登录：
前端页面：
<body>
<form action="/webtext/LogingServlet" method="post">
<input type="text" name="username"><br>
<input type="text" name="userpassword"><br>
<input type="submit" value="登录"><br>
</form>
</body>
domain：
public class user {
private int uid;
private String username;
private String userpassword;
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUserpassword() {
return userpassword;
}
public void setUserpassword(String userpassword) {
this.userpassword = userpassword;
}
@Override
public String toString() {
return "user [uid=" + uid + ", username=" + username + ", userpassword=" + userpassword + "]";
}
}
dao层：
public int load(user user) throws SQLException{
Connection conn=JDBCUtils.getConn();
String sql="select * from user where username=? and userpassword=?";
PreparedStatement pst=conn.prepareStatement(sql);
pst.setString(1, user.getUsername());
pst.setString(2, user.getUserpassword());
ResultSet rs = pst.executeQuery();
int count=0;
while(rs.next()){
count=rs.getInt(1);
}
JDBCUtils.close(rs, pst, conn);
return count;
}
service层：
public boolean load(user user){
boolean flag=false;
try {
int count=Dao.load(user);
if(count==1){
flag=true;
}else{
flag=false;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return flag;
}
登陆的同时检测登陆人数：
public class LogingServlet extends HttpServlet {
private service Service=new service();
public void init() throws ServletException {
//获取ServletContext对象
ServletContext servletContext=this.getServletContext();
//向ServletContext域存入初始count
int count=0;
servletContext.setAttribute("count", count);
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username=request.getParameter("username");
String password=request.getParameter("userpassword");
user user=new user();
user.setUsername(username);
user.setUserpassword(password);
boolean flag=Service.load(user);
if(flag==true){
//获取ServletContext对象
ServletContext servletContext=this.getServletContext();
//获取当前count值
int count=(int)servletContext.getAttribute("count");
//改变count值
count++;
response.getWriter().write("success"+user+"ni shi di"+count+"ge fang wen de ren");
//刷新count值
servletContext.setAttribute("count", count);
}else{
response.getWriter().write("failure");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
注册：
dao层
//注册验证
public int zhuceyz(String username) throws SQLException{
Connection conn=JDBCUtils.getConn();
String sql="select username from user where username=?";
PreparedStatement pst=conn.prepareStatement(sql);
pst.setString(1, username);
ResultSet rs = pst.executeQuery();
int count=0;
while(rs.next()){
count=rs.getInt(1);
}
JDBCUtils.close(rs, pst, conn);
return count;
}
//存入注册信息
public int zhuce(user user) throws SQLException{
Connection conn=JDBCUtils.getConn();
String sql="insert into user(username,userpassword) values(?,?)";
PreparedStatement pst=conn.prepareStatement(sql);
pst.setString(1, user.getUsername());
pst.setString(2, user.getUserpassword());
int row=pst.executeUpdate();
JDBCUtils.close(pst, conn);
return row;
}
}
service层
//注册验证
public boolean zhuceyz(String username){
boolean flag=false;
try {
int count=Dao.zhuceyz(username);
if(count==0){
flag=true;
}else{
flag=false;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return flag;
}
//存入注册信息
public boolean zhuce(user user){
boolean flag=false;
try {
int count=Dao.zhuce(user);
if(count==1){
flag=true;
}else{
flag=false;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return flag;
}
}
服务器端
public class ZhuceServlet extends HttpServlet {
private service Service=new service();
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
while(true){
String username=request.getParameter("username");
String password=request.getParameter("userpassword");
boolean flag=Service.zhuceyz(username);
if(flag==false){
response.getWriter().write("yibeizhanyong");
return;
}else if(flag==true){
user user=new user();
user.setUsername(username);
user.setUserpassword(password);
boolean flag1=Service.zhuce(user);
if(flag==true){
response.getWriter().write("success"+user);
}else{
response.getWriter().write("failure");
}
}
return;
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}