解读

把下面项目结构文件的代码放到你的项目内就可以用，位置随意可用不按我的目录来，不过，文件要都有，亲测有效可用。
切换数据源在第21个文件PersonServiceImpl.java文件内的注解@DataSource(DataSourceType.SLAVE)，前提是把配置文件内的从数据库打开并配置一下地址和用户

1.项目结构和所需文件

123.png

2.配置文件

spring:
  datasource:
      type: com.alibaba.druid.pool.DruidDataSource
      driverClassName: com.mysql.cj.jdbc.Driver
      druid:
        # 主库数据源
        master:
          url: jdbc:mysql://127.0.0.1:3306/ry_vue?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
          username: cheng_jiang_tao
          password: cheng123456
        # 从库数据源
        slave:
          # 从数据源开关/默认关闭
          enabled: false
          url:
          username: 
          password: 
        # 初始连接数
        initialSize: 5
        # 最小连接池数量
        minIdle: 10
        # 最大连接池数量
        maxActive: 20
        # 配置获取连接等待超时的时间
        maxWait: 60000
        # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
        timeBetweenEvictionRunsMillis: 60000
        # 配置一个连接在池中最小生存的时间，单位是毫秒
        minEvictableIdleTimeMillis: 300000
        # 配置一个连接在池中最大生存的时间，单位是毫秒
        maxEvictableIdleTimeMillis: 900000
        # 配置检测连接是否有效
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        webStatFilter:
          enabled: true
        statViewServlet:
          enabled: true
          # 设置白名单，不填则允许所有访问
          allow:
          url-pattern: /druid/*
          # 控制台管理用户名和密码
          login-username: ruoyi
          login-password: 123456
        filter:
          stat:
            enabled: true
            # 慢SQL记录
            log-slow-sql: true
            slow-sql-millis: 1000
            merge-sql: true
          wall:
            config:
              multi-statement-allow: true

# MyBatis配置
mybatis:
  # 搜索指定包别名
  typeAliasesPackage: com.example.**.domain
  # 配置mapper的扫描，找到所有的mapper.xml映射文件
  mapperLocations: classpath*:mapper/**/*Mapper.xml
  # 加载全局的配置文件
  configLocation: classpath:mybatis/mybatis-config.xml

3.在resources创建mybatis-config.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 配置全局属性 -->
    <settings>
        <!-- 使全局的映射器启用或禁用缓存 -->
        <setting name="cacheEnabled"   value="true"   />
        <!-- 使用jdbc的getGeneratedKeys获取数据库自增主键值 -->
        <setting name="useGeneratedKeys" value="true" />
        <!-- 使用列别名替换列名 默认:true -->
<!--        <setting name="useColumnLabel" value="true" />-->
        <!-- 开启驼峰命名转换:Table{create_time} -> Entity{createTime} -->
<!--        <setting name="mapUnderscoreToCamelCase" value="true" />-->
        <!-- 打印查询语句 -->
        <setting name="logImpl" value="STDOUT_LOGGING" />
        <!-- 配置默认的执行器.SIMPLE就是普通执行器;REUSE执行器会重用预处理语句(prepared statements);BATCH执行器将重用语句并执行批量更新 -->
        <setting name="defaultExecutorType"      value="SIMPLE" />
    </settings>

    <typeAliases>
        <package name="com.example.springboot.cheng.domain"/>
    </typeAliases>
</configuration>

4.添加依赖

<!-- 阿里数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.8</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.27</version>
        </dependency>
<!-- SpringBoot集成mybatis框架 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.0</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.9</version>
        </dependency>

5.注解文件DataSource

package com.example.springboot.common.annotation;

import com.example.springboot.common.enums.DataSourceType;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 自定义多数据源切换注解
 *
 * 优先级：先方法，后类，如果方法覆盖了类上的数据源类型，以方法的为准，否则以类上的为准
 */
@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface DataSource
{
    /**
     * 切换数据源名称
     */
    public DataSourceType value() default DataSourceType.MASTER;
}

