在Java中，我比较ORM熟悉的只有Hibernate和Mybatis,其他的并未实践使用过，在这二者之间我更喜欢Mybatis,因为它精简、灵活(毕竟我是上年纪的程序员，喜欢自己写SQL)。
刚才有提到Mybatis，但是这里的重点是介绍Mybatis-Plus，它是Mybatis的增强版，如果要了解Mybatis的细节的话请点击这里。
简介
据MyBatis-Plus官网介绍，MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。这看上去挺香的，所以必须得尝尝。
这里涉及到的环境、组件如下:
- MariaDB 10.3.10
- Windows 10
- IntelliJ IDEA 2019.3.1
- 64 bit JDK 1.8.0_231
- Spring Boot 2.2.3.RELEASE
- Lombok 1.18.10
- Knife4j 2.0.1
- Mybatis-plus 3.3.0
- Druid
Spring Boot 整合Mybatis-Plus
我之前一直是直接用的Mybatis,但是作为喜欢偷懒的人，当然得想办法来提高我们的效率，所以就想着用Mybatis-Plus来省去一些单表的CRUD操作再结合MyBatis-Plus配套的AutoGenerator代码生成器，就能为我们节省不少时间。
引入依赖包
首先，我们得引入Mybatis-Plus和mariadb-java-client等几个包:
com.github.xiaoymin
knife4j-spring-boot-starter
2.0.1
com.baomidou
mybatis-plus-boot-starter
3.3.0
org.mariadb.jdbc
mariadb-java-client
2.5.3
在application.yml配置我们的数据库连接信息
spring:
datasource:
driver-class-name: org.mariadb.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/nacos_config?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
username: root
password: root
minimum-idle: 5
maximum-pool-size: 50
auto-commit: true
idle-timeout: 30000
max-lifetime: 1800000
connection-timeout: 30000
connection-test-query: SELECT 1这里我新建一个名为User的实体,具体属性如下:
@Data
@Builder
@TableName("users")
public class User {
private String username;
private String password;
private int enabled;
}新建一个UserMapper接口:
public interface UserMapper extends BaseMapper {
} 在我们的启动类加上@MapperScan来指定我们的Mapper扫描目录:
@MapperScan("com.eyiadmin.demo.mapper")
我新建一个单元测试，来试试我们的UserMapper的selectList:
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserTests {
@Autowired
private UserMapper userMapper;
@Test
public void testUser() {
List userList = userMapper.selectList(null);
userList.forEach(System.out::println);
}
} 会看到Mybatis-Plus为我取出的数据:
2020-01-20 09:44:14.125 TRACE org.apache.ibatis.logging.jdbc.BaseJdbcLogger.trace(BaseJdbcLogger.java:149) 2CNU7X5OLAUE004 --- [ main] c.e.d.m.U.selectList : <== Columns: username, password, enabled
2020-01-20 09:44:14.125 TRACE org.apache.ibatis.logging.jdbc.BaseJdbcLogger.trace(BaseJdbcLogger.java:149) 2CNU7X5OLAUE004 --- [ main] c.e.d.m.U.selectList : <== Row: nacos, $2a$10$EuWPZHzz32dJN7jexM34MOeYirDdFAZm2kuWj7VEOJhhZkDrxfvUu, 1
2020-01-20 09:44:14.131 DEBUG org.apache.ibatis.logging.jdbc.BaseJdbcLogger.debug(BaseJdbcLogger.java:143) 2CNU7X5OLAUE004 --- [ main] c.e.d.m.U.selectList : <== Total: 1
User(username=nacos, password=$2a$10$EuWPZHzz32dJN7jexM34MOeYirDdFAZm2kuWj7VEOJhhZkDrxfvUu, enabled=1)我们再试试Mybatis-Plus为什么封装的Insert:
@Test
public void TestUserInsert() {
int row = userMapper.insert(User.builder().password("aaaa").username("bbbb").enabled(1).build());
Assert.assertEquals(row, 1);
}可以看到日志:
