简单账号管理系统的实现（b/s、servlet、html、mysql）
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2022-05-30 11:02:07
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漫漫学习路，无处是尽头。“技术是学不完的，只能学会学习能力，并不断学习才是真”这句绝对的真理。总结的虽是，斌哥布置的练习，但完成这个练习的过程中，却真心是温习了很多，学习了很多。
进入正题，下面总结下简单账号管理系统的实现过程。
设计如下：
一、表结构
表名：userinfo
字段信息：id-int
name-varchar
password-varchar
二、模块结构
1、数据操作模块
将数据库操作写在一个包下。
public class DAO {
//创建arrylist用以存放查询结果
private ArrayList<Userinfo> al;
/**
* 插入数据到数据库中的方法
*/
public ArrayList<Userinfo> add(Userinfo user){
//获取数据库连接对象
Connection conn=Until.getDBConnect();
//sql操作数据
String sql="insert into userinfo(name,pwd) values('"+user.name+"','"+user.password+"')";
try {
Statement stmt=conn.createStatement();
int i=stmt.executeUpdate(sql);
if(i>0){
System.out.println("插入数据成功！");
}
//关闭数据库连接
conn.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return searchAll();
}
/**
* 查询数据库所有数据
*/
public ArrayList<Userinfo> searchAll(){
al=new ArrayList<Userinfo>();
//获取数据库连接对象
Connection conn=Until.getDBConnect();
//sql操作数据
String sql="select * from userinfo";
try {
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
Userinfo user=new Userinfo(rs.getInt("id"), rs.getString("name"),rs.getString("pwd"));
this.al.add(user);
}
//清空结果集
rs.close();
//关闭数据库
conn.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return al;
}
/**
* 按给定的id查询数据的方法
*/
public ArrayList<Userinfo> searchById(int id){
//获得数据库连接对象
Connection conn=Until.getDBConnect();
//操作数据
String sql="select * from userinfo where id="+id;
try {
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
System.out.println("id="+rs.getInt("id")+",name="+rs.getString("name")+",password="+rs.getString(3));
}
conn.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return searchAll();
}
/**
* 删除指定id的数据的方法
*/
public ArrayList<Userinfo> deleteById(int id){
//获取数据库连接对象
Connection conn=Until.getDBConnect();
//操作数据
String sql="delete from userinfo where id="+id;
try {
Statement stmt=conn.createStatement();
int i=stmt.executeUpdate(sql);
if(i>0){
System.out.println("删除成功！！");
}
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return searchAll();
}
/**
* 根据指定id修改数据的方法
*/
public ArrayList<Userinfo> updateById(int id,Userinfo user){
//获取数据库连接对象
Connection conn=Until.getDBConnect();
//数据操作
String sql="update userinfo set name=?,pwd=? where id=?";
try {
//预编译
PreparedStatement ps=conn.prepareStatement(sql);
//设置对象参数
ps.setString(1, user.name);
ps.setString(2, user.password);
ps.setInt(3, id);
int i=ps.executeUpdate();
if(i>0){
System.out.println("数据修改成功！");
}
conn.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return searchAll();
}
}
2、用5个servlet、2个html页面进行页面
5个servlet：Userinfo-用户列表servlet-用于查找并显示所有用户
Deleteservlet-删除操作servlet-用于删除指定用户
Updateservlet-更新操作servlet-用于更新指定用户信息
Regesiterservlet-添加操作（注册）servlet-用于注册新用户
Logincheck-用户身份验证servlet-用于验证登陆用户是否为注册用户
2个html：page.html-登陆页面
register.html-注册页面
3、系统各页面交互流程
4、代码示例
userinfo：
/**显示用户servlet：用于显示当前全部用户信息
* Servlet implementation class Userinfo
*/
public class Userinfo extends HttpServlet {
DAO dao=new DAO();
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置响应文本字符集
response.setContentType("text/html;charset=gbk");
PrintWriter out=response.getWriter();
//创建arraylist来接收查询结果
ArrayList<test1_db.Userinfo> al_temp=dao.searchAll();
//拼出显示页面
out.println("<!DOCTYPE HTML PUBLIC\"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<html>");
out.println("<head><title>Userinfo</title></head>");
out.println("<body>");
out.println("userinfo show as follows:");
out.println("<table border=\"5\"width=\"250px\"bgcolor=\"green\"bordercolor=\"gray\">");
out.println("<tr><td>ID</td><td>姓名</td><td>密码</td><td>操作</td><td>操作</td></tr>");
//循环查询用户信息以显示
for(int i=0;i<al_temp.size();i++){
test1_db.Userinfo user_temp=al_temp.get(i);
int id=user_temp.id;
String name=user_temp.name;
String password=user_temp.password;
out.println("<tr><td>"+id+"</td><td>"+name+"</td><td>"+password+"</td><td><a href='Deleteservlet?id="+id+" '>删除用户</a></td><td><a href='Updateservlet?id="+id+"'>修改信息</a></td></tr>");
}
out.println("</border>");
out.println("</table>");
out.println("</body>");
out.println("</html>");
}
logincheck：
/**
* Servlet implementation class Logincheck
*/
public class Logincheck extends HttpServlet {
