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（三十一）web 开发基础项目

1.　　编写index.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10     <form action="servlet/login?action=add" method="post">
11         用户名:<input type="text" name="userName" /><br/>
12         密&nbsp;码:<input type="password" name="passWd" /><br/>
13         年&nbsp;龄:<input type="text" name="age" /><br/>
14         <input type="submit" />
15     </form>
16 </body>
17 </html>

2.　　设计数据库，确定po包、dao包、bo包、service包

　　2.1　　设计数据库

　　2.2　　确定po包，存放的是永久化对象，即与数据库的表一一对应。

userPO.java

 1 package po;
 2 
 3 import java.util.Date;
 4 
 5 public class UserPO {
 6     private String userName;
 7     private String passWd;
 8     private Date birthday;
 9     
10     public UserPO(){
11     }
12 
13     public UserPO(String userName, String passWd, Date birthday) {
14         super();
15         this.userName = userName;
16         this.passWd = passWd;
17         this.birthday = birthday;
18     }
19 
20     public String getUserName() {
21         return userName;
22     }
23 
24     public void setUserName(String userName) {
25         this.userName = userName;
26     }
27 
28     public String getPassWd() {
29         return passWd;
30     }
31 
32     public void setPassWd(String passWd) {
33         this.passWd = passWd;
34     }
35 
36     public Date getBirthday() {
37         return birthday;
38     }
39 
40     public void setBirthday(Date birthday) {
41         this.birthday = birthday;
42     }
46 }

2.3　　确定dao包，包里存的是操作数据的对象（对数据库的增删改查）,一般有接口+实现+工具类.

UserDAOI.java

 1 package dao;
 2 
 3 import java.util.List;
 4 
 5 import po.UserPO;
 6 
 7 public interface UserDAOI {
 8     public boolean addUser(UserPO user);
 9     public boolean delUser(String userName);
10     public boolean uptUser(UserPO user);
11     public List<UserPO> gets();
12 
13 }

DBUtil.java

  1 package dao;
  2 
  3 import java.beans.PropertyVetoException;
  4 import java.sql.Connection;
  5 import java.sql.PreparedStatement;
  6 import java.sql.ResultSet;
  7 import java.sql.SQLException;
  8 import java.text.DateFormat;
  9 import java.util.ArrayList;
 10 import java.util.List;
 11 
 12 import com.mchange.v2.c3p0.ComboPooledDataSource;
 13 
 14 import po.UserPO;
 15 
 16 public class DBUtil {
 17     public static ComboPooledDataSource  dateSource;
 18     
 19     static{
 20         dateSource=new ComboPooledDataSource();
 21         final String URL="jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=utf-8";
 22         final String USER="root";
 23         final String PASSWD="";
 24         final String Driver="com.mysql.jdbc.Driver";
 25             
 26         try {
 27             dateSource.setDriverClass(Driver);
 28             dateSource.setJdbcUrl(URL);
 29             dateSource.setUser(USER);
 30             dateSource.setPassword(PASSWD);
 31             dateSource.setMaxPoolSize(100);
 32             dateSource.setMinPoolSize(10);
 33             dateSource.setMaxStatements(10000);
 34         } catch (Exception e) {
 35             e.printStackTrace();
 36         }
 37     
 38     }
 39     
 40     /**
 41      * 
 42      * @return 连接池中的连接
 43      */
 44     public static Connection getConn(){
 45         try {
 46             return dateSource.getConnection();
 47         } catch (SQLException e) {
 48             e.printStackTrace();
 49         }
 50         return null;
 51     }
 52     
 53     /**
 54      * 
 55      * 增删改方法
 56      * @param sql sql语句
 57      * @param list sql语句中的？值
 58      * @return
 59      */
 60     public static boolean cud(String sql,List<Object> list){
 61         boolean flag=false;
 62         Connection conn=null;
 63         PreparedStatement pstat=null;
 64         try{
 65             conn=getConn();
 66             pstat=conn.prepareStatement(sql);
 67             
 68             if(list!=null){
 69                 for(int i=0;i<list.size();i++){
 70                     pstat.setObject(i+1, list.get(i));
 71                 }
 72             }
 73             
 74             int res=pstat.executeUpdate();
 75             if(res>0){
 76                 flag=true;
 77             }
 78             
 79             
 80         }catch(Exception e){
 81             e.printStackTrace();
 82         }finally{
 83             close(conn, pstat, null);
 84         }
 85         
 86     
 87         return flag;
 88     }
 89     
 90     /**
 91      * 关闭流
 92      * @param conn 连接流
 93      * @param pstat    sql语句流
 94      * @param res    结果集流
 95      */
 96     public static void close(Connection conn,PreparedStatement pstat,ResultSet res){
 97     
 98         try{
 99             if(conn!=null)
100             {
101                 conn.close();
102             }
103             if(pstat!=null)
104             {
105                 pstat.close();
106             }if(res!=null)
107             {
108                 res.close();
109             }
110         }
111         catch(Exception e)
112         {
113             e.printStackTrace();
114         }
115         
116         
117     }
118     
119     /**查找数据库中所有po对象并返回list
　　　　　*@param sql sql语句
　　　　　*@param list 存放sql预处理语句中的？值
　　　　　*/
120     public static List<UserPO> gets(String sql,List<Object> list) {
121         List<UserPO> users=new ArrayList<UserPO>();
122         UserPO user=null;
123         Connection conn=null;
124         PreparedStatement pstat=null;
125         ResultSet res=null;
126         try
127         {
128             conn=DBUtil.getConn();
129             pstat=conn.prepareStatement(sql);
130             
131             if(list!=null)
132             {
133                 for(int i=0;i<list.size();i++)
134                 {
135                     pstat.setObject(i+1, list.get(i));
136                 }
137     
138             }
139             
140             
141             
142             res=pstat.executeQuery();
143             
144             while(res.next())
145             {
146                 user=new UserPO();
147                 user.setUserName(res.getString("userName"));
148                 user.setBirthday(res.getDate("birthday"));
149                 user.setPassWd(res.getString("passWd"));
150                 users.add(user);
151             }
152             
153         }
154         catch(Exception e)
155         {
156             e.printStackTrace();
157         }finally
158         {
159             close(conn, pstat, res);
160         }
161         return users;
162     }
163 
164 }

