本文源碼：
一、項目案例簡介
1、多數據簡介
實際的項目中，經常會用到不同的數據庫以滿足項目的實際需求。隨著業務的併發量的不斷增加，一個項目使用多個數據庫：主從複製、讀寫分離、分佈式數據庫等方式，越來越常見。
2、MybatisPlus簡介
MyBatis-Plus（簡稱 MP）是一個MyBatis的增強工具，在MyBatis的基礎上只做增強不做改變，為簡化開發、提高效率而生。
插件特點
無代碼侵入：只做增強不做改變，引入它不會對現有工程產生影響。
強大的 CRUD 操作：通過少量配置即可實現單表大部分 CRUD 操作滿足各類使用需求。
支持 Lambda 形式調用：通過 Lambda 表達式，方便的編寫各類查詢條件。
支持主鍵自動生成：可自由配置，解決主鍵問題。
內置代碼生成器：採用代碼或者 Maven 插件可快速生成各層代碼。
內置分頁插件：基於 MyBatis 物理分頁，開發者無需關心具體操作。
內置性能分析插件：可輸出 Sql 語句以及其執行時間。
二、多數據源案例
1、項目結構
注意：mapper層和mapper.xml層分別放在不同目錄下，以便mybatis掃描加載。
2、多數據源配置
spring:
# 數據源配置
datasource:
type: com.alibaba.druid.pool.DruidDataSource
admin-data:
driverClassName: com.mysql.jdbc.Driver
dbUrl: jdbc:mysql://127.0.0.1:3306/cloud-admin-data?useUnicode=true&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull&useSSL=false
username: root
password: 123
initialSize: 20
maxActive: 100
minIdle: 20
maxWait: 60000
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 30
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 30000
maxEvictableIdleTimeMillis: 60000
validationQuery: SELECT 1 FROM DUAL
testOnBorrow: false
testOnReturn: false
testWhileIdle: true
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
filters: stat,wall
user-data:
driverClassName: com.mysql.jdbc.Driver
dbUrl: jdbc:mysql://127.0.0.1:3306/cloud-user-data?useUnicode=true&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull&useSSL=false
username: root
password: 123
initialSize: 20
maxActive: 100
minIdle: 20
maxWait: 60000
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 30
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 30000
maxEvictableIdleTimeMillis: 60000
validationQuery: SELECT 1 FROM DUAL
testOnBorrow: false
testOnReturn: false
testWhileIdle: true
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
filters: stat,wall
這裡參數的形式是多樣的，只需要配置參數掃描即可。
3、參數掃描類
@Component
@ConfigurationProperties(prefix = "spring.datasource.admin-data")
public class DruidOneParam {
private String dbUrl;
private String username;
private String password;
private String driverClassName;
private int initialSize;
private int maxActive;
private int minIdle;
private int maxWait;
private boolean poolPreparedStatements;
private int maxPoolPreparedStatementPerConnectionSize;
private int timeBetweenEvictionRunsMillis;
private int minEvictableIdleTimeMillis;
private int maxEvictableIdleTimeMillis;
private String validationQuery;
private boolean testWhileIdle;
private boolean testOnBorrow;
private boolean testOnReturn;
private String filters;
private String connectionProperties;
// 省略 GET 和 SET
}
4、配置Druid連接池
@Configuration
@MapperScan(basePackages = {"com.data.source.mapper.one"},sqlSessionTemplateRef = "sqlSessionTemplateOne")
public class DruidOneConfig {
private static final Logger LOGGER = LoggerFactory.getLogger(DruidOneConfig.class) ;
@Resource
private DruidOneParam druidOneParam ;
@Bean("dataSourceOne")
public DataSource dataSourceOne () {
DruidDataSource datasource = new DruidDataSource();
datasource.setUrl(druidOneParam.getDbUrl());
datasource.setUsername(druidOneParam.getUsername());
datasource.setPassword(druidOneParam.getPassword());
datasource.setDriverClassName(druidOneParam.getDriverClassName());
datasource.setInitialSize(druidOneParam.getInitialSize());
datasource.setMinIdle(druidOneParam.getMinIdle());
datasource.setMaxActive(druidOneParam.getMaxActive());
datasource.setMaxWait(druidOneParam.getMaxWait());
datasource.setTimeBetweenEvictionRunsMillis(druidOneParam.getTimeBetweenEvictionRunsMillis());
datasource.setMinEvictableIdleTimeMillis(druidOneParam.getMinEvictableIdleTimeMillis());
datasource.setMaxEvictableIdleTimeMillis(druidOneParam.getMaxEvictableIdleTimeMillis());
datasource.setValidationQuery(druidOneParam.getValidationQuery());
datasource.setTestWhileIdle(druidOneParam.isTestWhileIdle());
datasource.setTestOnBorrow(druidOneParam.isTestOnBorrow());
datasource.setTestOnReturn(druidOneParam.isTestOnReturn());
datasource.setPoolPreparedStatements(druidOneParam.isPoolPreparedStatements());
datasource.setMaxPoolPreparedStatementPerConnectionSize(druidOneParam.getMaxPoolPreparedStatementPerConnectionSize());
try {
datasource.setFilters(druidOneParam.getFilters());
} catch (Exception e) {
LOGGER.error("druid configuration initialization filter", e);
}
datasource.setConnectionProperties(druidOneParam.getConnectionProperties());
return datasource;
}
@Bean
