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实际的项目中,经常会用到不同的数据库以满足项目的实际需求。随着业务的并发量的不断增加,一个项目使用多个数据库:主从复制、读写分离、分布式数据库等方式,越来越常见。
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。
插件特点
无代码侵入:只做增强不做改变,引入它不会对现有工程产生影响。
强大的 CRUD 操作:通过少量配置即可实现单表大部分 CRUD 操作满足各类使用需求。
支持 Lambda 形式调用:通过 Lambda 表达式,方便的编写各类查询条件。
支持主键自动生成:可自由配置,解决主键问题。
内置代码生成器:采用代码或者 Maven 插件可快速生成各层代码。
内置分页插件:基于 MyBatis 物理分页,开发者无需关心具体操作。
内置性能分析插件:可输出 Sql 语句以及其执行时间。
注意:mapper层和mapper.xml层分别放在不同目录下,以便mybatis扫描加载。
spring:
# 数据源配置
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
这里参数的形式是多样的,只需要配置参数扫描即可。
@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
}
@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());
}
}
注意事项
@Service
public class AdminUserServiceImpl implements AdminUserService {
@Resource
private AdminUserMapper adminUserMapper ;
@Override
public AdminUser selectByPrimaryKey (Integer id) {
return adminUserMapper.selectByPrimaryKey(id) ;
}
}
@Service
public class UserBaseServiceImpl implements UserBaseService {
@Resource
private UserBaseMapper userBaseMapper ;
@Override
public UserBase selectByPrimaryKey(Integer id) {
return userBaseMapper.selectByPrimaryKey(id);
}
// 使用指定数据源的事务
@Transactional(value = "transactionManagerTwo")
@Override
public void insert(UserBase record) {
// 这里数据写入失败
userBaseMapper.insert(record) ;
// int i = 1/0 ;
}
}
注意:这里的需要指定该数据源配置的事务管理器。
com.baomidou
mybatis-plus-boot-starter
3.0.7.1
com.baomidou
mybatis-plus-generator
com.baomidou
mybatis-plus
3.0.7.1
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'
mapper层
UserBaseMapper extends BaseMapper
实现层
UserBaseServiceImpl extends ServiceImpl implements UserBaseService
接口层
UserBaseService extends IService
id, user_name, pass_word, phone, email, create_time, update_time, state
注意事项
BaseMapper中的方法都已默认实现;这里也可以自定义实现一些自己的方法。
@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().orderByDesc("create_time")) ;
LOGGER.info("倒叙取值:{}",userBase1.getUserName());
Integer count = userBaseService.count() ;
LOGGER.info("查询总数:{}",count);
UserBase userBase2 = new UserBase() ;
userBase2.setId(1);
userBase2.setUserName("spring");
boolean resFlag = userBaseService.saveOrUpdate(userBase2) ;
LOGGER.info("保存更新:{}",resFlag);
Map listByMap = new HashMap<>() ;
listByMap.put("state","0") ;
Collection listMap = userBaseService.listByMap(listByMap) ;
LOGGER.info("ListByMap查询:{}",listMap);
boolean removeFlag = userBaseService.removeById(3) ;
LOGGER.info("删除数据:{}",removeFlag);
return "success" ;
}
@RequestMapping("/queryPage")
public IPage 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 pageHelper (){
return userBaseService.pageHelper(new QueryParam()) ;
}
}
这里pageHelper方法是使用PageHelper插件自定义的方法。
GitHub·地址
https://github.com/cicadasmile/middle-ware-parent
GitEE·地址
https://gitee.com/cicadasmile/middle-ware-parent