6.DataSourceAspect.java

package com.example.springboot.common.aspectj;

import java.util.Objects;

import com.example.springboot.common.annotation.DataSource;
import com.example.springboot.datasource.DynamicDataSourceContextHolder;
import com.example.springboot.util.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * 多数据源处理
 */
@Aspect
@Order(1)
@Component
public class DataSourceAspect{
    protected Logger logger = LoggerFactory.getLogger(getClass());

    @Pointcut("@annotation(com.example.springboot.common.annotation.DataSource)"
            + "|| @within(com.example.springboot.common.annotation.DataSource)")
    public void dsPointCut()
    {

    }

    @Around("dsPointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable
    {
        DataSource dataSource = getDataSource(point);

        if (StringUtils.isNotNull(dataSource))
        {
            DynamicDataSourceContextHolder.setDataSourceType(dataSource.value().name());
        }

        try
        {
            return point.proceed();
        }
        finally
        {
            // 销毁数据源 在执行方法之后
            DynamicDataSourceContextHolder.clearDataSourceType();
        }
    }

    /**
     * 获取需要切换的数据源
     */
    public DataSource getDataSource(ProceedingJoinPoint point)
    {
        MethodSignature signature = (MethodSignature) point.getSignature();
        DataSource dataSource = AnnotationUtils.findAnnotation(signature.getMethod(), DataSource.class);
        if (Objects.nonNull(dataSource))
        {
            return dataSource;
        }

        return AnnotationUtils.findAnnotation(signature.getDeclaringType(), DataSource.class);
    }
}

7.DataSourceType.java

package com.example.springboot.common.enums;

/**
 * 数据源
 */
public enum DataSourceType{
    /**
     * 主库
     */
    MASTER,

    /**
     * 从库
     */
    SLAVE
}

8.SpringUtils.java

package com.example.springboot.common;

import com.example.springboot.util.StringUtils;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * spring工具类 方便在非spring管理环境中获取bean
 */
@Component
public final class SpringUtils implements BeanFactoryPostProcessor, ApplicationContextAware {
    /**
     * Spring应用上下文环境
     */
    private static ConfigurableListableBeanFactory beanFactory;

    private static ApplicationContext applicationContext;

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        SpringUtils.beanFactory = beanFactory;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringUtils.applicationContext = applicationContext;
    }

    /**
     * 获取对象
     *
     * @param name
     * @return Object 一个以所给名字注册的bean的实例
     * @throws org.springframework.beans.BeansException
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) throws BeansException {
        return (T) beanFactory.getBean(name);
    }

    /**
     * 获取类型为requiredType的对象
     *
     * @param clz
     * @return
     * @throws org.springframework.beans.BeansException
     */
    public static <T> T getBean(Class<T> clz) throws BeansException {
        T result = (T) beanFactory.getBean(clz);
        return result;
    }

    /**
     * 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
     *
     * @param name
     * @return boolean
     */
    public static boolean containsBean(String name) {
        return beanFactory.containsBean(name);
    }

    /**
     * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
     *
     * @param name
     * @return boolean
     * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
     */
    public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
        return beanFactory.isSingleton(name);
    }

    /**
     * @param name
     * @return Class 注册对象的类型
     * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
     */
    public static Class<?> getType(String name) throws NoSuchBeanDefinitionException {
        return beanFactory.getType(name);
    }

    /**
     * 如果给定的bean名字在bean定义中有别名，则返回这些别名
     *
     * @param name
     * @return
     * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
     */
    public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
        return beanFactory.getAliases(name);
    }

    /**
     * 获取aop代理对象
     *
     * @param invoker
     * @return
     */
    @SuppressWarnings("unchecked")
    public static <T> T getAopProxy(T invoker) {
        return (T) AopContext.currentProxy();
    }

    /**
     * 获取当前的环境配置，无配置返回null
     *
     * @return 当前的环境配置
     */
    public static String[] getActiveProfiles() {
        return applicationContext.getEnvironment().getActiveProfiles();
    }

