mxzdao.java

这是Java学习的一些常用的例子

//---------------------------------------------------------
// Application: Ch03
// Author     : helpsoft
// File       : MxzDAO.java
//
// Copyright 2004 www.helpsoft.org
//开发时间：2004-11-01 01:03:28 CST 2004
// 作者：曹广鑫
// 访问 http://www.helpsoft.org
//---------------------------------------------------------

package org.helpsoft.ch03.dao;

import java.io.*;
import java.sql.*;
import java.util.*;
import javax.sql.*;

import org.helpsoft.ch03.model.*;
import org.helpsoft.ch03.util.CacheManager;

public class MxzDAO extends DAO {

  public MxzDAO(DataSource ds) {
    super(ds);
  }

  public void insert(Mxz mxz) throws SQLException {
    String sql;
    sql = "INSERT INTO mxz (id, zy, sr, zc, rq) VALUES (?, ?, ?, ?, ?)";
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = ds.getConnection();
      pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, mxz.getId());
      pstmt.setString(2, mxz.getZy());
      pstmt.setFloat(3, mxz.getSr());
      pstmt.setFloat(4, mxz.getZc());
      pstmt.setString(5, mxz.getRq());
      pstmt.executeUpdate();
      pstmt.close();
      conn.commit();
    } catch (SQLException sqle) {
      close(rs);
      close(pstmt);
      rollback(conn);
      sqle.printStackTrace();
      throw sqle;
    } finally {
    	close(conn);
    }
  }

  public void update(Mxz mxz) throws SQLException {
  	Connection conn = null;
  	PreparedStatement pstmt = null;
    try {
      conn = ds.getConnection();
      String sql = "UPDATE mxz SET zy=?, sr=?, zc=?, rq=? WHERE id=?";
      pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, mxz.getZy());
      pstmt.setFloat(2, mxz.getSr());
      pstmt.setFloat(3, mxz.getZc());
      pstmt.setString(4, mxz.getRq());
      pstmt.setString(5, mxz.getId());
      pstmt.executeUpdate();
      close(pstmt);
      conn.commit();
    } catch (SQLException e) {
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
  }

  public void delete(String id) throws SQLException {
  	Connection conn = null;
  	PreparedStatement pstmt = null;
    try {
      conn = ds.getConnection();
      String sql = "DELETE FROM mxz WHERE id=?";
      pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, id);
      pstmt.executeUpdate();
      close(pstmt);
      conn.commit();
    } catch (SQLException e) {
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
    String[] objKeys = {"Mxz", String.valueOf(id)};
    String objKey = CacheManager.createKey(objKeys);
    DAOCacheManager.invalidate(objKey);
  }

  public Mxz retrieve(String id) throws SQLException {
    String[] objKeys = {"Mxz", String.valueOf(id)};
    String objKey = CacheManager.createKey(objKeys);
    Mxz mxz = (Mxz) DAOCacheManager.getCache(objKey);
    if (mxz != null)
      return mxz;
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = ds.getConnection();
      String sql = "SELECT * FROM mxz WHERE id=?";
      pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, id);
      rs = pstmt.executeQuery();
      if (rs.next()) {
        mxz = new Mxz();
        populate(mxz, rs);
      }
      close(rs);
      close(pstmt);
    } catch (SQLException e) {
      close(rs);
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
    DAOCacheManager.putCache(mxz, objKey, 1);
    return mxz;
  }

  public List list() throws SQLException {
    String[] objKeys = {"Mxz", "list"};
    String objKey = CacheManager.createKey(objKeys);
    ArrayList list = (ArrayList) DAOCacheManager.getCache(objKey);
    if (list != null)
      return list;
    list = new ArrayList();
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = ds.getConnection();
      String sql = "SELECT zy, sr, zc, rq, id FROM mxz";
      pstmt = conn.prepareStatement(sql);
      rs = pstmt.executeQuery();
      while(rs.next()) {
        Mxz mxz = new Mxz();
        populate(mxz, rs);
        list.add(mxz);
      }
      close(rs);
      close(pstmt);
    } catch (SQLException e) {
      close(rs);
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
    DAOCacheManager.putCache(list, objKey, 1);
    return list;
  }

  public List list(int offset, int limit) throws SQLException {
    String[] objKeys = {"Mxz", "list", String.valueOf(offset), String.valueOf(limit)};
    String objKey = CacheManager.createKey(objKeys);
    ArrayList list = (ArrayList) DAOCacheManager.getCache(objKey);
    if (list != null)
      return list;
    list = new ArrayList();
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = ds.getConnection();
      String sql = "SELECT zy, sr, zc, rq, id FROM mxz";
      pstmt = conn.prepareStatement(sql);
      rs = pstmt.executeQuery();
      if(offset > 0) rs.absolute(offset);
      int recCount = 0;
      while((recCount++ < limit) && rs.next()) {
        Mxz mxz = new Mxz();
        populate(mxz, rs);
        list.add(mxz);
      }
      close(rs);
      close(pstmt);
    } catch (SQLException e) {
      close(rs);
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
    DAOCacheManager.putCache(list, objKey, 1);
    return list;
  }

  public List newQuery(int offset, int limit, float sr, float zc, String rq) throws SQLException {
    String[] objKeys = {"Mxz", "newQuery", String.valueOf(offset), String.valueOf(limit), String.valueOf(sr), String.valueOf(zc), String.valueOf(rq)};
    String objKey = CacheManager.createKey(objKeys);
    ArrayList list = (ArrayList) DAOCacheManager.getCache(objKey);
    if (list != null)
      return list;
    list = new ArrayList();
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      conn = ds.getConnection();
      String sql = "SELECT zy, sr, zc, rq, id mxz";
      sql += " WHERE zy ? AND sr =? AND zc =? AND rq =?";
      pstmt = conn.prepareStatement(sql);
      pstmt.setFloat(1, sr);
      pstmt.setFloat(2, zc);
      pstmt.setString(3, rq);
      rs = pstmt.executeQuery();
      if(offset > 0) rs.absolute(offset);
      int recCount = 0;
      while((recCount++ < limit) && rs.next()) {
        Mxz mxz = new Mxz();
        populate(mxz, rs);
        list.add(mxz);
      }
      close(rs);
      close(pstmt);
    } catch (SQLException e) {
      close(rs);
      close(pstmt);
      rollback(conn);
      e.printStackTrace();
    } finally {
    	close(conn);
    }
    DAOCacheManager.putCache(list, objKey, 1);
    return list;
  }

}