jdbc_servlet.java

一个简单的JDBC操作

package li.service;

import java.io.IOException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import li.jdbc.connDB;

public class JDBC_servlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	private String driver=null;
	private String url=null;
	private String user=null;
	private String password=null;
	public JDBC_servlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		  String status=request.getParameter("status");
		  if(status.equals("select"))
		  {
			  this.select(request, response);
		  }
		  else if(status.equals("update"))
		  {
			  this.update(request, response);
		  }
		  else if(status.equals("delete"))
		  {
			  this.delete(request, response);
		  }
		  else if(status.equals("insert"))
		  {
			  this.insert(request, response);
		  }
		  else if(status.equals("getById"))
		  {
			  this.getById(request, response);
		  }
        
	}
    public void select(HttpServletRequest request, HttpServletResponse response)
	       throws ServletException, IOException {
    	connDB conndb=new connDB(this.driver,this.url,this.user,this.password);
        
    	String sql="SELECT * FROM user";
        ResultSet re=conndb.executeQuery(sql);
        List z=this.change(re);
        conndb.close();
        request.setAttribute("user", z);
        request.getRequestDispatcher("../List.jsp").forward(request, response);
        
    }
    public void getById(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
	  connDB conndb=new connDB(this.driver,this.url,this.user,this.password);
	  String id=request.getParameter("id");
	  String sql="SELECT * FROM user WHERE id="+id;
	  ResultSet re=conndb.executeQuery(sql);
	  List z=this.change(re);
	  conndb.close();
	  request.setAttribute("user", z);
	  request.getRequestDispatcher("../detail.jsp").forward(request, response);
	 
	}
    public void update(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {
    	 connDB conndb=new connDB(this.driver,this.url,this.user,this.password);
         String uname=request.getParameter("uname");
         String upassword=request.getParameter("upassword");
         String id=request.getParameter("id");
    	 String sql="UPDATE user SET uname='"+uname+"',upassword='"+upassword+"' WHERE id="+id;
    	 conndb.executeUpdate(sql);
    	 conndb.close();
    	 this.select(request, response);
    }
    public void delete(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {
	     connDB conndb=new connDB(this.driver,this.url,this.user,this.password);
         String id=request.getParameter("id");
	     String sql="DELETE FROM user WHERE id="+id;
	     conndb.delete(sql);
	     conndb.close();
	     this.select(request, response);
    }
    public void insert(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
    	  connDB conndb=new connDB(this.driver,this.url,this.user,this.password);
    	  String uname=request.getParameter("uname");
    	  String upassword=request.getParameter("upassword");
    	  String sql="INSERT INTO user(uname,upassword) VALUES ('"+uname+
                 "','"+upassword+"')";
    	  System.out.print(sql);
    	  conndb.insert(sql);
    	   conndb.close();
    		this.select(request, response);
    	  
    }
    public List change(ResultSet rs)
    {
    	HashMap rsTree;
    	List reList=new ArrayList();
    	try {
			ResultSetMetaData rsmd=rs.getMetaData();
			int columnum=rsmd.getColumnCount();
			while(rs.next())
			{
				rsTree=new HashMap(columnum);
				for(int i=1;i<=columnum;i++)
				{
					rsTree.put(rsmd.getColumnName(i), rs.getObject(i));
				}
				reList.add(rsTree);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return reList;
    }
	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	   this.driver=getServletConfig().getInitParameter("DBDRIVER");
	   this.url=getServletConfig().getInitParameter("DBURL");
	   this.user=getServletConfig().getInitParameter("DBUSER");
	   this.password=getServletConfig().getInitParameter("DBPASSWORD");
	}

}