    /**
     * 获取当前的环境配置，当有多个环境配置时，只获取第一个
     *
     * @return 当前的环境配置
     */
    public static String getActiveProfile() {
        final String[] activeProfiles = getActiveProfiles();
        return StringUtils.isNotEmpty(activeProfiles) ? activeProfiles[0] : null;
    }
}

9.DruidConfig.java

package com.example.springboot.datasource;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.alibaba.druid.spring.boot.autoconfigure.properties.DruidStatProperties;
import com.alibaba.druid.util.Utils;
import com.example.springboot.common.SpringUtils;
import com.example.springboot.common.enums.DataSourceType;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import javax.servlet.*;
import javax.sql.DataSource;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * druid 配置多数据源
 */
@Configuration
public class DruidConfig{
    @Bean
    @ConfigurationProperties("spring.datasource.druid.master")
    public DataSource masterDataSource(DruidProperties druidProperties)
    {
        DruidDataSource dataSource = DruidDataSourceBuilder.create().build();
        return druidProperties.dataSource(dataSource);
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid.slave")
    @ConditionalOnProperty(prefix = "spring.datasource.druid.slave", name = "enabled", havingValue = "true")
    public DataSource slaveDataSource(DruidProperties druidProperties)
    {
        DruidDataSource dataSource = DruidDataSourceBuilder.create().build();
        return druidProperties.dataSource(dataSource);
    }

    @Bean(name = "dynamicDataSource")
    @Primary
    public DynamicDataSource dataSource(DataSource masterDataSource)
    {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceType.MASTER.name(), masterDataSource);
        setDataSource(targetDataSources, DataSourceType.SLAVE.name(), "slaveDataSource");
        return new DynamicDataSource(masterDataSource, targetDataSources);
    }

    /**
     * 设置数据源
     *
     * @param targetDataSources 备选数据源集合
     * @param sourceName 数据源名称
     * @param beanName bean名称
     */
    public void setDataSource(Map<Object, Object> targetDataSources, String sourceName, String beanName)
    {
        try
        {
            DataSource dataSource = SpringUtils.getBean(beanName);
            targetDataSources.put(sourceName, dataSource);
        }
        catch (Exception e)
        {
        }
    }

    /**
     * 去除监控页面底部的广告
     */
    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Bean
    @ConditionalOnProperty(name = "spring.datasource.druid.statViewServlet.enabled", havingValue = "true")
    public FilterRegistrationBean removeDruidFilterRegistrationBean(DruidStatProperties properties)
    {
        // 获取web监控页面的参数
        DruidStatProperties.StatViewServlet config = properties.getStatViewServlet();
        // 提取common.js的配置路径
        String pattern = config.getUrlPattern() != null ? config.getUrlPattern() : "/druid/*";
        String commonJsPattern = pattern.replaceAll("\\*", "js/common.js");
        final String filePath = "support/http/resources/js/common.js";
        // 创建filter进行过滤
        Filter filter = new Filter()
        {
            @Override
            public void init(javax.servlet.FilterConfig filterConfig) throws ServletException
            {
            }
            @Override
            public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
                    throws IOException, ServletException
            {
                chain.doFilter(request, response);
                // 重置缓冲区，响应头不会被重置
                response.resetBuffer();
                // 获取common.js
                String text = Utils.readFromResource(filePath);
                // 正则替换banner, 除去底部的广告信息
                text = text.replaceAll("<a.*?banner\"></a><br/>", "");
                text = text.replaceAll("powered.*?shrek.wang</a>", "");
                response.getWriter().write(text);
            }
            @Override
            public void destroy()
            {
            }
        };
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(filter);
        registrationBean.addUrlPatterns(commonJsPattern);
        return registrationBean;
    }
}

10.DruidProperties.java

package com.example.springboot.datasource;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import com.alibaba.druid.pool.DruidDataSource;

