rspagedemo.java

学习参考,java基本语法练习,包括一些常用的技巧

//结果集分页显示
import java.sql.*;
public class RsPageDemo
{
	//打开数据库连接
	public Connection openDatabase()
	{
		try 
		{
			//加载JDBC驱动
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
			//创建数据库连接
			Connection conn = DriverManager.getConnection("jdbc:odbc:HappyChat");
        return conn;
    	}
    	catch (Exception e) 
    	{
    		System.out.println("连接数据库失败!");
        	return null;
     	}
	}
	//查询数据库中记录
	public void queryRecord(Connection con, String sql,int pageNo,int pageSize)
	{
		try
		{
			if(con==null)
				throw new Exception("数据库连接失败!");
     		if(sql==null) 
     			throw new Exception("查询字符串不能为空!");
     		int intRowCount;//记录总数
     		int intPageCount;//总页数
     		//声明语句
     		Statement sm = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
     		//执行查询
     		ResultSet rs = sm.executeQuery(sql); 
     		ResultSetMetaData rsmd = rs.getMetaData();
     		//获得数据字段个数
     		int intColumns = rsmd.getColumnCount();
     		//获取记录总数  
     		rs.last();  
     		intRowCount = rs.getRow(); 
     		//记算总页数  
     		intPageCount = (intRowCount+pageSize-1) / pageSize;
	 		//调整待显示的页码  
     		if(pageNo>intPageCount) pageNo = intPageCount; 
			if(intPageCount>0)
			{
     			//将记录指针定位到待显示页的第一条记录上  
     			rs.absolute((pageNo-1) * pageSize + 1); 
     			int i = 0;
     			while(i<pageSize && !rs.isAfterLast())
	 			{
	 				for(int j = 0;j< intColumns;j++)
	   				{
	   					String sTemp = rs.getString(j+1);
						System.out.print(sTemp+"  ");
	   				}
	   				i++;
	   				rs.next();
	  				System.out.println("");	
	 			}
			}
		}
		catch(Exception e)
		{
			System.out.println("数据查询错误!");
    	}
	}
	
	public static void main(String[] arg)
	{
		if(arg.length!=2)
		{
			System.out.println("参数错误!");
			System.out.println("use: java RsPageDemo NoPage PageSize");
			return;
    	}
    	RsPageDemo rpd = new RsPageDemo();
   		String sql = "select * from history order by H_no";
    	int intPageNo = Integer.parseInt(arg[0]);
    	int intPageSize = Integer.parseInt(arg[1]);
    	rpd.queryRecord(rpd.openDatabase(),sql,intPageNo,intPageSize);
  	}
}