关于spring cloud config的基本使用,前面的博客中已经说过了,如果不了解的话,请先看以前的博客
spring cloud config整合gitlab搭建分布式的配置中心
spring cloud config分布式配置中心的高可用
今天,我们的重点是如何实现数据源的热部署。
1、在客户端配置数据源
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@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();
}
}
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通过上面的几个步骤,就可以实现在gitlab上修改配置文件,刷新后,服务器不用重启,新的数据源就会生效。
2、自定义数据源的热部署
当我们使用spring boot集成druid,我们需要手动来配置数据源,代码如下:
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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;
}
}
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通过上面的示例,也可以实现数据源的动态刷新。接下来,我们就来看看,spring cloud config是怎么来实现数据源的热部署的。
从前面的博客中,我们不难发现,要想实现动态刷新,关键点就在post refresh的请求上,那我们就从刷新配置文件开始。
当我们post刷新请求的时候,这个请求会被actuator模块拦截,这点从启动的日志文件中就可以看出
Mapped "{[/refresh || /refresh.json],methods=[POST]}" onto public java.lang.Object org.springframework.cloud.endpoint.GenericPostableMvcEndpoint.invoke()
接下来,我们就来看actuator定义的EndPoint,然后我们就找到了RefreshEndpoint这个类,该类的源码如下:
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@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());
}
}
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从上面的源码,我们可以看到,重点在ContextRefresher这个类上,由于这个类太长了,下面把这个类的部分源码贴出来:
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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;
}
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从上面的代码不难看出,重点经历了4个步骤,上面代码中已标注。
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:http://blog.csdn.net/liuchuanhong1/article/details/75446850