UserDAOImpl.java

package dao;

import java.awt.geom.CubicCurve2D;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;

import po.UserPO;

public class UserPOImpl implements UserDAOI {

	public boolean addUser(UserPO user) {
		String sql="insert into user values(?,?,?)";
		List<Object> list=new ArrayList<Object>();
		list.add(user.getUserName());
		list.add(user.getPassWd());
		list.add(user.getBirthday());
		return DBUtil.cud(sql, list);
	}

	public boolean delUser(String userName) {
		String sql="delete from user where userName=?";
		List<Object> list=new ArrayList<Object>();
		list.add(userName);
		
		return DBUtil.cud(sql, list);
	}

	public boolean uptUser(UserPO user) {
		String sql="update user set passWd=?,birthday=? where userName=?";
		List<Object> list=new ArrayList<Object>();
		list.add(user.getPassWd());
		list.add(user.getBirthday());
		list.add(user.getUserName());
		

		return DBUtil.cud(sql, list);
	}

	public List<UserPO> gets() {
		String sql="select * from user";
		return DBUtil.gets(sql, null);
	}

}

2.4　　确定bo包，存放的是对象，即与用户提供的信息一一对应。

userBO.java

 1 package bo;
 2 
 3 public class UserBO {
 4     private String userName;
 5     private String passWd;
 6     private String age;
 7     
 8     public UserBO()
 9     {
10         
11     }
12 
13     public UserBO(String userName, String passWd, String age) {
14         super();
15         this.userName = userName;
16         this.passWd = passWd;
17         this.age = age;
18     }
19 
20     public String getUserName() {
21         return userName;
22     }
23 
24     public void setUserName(String userName) {
25         this.userName = userName;
26     }
27 
28     public String getPassWd() {
29         return passWd;
30     }
31 
32     public void setPassWd(String passWd) {
33         this.passWd = passWd;
34     }
35 
36     public String getAge() {
37         return age;
38     }
39 
40     public void setAge(String age) {
41         this.age = age;
42     }
43     
44     
45 }

　　解析： bo对象与po对象不同点在于： bo对象是业务对象，存放的数据是用户直接提供的，以本题为例，用户数据为userName、passWd、age，bo对象成员属性也为这三个，而

po对象则是存放于数据库中的数据，即用户数据经过处理之后才能存放于数据库中（比如用户注册的age数据，如果数据库中直接存放age毫无意义，因为第二年的时候age+1，数据库管理员还得给每个age+1），po对象存放的数据为userName、passWd、birthday。

