JavaWeb项目—BBS论坛

Posted 2020-08-11

项目步骤：

1)将静态html文件转换为JSP文件(涉及到了编码的问题)

2)封装DB

 1 package com.bjsxt.bbs;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 
 9 //封装DB，方便操作
10 public class DB {
11     public static Connection getConn() {
12         Connection conn = null;
13         try {
14             Class.forName("com.mysql.jdbc.Driver");
15             conn = DriverManager.getConnection(
16                     "jdbc:mysql://localhost:3306/bbs", "root", "123456");
17         } catch (ClassNotFoundException e) {
18             e.printStackTrace();
19         } catch (SQLException e) {
20             e.printStackTrace();
21         }
22         return conn;
23     }
24 
25     public static Statement createStmt(Connection conn) {
26         Statement stmt = null;
27         try {
28             stmt = conn.createStatement();
29         } catch (SQLException e) {
30             e.printStackTrace();
31         }
32         return stmt;
33     }
34 
35     public static ResultSet executeQuery(Statement stmt, String sql) {
36         ResultSet rs = null;
37         try {
38             rs = stmt.executeQuery(sql);
39         } catch (SQLException e) {
40             e.printStackTrace();
41         }
42         return rs;
43     }
44 
45     public static void close(Connection conn) {
46         if (conn != null) {
47             try {
48                 conn.close();
49             } catch (SQLException e) {
50                 e.printStackTrace();
51             }
52             conn = null;
53         }
54     }
55 
56     public static void close(Statement stmt) {
57         if (stmt != null) {
58             try {
59                 stmt.close();
60             } catch (SQLException e) {
61                 e.printStackTrace();
62             }
63             stmt = null;
64         }
65     }
66 
67     public static void close(ResultSet rs) {
68         if (rs != null) {
69             try {
70                 rs.close();
71             } catch (SQLException e) {
72                 e.printStackTrace();
73             }
74             rs = null;
75         }
76     }
77 }

3)树状结构展现(一)

主要代码：

Article.java

 1 package com.bjsxt.bbs;
 2 
 3 import java.util.Date;
 4 
 5 public class Article {
 6     private int id;
 7     private int pid;
 8     private int rootId;
 9     private String title;
10     private String cont;
11     private Date pDate;
12     private boolean isLeaf;
13     private int grade;
14 
15     public int getGrade() {
16         return grade;
17     }
18 
19     public void setGrade(int grade) {
20         this.grade = grade;
21     }
22 
23     public int getId() {
24         return id;
25     }
26 
27     public void setId(int id) {
28         this.id = id;
29     }
30 
31     public int getPid() {
32         return pid;
33     }
34 
35     public void setPid(int pid) {
36         this.pid = pid;
37     }
38 
39     public int getRootId() {
40         return rootId;
41     }
42 
43     public void setRootId(int rootId) {
44         this.rootId = rootId;
45     }
46 
47     public String getTitle() {
48         return title;
49     }
50 
51     public void setTitle(String title) {
52         this.title = title;
53     }
54 
55     public String getCont() {
56         return cont;
57     }
58 
59     public void setCont(String cont) {
60         this.cont = cont;
61     }
62 
63     public Date getpDate() {
64         return pDate;
65     }
66 
67     public void setpDate(Date pDate) {
68         this.pDate = pDate;
69     }
70 
71     public boolean isLeaf() {
72         return isLeaf;
73     }
74 
75     public void setLeaf(boolean isLeaf) {
76         this.isLeaf = isLeaf;
77     }
78 }

article.jsp文件

<%!
private void tree(Set<Article> articles,Connection conn,int id,int grade){
    String sql="select * from article where pid="+id;
    Statement stmt=DB.createStmt(conn);
    ResultSet rs=DB.executeQuery(stmt, sql);
    try{
    while(rs.next()){
    Article a=new Article();
    a.setId(rs.getInt("id"));
    a.setPid(rs.getInt("pid"));
    a.setRootId(rs.getInt("rootid"));
    a.setTitle(rs.getString("titel"));
    a.setLeaf(rs.getInt("isleaf")==0?true:false);
    a.setpDate(rs.getTimestamp("pdate"));
    a.setGrade(grade+1);
    articles.add(a);
    if(!a.isLeaf()){
    tree(articles, conn, id, grade+1);    
    }
    }catch (SQLException e){
    e.printStackTrace();
    }
    
}
 %>
 
 <%
 Set<Article> articles=new HashSet<Article>();
 Connection conn=DB.getConn();
 tree(articles,conn,0,0);
 DB.close(conn);
  %>

未完