2020-01-20 09:51:32.021 DEBUG org.apache.ibatis.logging.jdbc.BaseJdbcLogger.debug(BaseJdbcLogger.java:143) 2CNU7X5OLAUE004 --- [ main] c.e.d.m.U.insert : ==> Preparing: INSERT INTO users ( username, password, enabled ) VALUES ( ?, ?, ? )
2020-01-20 09:51:32.036 DEBUG org.apache.ibatis.logging.jdbc.BaseJdbcLogger.debug(BaseJdbcLogger.java:143) 2CNU7X5OLAUE004 --- [ main] c.e.d.m.U.insert : ==> Parameters: bbbb(String), aaaa(String), 1(Integer)其他高端操作请阅读相关文档
https://mp.baomidou.com/guide/quick-start.html
Spring Boot整合Druid数据库连接池
在Spring Boot 2.X默认使用了HikariCP作为数据库连接池,据说hikariCP性能最高(hikariCP>druid>dbcp>c3p0),但是我更喜欢Druid全面的功能和毫不逊色的性能。
开撸吧，首先当然还是引入我们的需要的Druid依赖包:
com.alibaba
druid-spring-boot-starter
1.1.21
接下来就是修改我们的的application.yml配置:
spring:
datasource:
driver-class-name: org.mariadb.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/nacos_config?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
username: root
password: root
### 连接池配置
druid:
initial-size: 50
max-active: 200
min-idle: 50
max-wait: 50
validation-query: SELECT 1可以看到我们的日志信息为:
2020-01-20 10:14:54.581 INFO com.alibaba.druid.pool.DruidDataSource.close(DruidDataSource.java:2003) 2CNU7X5OLAUE004 --- [extShutdownHook] c.a.d.p.DruidDataSource : {dataSource-1} closing ...
2020-01-20 10:14:54.691 INFO com.alibaba.druid.pool.DruidDataSource.close(DruidDataSource.java:2075) 2CNU7X5OLAUE004 --- [extShutdownHook] c.a.d.p.DruidDataSource : {dataSource-1} closed现在我们增加一个Controller来获取Druid的监控数据:
@RestController
public class DruidStatController {
@GetMapping("/druid/status")
public Object druidStat(){
// DruidStatManagerFacade#getDataSourceStatDataList 该方法可以获取所有数据源的监控数据，除此之外 DruidStatManagerFacade 还提供了一些其他方法，你可以按需选择使用。
return DruidStatManagerFacade.getInstance().getDataSourceStatDataList();
}
}访问
http://localhost:8080/druid/status可以得到一个json:
[{
"Identity": 1914285129,
"Name": "DataSource-1914285129",
"DbType": "mysql",
"DriverClassName": "org.mariadb.jdbc.Driver",
"URL": "jdbc:mysql://127.0.0.1:3306/nacos_config?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true",
"UserName": "root",
"FilterClassNames": [],
"WaitThreadCount": 0,
"NotEmptyWaitCount": 0,
"NotEmptyWaitMillis": 0,
"PoolingCount": 50,
"PoolingPeak": 50,
"PoolingPeakTime": "2020-01-20T02:26:22.466+0000",
"ActiveCount": 0,
"ActivePeak": 0,
"ActivePeakTime": null,
"InitialSize": 50,
"MinIdle": 50,
"MaxActive": 200,
"QueryTimeout": 0,
"TransactionQueryTimeout": 0,
"LoginTimeout": 0,
"ValidConnectionCheckerClassName": null,
"ExceptionSorterClassName": null,
"TestOnBorrow": false,
"TestOnReturn": false,
"TestWhileIdle": true,
"DefaultAutoCommit": true,
"DefaultReadOnly": null,
"DefaultTransactionIsolation": null,
"LogicConnectCount": 0,