private static final long serialVersionUID = 1L;
DAO dao=new DAO();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=gbk");
PrintWriter out=response.getWriter();
//获得参数
String name=request.getParameter("username");
String password=request.getParameter("password");
//创建用户列表以存放查询结果
ArrayList<test1_db.Userinfo> al_temp=dao.searchAll();
//循环得到每条记录以验证身份
for(int i=0;i<al_temp.size();i++){
test1_db.Userinfo user_temp=al_temp.get(i);
//判断用户名和密码是否存在
if(user_temp.name.equals(name)&&user_temp.password.equals(password)){
//是，则跳转到用户列表servlet并跳出循环
response.sendRedirect("Userinfo");
break;
}
}
//否，则拼出提示页面
out.println("<!DOCTYPE HTML PUBLIC\"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<html>");
out.println("<body>");
out.println("用户不存在，请注册……");
out.println("<p><a href='register.html'>注册</a></p>");
out.println("</body>");
out.println("</html>");
}
updateservlet：
/**
* Servlet implementation class Updateservlet
*/
public class Updateservlet extends HttpServlet {
private static final long serialVersionUID = 1L;
DAO dao = new DAO();
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=gbk");
PrintWriter out = response.getWriter();
//获得来自于用户列表servlet的参数id
String id_temp = request.getParameter("id");
int id = Integer.parseInt(id_temp);
//创建arraylist以存放查找的对应id的记录
ArrayList<test1_db.Userinfo> al_temp = dao.searchById(id);
//拼出查找结果显示页面
out.println("<!DOCTYPE HTML PUBLIC\"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<html>");
out.println("<head><title>Update</title></head>");
out.println("<body>");
out.println("please recorrect the information as follows:");
out.println("<table border=\"5\"width=\"250px\"bgcolor=\"green\"bordercolor=\"gray\">");
out.println("<tr><td>ID</td><td>姓名</td><td>密码</td></tr>");
//获得查找结果集中的参数以用于传入“修改”响应
test1_db.Userinfo user = al_temp.get(0);
String name = user.name;
String password = user.password;
String username = "username";
String userpassword = "userpassword";
// 1、重写url传值
// out.println("<form action='Updateservlet?id=" + user.id
// + "' method='post'>");
// out.println("<tr><td >" + id + "</td><td><input type='text' name='"
// + username + "' value='" + name
// + "'><br></td><td><input type='text' name='" + userpassword
// + "' value='" + password + "'><br></td></tr>");
// 2、表单传值
out.println("<form action='Updateservlet' method='post'>");
out.println("<tr><td >" + id + "</td><td><input type='text' name='"
+ username + "' value='" + name
+ "'><br></td><td><input type='text' name='" + userpassword
+ "' value='" + password + "'><br></td></tr>");
out.println("<input type='hidden' name='id' value='" + id + "'>");
out.println("<input type='submit' value='提交'><input type='reset' name='reset'>");
out.println("</form>");
out.println("</border>");
out.println("</table>");
out.println("</body>");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
//获得updateservlet中传入的更新数据所需的参数
String name_update = request.getParameter("username");
String password_update = request.getParameter("userpassword");
String id_update = request.getParameter("id");
int id = Integer.parseInt(id_update);
//创建更新后的用户对象、执行更新操作并跳转页面到用户列表servlet
test1_db.Userinfo user_update = new test1_db.Userinfo(id, name_update,
password_update);
dao.updateById(id, user_update);
response.sendRedirect("Userinfo");
}
}
registerservlet：
/**
* Servlet implementation class Register
*/
public class Register extends HttpServlet {
private static final long serialVersionUID = 1L;
DAO dao=new DAO();
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获得参数
String username=request.getParameter("username");
String password=request.getParameter("password");
//创建要添加的用户对象
test1_db.Userinfo user_temp=new test1_db.Userinfo(username, password);
dao.add(user_temp);
//跳转回登陆界面
response.sendRedirect("page.html");
}
deleteservlet：
/**
* Servlet implementation class Deleteservlet
*/
public class Deleteservlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setCharacterEncoding("gbk");
PrintWriter out=response.getWriter();
out.println("进入删除servlet！");
//获得需删除的用户信息的id
String id_temp=request.getParameter("id");
int id=Integer.parseInt(id_temp);
DAO dao=new DAO();
dao.deleteById(id);
//跳转回用户显示servlet
response.sendRedirect("Userinfo");
}
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