bug fixed resultSet null

src/main/java/com/alibaba/druid/mock/MockPreparedStatement.java

@@ -77,4 +77,14 @@ public class MockPreparedStatement extends PreparedStatementBase implements Prep
         return false;
     }
 
+    @Override
+    public ResultSet getResultSet() throws SQLException {
+        checkOpen();
+        
+        if (resultSet == null) {
+            resultSet = this.getConnection().getDriver().createResultSet(this);
+        }
+
+        return resultSet;
+    }
 }

src/main/java/com/alibaba/druid/pool/DruidPooledStatement.java

@@ -284,6 +284,9 @@ public class DruidPooledStatement extends PoolableWrapper implements Statement {
 
         try {
             ResultSet rs = stmt.getResultSet();
+            if (rs == null) {
+                return null;
+            }
 
             DruidPooledResultSet poolableResultSet = new DruidPooledResultSet(this, rs);
             resultSetTrace.add(poolableResultSet);

src/main/java/com/alibaba/druid/util/jdbc/StatementBase.java

@@ -27,8 +27,8 @@ public abstract class StatementBase implements Statement {
     protected boolean  closed = false;
     private boolean    poolable;
 
-    private ResultSet  generatedKeys;
-    private ResultSet  resultSet;
+    protected ResultSet  generatedKeys;
+    protected ResultSet  resultSet;
 
     public StatementBase(Connection connection){
         super();