commentbean.java

一个java

package bookstore.ejb;

import bookstore.util.*;

import java.sql.*;
import javax.sql.*;
import java.util.*;
import javax.ejb.*;
import javax.naming.*;


public class CommentBean implements EntityBean {
  java.lang.String commentID;
  java.lang.String customerID;
  java.lang.String bookID;
  int rank;
  java.lang.String content;

  private Connection con=null;
  EntityContext entityContext;
  /**************************business methods**********************************/
  public void setCommentID(java.lang.String commentID) {
    this.commentID = commentID;
  }
  public void setCustomerID(java.lang.String customerID) {
    this.customerID = customerID;
  }
  public void setBookID(java.lang.String bookID) {
    this.bookID = bookID;
  }
  public void setRank(int rank) {
    this.rank = rank;
  }
  public void setContent(java.lang.String content) {
    this.content = content;
  }
  public java.lang.String getCommentID() {
    return commentID;
  }
  public java.lang.String getCustomerID() {
    return customerID;
  }
  public java.lang.String getBookID() {
    return bookID;
  }
  public int getRank() {
    return rank;
  }
  public java.lang.String getContent() {
    return content;
  }
  public CommentDetails getDetails()
    {
       System.out.println("commentBean getDetails");

       return new CommentDetails (commentID,customerID ,bookID,rank,content);
    }//getDetails

   /********************************ejb methods**************************/
   public java.lang.String ejbCreate(CommentDetails commentValue) throws CreateException {
     System.out.println("commentBean ejbCreate");

         try
         {
           makeConnection();
           this.commentID=DBHelper.getNextCommentID(con);
         }catch(Exception ex)
         {
           throw new EJBException("ejbCreate: "+ex.getMessage());
         }

         this.customerID=commentValue.getCustomerID();
         this.bookID=commentValue.getBookID();
         this.rank=commentValue.getRank();
         this.content=commentValue.getContent();

         try {
             insertRow();
         } catch (Exception ex) {
              throw new EJBException("ejbCreate: " +
                  ex.getMessage());
         }

         return commentID;

   }

   public void ejbPostCreate(CommentDetails commentValue) throws CreateException {
     System.out.println("commentBean ejbPostCreate");
   }

   public java.util.Collection ejbFindByCondition(String condition) throws FinderException {
     System.out.println("commentBean ejbFindByCondition");

     Collection result;

     try {
            result = selectByCondition(condition);
        } catch (Exception ex) {
              throw new EJBException("ejbFindByCondition " +
                  ex.getMessage());
        }
        return result;

   }

   public void ejbRemove() throws RemoveException {
     System.out.println("commentBean ejbRemove");

     try {
             deleteRow(commentID);
          } catch (Exception ex) {
               throw new EJBException("ejbRemove: " +
                   ex.getMessage());
          }
   }//ejbRemove

   public java.lang.String ejbFindByPrimaryKey(java.lang.String primaryKey) throws FinderException {

          System.out.println("commentBean ejbFindByPrimaryKey");

          boolean result;

          try {
              result = selectByPrimaryKey(primaryKey);
          } catch (Exception ex) {
                throw new EJBException("ejbFindByPrimaryKey: " +
                    ex.getMessage());
          }

          if (result) {
              return primaryKey;
          }
          else {
              throw new ObjectNotFoundException
                  ("Row for id " + primaryKey + " not found.");
          }
      }

      public void ejbLoad() {

           System.out.println("commentBean ejbLoad");

           try {
               loadComment();
            } catch (Exception ex) {
                 throw new EJBException("ejbLoad: " +
                     ex.getMessage());
            }
       }//ejbLoad

       public void ejbStore()
       {

             System.out.println("commentBean ejbStore");

             try {
                 storeComment();
              } catch (Exception ex) {
                   throw new EJBException("ejbStore: " +
                       ex.getMessage());
              }
         }//ejbStore

   public void ejbActivate()
   {
         System.out.println("commentBean ejbActivate");
         //
         commentID = (String)entityContext.getPrimaryKey();
     }

     public void ejbPassivate()
     {
         System.out.println("commentBean ejbPassivate");

         commentID= null;
     }

   public void unsetEntityContext()
   {
     System.out.println("commentBean ussetEntiyContext");
     this.entityContext = null;
   }
   public void setEntityContext(EntityContext entityContext) {
     System.out.println("commentBean setEntiyContext");
     this.entityContext = entityContext;
   }

   /****************************util methods*******************************/
   private void makeConnection() {

