MVC、JSP实现mysql的增删改查功能的封装和简陋的界面交互

1、眼见为实

（1）欢迎界面，总索引：带下划线的三个都是链接

：

（2）搜索界面：--有颜色的为链接
 

（3）、点击上面图片中的修改链接之后就会弹出下面的修改界面：

 

（4）、修改用户信息的界面

 

（5）、项目总结构：（别忘了还有WEB-INF里面的lib的mysql连接包）

 （6）、源码：

package com.huai.dbc;

import java.sql.DriverManager;

public class DBConnection {

private final String Driver = "com.mysql.jdbc.Driver";
private final String url = "jdbc:mysql://localhost:3306/test";
private java.sql.Connection con;

public DBConnection()throws Exception{
Class.forName(Driver);
con = DriverManager.getConnection(url, "root", "mysql");
}

public java.sql.Connection getConnection(){
return this.con;
}

public void close()throws Exception{
if(this.con != null){
this.con.close();
}
}

// public static void main(String args[]){
// try {
// new Connection().getConnection();
// } catch (Exception e) {
// e.printStackTrace();
// }
// }
}

package com.huai.dao;

import java.util.*;
import com.huai.vo.*;

/*
* 数据库操作的接口，里面的方法分别是增删改查
*/
public interface IDAOImpl {

public ArrayList queryData(String keyWord)throws Exception;

public boolean deleteData(String keyWord)throws Exception;

public boolean updateData(User user)throws Exception;

public boolean insertData(User user)throws Exception;
}

package com.huai.dao.impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import com.huai.dao.IDAOImpl;
import com.huai.vo.User;

/*
* 此类实现数据库的操作接口
* 注意：在此还没有实现数据库连接的实例化（对象），
* 只是提供了一个构造放法，以便在后面的实例化后传入
*/
public class UserDAOImpl implements IDAOImpl{

Connection con = null;
PreparedStatement state = null;

public UserDAOImpl(Connection con) {
this.con = con;
}

@Override
public ArrayList queryData(String keyWord)throws Exception{
String sql = "select * from member where hobby like ? or name like ?";
ResultSet rs = null;
ArrayList users = new ArrayList();

this.state = con.prepareStatement(sql);
//百分号表示代表未知的字符
this.state.setString(1, "%"+keyWord+"%");
this.state.setString(2, "%"+keyWord+"%");

rs = this.state.executeQuery();
while(rs.next()){
User user = new User();
user.setId(rs.getString(1));
user.setName(rs.getString(2));
user.setSex(rs.getString(3));
user.setHobby(rs.getString(4));

users.add(user);
}

return users;
}

@Override
public boolean deleteData(String keyWord) throws Exception {
boolean flag = false;

String sql = "delete from member where id = ?";


this.state = con.prepareStatement(sql);
this.state.setString(1, keyWord);

int i = this.state.executeUpdate();
if(i != 0){
flag = true;
}
return flag;
}

@Override
public boolean updateData(User user) throws Exception {
boolean flag = false;

String sql = "update member set name=?, sex=?, hobby=? where id=?";

this.state = con.prepareStatement(sql);
this.state.setString(1, user.getName());
this.state.setString(2, user.getSex());
this.state.setString(3, user.getHobby());
this.state.setString(4, user.getId());

int i = this.state.executeUpdate();
if(i != 0){
flag = true;
}
return flag;
}

@Override
public boolean insertData(User user) throws Exception {

boolean flag = false;
String sql = "insert into member(id, name, sex, hobby) values(?, ?, ?, ?)";
this.state = con.prepareStatement(sql);
this.state.setString(1, user.getId());
this.state.setString(2, user.getName());
this.state.setString(3, user.getSex());
this.state.setString(4, user.getHobby());

int i = this.state.executeUpdate();
if(i != 0){
flag = true;
}
return flag;
}
}

package com.huai.dao.impl;

import java.util.ArrayList;

import com.huai.dao.IDAOImpl;
import com.huai.dbc.DBConnection;
import com.huai.vo.User;

/*
* 这个类和UserDAOImpl都实现了IDAOImpl接口
* 但是这个类是UserDAOImpl的代理类，目的是在大的项目中更好地进行代码的管理
*/
public class UserDAOImplProxy implements IDAOImpl{

UserDAOImpl userDAOImpl = null;
DBConnection dBConnection = null;

public UserDAOImplProxy()throws Exception{
dBConnection = new DBConnection();
userDAOImpl = new UserDAOImpl(dBConnection.getConnection());
}

@Override
public ArrayList queryData(String keyWord) throws Exception {
ArrayList list = null;
try{
list = userDAOImpl.queryData(keyWord);
}catch(Exception e){
throw e;
}
return list;
}

@Override
public boolean deleteData(String keyWord) throws Exception {
return userDAOImpl.deleteData(keyWord);

}

@Override
public boolean updateData(User user) throws Exception {

return userDAOImpl.updateData(user);
}

@Override
public boolean insertData(User user) throws Exception {

return userDAOImpl.insertData(user);
}

}

package com.huai.dao.factory;

import com.huai.dao.impl.UserDAOImplProxy;

public class DaoFactory {

public static UserDAOImplProxy getUserDAOImplProxy() throws Exception{
return new UserDAOImplProxy();
}
}

