[Java知识库]0004章：留言板功能 springboot+maven+mysql

1.????????数据库? ? ?数据库名：brog_database? ?表名：comments? 字段看下图

2.????????留言板项目目录：? springboot+mysql+idea+postman

3.????????com.oy.demo.controller? ?MessageController.java

package com.oy.demo.controller;

import com.oy.demo.pojo.Message;
import com.oy.demo.service.MessageService;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;
import java.util.Map;

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

    @Resource
    private MessageService messageService;

    /**
     * 找到所有留言信息
     * @return
     */
    @PostMapping("find")
    public List<Message> findAllMessage(){
        return messageService.findAllMessage();
    }

    /**
     * 发送一条留言信息
     * @param message
     * @return
     */
    @PostMapping("add")
    public Map<String, Object> addMessage(@RequestBody Message message){
        //  System.out.println("============================"+message);
        return messageService.addMessage(message);
    }
}

?

4.????????com.oy.demo.controller? ?UiController.java

package com.oy.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

@RestController
public class UiController {

    @GetMapping("/message")
    public ModelAndView message(){
        return new ModelAndView("message.html");
    }

}

5.????????com.oy.demo.mapper? MessageMapper接口

package com.oy.demo.mapper;

import com.oy.demo.pojo.Message;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface MessageMapper {
    /**
     * 查询所有留言信息
     * @return
     */
    @Select("SELECT * FROM comments")
    List<Message> selectAllMessage();

    /**
     * 新增一条留言信息
     * @param message
     * @return
     */
    @Insert("INSERT INTO comments(name,iphone, words,time)"+
            "VALUES(#{name}, #{iphone}, #{words}, #{time})")
    int insertMessage(Message message);
}

6.????????com.oy.demo.pojo? Message.java

package com.oy.demo.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDateTime;

@Data
@NoArgsConstructor //无参数的构建方法
@AllArgsConstructor //有参数的构建方法
public class Message {
    private Integer id; //留言编号
    private String name; //用户大名
    private String iphone; // 手机号码
    private String words; //留言内容
    private LocalDateTime time;  //留言时间
}

7.? ? ? com.oy.demo.service? ? MessageService.java

package com.oy.demo.service;

import com.oy.demo.mapper.MessageMapper;
import com.oy.demo.pojo.Message;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service  //Service类的注解
public class MessageService {

    @Resource  //注入MessageMapper接口
    private MessageMapper messageMapper;

    /**
     * 查找所有留言信息
     * @return
     */
    public List<Message> findAllMessage(){
        //查找所有留言信息
        List<Message> messageList = messageMapper.selectAllMessage();
        //测试
        for(Message message:messageList){
            System.out.println(message.toString());
        }
        //返回留言信息
        return messageList;
    }

    /**
     * 插入留言信息
     * @param message
     * @return
     */
    public Map<String, Object> addMessage(Message message){
        Map<String, Object> resultMap = new HashMap<>();
        System.out.println(message.toString());
        //补充插入信息
        message.setTime(LocalDateTime.now());
        //插入留言信息
        int result = messageMapper.insertMessage(message);
        if(result > 0){
            //留言信息插入成功
            resultMap.put("code" ,200);
            resultMap.put("message" , "信息发送成功！");
        }else{
            //留言信息插入失败
            resultMap.put("code" ,400);
            resultMap.put("message" , "！信息发送失败");
        }
        return resultMap;
    }
}

8.? ? ?com.oy.demo.service? ? MessageService.java

package com.oy.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.oy.demo.mapper")
@SpringBootApplication
public class SpringbootTestApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootTestApplication.class, args);
    }

}

9.? ?application.yml

server:
  port: 9999

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost/brog_database?characterEncoding=UTF8&useUnicode=true&useSSL=false
    username: root
    password: HDjava1702

mybatis:
  configuration:
    map-underscore-to-camel-case: true # 开启驼峰映射

10.? pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>springboot-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-test</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-thymeleaf -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
            <version>2.0.4.RELEASE</version>
        </dependency>



        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.7.2</version>
            </plugin>
        </plugins>
    </build>

</project>

11?.postman测试结果

?

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