📄 servletdemo4.java

📁 java程序设计语言源代码
💻 JAVA
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//Example 4 of Chapter 11

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;

public class ServletDemo4 extends HttpServlet
{
	private static final String CONTENT_TYPE = "text/html; charset=gbk";
	private String driver = "com.mysql.jdbc.Driver";
	private String url = "jdbc:mysql://localhost:3306/graduation_design";
	private String user = "root";
	private String password = "";
	private Connection connect;
	private Statement stmt;
	private ResultSet results;
	
	public void init( ServletConfig config ) throws ServletException
	{
		try{
			//载入JDBC驱动程序
			Class.forName( driver );
			//连接到数据库
			connect = DriverManager. getConnection( url, user, password );
			//创建Statement对象
			stmt = connect.createStatement();
		}
		catch ( SQLException sqlException )
		{
			sqlException.printStackTrace();
		}
		catch ( ClassNotFoundException classNotFound )
		{
			classNotFound.printStackTrace();
		}
	}
	protected void doPost( HttpServletRequest request,
		HttpServletResponse response ) throws ServletException, IOException
	{
		response.setContentType( CONTENT_TYPE );
		PrintWriter out = response.getWriter();
		out.println( "<?xml version = \"1.0\"?>" );
		out.println( "<!DOCTYPE html PUBLIC \"-//W3C//DTD " + 
			"XHTML 1.0 Strict//EN\" \"http://www.w3.org" + 
			"/TR/xhtml1/DTD/xhtml1-strict.dtd\">" );
		out.println( "<html xmlns = \"http://www.w3.org/1999/xhtml\">" );
		out.println( "<head>" );
		out.println( "<title>查询结果</title>" );
		out.println( "</head><body>" );
		out.println( "<p>谢谢您的关注，查询结果：</p><pre>" );
		//获取查询结果
		String phone = request.getParameter( "PHONE" );
		String query = "SELECT * FROM namelist WHERE PHONE = \"" + phone + "\"" ;
		try{
			results = stmt.executeQuery( query );
			//获取数据描述信息
			ResultSetMetaData metaData = results.getMetaData();
			int columns = metaData.getColumnCount();
			//输出数据记录
			while ( results.next() )
			{
				for ( int i = 1; i <= columns; i++ )
					out.write( "   " + results.getObject( i ) );
				out.print( "\n" );
			}
			out.println( "</pre></body></html>" );
			out.close();
		}
		catch ( SQLException sqlException )
		{
			sqlException.printStackTrace();
		}
	}
	
	public void destroy()
	{
		try{
			results.close();
			stmt.close();
			connect.close();
		}
		catch ( SQLException sqlException )
		{
			sqlException.printStackTrace();
		}
		catch ( NullPointerException nullpointerException )
		{
			nullpointerException.printStackTrace();
		}
	}
}
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