Servlet编写网页并与数据库连接
来源：互联网 发布：牛根生 知乎 编辑：程序博客网 时间：2024/06/03 13:21
首先要保证电脑已经安装tomcat 和mysql并用myeslipse(esplise)实现
//首页 登陆页面 Login.java
package nuc.exam.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Login extends HttpServlet {
/** * Constructor of the object. */public Login() { super();} public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response);} public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); request.setCharacterEncoding("utf-8"); PrintWriter out = response.getWriter(); out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>登陆界面</TITLE></HEAD>"); out.println(" <BODY>"); out.print("<form action='Insert' method='post'>"); out.print("<table border='1' align='center'>"); out.print("<tr align='center'>"); out.print("<td colspan='2'>");out.print("<h2>电影介绍</h2>");out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影名称：");out.print("</td>"); out.print("<td>");out.print("<input type='text' name='name' value=''>");out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影价格：");out.print("</td>"); out.print("<td>");out.print("<input type='text' name='price' value=''>");out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影产地：");out.print("</td>"); out.print("<td>"); out.print("<input type='radio' name='from' value='大陆'>大陆"); out.print("<input type='radio' name='from' value='香港'>香港"); out.print("<input type='radio' name='from' value='国外'>国外"); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影类型：");out.print("</td>"); out.print("<td>"); out.print("<select name='type'>"); out.print("<option>动作片</option>"); out.print("<option>动画片</option>"); out.print("<option>剧情片</option>"); out.print("</select>"); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影主演：");out.print("</td>"); out.print("<td>"); out.print("<input type='checkbox' name='actor' value='李小龙'>李小龙"); out.print("<input type='checkbox' name='actor' value='成龙'>成龙"); out.print("<input type='checkbox' name='actor' value='其他'>其他"); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影简介：");out.print("</td>"); out.print("<td height='100px'>"); out.print("<input type='textarea' style='height:100px;' name='' value=''> "); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>");out.print("电影详细介绍：");out.print("</td>"); out.print("<td>"); out.print("<input type='file' name='' calue=''>"); out.print("</td>"); out.print("</tr>"); out.print("<tr>"); out.print("<td colspan='2'>"); out.print(" "); out.print("<input type='submit' value='提交'>"); out.print(" "); out.print("<input type='reset' value='重置'>"); out.print("</td>"); out.print("</tr>"); out.print("</table>"); out.print("</form>"); out.println(""); out.println(" </BODY>"); out.println("</HTML>"); out.flush(); out.close();}} 
//这个是用servlet 写的。
链接数据库 UserCoon.java
package nuc.test.coon;
import java.sql.*;
public class UserCoon {
public static final String DBDRIVER=”org.gjt.mm.mysql.Driver”;
public static final String DBURL=”jdbc:mysql://localhost:3306/test”;
public static final String DBUSER=”root”;
public static final String DBPASS=”123456”;
Connection conn=null;
public Connection getCoon(){
try {
Class.forName(DBDRIVER);
conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
UserDao.java各种方法
package nuc.test.Dao;
import java.sql.*;
import nuc.test.coon.*;
import nuc.test.user.*;
public class UserDao {
public int Insert(User usera){
PreparedStatement pst=null;
int rs=0;
UserCoon coon=new UserCoon();
Connection coona=coon.getCoon();
String sql_insert=”insert into user(username,password,type) values(?,?,?)”;
try{
pst=coona.prepareStatement(sql_insert);
pst.setString(1, usera.getUsername());
pst.setString(2, usera.getPassword());
pst.setString(3,usera.getType());
rs=pst.executeUpdate();
}catch(Exception e){
e.printStackTrace();
}
