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content/posts/CLI.md

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+title = "CLI"
+date = "2024-10-15"
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+
+1. 网络带宽测试工具 speedtest-cli

content/posts/dm-migrate.md

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+title = "达梦数据库迁移"
+date = "2024-10-28"
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+
+# 环境
+1. 客户端：macos使用dbeaver, IDEA: 使用mysql连接修改驱动使用达梦数据库连接驱动
+# 函数
+1. str_to_date => to_date(date1, 'YYYY-MM-DD HH24:MI:SS')
+2. group_concat => wm_concat / listagg
+3. date_sub => add_days / add_months
+4. current_time => current_date() / sysdate() / curdate()
+5. date(var) => trunc(var) 
+6. convert => cast

content/posts/spring-boot-usage.md

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+title = "springboot usage"
+date = "2024-10-30"
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+
+1. jdbcTemplate配置sql日志打印
+```yaml
+logging:
+  level:
+    org.springframework.jdbc.core.JdbcTemplate: DEBUG
+```

content/posts/spring.md

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+title = "spring"
+date = "2024-10-15"
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+
+# Bean 缓存
+
+```java
+@Nullable
+protected Object getSingleton(String beanName, boolean allowEarlyReference) {
+    // 查询一级缓存
+    Object singletonObject = this.singletonObjects.get(beanName);
+    // 如果一级缓存不存在且当前 bean 正在创建
+    if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) {
+        // 查询二级缓存
+        singletonObject = this.earlySingletonObjects.get(beanName);
+        // 如果二级缓存不存在且允许提前引用
+        if (singletonObject == null && allowEarlyReference) {
+            synchronized (this.singletonObjects) {
+                // Consistent creation of early reference within full singleton lock
+               // 一级缓存重新获取 
+                singletonObject = this.singletonObjects.get(beanName);
+                if (singletonObject == null) {
+                    // 二级缓存重新获取
+                    singletonObject = this.earlySingletonObjects.get(beanName);
+                    if (singletonObject == null) {
+                        // 三级缓存获取
+                        ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);
+                        if (singletonFactory != null) {
+                            singletonObject = singletonFactory.getObject();
+                            this.earlySingletonObjects.put(beanName, singletonObject);
+                            this.singletonFactories.remove(beanName);
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return singletonObject;
+}
+```