package cn;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class MailDao {
/**
* @param args
*/
public List<Mail> getSelect(String recive){
List<Mail> list=new ArrayList<Mail>();
Connection con=null;
PreparedStatement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
String sql="select*from mail where recive=?";
st=con.prepareStatement(sql);
st.setString(1, recive);
rst=st.executeQuery();
while(rst.next()){
Mail mm=new Mail();
mm.setIds(rst.getInt("ids"));
mm.setSender(rst.getString("sender"));
mm.setTitle(rst.getString("title"));
mm.setContent(rst.getString("content"));
mm.setRecive(rst.getString("recive"));
mm.setDate(rst.getString("date"));
mm.setState(rst.getInt("state"));
list.add(mm);
}
return list;
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
}
//添加
public boolean insert(Mail mail){
Connection con=null;
Statement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
st=con.createStatement();
int row=st.executeUpdate("insert into mail values(‘"+mail.getIds()+"‘,‘"+mail.getSender()+"‘,‘"+mail.getTitle()+"‘,‘"+mail.getContent()+"‘,‘"+mail.getRecive()+"‘,‘"+mail.getDate()+"‘,‘"+mail.getState()+"‘"+")");
if(row==1){
return true;
}
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
return false;
}
//根据id查询内容
public Mail getSelects(int ids){
Connection con=null;
PreparedStatement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
String sql="select*from mail where ids=? ";
st=con.prepareStatement(sql);
st.setInt(1, ids);
rst=st.executeQuery();
while(rst.next()){
Mail mm=new Mail();
mm.setIds(rst.getInt("ids"));
mm.setSender(rst.getString("sender"));
mm.setTitle(rst.getString("title"));
mm.setContent(rst.getString("content"));
mm.setRecive(rst.getString("recive"));
mm.setDate(rst.getString("date"));
mm.setState(rst.getInt("state"));
return mm;
}
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
return null;
}
//根据id改变已读 图标
public boolean getChange(int ids){
Connection con=null;
PreparedStatement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
String sql="update mail set state=1 where ids=?";
st=con.prepareStatement(sql);
st.setInt(1, ids);
int row =st.executeUpdate();
if(row==1){
return true;
}
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
return false;
}
// 删除根据id
public boolean getDelete(int ids){
Connection con=null;
PreparedStatement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
String sql="delete from mail where ids=?";
st=con.prepareStatement(sql);
st.setInt(1, ids);
int row =st.executeUpdate();
if(row==1){
return true;
}
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
return false;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
package cn;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class UsDao {
public boolean getLogin(String zzhh,String mima){
Connection con=null;
PreparedStatement st=null;
ResultSet rst=null;
try{
con=JDBCUtils.getCon();
String sql="select*from us where zzhh=? and mima=?";
st=con.prepareStatement(sql);
st.setString(1, zzhh);
st.setString(2, mima);
rst=st.executeQuery();
if(rst.next()){
return true;
}
}catch(Exception e){
throw new RuntimeException(e);
}
finally{
JDBCUtils.closeAll(rst, st, con);
}
return false;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// UsDao d=new UsDao();
//
// System.out.println(d.getLogin("Lisa","123456"));
}
}
<body>
<form action="dologin.jsp" method="post">
账号:<input type="text" name="username"> <br> <br>
密码: <input type="text" name="password"> <br> <br>
<input type="submit" value="登录">
</form>
</body>
</html>
<body>
<%
String username=request.getParameter("username");
session.setAttribute("username", username);
String password=request.getParameter("password");
UsDao d=new UsDao();
if(d.getLogin(username, password)){
request.getRequestDispatcher("main.jsp").forward(request, response);
}else{
response.sendRedirect("login.jsp");
}
%>
</body>
<body>
<%
String username=(String)session.getAttribute("username");
%>
<h3>发件人:<%=username %></h3>
<form action="add2.jsp" method="post">
send to:<input type="text" name="res"><br><br>
标题: <input type="text" name="title"><br><br>
内容: <input type="text" name="content"><br><br>
<input type="submit" value="发送" >
</form>
</body>
<body>
<%
request.setCharacterEncoding("utf-8");
String username=(String)session.getAttribute("username");
String title=request.getParameter("title");
String content=request.getParameter("content");
String res=request.getParameter("res");
MailDao d=new MailDao();
Mail m=new Mail();
m.setSender(username);
m.setTitle(title);
m.setContent(conte
m.setRecive(res);
m.setDate("20200507");
m.setState(0);
d.insert(m);
<body>
<%
request.setCharacterEncoding("utf-8");
int id=Integer.parseInt(request.getParameter("titles"));
%>
<%
MailDao dd=new MailDao();
dd.getChange(id);
Mail m=dd.getSelects(id);
%>
<br>
来自于: <%=m.getSender() %>
<br><br>
标题: <%=m.getTitle() %>
<br><br>
内容: <%=m.getContent() %>
<br><br>
时间:<%=m.getDate() %>
<br><br>
<a href="main.jsp">返回</a>
</body>
<body>
<%
String sds=request.getParameter("sds");
session.setAttribute("key", sds);
%>
<form action="doreturn.jsp" method="post">
收件人: <%=sds %>
<br> <br>
标 题: <input type="text" name="tt">
<br> <br>
内容: <input type="text" name="cc">
<br> <br>
<input type="submit" value="发送">
<a href="main.jsp">返回</a>
</form>
</body>
<body>
<%
request.setCharacterEncoding("utf-8");
String username=(String)session.getAttribute("username");
String sds=(String)session.getAttribute("key");
String tt=request.getParameter("tt");
String cc=request.getParameter("cc");
MailDao md=new MailDao();
Mail mm=new Mail();
mm.setSender(username);
mm.setTitle(tt);
mm.setContent(cc);
mm.setRecive(sds);
mm.setDate("20200801");
mm.setState(0);
md.insert(mm);
request.getRequestDispatcher("return.jsp").forward(request,response);
%>
</body>
<body>
<%
request.setCharacterEncoding("utf-8");
String username=(String)session.getAttribute("username");
String sds=(String)session.getAttribute("key");
String tt=request.getParameter("tt");
String cc=request.getParameter("cc");
MailDao md=new MailDao();
Mail mm=new Mail();
mm.setSender(username);
mm.setTitle(tt);
mm.setContent(cc);
mm.setRecive(sds);
mm.setDate("20200801");
mm.setState(0);
md.insert(mm);
request.getRequestDispatcher("return.jsp").forward(request,response);
%>
</body>
request.getRequestDispatcher("login.jsp").forward(request, response); %
原文：https://www.cnblogs.com/gsfwxj1820/p/12859893.html