bug fixed for StatFilter resultSet multi-close

src/test/java/com/alibaba/druid/bvt/filter/StatFilterResultSetMultiCloseTest.java

@@ -0,0 +1,64 @@
+package com.alibaba.druid.bvt.filter;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.pool.DruidDataSource;
+import com.alibaba.druid.stat.JdbcSqlStat;
+import com.alibaba.druid.util.Histogram;
+import com.alibaba.druid.util.JdbcUtils;
+
+public class StatFilterResultSetMultiCloseTest extends TestCase {
+
+    private DruidDataSource dataSource;
+
+    protected void setUp() throws Exception {
+        dataSource = new DruidDataSource();
+
+        dataSource.setUrl("jdbc:mock:xxx");
+        dataSource.setFilters("stat");
+
+        dataSource.init();
+    }
+
+    protected void tearDown() throws Exception {
+        JdbcUtils.close(dataSource);
+    }
+
+    public void test_stat() throws Exception {
+
+        final String sql = "SELECT 1";
+        Assert.assertTrue(dataSource.isInited());
+
+        JdbcSqlStat sqlStat = dataSource.getDataSourceStat().getSqlStat(sql);
+
+        Assert.assertNull(sqlStat);
+
+        Connection conn = dataSource.getConnection();
+
+        PreparedStatement stmt = conn.prepareStatement(sql);
+        ResultSet rs = stmt.executeQuery();
+        rs.next();
+        rs.close();
+
+        sqlStat = dataSource.getDataSourceStat().getSqlStat(sql);
+        Assert.assertNotNull(sqlStat);
+
+        Histogram histogram = sqlStat.getExecuteAndResultHoldTimeHistogram();
+        Assert.assertEquals("first failed", 1, histogram.getValue(0) + histogram.getValue(1));
+        
+        rs.close();
+        
+        Assert.assertEquals("second failed", 1, histogram.getValue(0) + histogram.getValue(1));
+
+        stmt.close();
+
+        conn.close();
+
+        Assert.assertEquals(1, histogram.getValue(1));
+    }
+}