在myeclipse里可以运行没发现错误,但是用浏览器打开时就一个空白页面什么都没有。
哪位大虾帮小弟解决一下菜鸟问题!!!!!IdentityServlet.java
package com.helloweenvsfei.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class IdentityServlet extends HttpServlet {
public static final char[] CHARS={'2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','J','K',
'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
public static Random random=new Random();
public static String getRandomString(){
StringBuffer buffer=new StringBuffer();
for(int i=0;i<6;i++){
buffer.append(CHARS[random.nextInt(CHARS.length)]);
}
return buffer.toString();
}
public static Color getRandomColor(){
return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
}
public static Color getReverseColor(Color c){
return new Color(255-c.getRed(),255-c.getGreen(),255-c.getBlue());
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("image/jepg");
String randomString=getRandomString();
request.getSession(true).setAttribute("randomString", randomString);
int width=100;
int height=30;
Color color=getRandomColor();
Color reverse=getReverseColor(color);
BufferedImage bi=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics2D g=bi.createGraphics();
g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
g.setColor(color);
g.fillRect(0, 0, width, height);
g.setColor(reverse);
g.drawString(randomString, 18, 20);
for(int i=0,n=random.nextInt(100);i<n;i++){
g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
}
ServletOutputStream out=response.getOutputStream();
JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
encoder.encode(bi);
out.flush();
}}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>IdentityServlet</servlet-name>
<servlet-class>com.helloweenvsfei.servlet.IdentityServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>IdentityServlet</servlet-name>
<url-pattern>/servlet/IdentityServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
identity.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>identity.html</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=GB18030"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body><script>
function reloadImage() {
document.getElementById('btn').disabled = true;
document.getElementById('identity').src='servlet/IdentityServlet?ts=' + new Date().getTime();
}
</script> <img src="servlet/IdentityServlet" id="identity" onload="btn.disabled = false; " />
<input type=button value=" 换个图片 " onclick="reloadImage()" id="btn"> </body>
</html>
哪位大虾帮小弟解决一下菜鸟问题!!!!!IdentityServlet.java
package com.helloweenvsfei.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class IdentityServlet extends HttpServlet {
public static final char[] CHARS={'2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','J','K',
'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
public static Random random=new Random();
public static String getRandomString(){
StringBuffer buffer=new StringBuffer();
for(int i=0;i<6;i++){
buffer.append(CHARS[random.nextInt(CHARS.length)]);
}
return buffer.toString();
}
public static Color getRandomColor(){
return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
}
public static Color getReverseColor(Color c){
return new Color(255-c.getRed(),255-c.getGreen(),255-c.getBlue());
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("image/jepg");
String randomString=getRandomString();
request.getSession(true).setAttribute("randomString", randomString);
int width=100;
int height=30;
Color color=getRandomColor();
Color reverse=getReverseColor(color);
BufferedImage bi=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics2D g=bi.createGraphics();
g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
g.setColor(color);
g.fillRect(0, 0, width, height);
g.setColor(reverse);
g.drawString(randomString, 18, 20);
for(int i=0,n=random.nextInt(100);i<n;i++){
g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
}
ServletOutputStream out=response.getOutputStream();
JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
encoder.encode(bi);
out.flush();
}}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>IdentityServlet</servlet-name>
<servlet-class>com.helloweenvsfei.servlet.IdentityServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>IdentityServlet</servlet-name>
<url-pattern>/servlet/IdentityServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
identity.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>identity.html</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=GB18030"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body><script>
function reloadImage() {
document.getElementById('btn').disabled = true;
document.getElementById('identity').src='servlet/IdentityServlet?ts=' + new Date().getTime();
}
</script> <img src="servlet/IdentityServlet" id="identity" onload="btn.disabled = false; " />
<input type=button value=" 换个图片 " onclick="reloadImage()" id="btn"> </body>
</html>
document.getElementById('identity').src='"<%=request.getContextPath()%>/servlet/IdentityServlet?ts=' + new Date().getTime();