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URLString 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;}    }