How to use Java to develop the message board module of the CMS system

Foreword:
Under the current wave of Internet development, the website has become one of the main platforms for the dissemination and exchange of various information. As an important tool for communication between websites and users, message boards are also widely used in various CMS systems. This article will introduce how to use Java to develop the message board module of the CMS system, and give code examples for readers' reference.

1. Requirements Analysis
Before developing the message board module, we first need to analyze the requirements. Generally speaking, the message board module needs to implement the following functions:

1. users can post messages;
2. users can view all messages;
3. users can comment on messages ;
4. Administrators can review messages and delete non-compliant messages.

2. Technology selection
Based on the above requirements, we can choose to use the following technologies to implement the message board module:

1. Backend: Java language, Spring framework ;
2. Front-end: HTML, CSS, JavaScript;
3. Database: MySQL.

3. Database design
Before developing the message board module, we need to design the database table structure first. Generally, message forms and comment forms are required. The following is a design example of the message table and comment table:

1. Message table (message):

   • id: message ID, primary key
   • content: Message content
   • create_time: Creation time
   • user_id: User ID

2. Comment form (comment):

   • id: comment ID, primary key
   • content: comment content
   • create_time: creation time
   • message_id: message ID
   • user_id: user ID

4. Back-end development
Next we start back-end development. First create two entity classes, Message and Comment, and establish the relationship between them. The code example is as follows:

@Entity
@Table(name = "message")
public class Message {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

private String content;

@Column(name = "create_time")
private Date createTime;

@ManyToOne
@JoinColumn(name = "user_id")
private User user;

// 省略getter和setter方法

}

@Entity
@Table(name = "comment")
public class Comment {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

private String content;

@Column(name = "create_time")
private Date createTime;

@ManyToOne
@JoinColumn(name = "message_id")
private Message message;

@ManyToOne
@JoinColumn(name = "user_id")
private User user;

// 省略getter和setter方法

}

Next, we need to create the MessageRepository and CommentRepository interfaces for operating the database. The code example is as follows:

public interface MessageRepository extends JpaRepository {
}

public interface CommentRepository extends JpaRepository {
}

Then, we implement the MessageService and CommentService interfaces to implement specific business logic. The code example is as follows:

public interface MessageService {

void saveMessage(Message message);
void deleteMessage(Long messageId);
List<Message> getAllMessages();
List<Comment> getAllCommentsByMessage(Long messageId);
void addComment(Long messageId, Comment comment);
void deleteComment(Long commentId);

}

@Service
public class MessageServiceImpl implements MessageService {

// 省略代码实现

}

@Service
public class CommentServiceImpl implements CommentService {

// 省略代码实现

}

Finally, we can create MessageController and CommentController to handle front-end requests and return accordingly. The code example is as follows:

@RestController
@RequestMapping("/message")
public class MessageController {

// 省略代码实现

}

@RestController
@ RequestMapping("/comment")
public class CommentController {

// 省略代码实现

}

5. Front-end development
In front-end development, we need to create HTML and JavaScript files to implement user interface interaction. In the message board module, we can send requests to the backend through AJAX, obtain the content of messages and comments, and display them on the frontend. Here is a simple sample code:

<textarea id="message-content"></textarea>
<button type="submit">发表留言</button>