關(guān)于spring cloud config的基本使用，前面的博客中已經(jīng)說過了，如果不了解的話，請(qǐng)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，我們的重點(diǎn)是如何實(shí)現(xiàn)數(shù)據(jù)源的熱部署。
1、在客戶端配置數(shù)據(jù)源
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@RefreshScope@Configuration// 配置數(shù)據(jù)源 public class DataSourceConfigure { @Bean @RefreshScope// 刷新配置文件 @ConfigurationProperties(prefix="spring.datasource") // 數(shù)據(jù)源的自動(dòng)配置的前綴 public DataSource dataSource(){ return DataSourceBuilder.create().build(); } } |
通過上面的幾個(gè)步驟，就可以實(shí)現(xiàn)在gitlab上修改配置文件，刷新后，服務(wù)器不用重啟，新的數(shù)據(jù)源就會(huì)生效。
2、自定義數(shù)據(jù)源的熱部署
當(dāng)我們使用spring boot集成druid，我們需要手動(dòng)來配置數(shù)據(jù)源，代碼如下：
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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：如果不使用代碼手動(dòng)初始化DataSource的話，監(jiān)控界面的SQL監(jiān)控會(huì)沒有數(shù)據(jù)("是spring boot的bug???") * @author chhliu * 創(chuàng)建時(shí)間：2017年2月9日 下午7:33:08 * @version 1.2.0 */@Slf4j@Configuration@RefreshScopepublic 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 //聲明其為Bean實(shí)例 @Primary //在同樣的DataSource中，首先使用被標(biāo)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; } } |
通過上面的示例，也可以實(shí)現(xiàn)數(shù)據(jù)源的動(dòng)態(tài)刷新。接下來，我們就來看看，spring cloud config是怎么來實(shí)現(xiàn)數(shù)據(jù)源的熱部署的。
從前面的博客中，我們不難發(fā)現(xiàn)，要想實(shí)現(xiàn)動(dòng)態(tài)刷新，關(guān)鍵點(diǎn)就在post refresh的請(qǐng)求上，那我們就從刷新配置文件開始。
當(dāng)我們post刷新請(qǐng)求的時(shí)候，這個(gè)請(qǐng)求會(huì)被actuator模塊攔截，這點(diǎn)從啟動(dòng)的日志文件中就可以看出
復(fù)制代碼 代碼如下:
Mapped "{[/refresh || /refresh.json],methods=[POST]}" onto public java.lang.Object org.springframework.cloud.endpoint.GenericPostableMvcEndpoint.invoke()
接下來，我們就來看actuator定義的EndPoint，然后我們就找到了RefreshEndpoint這個(gè)類，該類的源碼如下：
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@ConfigurationProperties(prefix = "endpoints.refresh", ignoreUnknownFields = false) @ManagedResourcepublic 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()); } } |
從上面的源碼，我們可以看到，重點(diǎn)在ContextRefresher這個(gè)類上，由于這個(gè)類太長(zhǎng)了，下面把這個(gè)類的部分源碼貼出來：
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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，加載提取配置文件 addConfigFilesToEnvironment();// 2、將配置文件加載到環(huán)境中 Set<String> keys = changes(before, extract(this.context.getEnvironment().getPropertySources())).keySet();// 3、替換原來環(huán)境變量中的值 this.context.publishEvent(new EnvironmentChangeEvent(keys));// 4、發(fā)布變更事件， this.scope.refreshAll(); return keys; } |
從上面的代碼不難看出，重點(diǎn)經(jīng)歷了4個(gè)步驟，上面代碼中已標(biāo)注。
以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://blog.csdn.net/liuchuanhong1/article/details/75446850
