MyBatis-Ext快速入门实战

MyBatis-Ext快速入门实战攻略

MyBatis-Ext是MyBatis的一个增强工具包，可以提供更加便捷的使用方式，提高开发效率。本文将提供一个MyBatis-Ext的快速入门实战攻略，包含配置、实现及示例演示。

配置

1. 引入MyBatis-Ext的依赖

xml
<dependency>
<groupId>com.github.mybatis-ext</groupId>
<artifactId>mybatis-ext-core</artifactId>
<version>${mybatis-ext.version}</version>
</dependency>

1. 在mybatis-config.xml中添加MyBatis-Ext插件

xml
<configuration>
<plugins>
<plugin interceptor="org.mybatis.ext.interceptor.PaginationInterceptor" />
</plugins>
</configuration>

实现

1. 编写Mapper接口

```java
public interface UserMapper {

   /**
    * 根据用户ID查询用户
    * @param id 用户ID
    * @return User对象
    */
   User getUserById(Long id);

   /**
    * 分页查询所有用户
    * @param pageNum 第几页
    * @param pageSize 每页大小
    * @return 用户列表
    */
   List<User> listAllUsers(Integer pageNum, Integer pageSize);

}
```

1. 编写Mapper XML

```xml

 <select id="getUserById" parameterType="long" resultMap="userMap">
   select * from users where id = #{id}
 </select>

 <select id="listAllUsers" resultMap="userMap">
   select * from users
 </select>

```

1. 使用MyBatis-Ext进行分页插件配置

```java
@Bean
public PageHelper pageHelper(){
PageHelper pageHelper = new PageHelper();
return pageHelper;
}

@Bean
public PaginationInterceptor paginationInterceptor(){
    PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
    return paginationInterceptor;
}

/**
 * 在这里创建 SqlSessionFactory
 * @return
 */
@Bean
public SqlSessionFactoryBean getSqlSessionFactoryBean(){
    SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
    sqlSessionFactoryBean.setDataSource(dataSource());
    sqlSessionFactoryBean.setTypeAliasesPackage("com.sample.model");
    PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
    try {
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath*:mapper/*.xml"));
        sqlSessionFactoryBean.setPlugins(new Interceptor[]{pageHelper(), paginationInterceptor()});
    } catch (Exception e) {
        e.printStackTrace();
    }
    return sqlSessionFactoryBean;
}

```

示例

示例一：根据用户ID查询用户

1. 编写Controller

```java
@RestController
public class UserController {

   @Autowired
   private UserMapper userMapper;

   @RequestMapping(value = "/users/{id}", method = RequestMethod.GET)
   public User getUserById(@PathVariable Long id) {
       return userMapper.getUserById(id);
   }

}
```

1. 发起请求

请求示例：http://localhost:8080/users/1

返回结果：

json
{
"id": 1,
"name": "张三",
"age": 20,
"gender": "男",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
}

示例二：分页查询所有用户

1. 编写Controller

```java
@RestController
public class UserController {

   @Autowired
   private UserMapper userMapper;

   @RequestMapping(value = "/users", method = RequestMethod.GET)
   public List<User> listAllUsers(@RequestParam(defaultValue = "1") Integer pageNum,
                                  @RequestParam(defaultValue = "10") Integer pageSize) {
       return userMapper.listAllUsers(pageNum, pageSize);
   }

}
```

1. 发起请求

请求示例：http://localhost:8080/users?pageNum=2&pageSize=5

返回结果：

json
[
{
"id": 6,
"name": "赵六",
"age": 18,
"gender": "女",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
},
{
"id": 7,
"name": "钱七",
"age": 22,
"gender": "男",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
},
{
"id": 8,
"name": "孙八",
"age": 25,
"gender": "女",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
},
{
"id": 9,
"name": "吴九",
"age": 30,
"gender": "男",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
},
{
"id": 10,
"name": "郑十",
"age": 21,
"gender": "女",
"createTime": "2021-08-18 10:28:32",
"updateTime": "2021-08-18 10:28:32"
}
]

至此，我们完成了一个通过MyBatis-Ext进行快速入门的示例。