util.java

HR系统模拟企业对内部职员的管理

/*$Id: Util.java,v 1.1 2008/07/15 03:38:23 liqi Exp $
 *--------------------------------------
 * Apusic (Kingdee Middleware)
 *---------------------------------------
 * Copyright By Apusic ,All right Reserved
 * author   date   comment
 * chenhongxin  2008-4-14  Created
*/
package org.operamasks.example.ejb.hr.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.util.Random;

import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;
import javax.faces.event.MethodExpressionActionListener;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;

/**
 * 通用工具类
 * @author chenhongxin
 */
public class Util {
	private Util() {
	}

	/**
	 * 获取数字随机数
	 * @param size 随机数个数
	 * @return 指定个数的数字随机数的字符串
	 */
	public static String getRandom(int size) {
		Random random = new Random();
		StringBuilder sb = new StringBuilder(size);
		for (int i = 0; i < size; i++) {
			sb.append(random.nextInt(9));
		}
		return sb.toString();
	}

	/**
	 * 创建指定EL方法表达式的MethodExpressionActionListener
	 * @param context FacesContext
	 * @param expression EL方法表达式
	 * @return MethodExpressionActionListener
	 */
	public static MethodExpressionActionListener createMethodExpressionActionListener(FacesContext context, String expression) {
		return new MethodExpressionActionListener(context.getApplication()
				.getExpressionFactory().createMethodExpression(
						context.getELContext(), expression, Void.class,
						new Class[] { ActionEvent.class }));
	}

	/**
	 * 根据随即码以及宽高绘制图片函数
	 * @param g Graphics
	 * @param width 图片宽度
	 * @param height 图片高度
	 * @param randomCode 随机码
	 */
	public static void drawRandomPicture(Graphics g, int width, int height,
			String randomCode) {
		g.setColor(randColor(200, 250));
		g.fillRect(0, 0, width, height);
		g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
		g.setColor(randColor(160, 200));

		Random random = new Random(System.currentTimeMillis());

		//  随机产生155条干扰线，使图像中的验证码不易被识别
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}

		//  将验证码显示在图像中
		for (int i = 0; i < 4; i++) {
			g.setColor(randColor(20, 130));
			g.drawString(randomCode.substring(i, i + 1), 13 * i + 6, 16);
		}
	}

	/**
	 * 获得随机色
	 * @param fc 前景色
	 * @param bc 背景色
	 * @return 随机色
	 */
	private static Color randColor(int fc, int bc) {
		Random random = new Random(System.currentTimeMillis());
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}
	
	/**
	 * 获取绝对物理路径
	 * @param path 相对路径
 	 * @return 对应的绝对物理路径字符串
	 */
	public static String getRealPath(String path) {
		FacesContext context = FacesContext.getCurrentInstance();
		ExternalContext eContext = context.getExternalContext();
		ServletContext sContext = (ServletContext)eContext.getContext();
		return sContext.getRealPath(path);
	}
	
	/**
	 * 获取网站的BasePath
	 * @return 网站的BasePath的字符串
	 */
	public static String getBasePath() {
		FacesContext context = FacesContext.getCurrentInstance();
		ExternalContext eContext = context.getExternalContext();
		ServletRequest req = (ServletRequest)eContext.getRequest();
		return (req.getScheme()+"://"+req.getServerName()+":"+req.getServerPort() + eContext.getRequestContextPath() + "/");
	}
}