"LogicCloseCount": 0,
"LogicConnectErrorCount": 0,
"PhysicalConnectCount": 50,
"PhysicalCloseCount": 0,
"PhysicalConnectErrorCount": 0,
"DiscardCount": 0,
"ExecuteCount": 0,
"ExecuteUpdateCount": 0,
"ExecuteQueryCount": 0,
"ExecuteBatchCount": 0,
"ErrorCount": 0,
"CommitCount": 0,
"RollbackCount": 0,
"PSCacheAccessCount": 0,
"PSCacheHitCount": 0,
"PSCacheMissCount": 0,
"StartTransactionCount": 0,
"TransactionHistogram": [0, 0, 0, 0, 0, 0, 0],
"ConnectionHoldTimeHistogram": [0, 0, 0, 0, 0, 0, 0, 0],
"RemoveAbandoned": false,
"ClobOpenCount": 0,
"BlobOpenCount": 0,
"KeepAliveCheckCount": 0,
"KeepAlive": false,
"FailFast": false,
"MaxWait": 50,
"MaxWaitThreadCount": -1,
"PoolPreparedStatements": false,
"MaxPoolPreparedStatementPerConnectionSize": 10,
"MinEvictableIdleTimeMillis": 1800000,
"MaxEvictableIdleTimeMillis": 25200000,
"LogDifferentThread": true,
"RecycleErrorCount": 0,
"PreparedStatementOpenCount": 0,
"PreparedStatementClosedCount": 0,
"UseUnfairLock": true,
"InitGlobalVariants": false,
"InitVariants": false
}]我们还可以打开stat-view-servlet,需要加入如下配置:
spring:
datasource:
druid:
stat-view-servlet:
enabled: true
login-username: admin
login-password: admin
这是启动后，访问
http://localhost:8080/druid/index.html页面就会跳转到登录页面,输入我们配置的用户名和密码admin/admin:
可以看到Druid提供的功能是比较全面的，另外在第三张图可以看到我们的相关参数，大家也可以参照这个来配置连接池。
MyBatis-Plus的代码生成器
Mybatis有Generator工具为我们提高编码效率，MyBatis-Plus也不示弱，它也提供有MyBatis-Plus AutoGenerator 。在上面的简单实体只有3个属性，假如有几十个属性怎么办呢？这时候AutoGenerator就可以帮我们一个大忙。首先引入所需包:
com.baomidou
mybatis-plus-generator
3.3.0
org.apache.velocity
velocity-engine-core
2.1
具体使用方式，可以去`mybatis-plus`官网查看详细教程
Knife4j的使用
这里我引入了Knife4j包:
com.github.xiaoymin
knife4j-spring-boot-starter
2. 新建一个SwaggerConfiguration类配置我们的Swagger:
@Configuration
@EnableSwagger2
@EnableKnife4j
@Import(BeanValidatorPluginsConfiguration.class)
public class SwaggerConfiguration {
@Bean("createRestApi")
public Docket createRestApi() {
return new Docket(DocumentationType.SWAGGER_2)
.apiInfo( new ApiInfoBuilder()
//页面标题
.title("Demo Web Api文档")
//创建人
.contact(new Contact("eyiadmin", "https://springfox.github.io/springfox/", "eyiadmin@163.com"))
.version("1.0")
.description("Demo Web Api文档")
.build())
.select()
//API接口所在的包位置
.apis(RequestHandlerSelectors.basePackage("com.eyiadmin.demo.controller"))
.paths(PathSelectors.any())
.build();
}
}新建一个名为UserController的Controller:
@RequestMapping("/v1/user")
@RestController
@Api(tags = "User API展示")
public class UserController {
@Autowired
UserMapper userMapper;
@GetMapping("/list")
public ResponseResult getUserList()
{
return ResponseResult.success(userMapper.selectList(null));
}
}启动起来，访问localhost:8080/doc.html:
调用我们的接口，可以看到Druid监控到了我们SQL语句的执行情况
过于Swagger也可以看看我之前的一篇文章Spring Boot集成Swagger