         System.out.println("commentBean makeConnection in");
         try
            {
              InitialContext ic = new InitialContext();
              DataSource ds = (DataSource) ic.lookup("DBSource");
              con = ds.getConnection();
            }
            catch (Exception ex)
            {
              throw new EJBException("Unable to connect to database. " +
                                    ex.getMessage());
            }
         System.out.println("commentBean makeConnection out");
     } // makeConnection


     private void releaseConnection() {

         System.out.println("commentBean releaseConnection in");

         try {
             con.close();
         } catch (SQLException ex) {
              throw new EJBException("releaseConnection: " + ex.getMessage());
         }
         System.out.println("commentBean releaseConnection out");

     } // releaseConnection


     private void insertRow () throws SQLException {

         System.out.println("commentBean insertRow in");

         makeConnection();
         String insertStatement =
             "insert into comment values ( ? , ? , ? , ? ,?)";
         PreparedStatement prepStmt =
             con.prepareStatement(insertStatement);
         prepStmt.setString(1, commentID);
         prepStmt.setString(2, customerID);
         prepStmt.setString(3, bookID);
         prepStmt.setInt(4,rank);
         prepStmt.setString(5,content);

         prepStmt.executeUpdate();
         prepStmt.close();
         releaseConnection();
         System.out.println("commentBean insertRow out");
     }//insertRow

     private Collection selectByCondition(String condition) throws SQLException {

        System.out.println("commentBean selectByCondition in");

        makeConnection();
        String selectStatement =
                "select commentID " +
                "from comment where "+condition;
        System.out.println(selectStatement);
        Statement stmt=con.createStatement();
        ResultSet rs=stmt.executeQuery(selectStatement);

        ArrayList a = new ArrayList();
        while (rs.next())
        {
            a.add(rs.getString(1));
        }

        stmt.close();
        releaseConnection();
        System.out.println("commentBean selectByCondition out");
        return a;
    }//selectByCondition

    private boolean selectByPrimaryKey(String primaryKey) throws SQLException {
         //本函数主要目的还在于确保comment_id在数据库表中是存在的
         System.out.println("commentBean selectByPrimaryKey in");

         makeConnection();
         //a question here
         String selectStatement =
                 "select commentID " +
                 "from comment where commentID = ? ";
         PreparedStatement prepStmt =
                 con.prepareStatement(selectStatement);
         prepStmt.setString(1, primaryKey);

         ResultSet rs = prepStmt.executeQuery();
         boolean result = rs.next();
         prepStmt.close();
         releaseConnection();
         System.out.println("commentBean selectByPrimaryKey out");
         return result;
     }//selectByPrimaryKey

     private void loadComment() throws SQLException {

         System.out.println("commentBean loadcomment in");

         makeConnection();
         String selectStatement =
                 "select CustomerID, BookID,Rank,Content " +
                 "from comment where commentID = ? ";
         PreparedStatement prepStmt =
                 con.prepareStatement(selectStatement);

         prepStmt.setString(1, commentID);

         ResultSet rs = prepStmt.executeQuery();

         if (rs.next())
         {
             customerID = rs.getString(1);
             bookID = rs.getString(2);
             rank=rs.getInt(3);
             content=rs.getString(4);
             prepStmt.close();
             releaseConnection();
         }
         else {
             prepStmt.close();
             releaseConnection();
             throw new NoSuchEntityException("loadcomment:Row for id " +
                 commentID + " not found in database.");
         }
         System.out.println("commentBean loadcomment out");
     }//loadcomment

     private void storeComment() throws SQLException {

         System.out.println("commentBean storecomment in");

         makeConnection();

         String updateStatement =
                 "update comment " +
                 "set customerID = ? , bookID = ? , rank = ? ,content= ? " +
                 "where commentID = ? ";
         PreparedStatement prepStmt =
                 con.prepareStatement(updateStatement);

         prepStmt.setString(1,customerID);
         prepStmt.setString(2, bookID);
         prepStmt.setInt(3,rank);
         prepStmt.setString(4,content);
         prepStmt.setString(5, commentID);

         int rowCount = prepStmt.executeUpdate();
         prepStmt.close();
         releaseConnection();

         if (rowCount == 0) {
             throw new EJBException("storecomment:Storing row for id " + commentID + " failed.");
         }
         System.out.println("commentBean storecomment out");
     }//storecomment

     private void deleteRow(String id) throws SQLException {

         System.out.println("commentBean deleteRow in");

         makeConnection();
         String deleteStatement =
                 "delete from comment where commentID = ? ";
         PreparedStatement prepStmt =
                 con.prepareStatement(deleteStatement);

         prepStmt.setString(1, id);
         prepStmt.executeUpdate();
         prepStmt.close();
         releaseConnection();
         System.out.println("commentBean deleteRow out");
     }////deleteRow

}