java - 既然作者已经写了ProxyConnection，为什么要通过javaassist生成HikariProxyConnection呢？

Question

根据HikariCP的源代码，我发现作者通过javaassist生成了HikariProxyConnection，但是该类除了调用父类(super class)方法之外什么也没做。

例如，HikariProxyConnection 的父类(super class)是 ProxyConnection:

public class HikariProxyConnection extends ProxyConnection implements AutoCloseable, Connection, Wrapper {
   public Statement createStatement() throws SQLException {
     try {
        return super.createStatement();
     } catch (SQLException var2) {
        throw this.checkException(var2);
     }
   }

   public PreparedStatement prepareStatement(String var1) throws SQLException {
     try {
         return super.prepareStatement(var1);
     } catch (SQLException var3) {
         throw this.checkException(var3);
     }
   }    }

我发现ProxyConnection已经做了很多事情，HikariProxyConnection只是在每个方法中添加了一个try catch block 。

如果有人能给出解释就好了。

Answer 1

有一个Hikari issue关于 @brettwooldridge 回答的 HikariProxyConnection 的目的:

The proxies delegate to the real driver classes. Some proxies, like the one for ResultSet, only intercept a few methods. Without the code generation, the proxy would have to implement all 50+ methods which simply delegate to the wrapped instance.

Code generation, based on reflection, also means that nothing needs to be done when a new JDK version introduces new JDBC methods to existing interfaces.