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;
	}
    
}