Adding UCPServlet

Adding UCPServlet.java

Author: Nirmala Sundarappa

java/jdbc/Tomcat_Servlet/src/UCPServlet.java

@@ -0,0 +1,128 @@
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import javax.naming.Context;
+import javax.naming.InitialContext;
+import javax.naming.NamingException;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import oracle.ucp.admin.UniversalConnectionPoolManagerImpl;
+import oracle.ucp.jdbc.PoolDataSource;
+
+/**
+ * Servlet implementation class UCPServlet
+ */
+@WebServlet("/UCPServlet")
+public class UCPServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
+
+    /**
+     * @see HttpServlet#HttpServlet()
+     */
+    public UCPServlet() {
+        super();
+    }
+
+  /**
+   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
+   */
+  protected void doGet(HttpServletRequest request, HttpServletResponse response)
+           throws ServletException, IOException {
+    PrintWriter out = response.getWriter();
+
+    out.println("Servlet to test ATP using UCP");
+    Connection conn = null;
+    try {
+      // Get a context for the JNDI look up
+      PoolDataSource pds = getPoolInstance();
+      conn = pds.getConnection();
+
+      // Prepare a statement to execute the SQL Queries.
+      Statement statement = conn.createStatement();
+      // Create table EMP
+      statement.executeUpdate("create table EMP(EMPLOYEEID NUMBER,"
+          + "EMPLOYEENAME VARCHAR2 (20))");
+      out.println("New table EMP is created");
+      // Insert some records into the table EMP
+      statement.executeUpdate("insert into EMP values(1, 'Jennifer Jones')");
+      statement.executeUpdate("insert into EMP values(2, 'Alex Debouir')");
+      out.println("Two records are inserted.");
+
+      // Update a record on EMP table.
+      statement.executeUpdate("update EMP set EMPLOYEENAME='Alex Deborie'"
+          + " where EMPLOYEEID=2");
+      out.println("One record is updated.");
+
+      // Verify the table EMP
+      ResultSet resultSet = statement.executeQuery("select * from EMP");
+      out.println("\nNew table EMP contains:");
+      out.println("EMPLOYEEID" + " " + "EMPLOYEENAME");
+      out.println("--------------------------");
+      while (resultSet.next()) {
+        out.println(resultSet.getInt(1) + " " + resultSet.getString(2));
+      }
+      out.println("\nSuccessfully tested a connection to ATP using UCP");
+    }
+    catch (Exception e) {
+      response.setStatus(500);
+      response.setHeader("Exception", e.toString());
+      out.print("\n Web Request failed");
+      out.print("\n "+e.toString());
+      e.printStackTrace();
+    }
+    finally {
+      // Clean-up after everything
+      try (Statement statement = conn.createStatement()) {
+        statement.execute("drop table EMP");
+        conn.close();
+      }
+      catch (SQLException e) {
+        System.out.println("UCPServlet - "
+            + "doSQLWork()- SQLException occurred : " + e.getMessage());
+      }
+    }
+  }
+
+  /* Get the appropriate datasource */
+  private PoolDataSource getPoolInstance() throws NamingException {
+    Context ctx;
+    ctx = new InitialContext();
+    Context envContext = (Context) ctx.lookup("java:/comp/env");
+
+    // Look up a data source
+    javax.sql.DataSource ds
+          = (javax.sql.DataSource) envContext.lookup ("tomcat/UCP_atp");
+    PoolDataSource pds=(PoolDataSource)ds;
+
+    return pds;
+  }
+
+  public void destroy() {
+    try {
+
+      UniversalConnectionPoolManagerImpl.getUniversalConnectionPoolManager()
+          .destroyConnectionPool(getPoolInstance().getConnectionPoolName());
+      System.out.println("Pool Destroyed");
+    } catch (Exception e) {
+      System.out.println("destroy pool got Exception:");
+      e.printStackTrace();
+    }
+
+  }
+
+  /**
+    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
+  */
+  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+  }
+
+}