首页 > 代码库 > Servlet 商品留言
Servlet 商品留言
商品留言效果如图，实现某个商品留言的添加，删除，显示功能。
1、数据库设计
2、Javabean设计--Comment.java
package myshop;
public class Comment {
private int id;
private int gid;
private String content;
private String add_time;
private String add_user;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getGid() {
return gid;
}
public void setGid(int gid) {
this.gid = gid;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public String getAdd_time() {
String add_time=this.add_time.substring(0, 10);
return add_time;
}
public void setAdd_time(String add_time) {
this.add_time = add_time;
}
public String getAdd_user() {
return add_user;
}
public void setAdd_user(String add_user) {
this.add_user = add_user;
}
}
3、DAO设计--CommentDAO.java
package myshop;
import java.sql.*;
import java.util.*;
public class CommentDAO {
public LinkedList<Comment> search(int gid){
LinkedList<Comment> cs=new LinkedList<Comment>();
Connection conn=JDBC.getConnection();
String sql="select * from tb_comment where gid=?";
ResultSet rs=null;
try {
PreparedStatement ps=conn.prepareStatement(sql);
ps.setInt(1, gid);
rs=ps.executeQuery();
while(rs.next()){
Comment c=new Comment();
c.setId(rs.getInt("id"));
c.setGid(rs.getInt("gid"));
c.setContent(rs.getString("content"));
c.setAdd_user(rs.getString("add_user"));
c.setAdd_time(rs.getString("add_time"));
cs.add(c);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return cs;
}
public boolean add(Comment comment){
boolean flag=false;
Connection conn=JDBC.getConnection();
PreparedStatement ps=null;
String sql="insert into tb_comment(gid,content,add_user) "
+ "values(?,?,?)";
//1
try {
ps=conn.prepareStatement(sql);
//2
ps.setInt(1, comment.getGid());
ps.setString(2, comment.getContent());
ps.setString(3, comment.getAdd_user());
int n=ps.executeUpdate();
if(n>0){
flag=true;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return flag;
}
public boolean delete(int id,String username){
boolean flag=false;
return flag;
}
public boolean delete(int id){
boolean flag=false;
Connection conn=JDBC.getConnection();//1
String sql="delete tb_comment where id=?";
PreparedStatement ps=null;
try {
ps=conn.prepareStatement(sql);//2
ps.setInt(1, id);
int n=ps.executeUpdate(); //3
if(n>0)
{
flag=true;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try{
if(ps!=null){
ps.close();
}
if(conn!=null){
conn.close();
}
}catch(Exception e){
}
}
return flag;
}
}
4、Servlet实现处理商品留言功能，主要完成
（1）是添加还是删除留言?
（2）如果为删除，需要获得要删除留言的id，调用CommentDAO.delete(id),
返回detail.jsp页（要提交商品gid，否则会异常）
（3）添加留言
Servlet获得商品留言的信息content，作者（登录用户），商品gid
调用CommentDAO.add(comment)
返回detail.jsp页（要提交商品gid，否则会异常）
package myservlet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import myshop.Comment;
import myshop.CommentDAO;
public class CommentServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String action=request.getParameter("action");
CommentDAO dao=new CommentDAO();
if(action.equals("add")){
Comment comment=new Comment();
comment.setGid(Integer.parseInt(request.getParameter("gid")));
comment.setContent(request.getParameter("content"));
String add_user="无名氏";
comment.setAdd_user(add_user);
dao.add(comment);
request.getSession().setAttribute("gid",request.getParameter("gid"));
response.sendRedirect("/chap5/detail.jsp");
}else if(action.equals("delete")){
int id=Integer.parseInt(request.getParameter("id"));
dao.delete(id);
request.getSession().setAttribute("gid",request.getParameter("gid"));
response.sendRedirect("/chap5/detail.jsp");
}
}
}
web.xml
<servlet>
<servlet-name>CommentServlet</servlet-name>
<servlet-class>myservlet.CommentServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CommentServlet</servlet-name>
<url-pattern>/servlet/comment</url-pattern>
</servlet-mapping>
5、detail.jsp实现留言显示
<h2>评价</h2>
<%
CommentDAO cdao=new CommentDAO();
LinkedList<Comment> cs=cdao.search(gid);
for(Comment c:cs){
%>
<div class="msg">
<div class="msg_content"><%=c.getContent()%></div>
<div class="msg_time"><%=c.getAdd_time() %> <a href="http://www.mamicode.com/chap5/servlet/comment?action=delete&id=&gid=">删除</a></div>
</div>
<%} %>
6、实现商品留言删除
<a href="http://www.mamicode.com/chap5/servlet/comment?action=delete&id=&gid=">删除</a>
红色部分，另外detail.jsp部分代码更改,Servlet删除留言后，返回detail.jsp页需商品gid值
<%
int gid;
if(session.getAttribute("gid")!=null){
gid=Integer.parseInt((String)session.getAttribute("gid"));
}else{
gid= Integer.parseInt(request.getParameter("gid"));
}
GoodsDAO dao=new GoodsDAO();
Goods g=dao.getById(gid);
%>
7、实现商品留言
detail.jsp
<div class="msg">
<form action="/chap5/servlet/comment?action=add&gid=<%=gid%>" method="post">
<textarea class="msg_txt" name="content" ></textarea>
<input type="submit" value="http://www.mamicode.com/发表">
</form>
</div>
本文出自 “学而不思则罔” 博客，请务必保留此出处http://dyzyxy.blog.51cto.com/944775/1916593
Servlet 商品留言