Web——数据库的增加、删除、修改、查找
Web——数据库的增加、删除、修改、查找
package com.jredu.web.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import com.jredu.web.db.DBConnection;
import com.jredu.web.entity.User;
public class UserDao {
public List selectAll(){
Connection con=DBConnection.getConnection();
Statement stmt;
List list=new ArrayList();
try {
stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("SELECT * FROM users");
while(rs.next()){
User user=new User();
user.setId(rs.getInt("id"));
user.setUserName(rs.getString("user_name"));
user.setPwd(rs.getString("pwd"));
user.setDisplayName(rs.getString("display_name"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBConnection.closeConnection();
}
return list;
}
public User selectwhere(String whereOption){
Connection con=DBConnection.getConnection();
Statement stmt;
User user=null;
try {
stmt=con.createStatement();
String sql=("SELECT * FROM users");
if(!whereOption.equals("")){
sql+=whereOption;
}
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()){
user=new User();
user.setUserName(rs.getString("user_name"));
user.setPwd(rs.getString("pwd"));
user.setDisplayName(rs.getString("display_name"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBConnection.closeConnection();
}
return user;
}
public boolean selectwhere2(String whereOption2){
Connection con=DBConnection.getConnection();
Statement stmt;
User user=null;
try {
stmt=con.createStatement();
String sql=("SELECT * FROM users");
if(!whereOption2.equals("")){
sql+=whereOption2;
}
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()){
user=new User();
user.setUserName(rs.getString("user_name"));
user.setPwd(rs.getString("pwd"));
user.setDisplayName(rs.getString("display_name"));
return true;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBConnection.closeConnection();
}
return false;
}
public int insert(User user){
Connection con=DBConnection.getConnection();
PreparedStatement pstmt=null;
int count=0;
String sql=" insert into users(user_name,pwd,display_name) values(?,?,?)";
try {
pstmt=con.prepareStatement(sql);
pstmt.setString(1, user.getUserName());
pstmt.setString(2, user.getPwd());
pstmt.setString(3, user.getDisplayName());
count=pstmt.executeUpdate();
if(count==0){
//throw new DataAlreadyExistException();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return count;
}
public int update(User user){
Connection con=DBConnection.getConnection();
PreparedStatement pstmt=null;
String sql = " update users " +
" set user_name = ? ," +
" pwd = ? ," +
" display_name = ? " +
" where id = ? ";
int affCount=0;
try {
pstmt=con.prepareStatement(sql);
pstmt.setString(1, user.getUserName());
pstmt.setString(2, user.getPwd());
pstmt.setString(3, user.getDisplayName());
pstmt.setInt(4, user.getId());
affCount=pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return affCount;
}
public int delete(int id) {
Connection con = DBConnection.getConnection();
PreparedStatement pstmt = null;
int affCount=0;
String sql = " delete from users where id = ? ";
try {
pstmt = con.prepareStatement(sql);
pstmt.setInt(1, id);
affCount=pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return affCount;
}
/*public void delete(int id){
Connection con=DBConnection.getConnection();
PreparedStatement pstmt=null;
String sql=" delete from users where is= ? ";
try {
pstmt = con.prepareStatement(sql);
pstmt.setInt(1, id);
pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
}*/
public List selectPage(int from,int rows){
Connection con=DBConnection.getConnection();
Statement stmt;
List list=new ArrayList();
try {
stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("SELECT * FROM users LIMIT "+from+","+rows);
while(rs.next()){
User user=new User();
user.setId(rs.getInt("id"));
user.setUserName(rs.getString("user_name"));
user.setPwd(rs.getString("pwd"));
user.setDisplayName(rs.getString("display_name"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBConnection.closeConnection();
}
return list;
}
public int selectCount(){
Connection con=DBConnection.getConnection();
Statement stmt;
int count=0;
try {
stmt=con.createStatement();
String sql="SELECT count(1) as count FROM users ";
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()){
count=rs.getInt("count");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBConnection.closeConnection();
}
return count;
}
}
package com.jredu.web.db;
import java.sql.*;
public class DBConnection {
private static Connection con=null;
//mysql驱动mingz
private static String driverName="com.mysql.jdbc.Driver";
//数据库用户名
private static String userName="root";
//密码
private static String userPasswd = "ffffff";
//数据库名
private static String dbName = "shcoolapp";
//联结字符串
private static String url = "jdbc:mysql://localhost/" + dbName
+ "?user="+ userName
+ "&password=" + userPasswd
+ "&useUnicode=true&characterEncoding=gbk";
public static Connection getConnection(){
try {
Class.forName(driverName);
con =DriverManager.getConnection(url);
} catch (ClassNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
}catch(SQLException e){
e.printStackTrace();
}
return con;
}
public static void closeConnection(){
if(con!=null){
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
package com.jredu.web.entity;
public class User {
private int id;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
private String userName;
private String pwd;
private String displayName;
public User(){}
public User(String userName, String pwd, String displayName) {
super();
this.userName = userName;
this.pwd = pwd;
this.displayName = displayName;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public String getDisplayName() {
return displayName;
}
public void setDisplayName(String displayName) {
this.displayName = displayName;
}
}
package com.jredu.web.servlet;
import java.io.IOException;
import java.io.PrintWriter;
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 net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import org.apache.commons.collections.map.HashedMap;
import com.jredu.web.dao.UserDao;
import com.jredu.web.entity.User;
public class UserServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public UserServlet() {
super();
}
/**
* Destruction of the servlet.
