《Mycat分布式数据库架构》之应用层连接mycat数据源

前文回顾：

《Mycat分布式数据库架构》之原理及架构
《Mycat分布式数据库架构》之搭建详解
《Mycat分布式数据库架构》之配置详解
《Mycat分布式数据库架构》之数据切分和读写分离
《Mycat分布式数据库架构》之故障切换
《Mycat分布式数据库架构》之数据切分实战
《Mycat分布式数据库架构》之全局自增ID
《Mycat分布式数据库架构》之ER分片
《Mycat分布式数据库架构》之高可用集群
《Mycat分布式数据库架构》之Mycat管理

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1、添加maven依赖

简单使用springboot+mybatis框架来进行演示，创建springboot项目后，在pom.xml文件中引入相关依赖，其实就是使用MySQL数据库驱动来连接mycat，如下。

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
        <dependency>
            <groupId>org.mybatis.spring.bootgroupId>
            <artifactId>mybatis-spring-boot-starterartifactId>
            <version>2.0.0version>
        dependency>

        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <scope>runtimescope>
        dependency>
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <optional>trueoptional>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>
        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-jdbcartifactId>
        dependency>
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2、添加配置文件

创建application.yml文件，内容如下：

#设置应用端口
server:
  port: 8080

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    # Mycat连接
    url: jdbc:mysql://192.168.157.129:8066/mycats?useUnicode=true&characterEncoding=utf-8&autoReconnect=true&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=GMT%2B8
    username: yxc
    password: xxxxxx

# MyBatis
mybatis:
  type-aliases-package: com.example.springbootmybatismycat.domain
  mapper-locations: classpath:/mybatis/*.xml
  #sql打印配置
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
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3、实体类

public class User implements Serializable {
    private static final long serialVersionUID = 5088697673359856350L;
    private Integer userId;
    private String userName;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }
}
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4、dao层

具体源码如下：

public interface UserMapper {
    List<User> selectUserList();
    void addUser(final User user);
}
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5、service

创建Service，源码如下：

public interface UserService {
    List<User> listUser();
    void addUser(final User user);
}
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6、xml

DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springbootmybatismycat.mapper.UserMapper">
    <resultMap type="User" id="UserResult">
        <id property="userId" column="id"/>
        <result property="userName" column="name"/>
    resultMap>

    <select id="selectUserList" parameterType="User" resultMap="UserResult">
        select * from tb_user order by ID asc;
    select>

    <insert id="addUser" parameterType="User">
        insert into tb_user(ID,NAME) values (125,'test');
    insert>
mapper>
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7、Controller

@RestController
@RequestMapping("/cat")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping(value = "listUser")
    public List<User> listUser() {
        return userService.listUser();
    }

    @GetMapping(value = "addUser")
    public String addUser(User user) {
        userService.addUser(user);
        return "添加成功！";
    }
}
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运行结果如下所示：