/**
 * druid 配置属性
 */
@Configuration
public class DruidProperties{
    @Value("${spring.datasource.druid.initialSize}")
    private int initialSize;

    @Value("${spring.datasource.druid.minIdle}")
    private int minIdle;

    @Value("${spring.datasource.druid.maxActive}")
    private int maxActive;

    @Value("${spring.datasource.druid.maxWait}")
    private int maxWait;

    @Value("${spring.datasource.druid.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;

    @Value("${spring.datasource.druid.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;

    @Value("${spring.datasource.druid.maxEvictableIdleTimeMillis}")
    private int maxEvictableIdleTimeMillis;

    @Value("${spring.datasource.druid.validationQuery}")
    private String validationQuery;

    @Value("${spring.datasource.druid.testWhileIdle}")
    private boolean testWhileIdle;

    @Value("${spring.datasource.druid.testOnBorrow}")
    private boolean testOnBorrow;

    @Value("${spring.datasource.druid.testOnReturn}")
    private boolean testOnReturn;

    public DruidDataSource dataSource(DruidDataSource datasource)
    {
        /** 配置初始化大小、最小、最大 */
        datasource.setInitialSize(initialSize);
        datasource.setMaxActive(maxActive);
        datasource.setMinIdle(minIdle);

        /** 配置获取连接等待超时的时间 */
        datasource.setMaxWait(maxWait);

        /** 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 */
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);

        /** 配置一个连接在池中最小、最大生存的时间，单位是毫秒 */
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setMaxEvictableIdleTimeMillis(maxEvictableIdleTimeMillis);

        /**
         * 用来检测连接是否有效的sql，要求是一个查询语句，常用select 'x'。如果validationQuery为null，testOnBorrow、testOnReturn、testWhileIdle都不会起作用。
         */
        datasource.setValidationQuery(validationQuery);
        /** 建议配置为true，不影响性能，并且保证安全性。申请连接的时候检测，如果空闲时间大于timeBetweenEvictionRunsMillis，执行validationQuery检测连接是否有效。 */
        datasource.setTestWhileIdle(testWhileIdle);
        /** 申请连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。 */
        datasource.setTestOnBorrow(testOnBorrow);
        /** 归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。 */
        datasource.setTestOnReturn(testOnReturn);
        return datasource;
    }
}

11.DynamicDataSource.java

package com.example.springboot.datasource;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

import javax.sql.DataSource;
import java.util.Map;

/**
 * 动态数据源
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }

    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

12.DynamicDataSourceContextHolder.java

package com.example.springboot.datasource;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 数据源切换处理
 */
public class DynamicDataSourceContextHolder {
    public static final Logger log = LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);

    /**
     * 使用ThreadLocal维护变量，ThreadLocal为每个使用该变量的线程提供独立的变量副本，
     * 所以每一个线程都可以独立地改变自己的副本，而不会影响其它线程所对应的副本。
     */
    private static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<>();

    /**
     * 设置数据源的变量
     */
    public static void setDataSourceType(String dsType) {
        log.info("切换到{}数据源", dsType);
        CONTEXT_HOLDER.set(dsType);
    }

    /**
     * 获得数据源的变量
     */
    public static String getDataSourceType() {
        return CONTEXT_HOLDER.get();
    }

    /**
     * 清空数据源变量
     */
    public static void clearDataSourceType() {
        CONTEXT_HOLDER.remove();
    }
}

13.MyBatisConfig.java

package com.example.springboot.datasource;

import com.example.springboot.util.StringUtils;
import org.apache.ibatis.io.VFS;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.boot.autoconfigure.SpringBootVFS;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.util.ClassUtils;

import javax.sql.DataSource;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;