2.5　确定service包，将servlet得到的原始数据（即用户数据）转换为DAO包里的数据格式。

userServiceI.java

 1 package service;
 2 
 3 import java.util.List;
 4 
 5 import bo.UserBO;
 6 
 7 public interface UserServiceI {
 8     public boolean addUser(UserBO user);
 9     public boolean delUser(String userName);
10     public boolean uptUser(UserBO user);
11     public List<UserBO> gets();
12 }

userServiceImpl.java

 1 package service;
 2 
 3 import java.util.ArrayList;
 4 import java.util.Date;
 5 import java.util.List;
 6 
 7 import bo.UserBO;
 8 import dao.UserPOImpl;
 9 import po.UserPO;
10 
11 public class UserServiceImpl implements UserServiceI {
12     UserPOImpl im=new UserPOImpl();
13 
14     public boolean addUser(UserBO user) {
15 
16         return im.addUser(bo2po(user));
17     }
18 
19     public boolean delUser(String userName) {
20         im.delUser(userName);        
21         return true;
22     }
23 
24     public boolean uptUser(UserBO user) {
25         
26         return im.uptUser(bo2po(user));
27     }
28 
29     public List<UserBO> gets() {
30         
31         
32         List<UserPO> poList=im.gets();
33         
34         return po2bo(poList);
35     }
36 
37     /**
38      * 把BO对象转为PO对象，这个方法只适用于增加和修改操作
39      * 
40      * @param user
41      * @return
42      */
43     private UserPO bo2po(UserBO user)
44     {
45             
46         UserPO userpo=new UserPO();
47         
48         Date date=new Date();
49         @SuppressWarnings("deprecation")
50         int year=date.getYear(); //拿到今年第几年
51         int yearDB=year-Integer.parseInt(user.getAge()); //得到存入数据库的年份
52         @SuppressWarnings("deprecation")
53         Date date1=new Date(yearDB,date.getMonth(),date.getDay());
54         
55         userpo.setBirthday(date1);
56         userpo.setUserName(user.getUserName());
57         userpo.setPassWd(user.getPassWd());
58     
59         return userpo;
60     }
61     /**
62      * 把存有PO对象的List转为存有BO对象的List
63      * 步骤：
64      *  1. 拿到存有PO对象的list容器之后，进行遍历
65      *     2.  每次遍历都要new一个BO对象，然后把PO对象的值对应转化为BO对象
66      *     3. 返回存放BO对象的list
67      * @param userpo
68      * @return BO对象
69      */
70     private List<UserBO> po2bo(List<UserPO> poList)
71     {
72         List<UserBO> boList=new ArrayList<UserBO>();
73         UserBO userbo=null;
74         for(int i=0;i<poList.size();i++)
75         {
76             userbo=new UserBO();
77             userbo.setUserName(poList.get(i).getUserName());
78             userbo.setPassWd(poList.get(i).getPassWd());
79             Date birthday=poList.get(i).getBirthday();
80             Date getYear=new Date();
81             int age=getYear.getYear()-birthday.getYear();
82             userbo.setAge(String.valueOf(age));
83             
84             boList.add(userbo);
85         }
86         
87         return boList;
88     }
89     
90 }

3. 编写servlet包

LoginServlet.java

package srevlet;

import java.io.IOException;
import java.util.List;

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

import bo.UserBO;
import service.UserServiceImpl;

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

    public LoginServlet() {
        super();

    }

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


    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //拿到用户数据
        UserBO user=null;
        UserServiceImpl userIm=new UserServiceImpl();
        String userName=request.getParameter("userName");
        String passWd=request.getParameter("passWd");
        String age=request.getParameter("age");
        
        String action=request.getParameter("action");
        
        if(action.equals("add"))
        {
            //增加一条记录
            user=new UserBO();
            user.setUserName(userName);
            user.setPassWd(passWd);
            user.setAge(age);
            userIm.addUser(user);
        }
        if(action.equals("del"))
        {
            //删除一条记录
            String name=request.getParameter("userName");
            userIm.delUser(name);
        }
        if(action.equals("upt"))
        {
            user=new UserBO();
            user.setAge(request.getParameter("age"));
            user.setPassWd(request.getParameter("passWd"));
            user.setUserName(request.getParameter("userName"));
            userIm.uptUser(user);
            
        }
        if(action.equals("gets"))
        {
            //拿到数据库的全部数据
            List<UserBO> listbo=userIm.gets();
            for(int i=0;i<listbo.size();i++)
            {
                System.out.println(listbo.get(i).getUserName()+" "+listbo.get(i).getAge()+" "+listbo.get(i).getPassWd());
            }
            
        }
    }

}

结果：

解析：查看servlet 当action=del的时候，会执行servlet的相应操作，request.getParameter("userName"); 可以得到地址栏里的userName的值“nihao”，这样就可以从数据库中删除。

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原文地址：https://www.cnblogs.com/shyroke/p/6534639.html