 

package com.huai.servlet;

import java.io.IOException;
import java.util.ArrayList;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.huai.dao.factory.DaoFactory;
import com.huai.dao.impl.UserDAOImplProxy;
import com.huai.vo.User;

//此处是新建servlet文件是自动加上的，如果没有它，需要在项目中增加web.xml文件，并且进行相关的映射配置
//否则的话jsp文件找不到这个MyServlet文件
@WebServlet("/MyServlet")

public class MyServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

UserDAOImplProxy userDAOImplProxy = null;

public MyServlet() {
try {
userDAOImplProxy = DaoFactory.getUserDAOImplProxy();
} catch (Exception e) {
e.printStackTrace();
}
}

protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("gbk");

//status表示的是hidden域，目的是辨清是哪张表所发出的命令
String status = request.getParameter("status");

if ("search".equals(status)) {
try {

ArrayList list = null;

list = userDAOImplProxy.queryData(request
.getParameter("keyWord"));

request.setAttribute("users", list);

request.getRequestDispatcher("searchPage.jsp").forward(request,
response);

} catch (Exception e) {
e.printStackTrace();
}
} else if ("insert".equals(status)) {
String info = "";

String name = request.getParameter("name");
String sex = request.getParameter("sex");
String hobby = request.getParameter("hobby");
if (name == null || sex == null || hobby == null || "".equals(name)
|| "".equals(sex) || "".equals(hobby)) {
info = "The information is not completed";
} else {
User user = new User();
user.setName(name);
user.setSex(sex);
user.setHobby(hobby);

try {
if (userDAOImplProxy.insertData(user)) {
info = "succeed to insert!";
} else {
info = "failed to insert!";
}
} catch (Exception e) {
e.printStackTrace();
}

}
request.setAttribute("info", info);
request.getRequestDispatcher("insertPage.jsp").forward(request,
response);

} else if ("delete".equals(status)) {
String keyWord = request.getParameter("id");

try {
String info = "";
if (userDAOImplProxy.deleteData(keyWord)) {
info = "succeed to delete!";
} else {
info = "failed to delete!";
}
request.setAttribute("info", info);

//注意：这里的是内部跳转，也就是服务器端的跳转。外在表现是地址栏没变。好处就是提高性能
request.getRequestDispatcher("searchPage.jsp").forward(request,
response);
} catch (Exception e) {
e.printStackTrace();
}
} else if ("update".equals(status)) {
String info = "";
String path = null;

String id = request.getParameter("id");
String name = request.getParameter("name");
String sex = request.getParameter("sex");
String hobby = request.getParameter("hobby");
if (name == null || sex == null || hobby == null || "".equals(name)
|| "".equals(sex) || "".equals(hobby)) {
info = "The information is not completed";
path = "updatePage.jsp";
} else {
User user = new User();
user.setId(id);
user.setName(name);
user.setSex(sex);
user.setHobby(hobby);

try {
if (userDAOImplProxy.updateData(user)) {
info = "succeed to update!";
path = "searchPage.jsp";
} else {
info = "failed to update!";
path = "updatePage.jsp";
}
} catch (Exception e) {
e.printStackTrace();
}
}
request.setAttribute("info", info);
request.getRequestDispatcher(path).forward(request,
response);

}
}

protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}

}

package com.huai.vo;

public class User {

private String id;
private String name;
private String sex;
private String hobby;

public User(){

}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}

public String getHobby() {
return hobby;
}

public void setHobby(String hobby) {
this.hobby = hobby;
}


}

<%@ page language="java" contentType="text/html; charset=gbk"
pageEncoding="GB18030"%>

<%request.setCharacterEncoding("gbk"); %>

Welcome !

search_page

insert_page

update_page

<%@ page language="java" contentType="text/html; charset=gbk "
pageEncoding="GB18030"%>

<%request.setCharacterEncoding("gbk"); %>

Insert_Page

${requestScope.info}

name:

UserSex:

Hobby:






-->>index_page

<%@ page language="java" contentType="text/html; charset=gbk"
pageEncoding="GB18030"%>
<%@page import="java.util.*" %>

<%request.setCharacterEncoding("gbk"); %>

${requestScope.info}

-->>index_page

<%request.setCharacterEncoding("gbk"); %>
<%List list = (List)request.getAttribute("users");
if(list != null){
%>









<%
Iterator iter = list.iterator();
while(iter.hasNext()){
pageContext.setAttribute("de", iter.next());
%>








<%

}
%>

id	name	sex	hobby
${de.id}	${de.name}	${de.sex}	${de.hobby}	修改	删除

<%
}
%>

<%@ page language="java" contentType="text/html; charset=gbk"
pageEncoding="gbk"%>

<%request.setCharacterEncoding("gbk"); %>

Update_Page

id = ${param.id}

name:

sex:

hobby:






-->index_page

下面是对上面的项目的相关重构，我加入了sun公司开发的jsp标准标签库，利用标签来换掉view层的<%%>中的代码。其他的不变！！！（重点只修改了search.jsp中的代码）

<%@ page language="java" contentType="text/html; charset=gbk"
pageEncoding="gbk"%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>





<%
request.setCharacterEncoding("gbk");
%>

${requestScope.info}

-->>index_page

num	id	name	sex	hobby	修改	删除
					修改	删除

注意新增加的包，这些包可以在http://tomcat.apache.org/taglibs/以及xalan官网中下载到