/**
 * Mybatis支持*匹配扫描包
 */
@Configuration
public class MyBatisConfig{
    @Autowired
    private Environment env;

    static final String DEFAULT_RESOURCE_PATTERN = "**/*.class";

    public static String setTypeAliasesPackage(String typeAliasesPackage)
    {
        ResourcePatternResolver resolver = (ResourcePatternResolver) new PathMatchingResourcePatternResolver();
        MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resolver);
        List<String> allResult = new ArrayList<String>();
        try
        {
            for (String aliasesPackage : typeAliasesPackage.split(","))
            {
                List<String> result = new ArrayList<String>();
                aliasesPackage = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
                        + ClassUtils.convertClassNameToResourcePath(aliasesPackage.trim()) + "/" + DEFAULT_RESOURCE_PATTERN;
                Resource[] resources = resolver.getResources(aliasesPackage);
                if (resources != null && resources.length > 0)
                {
                    MetadataReader metadataReader = null;
                    for (Resource resource : resources)
                    {
                        if (resource.isReadable())
                        {
                            metadataReader = metadataReaderFactory.getMetadataReader(resource);
                            try
                            {
                                result.add(Class.forName(metadataReader.getClassMetadata().getClassName()).getPackage().getName());
                            }
                            catch (ClassNotFoundException e)
                            {
                                e.printStackTrace();
                            }
                        }
                    }
                }
                if (result.size() > 0)
                {
                    HashSet<String> hashResult = new HashSet<String>(result);
                    allResult.addAll(hashResult);
                }
            }
            if (allResult.size() > 0)
            {
                typeAliasesPackage = String.join(",", (String[]) allResult.toArray(new String[0]));
            }
            else
            {
                throw new RuntimeException("mybatis typeAliasesPackage 路径扫描错误,参数typeAliasesPackage:" + typeAliasesPackage + "未找到任何包");
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        return typeAliasesPackage;
    }

    public Resource[] resolveMapperLocations(String[] mapperLocations)
    {
        ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
        List<Resource> resources = new ArrayList<Resource>();
        if (mapperLocations != null)
        {
            for (String mapperLocation : mapperLocations)
            {
                try
                {
                    Resource[] mappers = resourceResolver.getResources(mapperLocation);
                    resources.addAll(Arrays.asList(mappers));
                }
                catch (IOException e)
                {
                    // ignore
                }
            }
        }
        return resources.toArray(new Resource[resources.size()]);
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception
    {
        String typeAliasesPackage = env.getProperty("mybatis.typeAliasesPackage");
        String mapperLocations = env.getProperty("mybatis.mapperLocations");
        String configLocation = env.getProperty("mybatis.configLocation");
        typeAliasesPackage = setTypeAliasesPackage(typeAliasesPackage);
        VFS.addImplClass(SpringBootVFS.class);

        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.setTypeAliasesPackage(typeAliasesPackage);
        sessionFactory.setMapperLocations(resolveMapperLocations(StringUtils.split(mapperLocations, ",")));
        sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(configLocation));
        return sessionFactory.getObject();
    }
}

14.StringUtils.java

package com.example.springboot.util;

import java.util.*;

/**
 * 字符串工具类
 *
 * @author 钟俊 (zhongjun), email: zhongjun@toguide.cn, date: 5/12/2021 2:11 PM
 */
public class StringUtils extends org.apache.commons.lang3.StringUtils {
    /**
     * 空字符串
     */
    private static final String NULLSTR = "";

    /**
     * 下划线
     */
    private static final char SEPARATOR = '_';

    /**
     * 获取参数不为空值
     *
     * @param value defaultValue 要判断的value
     * @return value 返回值
     */
    public static <T> T nvl(T value, T defaultValue) {
        return value != null ? value : defaultValue;
    }

    /**
     * * 判断一个Collection是否为空， 包含List，Set，Queue
     *
     * @param coll 要判断的Collection
     * @return true：为空 false：非空
     */
    public static boolean isEmpty(Collection<?> coll) {
        return isNull(coll) || coll.isEmpty();
    }

    /**
     * * 判断一个Collection是否非空，包含List，Set，Queue
     *
     * @param coll 要判断的Collection
     * @return true：非空 false：空
     */
    public static boolean isNotEmpty(Collection<?> coll) {
        return !isEmpty(coll);
    }

