详解spring cloud config实现datasource的热部署

@RefreshScope 
@Configuration// 配置数据源 
public class DataSourceConfigure { 
 
  @Bean 
  @RefreshScope// 刷新配置文件 
  @ConfigurationProperties(prefix="spring.datasource") // 数据源的自动配置的前缀 
  public DataSource dataSource(){ 
    return DataSourceBuilder.create().build(); 
  } 
} 

package com.chhliu.springcloud.config;  
import java.sql.SQLException; 
import javax.sql.DataSource; 
import org.springframework.beans.factory.annotation.Value; 
import org.springframework.cloud.context.config.annotation.RefreshScope; 
import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.context.annotation.Primary;  
import com.alibaba.druid.pool.DruidDataSource; 
import lombok.extern.slf4j.Slf4j; 
 
/** 
 * 
 * 描述：如果不使用代码手动初始化DataSource的话，监控界面的SQL监控会没有数据("是spring boot的bug???") 
 * @author chhliu 
 * 创建时间：2017年2月9日 下午7:33:08 
 * @version 1.2.0 
 */ 
@Slf4j 
@Configuration 
@RefreshScope 
public class DruidConfiguration { 
  @Value("${spring.datasource.url}") 
  private String dbUrl; 
  @Value("${spring.datasource.username}") 
  private String username; 
  @Value("${spring.datasource.password}") 
  private String password; 
  @Value("${spring.datasource.driverClassName}") 
  private String driverClassName; 
  @Value("${spring.datasource.initialSize}") 
  private int initialSize; 
  @Value("${spring.datasource.minIdle}") 
  private int minIdle; 
  @Value("${spring.datasource.maxActive}") 
  private int maxActive; 
  @Value("${spring.datasource.maxWait}") 
  private int maxWait; 
  @Value("${spring.datasource.timeBetweenEvictionRunsMillis}") 
  private int timeBetweenEvictionRunsMillis; 
  @Value("${spring.datasource.minEvictableIdleTimeMillis}") 
  private int minEvictableIdleTimeMillis; 
  @Value("${spring.datasource.validationQuery}") 
  private String validationQuery; 
  @Value("${spring.datasource.testWhileIdle}") 
  private boolean testWhileIdle; 
  @Value("${spring.datasource.testOnBorrow}") 
  private boolean testOnBorrow; 
  @Value("${spring.datasource.testOnReturn}") 
  private boolean testOnReturn; 
  @Value("${spring.datasource.poolPreparedStatements}") 
  private boolean poolPreparedStatements; 
  @Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}") 
  private int maxPoolPreparedStatementPerConnectionSize; 
  @Value("${spring.datasource.filters}") 
  private String filters; 
  @Value("${spring.datasource.connectionProperties}") 
  private String connectionProperties; 
  @Value("${spring.datasource.useGlobalDataSourceStat}") 
  private boolean useGlobalDataSourceStat; 
 
  @Bean   //声明其为Bean实例 
  @Primary //在同样的DataSource中，首先使用被标注的DataSource 
  @RefreshScope 
  public DataSource dataSource(){ 
    DruidDataSource datasource = new DruidDataSource(); 
    datasource.setUrl(this.dbUrl); 
    datasource.setUsername(username); 
    datasource.setPassword(password); 
    datasource.setDriverClassName(driverClassName); 
 
    //configuration 
    datasource.setInitialSize(initialSize); 
    datasource.setMinIdle(minIdle); 
    datasource.setMaxActive(maxActive); 
    datasource.setMaxWait(maxWait); 
    datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis); 
    datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis); 
    datasource.setValidationQuery(validationQuery); 
    datasource.setTestWhileIdle(testWhileIdle); 
    datasource.setTestOnBorrow(testOnBorrow); 
    datasource.setTestOnReturn(testOnReturn); 
    datasource.setPoolPreparedStatements(poolPreparedStatements); 
    datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize); 
    datasource.setUseGlobalDataSourceStat(useGlobalDataSourceStat); 
    try { 
      datasource.setFilters(filters); 
    } catch (SQLException e) { 
      log.error("druid configuration initialization filter: "+ e); 
    } 
    datasource.setConnectionProperties(connectionProperties); 
    return datasource; 
  } 
} 

@ConfigurationProperties(prefix = "endpoints.refresh", ignoreUnknownFields = false) 
@ManagedResource 
public class RefreshEndpoint extends AbstractEndpoint<Collection<String>> { 
   private ContextRefresher contextRefresher; 
   public RefreshEndpoint(ContextRefresher contextRefresher) { 
    super("refresh"); 
    this.contextRefresher = contextRefresher; 
  }  
  @ManagedOperation 
  public String[] refresh() { 
    Set<String> keys = contextRefresher.refresh(); 
    return keys.toArray(new String[keys.size()]); 
  } 
   @Override 
  public Collection<String> invoke() { 
    return Arrays.asList(refresh()); 
  }  
} 

private RefreshScope scope; 
   public ContextRefresher(ConfigurableApplicationContext context, RefreshScope scope) { 
    this.context = context; 
    this.scope = scope; 
  }  
  public synchronized Set<String> refresh() { 
    Map<String, Object> before = extract( 
        this.context.getEnvironment().getPropertySources());// 1、before，加载提取配置文件 
    addConfigFilesToEnvironment();// 2、将配置文件加载到环境中 
    Set<String> keys = changes(before, 
        extract(this.context.getEnvironment().getPropertySources())).keySet();// 3、替换原来环境变量中的值 
    this.context.publishEvent(new EnvironmentChangeEvent(keys));// 4、发布变更事件， 
    this.scope.refreshAll(); 
    return keys; 
  }