struct2生成验证码

1.首先要有生成验证码图片的代码

package info.frady.result;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

public class VerifyImage
{
	
    public String GetImage(OutputStream outputStream)
    {
        int width = 60, height = 20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        
        Graphics g = image.getGraphics();
        
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        g.setColor(getRandColor(160, 200));

        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);
        }

        String sRand = "";

        for (int i = 0; i < 4; i++)
        {
            String rand = String.valueOf(random.nextInt(10));
            sRand += rand;
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random
                    .nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
        }
        g.dispose();
        try
        {
            ImageIO.write(image, "JPEG", outputStream);
            outputStream.flush();
            return sRand;
        } catch (IOException e)
        {
            e.printStackTrace();
            return "fail";
        }
    }

    public Color getRandColor(int fc, int bc)
    {
        Random random = new Random();
        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);
    }

}

2.自定义一个result，来调用生成验证码的代码，并将验证码写入session

package info.frady.result;

import java.io.OutputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.StrutsResultSupport;

import com.opensymphony.xwork2.ActionInvocation;

public class ImageResult extends StrutsResultSupport{
	private HttpSession session;
    protected void doExecute(String arg0, ActionInvocation invocation) throws Exception
    {
        //获得Request
        HttpServletRequest request = (HttpServletRequest) invocation.getInvocationContext().get(
                ServletActionContext.HTTP_REQUEST);
        //获得session
        session = request.getSession(true);
        //获得response
        HttpServletResponse response = (HttpServletResponse) invocation.getInvocationContext().get(
                ServletActionContext.HTTP_RESPONSE);
        //设置无缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        
        VerifyImage verify = new VerifyImage();
        OutputStream os = response.getOutputStream();
        //获得随机验证码
        String str = verify.GetImage(os);
        
        //将验证码放入session
        if(session.getAttribute("rand")!=null){
        	session.removeAttribute("rand");
        }
        session.setAttribute("rand", str);
    }
}

3.使用此验证码，在action中配置

<result-types>
			<result-type name="image" class="info.frady.result.ImageResult" />
		</result-types>
		<action name="image" class="info.frady.action.ImageAction">
			<result name="success" type="image" />
		</action>

4.当然了，有人会问ImageAction的代码是什么，答案是空的

package info.frady.action;
import com.opensymphony.xwork2.ActionSupport;
public class ImageAction extends ActionSupport {
	public String execute() throws Exception {
		return SUCCESS;
	}
}

使用的话，就用image.action来访问。。。。