public SqlSessionFactory sqlSessionFactoryOne() throws Exception{
SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
factory.setDataSource(dataSourceOne());
factory.setMapperLocations(resolver.getResources("classpath*:/dataOneMapper/*.xml"));
return factory.getObject();
}
@Bean(name="transactionManagerOne")
public DataSourceTransactionManager transactionManagerOne(){
return new DataSourceTransactionManager(dataSourceOne());
}
@Bean(name = "sqlSessionTemplateOne")
public SqlSessionTemplate sqlSessionTemplateOne() throws Exception {
return new SqlSessionTemplate(sqlSessionFactoryOne());
}
}
注意事項
- MapperScan 在指定數據源上配置;
- SqlSessionFactory 配置掃描的Mapper.xml地址 ;
- DataSourceTransactionManager 配置該數據源的事務;
- 兩個數據源的配置手法相同，不贅述 ;
5、操作案例
- 數據源一：簡單查詢
@Service
public class AdminUserServiceImpl implements AdminUserService {
@Resource
private AdminUserMapper adminUserMapper ;
@Override
public AdminUser selectByPrimaryKey (Integer id) {
return adminUserMapper.selectByPrimaryKey(id) ;
}
}
- 數據源二：事務操作
@Service
public class UserBaseServiceImpl implements UserBaseService {
@Resource
private UserBaseMapper userBaseMapper ;
@Override
public UserBase selectByPrimaryKey(Integer id) {
return userBaseMapper.selectByPrimaryKey(id);
}
// 使用指定數據源的事務
@Transactional(value = "transactionManagerTwo")
@Override
public void insert(UserBase record) {
// 這裡數據寫入失敗
userBaseMapper.insert(record) ;
// int i = 1/0 ;
}
}
注意：這裡的需要指定該數據源配置的事務管理器。
三、MybatisPlus案例
1、核心依賴
<dependency>
<groupid>com.baomidou/<groupid>
<artifactid>mybatis-plus-boot-starter/<artifactid>
<version>3.0.7.1/<version>
<exclusions>
<exclusion>
<groupid>com.baomidou/<groupid>
<artifactid>mybatis-plus-generator/<artifactid>
/<exclusion>
/<exclusions>
/<dependency>
<dependency>
<groupid>com.baomidou/<groupid>
<artifactid>mybatis-plus/<artifactid>
<version>3.0.7.1/<version>
/<dependency>
2、配置文件
mybatis-plus:
mapper-locations: classpath*:/mapper/*.xml
typeAliasesPackage: com.digital.market.*.entity
global-config:
db-config:
id-type: AUTO
field-strategy: NOT_NULL
logic-delete-value: -1
logic-not-delete-value: 0
banner: false
configuration:
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
map-underscore-to-camel-case: true
cache-enabled: false
call-setters-on-nulls: true
jdbc-type-for-null: 'null'
3、分層配置
mapper層
UserBaseMapper extends BaseMapper<userbase>
實現層
UserBaseServiceImpl extends ServiceImpl<userbasemapper> implements UserBaseService
接口層
UserBaseService extends IService<userbase>
/<userbase>/<userbasemapper>/<userbase>
4、mapper.xml文件
<mapper>
<resultmap>
<result>
<result>
<result>
<result>
<result>
<result>
<result>
/<resultmap>
id, user_name, pass_word, phone, email, create_time, update_time, state
<select>
select * from hc_user_base
/<select>
/<mapper>
注意事項
BaseMapper中的方法都已默認實現；這裡也可以自定義實現一些自己的方法。
5、演示接口
@RestController
@RequestMapping("/user")
public class UserBaseController {
private static final Logger LOGGER = LoggerFactory.getLogger(UserBaseController.class) ;
@Resource
private UserBaseService userBaseService ;
@RequestMapping("/info")
public UserBase getUserBase (){
return userBaseService.getById(1) ;
}
@RequestMapping("/queryInfo")
public String queryInfo (){
UserBase userBase1 = userBaseService.getOne(new QueryWrapper<userbase>().orderByDesc("create_time")) ;
LOGGER.info("倒敘取值：{}",userBase1.getUserName());
Integer count = userBaseService.count() ;
LOGGER.info("查詢總數：{}",count);
UserBase userBase2 = new UserBase() ;
userBase2.setId(1);
userBase2.setUserName("spring");
boolean resFlag = userBaseService.saveOrUpdate(userBase2) ;
LOGGER.info("保存更新：{}",resFlag);
Map<string> listByMap = new HashMap<>() ;
listByMap.put("state","0") ;
Collection<userbase> listMap = userBaseService.listByMap(listByMap) ;
LOGGER.info("ListByMap查詢：{}",listMap);
boolean removeFlag = userBaseService.removeById(3) ;
LOGGER.info("刪除數據：{}",removeFlag);
return "success" ;
}
@RequestMapping("/queryPage")
public IPage<userbase> queryPage (){
QueryParam param = new QueryParam() ;
param.setPage(1);
param.setPageSize(10);
param.setUserName("cicada");
param.setState(0);
return userBaseService.queryPage(param) ;
}
@RequestMapping("/pageHelper")
public PageInfo<userbase> pageHelper (){
return userBaseService.pageHelper(new QueryParam()) ;
}
}
/<userbase>/<userbase>/<userbase>/<string>/<userbase>
這裡pageHelper方法是使用PageHelper插件自定義的方法。
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