first commit for openGauss connector jdbc

docs/documentation/head/java8-date-time.md

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+---
+layout: default_docs
+title: Using Java 8 Date and Time classes
+header: Chapter 5. Using Java 8 Date and Time classes
+resource: media
+previoustitle: Creating and Modifying Database Objects
+previous: ddl.html
+nexttitle: Chapter 6. Calling Stored Functions
+next: callproc.html
+---
+
+The PostgreSQL™ JDBC driver implements native support for the
+[Java 8 Date and Time API](http://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html)
+(JSR-310) using JDBC 4.2.
+
+<a name="8-date-time-supported-data-types"></a>
+**Table 5.1. Supported Java 8 Date and Time classes**
+
+<table summary="Supported data type" class="CALSTABLE" border="1">
+  <tr>
+    <th>PostgreSQL™</th>
+    <th>Java SE 8</th>
+  </tr>
+  <tbody>
+    <tr>
+      <td>DATE</td>
+      <td>LocalDate</td>
+    </tr>
+    <tr>
+      <td>TIME [ WITHOUT TIME ZONE ]</td>
+      <td>LocalTime</td>
+    </tr>
+    <tr>
+      <td>TIMESTAMP [ WITHOUT TIME ZONE ]</td>
+      <td>LocalDateTime</td>
+    </tr>
+    <tr>
+      <td>TIMESTAMP WITH TIME ZONE</td>
+      <td>OffsetDateTime</td>
+    </tr>
+  </tbody>
+</table>
+
+This is closely aligned with tables B-4 and B-5 of the JDBC 4.2 specification.
+Note that `ZonedDateTime`, `Instant` and
+`OffsetTime / TIME WITH TIME ZONE` are not supported. Also note
+that all `OffsetDateTime` instances will have be in UTC (have offset 0).
+This is because the backend stores them as UTC.
+
+<a name="reading-example"></a>
+**Example 5.2. Reading Java 8 Date and Time values using JDBC**
+
+```java
+Statement st = conn.createStatement();
+ResultSet rs = st.executeQuery("SELECT * FROM mytable WHERE columnfoo = 500");
+while (rs.next())
+{
+    System.out.print("Column 1 returned ");
+    LocalDate localDate = rs.getObject(1, LocalDate.class));
+    System.out.println(localDate);
+}
+rs.close();
+st.close();
+```
+
+For other data types simply pass other classes to `#getObject`.
+Note that the Java data types needs to match the SQL data types in table 7.1.
+
+
+<a name="writing-example"></a>
+**Example 5.3. Writing Java 8 Date and Time values using JDBC**
+
+```java
+LocalDate localDate = LocalDate.now();
+PreparedStatement st = conn.prepareStatement("INSERT INTO mytable (columnfoo) VALUES (?)");
+st.setObject(1, localDate);
+st.executeUpdate();
+st.close();
+```
+