我有一个画图的servlet,jsp中如何调用这个servelt呢,
并且如果看不清可以再换一张的功能,主要是后面的这个换的问题。
jsp页面应如何写呢?
我的Servelt为:package com.vogoal.util.img;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;public class RandImgCreater {
private static final String CODE_LIST = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
private HttpServletResponse response = null;
private static final int HEIGHT = 20;
private static final int FONT_NUM = 4;
private int width = 0;
private int iNum = 0;
private String codeList = "";
private boolean drawBgFlag = false;
private int rBg = 0;
private int gBg = 0;
private int bBg = 0;
public RandImgCreater(HttpServletResponse response) {
this.response = response;
this.width = 13 * FONT_NUM + 12;
this.iNum = FONT_NUM;
this.codeList = CODE_LIST;
}
public RandImgCreater(HttpServletResponse response,int iNum,String codeList) {
this.response = response;
this.width = 13 * iNum + 12;
this.iNum = iNum;
this.codeList = codeList;
}
public String createRandImage(){
BufferedImage image = new BufferedImage(width, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
if ( drawBgFlag ){
g.setColor(new Color(rBg,gBg,bBg));
g.fillRect(0, 0, width, HEIGHT);
}else{
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, HEIGHT);
for (int i = 0; i < 155; i++) {
g.setColor(getRandColor(140, 200));
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);
}
}
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
String sRand="";
for (int i=0;i<iNum;i++){
int rand=random.nextInt(codeList.length());
String strRand=codeList.substring(rand,rand+1);
sRand+=strRand;
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
g.drawString(strRand,13*i+6,16);
}
g.dispose();
try{
ImageIO.write(image, "JPEG", response.getOutputStream());
}catch(IOException e){
}
return sRand;
}
public void setBgColor(int r,int g,int b){
drawBgFlag = true;
this.rBg = r;
this.gBg = g;
this.bBg = b;
}
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);
}
}
并且如果看不清可以再换一张的功能,主要是后面的这个换的问题。
jsp页面应如何写呢?
我的Servelt为:package com.vogoal.util.img;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;public class RandImgCreater {
private static final String CODE_LIST = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
private HttpServletResponse response = null;
private static final int HEIGHT = 20;
private static final int FONT_NUM = 4;
private int width = 0;
private int iNum = 0;
private String codeList = "";
private boolean drawBgFlag = false;
private int rBg = 0;
private int gBg = 0;
private int bBg = 0;
public RandImgCreater(HttpServletResponse response) {
this.response = response;
this.width = 13 * FONT_NUM + 12;
this.iNum = FONT_NUM;
this.codeList = CODE_LIST;
}
public RandImgCreater(HttpServletResponse response,int iNum,String codeList) {
this.response = response;
this.width = 13 * iNum + 12;
this.iNum = iNum;
this.codeList = codeList;
}
public String createRandImage(){
BufferedImage image = new BufferedImage(width, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
if ( drawBgFlag ){
g.setColor(new Color(rBg,gBg,bBg));
g.fillRect(0, 0, width, HEIGHT);
}else{
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, HEIGHT);
for (int i = 0; i < 155; i++) {
g.setColor(getRandColor(140, 200));
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);
}
}
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
String sRand="";
for (int i=0;i<iNum;i++){
int rand=random.nextInt(codeList.length());
String strRand=codeList.substring(rand,rand+1);
sRand+=strRand;
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
g.drawString(strRand,13*i+6,16);
}
g.dispose();
try{
ImageIO.write(image, "JPEG", response.getOutputStream());
}catch(IOException e){
}
return sRand;
}
public void setBgColor(int r,int g,int b){
drawBgFlag = true;
this.rBg = r;
this.gBg = g;
this.bBg = b;
}
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);
}
}
<servlet>
<servlet-name>validImgServlet</servlet-name>
<servlet-class>com.vogoal.util.img.RandImgCreater</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>validImgServlet</servlet-name>
<url-pattern>/validImg</url-pattern>
</servlet-mapping>页面:
<img src="/validImg" onclick="this.src = '/validImg' + new Date();" />
<img src="/validImg" onclick="this.src = '/validImg?' + new Date();" />
<script type="text/javascript">
function validImg() {
document.getElementById("img1").src = "/validImg";
}
<script >
<img src="/validImg" id="img1" onclick="validImg()" />
然后 写个javascript代码 当点击刷新的时候 重新设置img 的src为原来那个就可以了!
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<html>
<head>
<title>JSP for UserForm form</title>
</head>
<body>
<html:form action="user?mmmm=login">
<br>用户名 : <html:text property="uname"/><html:errors property="uname"/><br/>
密码 : <html:password property="upassword"/><html:errors property="upassword"/><br/>
验证码 : <html:text property="yzm"/><html:errors property="yzm"/><img id="aaa" alt="看不清,点击重选一张" src="<%=request.getContextPath() %>/yzm.do" onclick="f();"><br/>
<html:submit value="提交"/><html:cancel value="重置"/>
</html:form>
</body>
<script type="text/javascript">
function f()
{
document.all.aaa.src = '<%=request.getContextPath() %>/yzm.do?a='+Math.random();
} function check(){
var yzm = document.all.yzm.value;
if(yzm==""){
alert("验证码不能为空");
return false;
}else if(isNaN(yzm)){
alert("验证码只能是数字呢");
return false;
}else if(yzm.length!=4){
alert("验证码长度不对");
return false;
}
}
</script>
</html>
这是我做的,可以正常使用
点击重新获得的时候,要产生一个随机数,不然就直接返回同一张图片