咖啡豆（JavaBean）•常用JavaBean

数据库操作封装JavaBean

在使用Hibernate之前常常使用这个JavaBean，类似于Net中的sqlHelper。

package beans; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class DBUtil { /** * 取得一个数据库连接 * @return * @throws SQLException * @throws InstantiationException * @throws IllegalAccessException * @throws ClassNotFoundException */ public Connection getConnection() throws SQLException, InstantiationException, IllegalAccessException, ClassNotFoundException { Connection conn = null; //加载数据库驱动类 Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver") .newInstance(); //数据库连接URL String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=pubs"; //数据库用户名 String user = "sa"; //数据库密码 String password = "1985315"; //根据数据库参数取得一个数据库连接 conn = DriverManager.getConnection(url, user, password); return conn; } /** * 根据传入的SQL语句返回一个结果集 * @param sql * @return * @throws Exception */ public ResultSet select(String sql) throws Exception { Connection conn = null; Statement stmt = null; ResultSet rs = null; try { conn = getConnection(); stmt = conn.createStatement(); rs = stmt.executeQuery(sql); return rs; } catch (SQLException sqle) { throw new SQLException("select data exception: " + sqle.getMessage()); } catch (Exception e) { throw new Exception("System e exception: " + e.getMessage()); } } /** * 根据传入的SQL语句向数据库增加一条记录 * @param sql * @throws Exception */ public void insert(String sql) throws Exception { Connection conn = null; PreparedStatement ps = null; try { conn = getConnection(); ps = conn.prepareStatement(sql); ps.executeUpdate(); } catch (SQLException sqle) { throw new Exception("insert data exception: " + sqle.getMessage()); } finally { try { if (ps != null) { ps.close(); } } catch (Exception e) { throw new Exception("ps close exception: " + e.getMessage()); } } try { if (conn != null) { conn.close(); } } catch (Exception e) { throw new Exception("connection close exception: " + e.getMessage()); } } /** * 根据传入的SQL语句更新数据库记录 * @param sql * @throws Exception */ public void update(String sql) throws Exception { Connection conn = null; PreparedStatement ps = null; try { conn = getConnection(); ps = conn.prepareStatement(sql); ps.executeUpdate(); } catch (SQLException sqle) { throw new Exception("update exception: " + sqle.getMessage()); } finally { try { if (ps != null) { ps.close(); } } catch (Exception e) { throw new Exception("ps close exception: " + e.getMessage()); } } try { if (conn != null) { conn.close(); } } catch (Exception e) { throw new Exception("connection close exception: " + e.getMessage()); } } /** * 根据传入的SQL语句删除一条数据库记录 * @param sql * @throws Exception */ public void delete(String sql) throws Exception { Connection conn = null; PreparedStatement ps = null; try { conn = getConnection(); ps = conn.prepareStatement(sql); ps.executeUpdate(); } catch (SQLException sqle) { throw new Exception("delete data exception: " + sqle.getMessage()); } finally { try { if (ps != null) { ps.close(); } } catch (Exception e) { throw new Exception("ps close exception: " + e.getMessage()); } } try { if (conn != null) { conn.close(); } } catch (Exception e) { throw new Exception("connection close exception: " + e.getMessage()); } } }

分页操作JavaBean

在操作报表的时候常常用到，方便分页显示。

package beans; public class Page { private int totalPage;//总页数 private int currentPage;//当前页数 private int totalRecord;//总的记录条数 private int currentRecord;//当前记录的条数 private int pageSize = 6;//每页显示的记录数量,这里默认每页显示6条 public int getCurrentPage() { return currentPage; } public void setCurrentPage(int currentRecord,int pageSize ) { //如果当前记录数除以每页显示条数可以整除，商就是当前的页码 if(currentRecord%pageSize == 0) { currentPage = currentRecord/pageSize; }else { //如果当前记录数除以每页显示条数不能整除，商加1才是当前的页码 currentPage = currentRecord/pageSize+1; } } public int getCurrentRecord() { return currentRecord; } public void setCurrentRecord(int currentRecord) { this.currentRecord = currentRecord; } public int getPageSize() { return pageSize; } public void setPageSize(int pageSize) { this.pageSize = pageSize; } public int getTotalPage() { return totalPage; } public void setTotalPage(int totalRecord,int pageSize) { //如果总记录数除以每页显示条数可以整除，商就是总页码 if(totalRecord%pageSize == 0) { totalPage = totalRecord/pageSize; }else { //如果总记录数除以每页显示条数不能整除，商加1才是总页码 totalPage = totalRecord/pageSize+1; } } public int getTotalRecord() { return totalRecord; } public void setTotalRecord(int totalRecord) { this.totalRecord = totalRecord; } }