return rs;}//查询public ResultSet Query(){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_query="select * from user"; try { pst=coona.prepareStatement(sql_query); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}public ResultSet Select(User usera){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection conna=coon.getCoon(); String sql_Select="select * from user where id=?"; try { pst=conna.prepareStatement(sql_Select); pst.setString(1, usera.getId()); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//更新public int Update(User usera){ PreparedStatement pst=null; int rs=0; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_update="update user set username=?,password=?,type=? where id=?"; try { pst=coona.prepareStatement(sql_update); pst.setString(1, usera.getUsername()); pst.setString(2, usera.getPassword()); pst.setString(3, usera.getType()); pst.setString(4, usera.getId()); rs=pst.executeUpdate(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//删除public int Delete(User usera){ PreparedStatement pst=null; int rs=0; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_delete="delete from user where id=?"; try { pst=coona.prepareStatement(sql_delete); pst.setString(1, usera.getId()); rs=pst.executeUpdate(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}public ResultSet Login(User usera){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection conna=coon.getCoon(); String sql_Select="select * from user where username=? and password=? and type=?"; try { pst=conna.prepareStatement(sql_Select); pst.setString(1, usera.getUsername()); pst.setString(2, usera.getPassword()); pst.setString(3, usera.getType()); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}}
UserDao.java 各种方法
package nuc.test.Dao;
import java.sql.*;
import nuc.test.coon.*;
import nuc.test.user.*;
//插入
public class UserDao {
public int Insert(User usera){
PreparedStatement pst=null;
int rs=0;
UserCoon coon=new UserCoon();
Connection coona=coon.getCoon();
String sql_insert=”insert into user(username,password,type) values(?,?,?)”;
try{
pst=coona.prepareStatement(sql_insert);
pst.setString(1, usera.getUsername());
pst.setString(2, usera.getPassword());
pst.setString(3,usera.getType());
rs=pst.executeUpdate();
}catch(Exception e){
e.printStackTrace();
}
return rs;}//查询public ResultSet Query(){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_query="select * from user"; try { pst=coona.prepareStatement(sql_query); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//查找public ResultSet Select(User usera){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection conna=coon.getCoon(); String sql_Select="select * from user where id=?"; try { pst=conna.prepareStatement(sql_Select); pst.setString(1, usera.getId()); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//更新public int Update(User usera){ PreparedStatement pst=null; int rs=0; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_update="update user set username=?,password=?,type=? where id=?"; try { pst=coona.prepareStatement(sql_update); pst.setString(1, usera.getUsername()); pst.setString(2, usera.getPassword()); pst.setString(3, usera.getType()); pst.setString(4, usera.getId()); rs=pst.executeUpdate(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//删除public int Delete(User usera){ PreparedStatement pst=null; int rs=0; UserCoon coon=new UserCoon(); Connection coona=coon.getCoon(); String sql_delete="delete from user where id=?"; try { pst=coona.prepareStatement(sql_delete); pst.setString(1, usera.getId()); rs=pst.executeUpdate(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}//查找某一项数据 可用来更新public ResultSet Login(User usera){ PreparedStatement pst=null; ResultSet rs=null; UserCoon coon=new UserCoon(); Connection conna=coon.getCoon(); String sql_Select="select * from user where username=? and password=? and type=?"; try { pst=conna.prepareStatement(sql_Select); pst.setString(1, usera.getUsername()); pst.setString(2, usera.getPassword()); pst.setString(3, usera.getType()); rs=pst.executeQuery(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return rs;}}
servlet各个方法
按提交键就会调用Insert方法
以下方法都是由网页jsp方法改写的，然后调用UserDao里的方法来实现
//插入方法 Insert.java
package nuc.test.servet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nuc.test.Dao.UserDao;
import nuc.test.user.User;
public class Insert extends HttpServlet {
/** * Constructor of the object. */public Insert() { super();}/** * 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 {}/** * 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 { response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); request.setCharacterEncoding("utf-8"); User user=new User(); UserDao dao =new UserDao(); user.setUsername(request.getParameter("username")); user.setPassword(request.getParameter("password")); user.setType(request.getParameter("type")); int a=dao.Insert(user); if(a!=0){ out.print("插入成功"); } response.setHeader("refresh", null );}}
