ZB-045-01Spring生态系统

目标

  • 在 Spring 容器中引入 Bean
  • Spring + Mybatis(H2/MySQL/Postgres)
  • 模版引擎 后端渲染HTML
  • 前后端分离和后端渲染

初始项目结构如下仓库内容

后端开发三层

  • Controller
  • Service
  • Dao
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    HTTP
    ^
    |   |
        v
________________
    Controller 只做和HTTP请求相关

    Service 具体的业务逻辑 业务代码

    Dao  只做数据库
________________
    ^
    |   |
        v
    db数据库

配置MyBatis

001MyBatis依赖

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搜索 springboot mybatis starter
得到 https://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/
找到依赖，添加到pom.xml

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

002数据库依赖，我们先用h2

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搜索 h2 maven
得到 https://mvnrepository.com/artifact/com.h2database/h2/1.4.200
找到依赖，添加到pom.xml

<!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.200</version>
    <!--注释掉这句 -->
    <!--<scope>test</scope>-->
</dependency>

003添加 src/main/resources/application.properties

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spring.datasource.url=jdbc:h2:file:./target/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=org.h2.Driver
mybatis.config-location=classpath:db/mybatis/config.xml

004 新建数据库初始化文件

src/main/resources/db/migration/V1__CreateTables.sql

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create table user(
  id bigint primary key auto_increment,
  name varchar(100)
);

create table match(
  id bigint primary key auto_increment,
  user_id bigint,
  score int
);

insert into user(id,name) values(1,'AAA');
insert into user(id,name) values(2,'BBB');
insert into user(id,name) values(3,'CCC');


insert into match(id,user_id,score) values(1,1,1000);
insert into match(id,user_id,score) values(2,1,2000);
insert into match(id,user_id,score) values(3,2,500);
insert into match(id,user_id,score) values(4,3,300);

005 安装 flyway 数据库迁移工具

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# pom.xml 里添加
<plugin>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-maven-plugin</artifactId>
    <version>6.0.7</version>
</plugin>


#配置用户名密码
<plugin>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-maven-plugin</artifactId>
    <version>6.0.7</version>
    <configuration>
        <url>jdbc:h2:file:${project.basedir}/target/test</url>
        <user>root</user>
        <password>root</password>
    </configuration>
</plugin>

006点击maven里 plugin里的 flyway –> migrate 运行 此时数据库初始化完成

007 配置 MyBatis

  • 修改src/main/resources/application.properties.xml
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spring.datasource.url=jdbc:h2:file:.target/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=org.h2.Driver
# 配置mybatis
mybatis.config-location=classpath:db/mybatis/config.xml
  • 新建 src/main/resources/db/mybatis/config.xml
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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>
    <mappers>
        <mapper resource="db/mybatis/MyMapper.xml"/>
    </mappers>
</configuration>

008创建 Mapper和 Entity

  • 创建 src/main/java/dao/UserMappper.java
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@Mapper
public interface UserMapper {
    @Select("select * from user where id = #{id}")
    public User getUserById(@Param("id") Integer id);
}
  • 创建 src/main/java/entity/User.java
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public class User {
    private Integer id;
    private String name;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

009 新建 src/main/resources/db/mybatis/MyMapper.xml

  • 搜 mybatis 入门文档抄过来
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<?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 namespace="org.mybatis.example.BlogMapper">
    <!-- 你是注解方式写的sql -->
</mapper>

010 修改 config.xml

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--<settings>-->
        <!--<setting name="logImpl" value="LOG4J"/>-->
    <!--</settings>-->
    <mappers>
        <mapper resource="db/mybatis/MyMapper.xml"/>
        <mapper class="hello.dao.UserMapper"/>
    </mappers>
</configuration>

如何在 Spring 中使用 Bean

@Service

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@Service
public class RankService {
    @Autowired
    private UserMapper userMapper;

    @Autowired
    RankDao rankDao;

    public void doService(){

    }
}

待更新

模版引擎

搜索freemarker springboot starter

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<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>

新建 rescources/templates/index.ftl

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<head>
    <title>排行榜</title>
</head>
<body>
<h1>排行榜！</h1>
<table>
    <tr>
        <th>排名</th>
        <th>名字</th>
        <th>分数</th>
    </tr>

   <#list items as item>
       <tr>
           <td>${item?index}</td>
           <td>${item.user.name}</td>
           <td>${item.score}</td>
       </tr>
   </#list>

</table>
</body>

HelloController.java

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@RequestMapping("/rank2")
public ModelAndView rank2() {
    List<RankItem> items = rankService.doService();
    HashMap<String,Object> model = new HashMap<>();
    model.put("items",items);
    // 自动去 templates目录找 index.ftl
    return new ModelAndView("index",model);
}