浪漫编码：手把手教你实现校园表白墙功能

DROP TABLE IF EXISTS message_info;
  CREATE TABLE `message_info` (
  `id` INT ( 11 ) NOT NULL AUTO_INCREMENT,
  `from` VARCHAR ( 127 ) NOT NULL,
  `to` VARCHAR ( 127 ) NOT NULL,
  `message` VARCHAR ( 256 ) NOT NULL,
  `delete_flag` TINYINT ( 4 ) DEFAULT 0 COMMENT '0-正常, 1-删除',
  `create_time` DATETIME DEFAULT now(),
  `update_time` DATETIME DEFAULT now() ON UPDATE now(),
  PRIMARY KEY ( `id` )
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4;

<dependency>
  <groupId>org.mybatis.spring.boot</groupId>
  <artifactId>mybatis-spring-boot-starter</artifactId>
  <version>3.0.3</version>
</dependency>
<dependency>
  <groupId>com.mysql</groupId>
  <artifactId>mysql-connector-j</artifactId>
  <scope>runtime</scope>
</dependency>

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/mybatis_test?
characterEncoding=utf8&useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  configuration: # 配置打印 MyBatis⽇志
    map-underscore-to-camel-case: true #配置驼峰自动转换

import lombok.Data;
@Data
public class MessageInfo {
  private Integer id;
  private String from;
  private String to;
  private String message;
  private Integer deleteFlag;
  private Date createTime;
  private Date updateTime;
}

import com.example.demo.model.MessageInfo;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import java.util.List;
@Mapper
public interface MessageInfoMapper {
  @Select("select `id`, `from`, `to`, `message` from message_info where delete_flag=0")
  List<MessageInfo> queryAll();
  
  @Insert("insert into message_info (`from`,`to`, `message`) values(#{from},#{to},#{message})")
  Integer addMessage(MessageInfo messageInfo);
}

import com.example.demo.mapper.MessageInfoMapper;
import com.example.demo.model.MessageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class MessageInfoService {
  @Autowired
  private MessageInfoMapper messageInfoMapper;
  
  public List<MessageInfo> queryAll() {
    return messageInfoMapper.queryAll();
  }
  
  public Integer addMessage(MessageInfo messageInfo) {
    return messageInfoMapper.addMessage(messageInfo);
  }
}

import com.example.demo.model.MessageInfo;
import com.example.demo.service.MessageInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RequestMapping("/message")
@RestController
public class MessageController {
    @Autowired
    private MessageInfoService messageInfoService;
    /**
     * 获取留言列表
     * @return
     */
    @RequestMapping("/getList")
    public List<MessageInfo> getList() {
        return messageInfoService.queryAll();
    }
    /**
     * 发表留言
     * @param messageInfo
     * @return
     */
    @RequestMapping("/publish")
    public boolean publish(MessageInfo messageInfo) {
        System.out.println(messageInfo);
        if (StringUtils.hasLength(messageInfo.getFrom())
                && StringUtils.hasLength(messageInfo.getTo())
                && StringUtils.hasLength(messageInfo.getMessage())) {
            messageInfoService.addMessage(messageInfo);
            return true;
        }
        return false;
    }
}