    /**
     * * 判断一个对象数组是否为空
     *
     * @param objects 要判断的对象数组
     *                * @return true：为空 false：非空
     */
    public static boolean isEmpty(Object[] objects) {
        return isNull(objects) || (objects.length == 0);
    }

    /**
     * * 判断一个对象数组是否非空
     *
     * @param objects 要判断的对象数组
     * @return true：非空 false：空
     */
    public static boolean isNotEmpty(Object[] objects) {
        return !isEmpty(objects);
    }

    /**
     * * 判断一个Map是否为空
     *
     * @param map 要判断的Map
     * @return true：为空 false：非空
     */
    public static boolean isEmpty(Map<?, ?> map) {
        return isNull(map) || map.isEmpty();
    }

    /**
     * * 判断一个Map是否为空
     *
     * @param map 要判断的Map
     * @return true：非空 false：空
     */
    public static boolean isNotEmpty(Map<?, ?> map) {
        return !isEmpty(map);
    }

    /**
     * * 判断一个字符串是否为空串
     *
     * @param str String
     * @return true：为空 false：非空
     */
    public static boolean isEmpty(String str) {
        return isNull(str) || NULLSTR.equals(str.trim());
    }

    /**
     * * 判断一个字符串是否为非空串
     *
     * @param str String
     * @return true：非空串 false：空串
     */
    public static boolean isNotEmpty(String str) {
        return !isEmpty(str);
    }

    /**
     * * 判断一个对象是否为空
     *
     * @param object Object
     * @return true：为空 false：非空
     */
    public static boolean isNull(Object object) {
        return object == null;
    }

    /**
     * * 判断一个对象是否非空
     *
     * @param object Object
     * @return true：非空 false：空
     */
    public static boolean isNotNull(Object object) {
        return !isNull(object);
    }

    /**
     * * 判断一个对象是否是数组类型（Java基本型别的数组）
     *
     * @param object 对象
     * @return true：是数组 false：不是数组
     */
    public static boolean isArray(Object object) {
        return isNotNull(object) && object.getClass().isArray();
    }

    /**
     * 去空格
     */
    public static String trim(String str) {
        return (str == null ? "" : str.trim());
    }

    /**
     * 截取字符串
     *
     * @param str   字符串
     * @param start 开始
     * @return 结果
     */
    public static String substring(final String str, int start) {
        if (str == null) {
            return NULLSTR;
        }

        if (start < 0) {
            start = str.length() + start;
        }

        if (start < 0) {
            start = 0;
        }
        if (start > str.length()) {
            return NULLSTR;
        }

        return str.substring(start);
    }

    /**
     * 截取字符串
     *
     * @param str   字符串
     * @param start 开始
     * @param end   结束
     * @return 结果
     */
    public static String substring(final String str, int start, int end) {
        if (str == null) {
            return NULLSTR;
        }

        if (end < 0) {
            end = str.length() + end;
        }
        if (start < 0) {
            start = str.length() + start;
        }

        if (end > str.length()) {
            end = str.length();
        }

        if (start > end) {
            return NULLSTR;
        }

        if (start < 0) {
            start = 0;
        }
        if (end < 0) {
            end = 0;
        }

        return str.substring(start, end);
    }

    /**
     * 字符串转set
     *
     * @param str 字符串
     * @param sep 分隔符
     * @return set集合
     */
    public static final Set<String> str2Set(String str, String sep) {
        return new HashSet<String>(str2List(str, sep, true, false));
    }

    /**
     * 字符串转list
     *
     * @param str         字符串
     * @param sep         分隔符
     * @param filterBlank 过滤纯空白
     * @param trim        去掉首尾空白
     * @return list集合
     */
    public static final List<String> str2List(String str, String sep, boolean filterBlank, boolean trim) {
        List<String> list = new ArrayList<String>();
        if (StringUtils.isEmpty(str)) {
            return list;
        }

