└─com
    └─steak
        └─transaction
            │  TransactionDemoApplication.java
            │  
            ├─datasource
            │  │  DatasourceChooser.java
            │  │  DatasourceConfiguration.java
            │  │  DatasourceContext.java
            │  │  DatasourceScope.java
            │  │  DynamicDatasourceAspect.java
            │  │  
            │  └─properties
            │          DynamicDatasourceProperties.java
            │          MainDatasourceProperties.java
            │          
            ├─execute
            │      PlaceOrderExecute.java
            │      
            ├─rest
            │      PlaceOrderApi.java
            │      
            ├─result
            │      R.java
            │      
            └─service
                    IntegralService.java
                    OrderService.java
                    StockService.java

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    druid:
      username: root
      password: 123456
      url: jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC
      driver-class-name: com.mysql.cj.jdbc.Driver

dynamic:
  datasource: {
    slave1: {
      username: 'root',
      password: '123456',
      url: ' url: jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC',
      driver-class-name: 'com.mysql.cj.jdbc.Driver'
    },
    slave2: {
      username: 'root',
      password: '123456',
      url: ' url: jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC',
      driver-class-name: 'com.mysql.cj.jdbc.Driver'
    }
  }

/**
 * @author 劉牌
 * @date 2022/3/220:14
 */
@Component
@ConfigurationProperties(prefix = "spring.datasource.druid")
@Data
public class MainDatasourceProperties {
    private String username;
    private String password;
    private String url;
    private String driverClassName;
}

/**
 * @author 劉牌
 * @date 2022/3/213:47
 */
@Component
@ConfigurationProperties(prefix = "dynamic")
@Data
public class DynamicDatasourceProperties {
    private Map<String,Map<String,String>> datasource;
}

/**
 * @author 劉牌
 * @date 2022/3/111:34
 */
@Configuration
@AllArgsConstructor
public class DatasourceConfiguration {

    final MainDatasourceProperties mainDatasourceProperties;
    final DynamicDatasourceProperties dynamicDatasourceProperties;

    @Bean
    public DataSource datasource(){
        Map<Object,Object> datasourceMap = new HashMap<>();
        DatasourceChooser datasourceChooser = new DatasourceChooser();
        /**
         * main database
         */
        DruidDataSource mainDataSource = new DruidDataSource();
        mainDataSource.setUsername(mainDatasourceProperties.getUsername());
        mainDataSource.setPassword(mainDatasourceProperties.getPassword());
        mainDataSource.setUrl(mainDatasourceProperties.getUrl());
        mainDataSource.setDriverClassName(mainDatasourceProperties.getDriverClassName());
        datasourceMap.put("main",mainDataSource);
        /**
         * other database
         */
        Map<String, Map<String, String>> sourceMap = dynamicDatasourceProperties.getDatasource();
        sourceMap.forEach((datasourceName,datasourceMaps) -> {
            DruidDataSource dataSource = new DruidDataSource();
            datasourceMaps.forEach((K,V) -> {
                String setField = "set" + K.substring(0, 1).toUpperCase() + K.substring(1);
                //轉(zhuǎn)換yml文件中帶有-符號(hào)的屬性
                String[] strings = setField.split("");
                StringBuilder newStr = new StringBuilder();
                for (int i = 0; i < strings.length; i++) {
                    if (strings[i].equals("-")) strings[i + 1] = strings[i + 1].toUpperCase();
                    if (!strings[i].equals("-")) newStr.append(strings[i]);
                }
                try {
                    DruidDataSource.class.getMethod(newStr.toString(),String.class).invoke(dataSource,V);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            });
            datasourceMap.put(datasourceName,dataSource);
        });
        //設(shè)置目標(biāo)數(shù)據(jù)源
        datasourceChooser.setTargetDataSources(datasourceMap);
        //設(shè)置默認(rèn)數(shù)據(jù)源
        datasourceChooser.setDefaultTargetDataSource(mainDataSource);
        return datasourceChooser;
    }
}

/**
 * @author 劉牌
 * @date 2022/3/112:21
 */
public class DatasourceChooser extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DatasourceContext.getDatasource();
    }
}

package org.springframework.jdbc.datasource.lookup;

public abstract class AbstractRoutingDataSource extends AbstractDataSource implements InitializingBean {
    @Nullable
    private Map<Object, DataSource> resolvedDataSources;
    public AbstractRoutingDataSource() {
    }
    protected DataSource determineTargetDataSource() {
        Object lookupKey = this.determineCurrentLookupKey();
        DataSource dataSource = (DataSource)this.resolvedDataSources.get(lookupKey);
    }

    @Nullable
    protected abstract Object determineCurrentLookupKey();
}

/**
 * @author 劉牌
 * @date 2022/3/112:22
 */
public class DatasourceContext {
    private static final ThreadLocal<String> threadLocal = new ThreadLocal<>();
    public static void setDatasource(String key){
        threadLocal.set(key);
    }
    public static String getDatasource(){
        return threadLocal.get();
    }
}

/**
 * @author 劉牌
 * @date 2022/3/111:22
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DatasourceScope {
    String scope() default "main";
}

/**
 * @author 劉牌
 * @date 2022/3/111:34
 */
@Aspect
@Component
public class DynamicDatasourceAspect {

    @Pointcut("@annotation(dataSourceScope)")
    public void dynamicPointcut(DatasourceScope dataSourceScope){}

    @Around(value = "dynamicPointcut(dataSourceScope)", argNames = "joinPoint,dataSourceScope")
    public Object dynamicAround(ProceedingJoinPoint joinPoint , DatasourceScope dataSourceScope) throws Throwable {
        String scope = dataSourceScope.scope();
        DatasourceContext.setDatasource(scope);
        return joinPoint.proceed();
    }
}

/**
 * @author 劉牌
 * @date 2022/3/19:49
 */
@Service
@AllArgsConstructor
public class OrderService {
    
    private JdbcTemplate jdbcTemplate;
    
    @DatasourceScope(scope = "slave1")
    public R saveOrder(Integer userId , Integer commodityId){
        String sql = "INSERT INTO `order`(user_id,commodity_id) VALUES("+userId+","+commodityId+")";
        jdbcTemplate.execute(sql);
        return R.builder().code(200).msg("save order success").build();
    }
}