servlet增删查改
数据库：
usebean映射数据库中的表
package com.example;
public class userBean {
private int userId;
private String username;
private String passwd;
private int grade;
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPasswd() {
return passwd;
}
public void setPasswd(String passwd) {
this.passwd = passwd;
}
public int getGrade() {
return grade;
}
public void setGrade(int grade) {
this.grade = grade;
}
}
userbeanCl对数据库处理：
package com.example;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
public class userBeanCL {
private Connection ct = null;
private PreparedStatement ps = null;
private ResultSet rs = null;
private int pageCount = 0;//共有多少页(计算)
public int getPageCount(){
return this.pageCount;
}
//修改用户
public boolean updateUser(String id,String passwd, String grade){
boolean b = false;
try
{
//得到连接
connDB cd = new connDB();
ct = cd.getConn();
String sql = "UPDATE users SET passwd='"+passwd+ "', grade='"+grade+"' WHERE userId='"+id + "'";
ps = ct.prepareStatement(sql);
int num = ps.executeUpdate();
if(num == 1){
//删除成功
b = true;
}
} catch (Exception e) {
e.printStackTrace();
}finally{
this.close();
}
return b;
}
//删除用户
public boolean delUser(String id){
boolean b = false;
try
{
//得到连接
connDB cd = new connDB();
ct = cd.getConn();
String sql = "delete from users WHERE userid='"+id + "'";
ps = ct.prepareStatement(sql);
int num = ps.executeUpdate();
if(num == 1){
//删除成功
b = true;
}
} catch (Exception e) {
e.printStackTrace();
}finally{
this.close();
}
return b;
}
//分页显示结果
public ArrayList getResultByPage(int pageNow,int pageSize){
ArrayList al = new ArrayList();
int rowCount = 0;//共有多少条记录（查表）
try
{
//得到rowCount
connDB cd = new connDB();
ct = cd.getConn();
ps = ct.prepareStatement("SELECT COUNT(*) FROM users");
rs = ps.executeQuery();
if(rs.next())
rowCount = rs.getInt(1);
//共分为多少页
if(rowCount % pageSize == 0){
pageCount = rowCount/pageSize;
}else{
pageCount = rowCount/pageSize + 1;
}
ps.close();
rs.close();
//每页上需要显示的结果
ps = ct.prepareStatement("SELECT * FROM users LIMIT " + (pageNow-1)*pageSize + ","
+ pageSize +";");
rs = ps.executeQuery();
while(rs.next()){
//将rs中的每条记录封装到userbean中
userBean ub = new userBean();
ub.setUserId(rs.getInt(1));
ub.setUsername(rs.getString(2));
ub.setPasswd(rs.getString(3));
ub.setGrade(rs.getInt(4));
//将ub放入ArrayList中
al.add(ub);
}
}catch(Exception ex){
ex.printStackTrace();
}finally{
this.close();
}
return al;
}
//验证用户
public boolean checkUser(String u,String p){
boolean b = false;
try
{
//得到连接
connDB cd = new connDB();
ct = cd.getConn();
ps = ct.prepareStatement("SELECT passwd FROM users WHERE username=? LIMIT 1;");
ps.setString(1, u);
rs = ps.executeQuery();
if(rs.next()){
String dbPasswd = rs.getString(1);
if(dbPasswd.equals(p)){
b = true;
}
}
} catch (Exception e) {
e.printStackTrace();
}finally{
this.close();
}
return b;
}
//关闭资源
public void close(){
try {
if(rs != null){
rs.close();
rs = null;
}
if(ps != null){
ps.close();
ps = null;
}
if(ct != null){
ct.close();
ct = null;
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
connDB连接数据库得到Connection
package com.example;
import java.sql.Connection;
import java.sql.DriverManager;
public class connDB {
private Connection ct = null;
public Connection getConn() {
try
{
Class.forName("com.mysql.jdbc.Driver");
ct = DriverManager.getConnection("jdbc:mysql://localhost:3306/yuippe", "root", "123456");
} catch (Exception ex) {
ex.printStackTrace();
}
return ct;
}
}
----------------------------------------------------------------------------------------------------------------------------------------------
登陆页面login：
package com.example;
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{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("
");
pw.println("登陆界面
");
pw.println(" ");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
主页面Main
//主界面
package com.example;
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 Main extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("
");
pw.println("主界面
");
pw.println("管理用户
");
pw.println("添加用户
");
pw.println("查找用户
");
pw.println("安全退出
");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
loginCl登陆验证处理：
//用户验证
package com.example;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LoginCL extends HttpServlet{
//重写
public void init() throws ServletException {
try {
FileReader fr = new FileReader("E:/workspace/myWebApp/MyCount.txt");
BufferedReader br = new BufferedReader(fr);
//读取一行数据
String numVal = br.readLine();
//关闭
br.close();
//将文本中的数据写入Context中
this.getServletContext().setAttribute("visitTimes", numVal);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void destroy() {
try {
FileWriter fw = new FileWriter("E:/workspace/myWebApp/MyCount.txt");
BufferedWriter bw = new BufferedWriter(fw);
bw.write(this.getServletContext().getAttribute("visitTimes").toString());
bw.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
//接受用户名和密码
