt.executeUpdate(sql);
} catch (Exception ex) {
System.out.print("执行SQL发生错误:" + ex.getMessage());
}
}


}

IsExist 类如下，此类用来判断插入的数据是否是已经有的（主要是checktime时间字段）
package myclass;



import myclass.*;

import java.sql.*;

public class IsExist 
{



ResultSet rs = null;

String sql11 = null;
ConnectMysql connectmysql = new ConnectMysql();

ResultSet rs1 = null;

boolean flag = false;
public boolean IsExistKaoqin() 
{
try
{

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

String dbUrl = "jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=D:\\myapp\\access\\attBackup.mdb";

Connection con = DriverManager.getConnection(dbUrl, "", "");
Statement stmt1 = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);

String sql1 = "select a.USERID,a.Name,b.CHECKTIME, b.CHECKTYPE from USERINFO a,CHECKINOUT b where a.USERID = b.USERID ";
rs1 = stmt1.executeQuery(sql1);


try 
{
while (rs1.next())
{
sql11 = "select checktime from KQ_USER_SYSUSER where checktime='"
+ rs1.getString("CHECKTIME") + "';";
connectmysql.createDb();
rs = connectmysql.executeQuery(sql11);
//System.out.println("sql11="+sql11);
}

if (rs.next())
{
flag = true;
}
rs.close();