//查找方法 ShowPage.java
package nuc.test.servet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nuc.test.Dao.Find;
import nuc.test.user.User;
public class ShowPage extends HttpServlet {
/** * Constructor of the object. */public ShowPage() { super();}/** * 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 { response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); request.setCharacterEncoding("utf-8"); out.print(" <table align='center' width='800' border='1'>"); out.print("<tr>"); out.print("<td align='center' colspan='5'>"); out.print("所有用户信息"); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'>"); out.print("<td>用户名</td><td>密码</td><td>用户类型</td><td colspan='2'>操作方法</td>"); out.print("</tr>"); int currpage=1; if(request.getParameter("page")!=null){ currpage=Integer.parseInt(request.getParameter("page")); } Find find=new Find(); List<User> listall=new ArrayList<User>(); listall=find.Selectcontent(currpage); Iterator<User> it=listall.iterator(); while(it.hasNext()){ User usera=it.next(); out.print("<tr align='center'>"); out.print("<td>"+usera.getUsername()+"</td>"); out.print("<td>"+usera.getPassword()+"</td>"); out.print("<td>"+usera.getType()+"</td>"); out.print("<td><a href='servlet/Update?id="+usera.getId()+"'>修改</a></td>"); out.print("<td><a href='servlet/Delete?id="+usera.getId()+"'>删除</a></td>"); out.print("</tr>"); } out.print("<tr>"); out.print("<td align='center' colspan='5'>"); out.print("<jsp:include page='Bar.jsp'>"); out.print("</td>"); out.print("</tr>"); out.print("<tr align='center'><td colspan='5'><a hraf='first.jsp'>添加用户</a></td></tr>"); out.print("</table>");}}
Delete.java
package nuc.test.servet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nuc.test.Dao.UserDao;
import nuc.test.user.User;
public class Delete extends HttpServlet {
/** * 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 { response.setContentType("text/html;charset=utf-8"); request.setCharacterEncoding("utf-8"); PrintWriter out = response.getWriter(); User user=new User(); user.setId(request.getParameter("id")); UserDao dao=new UserDao(); int result=dao.Delete(user); if(result!=0){ out.println("删除成功"); //response.sendRedirect("servlet/FindPage"); }}}
update.java//先查出某一条记录，准备删除
package nuc.test.servet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nuc.test.Dao.UserDao;
import nuc.test.user.User;
public class Update extends HttpServlet {
public Update(){
super();
}
/** * 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 { response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); request.setCharacterEncoding("utf-8"); User user=new User(); UserDao dao =new UserDao(); user.setId(request.getParameter("id")); ResultSet result=dao.Select(user); try{ if(result.next()){ out.println("<form action='doUpdate?id="+result.getString("id")+"' method='post'>"); out.println("用户名：<input type='text' value='"+result.getString("username")+"' name='username'>"); out.println("密 码：<input type='text' value='"+result.getString("password")+"' name='password'>"); out.println("用户类型<select>"); out.println("<option value='管理员'>管理员</option>"); out.println("<option value='普通用户'>普通用户</option>"); out.println("</select>"); out.println("<input type='submit' value='修改'>"); out.println("<input type='reset' value='取消'>"); out.println("</form>"); } }catch(Exception e){
e.printStackTrace();
}}}
doupdate.java
package nuc.test.servet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nuc.test.Dao.UserDao;
import nuc.test.user.User;
public class doUpdate extends HttpServlet {
/** * Constructor of the object. */public doUpdate() { super();}/** * 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 { response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); request.setCharacterEncoding("utf-8"); User user=new User(); UserDao dao=new UserDao(); user.setId(request.getParameter("id")); user.setUsername(request.getParameter("username")); user.setPassword(request.getParameter("password")); user.setType(request.getParameter("type")); int result=0; result=dao.Update(user); if(result!=0){ out.print("更新成功"); }}}
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