        // 过滤空白字符串
        if (filterBlank && StringUtils.isBlank(str)) {
            return list;
        }
        String[] split = str.split(sep);
        for (String string : split) {
            if (filterBlank && StringUtils.isBlank(string)) {
                continue;
            }
            if (trim) {
                string = string.trim();
            }
            list.add(string);
        }

        return list;
    }

    /**
     * 驼峰转下划线命名
     */
    public static String toUnderScoreCase(String str) {
        if (str == null) {
            return null;
        }
        StringBuilder sb = new StringBuilder();
        // 前置字符是否大写
        boolean preCharIsUpperCase = true;
        // 当前字符是否大写
        boolean curreCharIsUpperCase = true;
        // 下一字符是否大写
        boolean nexteCharIsUpperCase = true;
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (i > 0) {
                preCharIsUpperCase = Character.isUpperCase(str.charAt(i - 1));
            } else {
                preCharIsUpperCase = false;
            }

            curreCharIsUpperCase = Character.isUpperCase(c);

            if (i < (str.length() - 1)) {
                nexteCharIsUpperCase = Character.isUpperCase(str.charAt(i + 1));
            }

            if (preCharIsUpperCase && curreCharIsUpperCase && !nexteCharIsUpperCase) {
                sb.append(SEPARATOR);
            } else if ((i != 0 && !preCharIsUpperCase) && curreCharIsUpperCase) {
                sb.append(SEPARATOR);
            }
            sb.append(Character.toLowerCase(c));
        }

        return sb.toString();
    }

    /**
     * 是否包含字符串
     *
     * @param str  验证字符串
     * @param strs 字符串组
     * @return 包含返回true
     */
    public static boolean inStringIgnoreCase(String str, String... strs) {
        if (str != null && strs != null) {
            for (String s : strs) {
                if (str.equalsIgnoreCase(trim(s))) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * 将下划线大写方式命名的字符串转换为驼峰式。如果转换前的下划线大写方式命名的字符串为空，则返回空字符串。 例如：HELLO_WORLD->HelloWorld
     *
     * @param name 转换前的下划线大写方式命名的字符串
     * @return 转换后的驼峰式命名的字符串
     */
    public static String convertToCamelCase(String name) {
        StringBuilder result = new StringBuilder();
        // 快速检查
        if (name == null || name.isEmpty()) {
            // 没必要转换
            return "";
        } else if (!name.contains("_")) {
            // 不含下划线，仅将首字母大写
            return name.substring(0, 1).toUpperCase() + name.substring(1);
        }
        // 用下划线将原始字符串分割
        String[] camels = name.split("_");
        for (String camel : camels) {
            // 跳过原始字符串中开头、结尾的下换线或双重下划线
            if (camel.isEmpty()) {
                continue;
            }
            // 首字母大写
            result.append(camel.substring(0, 1).toUpperCase());
            result.append(camel.substring(1).toLowerCase());
        }
        return result.toString();
    }

    /**
     * 驼峰式命名法 例如：user_name->userName
     */
    public static String toCamelCase(String s) {
        if (s == null) {
            return null;
        }
        s = s.toLowerCase();
        StringBuilder sb = new StringBuilder(s.length());
        boolean upperCase = false;
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);

            if (c == SEPARATOR) {
                upperCase = true;
            } else if (upperCase) {
                sb.append(Character.toUpperCase(c));
                upperCase = false;
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    @SuppressWarnings("unchecked")
    public static <T> T cast(Object obj) {
        return (T) obj;
    }
}

15.测试文件

456.png

16.DataTestController.java

package com.example.springboot.cheng.controller;

import com.example.springboot.cheng.domain.Person;
import com.example.springboot.cheng.domain.SubSign;
import com.example.springboot.cheng.service.IPersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/person")
public class DataTestController {
    @Autowired
    private IPersonService personService;

    @GetMapping("/a01")
    public Object getPersonMsg(Person person){
        return personService.selectList(person);
    }

