databaseinquire.java

可以让初学者有一个感性的认识

import java.sql.*;

public class DataBaseInquire
{
	String keyword;
	
	public DataBaseInquire()
	{
		keyword="";
		try
		{	Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
		}catch(ClassNotFoundException e1){}
	}

	public void setKeyword(String s)
	{
		keyword=s;
		try
		{
			byte a[]=keyword.getBytes("ISO-8859-1");
			keyword =new String(a);
		}catch(Exception e){}
	}

	public StringBuffer byKeywordInquire()
	{
		String xingming,number;

		Connection con=null;
		Statement sql=null;
		ResultSet rs=null;

		StringBuffer buffer=new StringBuffer();
		int math,english,physics;

		try
		{
			con=DriverManager.getConnection("jdbc:odbc:sun","","");
			sql=con.createStatement();
			String condition="SELECT * FROM students WHERE 学号="+keyword;
			rs=sql.executeQuery(condition);
			buffer.append("<Table Border>");
			buffer.append("<TR>");
				buffer.append("<TH width=100>"+"学号");
				buffer.append("<TH width=100>"+"姓名");
				buffer.append("<TH width=50>" +"数学成绩");
				buffer.append("<TH width=50>" +"英语成绩");
				buffer.append("<TH width=50>" +"物理成绩");
			buffer.append("</TR>");
			while(rs.next())
			{	number=rs.getString(1);
				xingming= rs.getString(2);
				buffer.append("<TR>");
					buffer.append("<TD>"+number+"</TD>");
					buffer.append("<TD>"+xingming+"</TD>");
					math=rs.getInt("数学成绩");
					buffer.append("<TD>"+math+"</TD>");
					english=rs.getInt("英语成绩");
					buffer.append("<TD>"+english+"</TD>");
					physics=rs.getInt("物理成绩");
					buffer.append("<TD>"+physics+"</TD>");
				buffer.append("</TR>");
			}
			buffer.append("</Table>");
			con.close();
			return buffer;
		}catch(SQLException e1)
		{return new StringBuffer("无法建立查询"); }
	}
}