SpringBoot教学资料5-SpringBoot一对多查询（带简单前端）-526互联

项目展示：

项目结构：

SQL：

CREATE TABLE `t_article` (
  `id` int(20) NOT NULL AUTO_INCREMENT COMMENT '文章id',
  `title` varchar(200) DEFAULT NULL COMMENT '文章标题',
  `content` longtext COMMENT '文章内容',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8

CREATE TABLE `t_comment` (
  `id` int(20) NOT NULL AUTO_INCREMENT COMMENT '评论id',
  `content` longtext COMMENT '评论内容',
  `author` varchar(200) DEFAULT NULL COMMENT '评论作者',
  `a_id` int(20) DEFAULT NULL COMMENT '关联的文章id',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8

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>2.6.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>springbootsy</groupId>
    <artifactId>sy2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sy2</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </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>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </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>
            </plugin>
        </plugins>
    </build>

</project>

application.properties:

spring.thymeleaf.cache=false
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.mode=HTML5
spring.thymeleaf.prefix=classpath:/templates/
spring.thymeleaf.suffix=.html

spring.datasource.url=jdbc:mysql://localhost:3306/springboottest
spring.datasource.username=root
spring.datasource.password=123456

mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=springbootsy.sy2.domain

articleList.html:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www. .org/">
<head>
    <meta charset="UTF-8">
    <title>article列表</title>
</head>
<body>
<form method="get" th:action="@{'/article/findAll'}">
    <!--th:action相当于action-->
    <input type="submit" value="查询">
</form>
<table cellspacing="1">
    <thead>
    <tr>
        <th>id</th>
        <th>标题</th>
        <th>内容</th>
        <th>操作</th>
    </tr>
    </thead>

    <tbody th:each="article:${articleLists}">
    <tr>
        <td th:text="${article.id}"></td>
        <td th:text="${article.title}"></td>
        <td th:text="${article.content}"></td>
        <td>
            <a th:href="@{/article/findById(id=${article.id})}">查看详情</a>
        </td>
    </tr>
    </tbody>
</table>
</body>
</html>

articleDetail.html:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org/">
<head>
    <meta charset="UTF-8">
    <title>article 详情</title>
</head>
<body>
<!--自行发挥展示article的title、content、commentList等内容-->

<table>
    <tr>
        <td>title:</td>
        <td th:text="${article.title}"></td>
    </tr>
    <tr>
        <td>content:</td>
        <td th:text="${article.content}"></td>
    </tr>
</table>
<table cellspacing="1">
    <thead>
    <tr>
        <th>id</th>
        <th>author</th>
        <th>content</th>
    </tr>
    </thead>
    <tbody th:each="comment:${article.commentList}">
    <tr>
        <td th:text="${comment.id}"></td>
        <td th:text="${comment.author}"></td>
        <td th:text="${comment.content}"></td>
    </tr>
    </tbody>
</table>

</body>
</html>

Article.java:

package springbootsy.sy2.domain;

import java.util.List;

public class Article {
    private int id;
    private String title;
    private String content;
    private List<Comment> commentList;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public List<Comment> getCommentList() {
        return commentList;
    }

    public void setCommentList(List<Comment> commentList) {
        this.commentList = commentList;
    }

    @Override
    public String toString() {
        return "Article{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", content='" + content + '\'' +
                ", commentList=" + commentList +
                '}';
    }
}

Comment.java:

package springbootsy.sy2.domain;

public class Comment {
    private int id;
    private String content;
    private String author;
    private int aId;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public int getaId() {
        return aId;
    }

    public void setaId(int aId) {
        this.aId = aId;
    }

    @Override
    public String toString() {
        return "Comment{" +
                "id=" + id +
                ", content='" + content + '\'' +
                ", author='" + author + '\'' +
                ", aId=" + aId +
                '}';
    }
}

ArticleMapper.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--<mapper>及<mapper>中内容自行补充-->
<mapper namespace="springbootsy.sy2.mapper.ArticleMapper">

    <resultMap id="articleWithComment" type="Article">
        <id property="id" column="id"/>
        <result property="title" column="title"/>
        <result property="content" column="content"/>
        <collection property="commentList" ofType="Comment">
            <id property="id" column="cid"/>
            <result property="content" column="bcontent"/>
            <result property="author" column="author"/>
            <result property="aId" column="a_id"/>
        </collection>
    </resultMap>

    <select id="findById" parameterType="Integer" resultMap="articleWithComment">
        select a.*,b.id as cid ,b.content as bcontent ,author,a_id
        from t_article a left join t_comment b
                                   on a.id=a_id
        where a_id=#{id}
    </select>

    <select id="findAll" parameterType="Integer" resultMap="articleWithComment">
        select *
        from t_article
    </select>


</mapper>

ArticleMapper.java:

package springbootsy.sy2.mapper;

import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import springbootsy.sy2.domain.Article;

import java.util.List;

@Repository
@Mapper
public interface ArticleMapper {
    public Article findById(int id);
    public List<Article> findAll();
}

MyConfig.java:

package springbootsy.sy2.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyConfig implements WebMvcConfigurer {
    @Override
    public void addViewControllers(ViewControllerRegistry registraty){
        registraty.addViewController("/article/findAll").setViewName("articleDetail");
    }
}

ArticleController.java:

package springbootsy.sy2.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import springbootsy.sy2.domain.Article;
import springbootsy.sy2.mapper.ArticleMapper;

import java.util.List;

@Controller
@RequestMapping("/article")
public class ArticleController {
    @Autowired
    private ArticleMapper articleMapper;

    @GetMapping("/findAll")
    public  String findAll(Model model){
        List<Article> articleList = articleMapper.findAll();
        model.addAttribute("articleLists",articleList);
        return "articleList";
    }

    @GetMapping("/findById")
    public String findById(int id,Model model){
        Article article = articleMapper.findById(id);
        model.addAttribute("article",article);
        return "articleDetail";
    }
}

Sy2Application.java:

package springbootsy.sy2;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Sy2Application {

    public static void main(String[] args) {
        SpringApplication.run(Sy2Application.class, args);
    }

}

访问网址：http://localhost:8080/article/findAll

springboot mybatis项目教学