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet.
*
* 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.
*
* 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.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
response.setContentType("textml;charset=utf-8");
String action=request.getParameter("action");
if(null==action||action.equals("select")){
select(request,response);
}else if(action.equals("update")){
update(request,response);
}else if(action.equals("add")){
add(request,response);
}else if(action.equals("delect")){
delect(request,response);
}
}
//添加
public void add(HttpServletRequest request, HttpServletResponse response) throws IOException{
String userName=request.getParameter("userName");
String pwd=request.getParameter("pwd");
String displayName=request.getParameter("displayName");
User user=new User();
user.setUserName(userName);
user.setPwd(pwd);
user.setDisplayName(displayName);
UserDao userDao = new UserDao();
int affCount=userDao.insert(user);
PrintWriter out = response.getWriter();
out.print(affCount);
}
//删除
public void delect(HttpServletRequest request, HttpServletResponse response) throws IOException{
String ids[]=request.getParameterValues("uid[]");
UserDao userDao = new UserDao();
int affCount=0;
for(int i=0;i0){
from=rows*(pages-1);
}
UserDao userDao = new UserDao();
List list = userDao.selectPage(from,rows);
HashMap map=new HashMap();
map.put("total", userDao.selectCount());
map.put("rows", list);
PrintWriter out = response.getWriter();
JSONObject ja=JSONObject.fromObject(map);
//List list = userDao.selectAll();
//变成单个对象
//JSONObject jo=JSONObject.fromObject(user);
//把list变成JSONArray
//JSONArray ja = JSONArray.fromObject(list);
//PrintWriter out = response.getWriter();
System.out.println(ja.toString());
out.print(ja.toString());
}
/**
* Initialization of the servlet.
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
<%@page import="java.net.URLDecoder"%>
<%@ page language="java" import="java.util.*"
pageEncoding="utf-8"%>
<%
request.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
if(request.getParameter("zyf")!=null){
String zyf= URLDecoder.decode(request.getParameter("zyf"),"utf-8");
out.print(zyf);
}
%>
My JSP 'login.jsp' starting page
<%@page import="java.net.URLDecoder"%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
request.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
String zyf = "11";
if (request.getParameter("zyf") != null) {
zyf = URLDecoder.decode(request.getParameter("zyf"), "utf-8");
}
%>
My JSP 'main.jsp' starting page
<%=zyf%>
This is my main.JSP page.
${sessionScope.user.displayName}
package com.jredu.web.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class URLfilter implements Filter {
public URLfilter(){
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
// TODO Auto-generated method stub
HttpServletResponse response=(HttpServletResponse)arg1;
HttpServletRequest request=(HttpServletRequest )arg0;
HttpSession session=request.getSession();
System.out.println("过滤器运行");
if(session.getAttribute("user")==null){
if(request.getRequestURI().indexOf("login/login.jsp")>0){
arg2.doFilter(request, response);
}else{
System.out.println("非法用户");
response.sendRedirect("login.jsp");
}
}
else{
arg2.doFilter(request, response);
}
//login/main.jsp *.jsp /login.jsp
// if(session.getAttribute("user")==null){
// if(request.getRequestURI().indexOf("login/login.jsp")>0){
// arg2.doFilter(request, response);
// }else{
//
// System.out.println("非法用户");
// response.sendRedirect("login.jsp");
// }
// }
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
}