    @GetMapping("/a02")
    public Object getPersonMsg(SubSign subSign){
        return personService.selectSubSignList(subSign);
    }
}

17.Person.java

package com.example.springboot.cheng.domain;

import lombok.Data;

@Data
public class Person {
    private int id;
    private String name;
    private String age;
    private String sex;
    private String workCompany;
}

18.SubSign.java

package com.example.springboot.cheng.domain;

import lombok.Data;

@Data
public class SubSign {
    private static final long serialVersionUID = 1L;
    /** 签到主键 */
    private Long id;
    /** 用户id */
    private String userId;
    /** 签入时间 */
    private String signInTime;
    /** 签出时间 */
    private String signOutTime;
    /** 创建时间" */
    private String createTime;
}

19.PersonMapper

package com.example.springboot.cheng.mapper;

import com.example.springboot.cheng.domain.Person;
import com.example.springboot.cheng.domain.SubSign;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface PersonMapper {
    List<Person> selectList(Person person);

    List<SubSign> selectSubSignList(SubSign subSign);
}

20.IPersonService

package com.example.springboot.cheng.service;

import com.example.springboot.cheng.domain.Person;
import com.example.springboot.cheng.domain.SubSign;

import java.util.List;

public interface IPersonService {
    List<Person> selectList(Person person);

    List<SubSign> selectSubSignList(SubSign subSign);
}

21.PersonServiceImpl.java

package com.example.springboot.cheng.service.impl;

import com.example.springboot.cheng.domain.Person;
import com.example.springboot.cheng.domain.SubSign;
import com.example.springboot.cheng.mapper.PersonMapper;
import com.example.springboot.cheng.service.IPersonService;
import com.example.springboot.common.annotation.DataSource;
import com.example.springboot.common.enums.DataSourceType;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class PersonServiceImpl implements IPersonService {
    @Autowired
    private PersonMapper personMapper;

    @Override
    public List<Person> selectList(Person person) {
        return personMapper.selectList(person);
    }

    @Override
    @DataSource(DataSourceType.SLAVE)
    public List<SubSign> selectSubSignList(SubSign subSign) {
        return personMapper.selectSubSignList(subSign);
    }
}

22.PersonMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springboot.cheng.mapper.PersonMapper">
    <resultMap id="PersonResult" type="Person">
        <id property="id" column="id"/>
        <result property="name" column="name"    />
        <result property="age" column="age"    />
        <result property="sex" column="sex"    />
        <result property="workCompany" column="work_company"    />
    </resultMap>
    <select id="selectList" parameterType="Person" resultMap="PersonResult">
        select * from person
        <where>
            <if test="id != null and id != ''">id = #{id}</if>
            <if test="name != null and name != ''">name = #{name}</if>
            <if test="age != null and age != ''">age = #{age}</if>
            <if test="sex != null and sex != ''">sex = #{sex}</if>
            <if test="workCompany != null and workCompany != ''">work_company = #{workCompany}</if>
        </where>
    </select>

    <resultMap type="SubSign" id="SubSignResult">
        <result property="id"    column="id"    />
        <result property="userId"    column="user_id"    />
        <result property="signInTime"    column="sign_in_time"    />
        <result property="signOutTime"    column="sign_out_time"    />
        <result property="createTime"    column="create_time"    />
    </resultMap>

    <select id="selectSubSignList" parameterType="SubSign" resultMap="SubSignResult">
        select id, user_id, sign_in_time, sign_out_time,create_time from sub_sign
        <where>
            <if test="id != null  and id != ''"> and id = #{id}</if>
            <if test="userId != null  and userId != ''"> and user_id = #{userId}</if>
            <if test="signInTime != null and signInTime !=''">
                AND LEFT(sign_in_time, 7) = #{signInTime}
            </if>
            <if test="createTime != null and createTime !=''">
                AND LEFT(create_time, 10) = LEFT(#{createTime}, 10)
            </if>
        </where>
    </select>
</mapper>