String u = req.getParameter("username");
String p = req.getParameter("passwd");
//操作数据库
Connection ct = null;
Statement stat = null;
ResultSet rs = null;
try {
//调用userBeanCL
userBeanCL ubc = new userBeanCL();
if(ubc.checkUser(u, p)){
//查看是否有需要设置cookie
String keep = req.getParameter("keep");
if(keep != null){
//将用户名与密码保存在客户端
Cookie name = new Cookie("myname", u);
Cookie pass = new Cookie("mypasswd", p);
//设置时间
name.setMaxAge(14*24*3600);
pass.setMaxAge(14*24*3600);
resp.addCookie(name);
resp.addCookie(pass);
}
//用户信息存入session
HttpSession hs = req.getSession(true);
hs.setMaxInactiveInterval(60);
hs.setAttribute("name", u);
//将访问次数加1
String time = this.getServletContext().getAttribute("visitTimes").toString();
this.getServletContext().setAttribute("visitTimes", (Integer.parseInt(time) + 1)+"");
//跳转
resp.sendRedirect("Main");
}
else{
resp.sendRedirect("login");
}
} catch (Exception e) {
e.printStackTrace();
}finally{
try
{
if(rs != null){
rs.close();
}
if(stat != null){
stat.close();
}
if(ct != null){
ct.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
package com.example;
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 Update extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("
");
pw.println("修改用户界面
");
pw.println("");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
package com.example;
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 UpdateCl extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
try
{
resp.setContentType("text/html;charset=utf-8");
userBeanCL ubc = new userBeanCL();
//接受从wel.java中传递的id
if(ubc.updateUser(req.getParameter("userid"), req.getParameter("newPass"), req.getParameter("newGrade")))
{
//删除成功
resp.sendRedirect("Ok");
}else
{
//删除失败
resp.sendRedirect("Err");
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
delUserCl
package com.example;
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 DelUserCl extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
try
{
resp.setContentType("text/html;charset=utf-8");
userBeanCL ubc = new userBeanCL();
//接受从wel.java中传递的id
String id = req.getParameter("userid");
if(ubc.delUser(id))
{
//删除成功
resp.sendRedirect("Ok");
}else
{
//删除失败
resp.sendRedirect("Err");
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
wel：
//欢迎界面
package com.example;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class Wel extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
HttpSession hs = req.getSession(true);
String val = (String)hs.getAttribute("name");
String name="";
String passwd="";
//判断
if(val == null){
//session中没有用户信息,在查看cookie信息
Cookie[] allCookies = req.getCookies();
int i = 0;
if(allCookies != null){
for(i = 0; i < allCookies.length; i++){
//依次取出
Cookie temp = allCookies[i];
if(temp.getName().equals("myname")){
name = temp.getValue();
}else if(temp.getName().equals("mypasswd")){
passwd = temp.getValue();
}
}
if(!name.equals("")&&!passwd.equals("")){
//跳转到logincl去验证信息
resp.sendRedirect("logincl?username=" + name + "&passwd=" + passwd);
return;
}
}
resp.sendRedirect("login");
}
//分页
int pageSize = 3;//一页显示几条记录
int pageNow = 1; //目前显示的页数
//动态的接受pageNow
String spageNow = req.getParameter("pageNow");
if(spageNow != null)
pageNow = Integer.parseInt(spageNow);
//调用userBeanCL
userBeanCL ubc = new userBeanCL();
ArrayList al = ubc.getResultByPage(pageNow, pageSize);
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("");
pw.println("返回到主界面");
pw.println("
管理用户
");
//做一个超链接
pw.println("
返回重新登陆");
pw.println("");
//显示结果表格
pw.println("userId username passwd grade "+
"修改用户 删除用户 "+"");
pw.println("" + ub.getUserId() + " ");
pw.println("" + ub.getUsername() + " ");
pw.println("" + ub.getPasswd() + " ");
pw.println("" + ub.getGrade() + " ");
pw.println("修改用户 ");
pw.println("删除用户 ");
pw.println(" ");
}
pw.println("
");
//显示上一页
if(pageNow != 1)
pw.println(""+"上一页"+"");
//显示5个页面超链接
for(int i=pageNow; i < pageNow+5; i++){
pw.println("" +i+ "");
}
//显示下一页
int pageCount = ubc.getPageCount();
if(pageNow != pageCount)
pw.println(""+"下一页"+"
");
//指定跳转到页
pw.println("");
pw.println("您的页面被访问了" + this.getServletContext().getAttribute("visitTimes") +"次
");
pw.println("您的ip=" + req.getRemoteAddr() + "
");
pw.println("您的机器名为=" + req.getRemoteHost() + "
");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
Err：
package com.example;
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 Err extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("
");
pw.println("很遗憾，操作失败
");
pw.println("返回主界面 继续删除");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}
package com.example;
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 Ok extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter pw = resp.getWriter();
pw.println("");
pw.println("");
pw.println("
");
pw.println("恭喜你，操作成功
");
pw.println("返回主界面 继续");
pw.println("
");
pw.println("");
pw.println("");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doGet(req, resp);
}
}