ssh生成随机数字验证码操作步骤

<script type="text/javascript">
function changevalidatecode(obj) {
//获取当前的时间作为参数，无具体意义
var timenow = new date().gettime();
//每次请求需要一个不同的参数，否则可能会返回同样的验证码
//这和浏览器的缓存机制有关系，也可以把页面设置为不缓存，这样就不用这个参数了。
obj.src="rand.action?d="+timenow;
}
</script>

<s:text name="random"></s:text>：<s:textfield name="rand" size="5"></s:textfield><img src="rand.action" onclick="changevalidatecode(this)" title="点击图片刷新验证码"/>

import java.awt.color;
import java.awt.font;
import java.awt.graphics;
import java.awt.image.bufferedimage;
import java.io.bytearrayinputstream;
import java.io.bytearrayoutputstream;
import java.util.random;
import javax.imageio.imageio;
import javax.imageio.stream.imageoutputstream;
public class randomnumutil {
private bytearrayinputstream image;//图像
private string str;//验证码
private randomnumutil(){
init();//初始化属性
}
/*
* 取得randomnumutil实例
*/
public static randomnumutil instance(){
return new randomnumutil();
}
/*
* 取得验证码图片
*/
public bytearrayinputstream getimage(){
return this.image;
}
/*
* 取得图片的验证码
*/
public string getstring(){
return this.str;
}
private void init() {
// 在内存中创建图象
int width=85, height=20;
bufferedimage image = new bufferedimage(width, height, bufferedimage.type_int_rgb);
// 获取图形上下文
graphics g = image.getgraphics();
// 生成随机类
random random = new random();
// 设定背景色
g.setcolor(getrandcolor(200,250));
g.fillrect(0, 0, width, height);
// 设定字体
g.setfont(new font("times new roman",font.plain,18));
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
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);
}
// 取随机产生的认证码(6位数字)
string srand="";
for (int i=0;i<6;i++){
string rand=string.valueof(random.nextint(10));
srand+=rand;
// 将认证码显示到图象中
g.setcolor(new color(20+random.nextint(110),20+random.nextint(110),20+random.nextint(110)));
// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawstring(rand,13*i+6,16);
}
//赋值验证码
this.str=srand;
//图象生效
g.dispose();
bytearrayinputstream input=null;
bytearrayoutputstream output = new bytearrayoutputstream();
try{
imageoutputstream imageout = imageio.createimageoutputstream(output);
imageio.write(image, "jpeg", imageout);
imageout.close();
input = new bytearrayinputstream(output.tobytearray());
}catch(exception e){
system.out.println("验证码图片产生出现错误："+e.tostring());
}
this.image=input;/* 赋值图像 */
}
/*
* 给定范围获得随机颜色
*/
private 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);
}
}

import java.io.bytearrayinputstream;
import com.mxl.util.randomnumutil;
import com.opensymphony.xwork2.actioncontext;
import com.opensymphony.xwork2.actionsupport;
public class randomaction extends actionsupport{
private bytearrayinputstream inputstream;
public string execute() throws exception{
randomnumutil rdnu=randomnumutil.instance();
this.setinputstream(rdnu.getimage());//取得带有随机字符串的图片
actioncontext.getcontext().getsession().put("random", rdnu.getstring());//取得随机字符串放入httpsession
return success;
}
public void setinputstream(bytearrayinputstream inputstream) {
this.inputstream = inputstream;
}
public bytearrayinputstream getinputstream() {
return inputstream;
}
}

private string rand; //表单中的rand
public string getrand() {
return rand;
}
public void setrand(string rand) {
this.rand = rand;
}
//从session中取出randomaction.java 中生成的验证码random
string arandom=(string)(actioncontext.getcontext().getsession().get("random"));
//下面就是将session中保存验证码字符串与客户输入的验证码字符串对比了
if(arandom.equals(this.getrand())) {
actioncontext.getcontext().getsession().put("user", this.getusername());
return success;
}
else {
return error;
}

<!-- random验证码 -->
<action name="rand" class="com.mxl.rand.randomaction">
<result type="stream">
<param name="contenttype">image/jpeg</param>
<param name="inputname">inputstream</param>
</result>
</action>