Improve JavassistProxyFactory (#2244)

1. use `"target" + File.separator + "classes"` instead of `"target/classes"`
2. print target directory

pom.xml

@@ -421,7 +421,7 @@
                   <argument>-cp</argument>
                   <argument>${project.build.outputDirectory}${path.separator}${maven.compile.classpath}</argument>
                   <argument>com.zaxxer.hikari.util.JavassistProxyFactory</argument>
-                  <argument>${project.basedir}${file.separator}</argument>
+                  <argument>${project.basedir}</argument>
                </arguments>
             </configuration>
          </plugin>

src/main/java/com/zaxxer/hikari/util/JavassistProxyFactory.java

@@ -20,6 +20,7 @@ import com.zaxxer.hikari.pool.*;
 import javassist.*;
 import javassist.bytecode.ClassFile;
 
+import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.Array;
 import java.sql.*;
@@ -35,11 +36,12 @@ import java.util.Set;
  * instances of the generated proxies.
  *
  * @author Brett Wooldridge
+ * @author Yanming Zhou
  */
 public final class JavassistProxyFactory
 {
    private static ClassPool classPool;
-   private static String genDirectory = "";
+   private static String genDirectory = "target" + File.separator + "classes";
 
    public static void main(String... args) throws Exception {
       classPool = new ClassPool();
@@ -47,8 +49,14 @@ public final class JavassistProxyFactory
       classPool.appendClassPath(new LoaderClassPath(JavassistProxyFactory.class.getClassLoader()));
 
       if (args.length > 0) {
-         genDirectory = args[0];
+         String parentDir = args[0];
+         if (!parentDir.endsWith(File.separator)) {
+            parentDir += File.separator;
          }
+         genDirectory = parentDir + genDirectory;
+      }
+
+      System.out.println("Generating following classes to " + genDirectory);
 
       // Cast is not needed for these
       String methodBody = "{ try { return delegate.method($$); } catch (SQLException e) { throw checkException(e); } }";
@@ -96,7 +104,7 @@ public final class JavassistProxyFactory
          }
       }
 
-      proxyCt.writeFile(genDirectory + "target/classes");
+      proxyCt.writeFile(genDirectory);
    }
 
    /**
@@ -173,7 +181,7 @@ public final class JavassistProxyFactory
       }
 
       targetCt.getClassFile().setMajorVersion(ClassFile.JAVA_8);
-      targetCt.writeFile(genDirectory + "target/classes");
+      targetCt.writeFile(genDirectory);
    }
 
    private static boolean isThrowsSqlException(CtMethod method)

src/test/java/com/zaxxer/hikari/pool/TestJavassistCodegen.java

@@ -19,7 +19,7 @@ public class TestJavassistCodegen {
    @Test
    public void testCodegen() throws Exception {
       String tmp = System.getProperty("java.io.tmpdir");
-      JavassistProxyFactory.main(tmp + (tmp.endsWith("/") ? "" : "/"));
+      JavassistProxyFactory.main(tmp);
 
       Path base = Paths.get(tmp, "target/classes/com/zaxxer/hikari/pool".split("/"));
       Assert.assertTrue("", Files.isRegularFile(base.resolve("HikariProxyConnection.class")));