增加数据库主备自动切换功能

common/pom.xml

@@ -55,12 +55,24 @@
         </dependency>
         <!-- cglib end -->
 
-        <!-- springboot freemarker start -->
+        <!-- freemarker start -->
         <dependency>
-            <groupId>org.springframework.boot</groupId>
+            <groupId>org.freemarker</groupId>
-            <artifactId>spring-boot-starter-freemarker</artifactId>
+            <artifactId>freemarker</artifactId>
         </dependency>
-        <!-- springboot freemarker end -->
+        <!-- freemarker end -->
+
+        <!-- durid start -->
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>druid</artifactId>
+        </dependency>
+        <!-- durid end -->
+
+<!--        <dependency>-->
+<!--            <groupId>mysql</groupId>-->
+<!--            <artifactId>mysql-connector-java</artifactId>-->
+<!--        </dependency>-->
 
     </dependencies>
 

common/src/main/java/ink/wgink/common/datasource/StandbyDataSource.java

@@ -0,0 +1,188 @@
+package ink.wgink.common.datasource;
+
+import com.alibaba.druid.filter.config.ConfigFilter;
+import com.alibaba.druid.filter.encoding.EncodingConvertFilter;
+import com.alibaba.druid.filter.logging.CommonsLogFilter;
+import com.alibaba.druid.filter.logging.Log4j2Filter;
+import com.alibaba.druid.filter.logging.Log4jFilter;
+import com.alibaba.druid.filter.logging.Slf4jLogFilter;
+import com.alibaba.druid.filter.stat.StatFilter;
+import com.alibaba.druid.pool.DruidDataSource;
+import com.alibaba.druid.wall.WallFilter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Component;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @ClassName: StandbyMySqlDataSource
+ * @Description: 主备mysql数据库源
+ * @Author: wanggeng
+ * @Date: 2021/11/28 9:32 下午
+ * @Version: 1.0
+ */
+@Primary
+@Component
+@ConfigurationProperties("spring.datasource.druid")
+public class StandbyDataSource extends DruidDataSource implements InitializingBean {
+    private static final Logger LOG = LoggerFactory.getLogger(StandbyDataSource.class);
+    private ScheduledExecutorService scheduledExecutorService = new ScheduledThreadPoolExecutor(2);
+
+    @Autowired
+    private DataSourceProperties basicProperties;
+
+    private boolean lastInited;
+    /**
+     * 备库url连接
+     */
+    private String[] standbyUrls;
+    private volatile int standbyIndex = 0;
+
+    @Override
+    public void init() throws SQLException {
+        lastInited = inited;
+        super.init();
+        // 第一次初始化
+        if (!lastInited && inited) {
+            // 如果没有配置，不启用主备切换
+            if (standbyUrls == null || standbyUrls.length == 0) {
+                return;
+            }
+            scheduledExecutorService.schedule(new ValidateUrlTask(), 1, TimeUnit.SECONDS);
+        }
+    }
+
+    /**
+     * 验证连接
+     */
+    private class ValidateUrlTask implements Runnable {
+        @Override
+        public void run() {
+            // 备库下标
+            while (true) {
+                // 如果这个数据源被关闭了,就结束这个定时任务
+                if (isClosed()) {
+                    LOG.debug("Jdbc connection closed");
+                    break;
+                }
+                //如果这个数据源已经被初始化了,同时连接异常才进行处理
+                if (isInited() && !isConnectionActive()) {
+                    // 主库有问题时，切换备库
+                    LOG.debug("Change standby urls, index:{}", standbyIndex);
+                    String standbyUrl = standbyUrls[standbyIndex];
+                    changeUrl(standbyUrl);
+                    standbyIndex++;
+                    break;
+                }
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    LOG.error(e.getMessage(), e);
+                }
+            }
+        }
+    }
+
+    /**
+     * 切换连接
+     *
+     * @param url
+     */
+    private void changeUrl(String url) {
+        LOG.debug("jdbc url: {}", url);
+        inited = false;
+        setUrl(url);
+    }
+
+    public void setStandbyUrls(String[] standbyUrls) {
+        this.standbyUrls = standbyUrls;
+    }
+
+    /**
+     * 判断连接是否存活
+     *
+     * @return
+     */
+    public boolean isConnectionActive() {
+        try (Connection conn = getConnection();
+             Statement stmt = conn.createStatement();
+        ) {
+            stmt.execute("select 1");
+            return true;
+        } catch (SQLException e) {
+            LOG.error(e.getMessage());
+            return false;
+        }
+    }
+
+    public void afterPropertiesSet() throws Exception {
+        if (super.getUsername() == null) {
+            super.setUsername(this.basicProperties.determineUsername());
+        }
+
+        if (super.getPassword() == null) {
+            super.setPassword(this.basicProperties.determinePassword());
+        }
+
+        if (super.getUrl() == null) {
+            super.setUrl(this.basicProperties.determineUrl());
+        }
+
+        if (super.getDriverClassName() == null) {
+            super.setDriverClassName(this.basicProperties.getDriverClassName());
+        }
+
+    }
+
+    @Autowired(required = false)
+    public void addStatFilter(StatFilter statFilter) {
+        super.filters.add(statFilter);
+    }
+
+    @Autowired(required = false)
+    public void addConfigFilter(ConfigFilter configFilter) {
+        super.filters.add(configFilter);
+    }
+
+    @Autowired(required = false)
+    public void addEncodingConvertFilter(EncodingConvertFilter encodingConvertFilter) {
+        super.filters.add(encodingConvertFilter);
+    }
+
+    @Autowired(required = false)
+    public void addSlf4jLogFilter(Slf4jLogFilter slf4jLogFilter) {
+        super.filters.add(slf4jLogFilter);
+    }
+
+    @Autowired(required = false)
+    public void addLog4jFilter(Log4jFilter log4jFilter) {
+        super.filters.add(log4jFilter);
+    }
+
+    @Autowired(required = false)
+    public void addLog4j2Filter(Log4j2Filter log4j2Filter) {
+        super.filters.add(log4j2Filter);
+    }
+
+    @Autowired(required = false)
+    public void addCommonsLogFilter(CommonsLogFilter commonsLogFilter) {
+        super.filters.add(commonsLogFilter);
+    }
+
+    @Autowired(required = false)
+    public void addWallFilter(WallFilter wallFilter) {
+        super.filters.add(wallFilter);
+    }
+
+}