src/main/java/com/example/g8backend/entity/Message.java

// Message.java（新增）
package com.example.g8backend.entity;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import lombok.experimental.Accessors;

import java.time.LocalDateTime;

@Data
@Accessors(chain = true)
@TableName("private_messages")
public class Message {
    @TableId(type = IdType.AUTO)
    private Long messageId;
    private Long senderId;
    private Long receiverId;
    private String content;
    private LocalDateTime sentAt;
    @TableField("is_read")
    private Boolean isRead = false; // ✅ 默认值
}