Merge branch 'master' of Munin/demo-driver-loader into master

README.md

@@ -8,7 +8,8 @@
  
  启用该插件以后，需要在WEB-INF目录下新建一个driverlib文件夹，将对应的驱动jar包放入这个文件夹内即可
  
- 注意：使用了隔离插件以后驱动jar包不需要放在lib目录下
+ 注意A：使用了隔离插件以后驱动jar包不需要放在lib目录下
+ 注意B：HIVE驱动依赖于slf4j的jar，同样需要放入dirverlib文件夹中
  
  目前该插件默认是隔离MySQL的驱动，如果是其他数据源，只需要修改DRIVER_NAME_KEY为对应的驱动即可
 

plugin.xml

@@ -12,6 +12,7 @@
       [2019-05-20]优化逻辑。<br/>
       [2019-05-30]实现一个可用的ClassLoader。<br/>
       [2019-05-31]修改Mysql的key为Hive。<br/>
+      [2019-05-31]考虑一下并发问题，针对hive修改了一下加载机制。<br/>
     ]]></change-notes>
     <main-package>com.fr.plugin.dialect.classloader</main-package>
     <extra-core>

src/main/java/com/fr/plugin/dialect/classloader/ClassLoaderHandler.java

@@ -20,10 +20,11 @@ import java.util.List;
 
 @EnableMetrics
 public class ClassLoaderHandler extends AbstractDataSourceDriverLoader {
+    private ClassLoader driverClassLoader;
     //插件获取jar的路径，和lib同级的driverlib目录
     public static final String DRIVER_LIB_DIR = "driverlib";
 
-    //demo设置为mysql为目标驱动
+    //demo设置为hive为目标驱动
     private static final String DRIVER_NAME_KEY = "org.apache.hive.jdbc.HiveDriver";
 
     @Focus(id = "com.fr.plugin.dialect.classloader.ClassLoaderHandler", text = "", source = Original.PLUGIN)
@@ -41,11 +42,14 @@ public class ClassLoaderHandler extends AbstractDataSourceDriverLoader {
 
     @Focus(id = "com.fr.plugin.dialect.classloader.ClassLoaderHandler", text = "", source = Original.PLUGIN)
     public ClassLoader getClassLoader() {
-        FineLoggerFactory.getLogger().info("====== Loading Mysql ClassLoader ... ======");
-        URL[] urls = getJarURLS();
-        ClassLoader cl = new DriverClassLoader(urls);
-        Thread.currentThread().setContextClassLoader(cl);
-        return cl;
+        FineLoggerFactory.getLogger().info("====== Loading Hive ClassLoader ... ======");
+        synchronized (this) {
+            if (this.driverClassLoader == null) {
+                URL[] urls = getJarURLS();
+                this.driverClassLoader = new DriverClassLoader(urls);
+            }
+            return driverClassLoader;
+        }
     }
 
 

src/main/java/com/fr/plugin/dialect/classloader/DriverClassLoader.java

@@ -33,8 +33,8 @@ public class DriverClassLoader extends URLClassLoader {
                 FineLoggerFactory.getLogger().debug("Did not find class{}, in the paths {}, try to get from common lib", name, this.getUrlStrings());
                 c = super.loadClass(name);
             }
-
             return c;
+
         }
 
     }