Question

我有一个从随机String生成图像的java类，当我单独运行并且图像保存在本地目录中时，java代码工作正常。

现在我创建了一个简单的JSP表单进行注册，如何在JSP中的html <img>中显示图像。以下是我的代码：

的index.jsp

<%@page import="javax.imageio.ImageIO"%>
<%@page import="java.awt.image.BufferedImage"%>
<%@page import="convert.references"%>
<%@page import="java.io.*, java.util.*"%>
<html>
<head>
<title>Echoing HTML Request Parameters</title>
</head>
<body>  
<h3>Registering user...</h3>
<form method="get">
    Please enter your Username:
    <input type="text" name="username"/><br>
    Please enter your Email:
    <input type="text" name="email"><br>
    Please enter your Security Question:
    <input type="text" name="qn"><br>
    Please enter your Security Answer:
    <input type="text" name="ans"><br>
    Please enter your Recovery Password:
    <input type="password" name="pass"><br>    
    <input type="submit" value="Enter">
</form> 
<%
    String username = request.getParameter("username");
    String email = request.getParameter("email");
    String qn = request.getParameter("qn");
    String ans = request.getParameter("ans");
    String pass = request.getParameter("pass");

    if (username != null) {          
        references test = new references();
        BufferedImage image = test.stringToImage(); 
        File outputfile = new File("saved.png");
        ImageIO.write(image, "png", outputfile);
%>  
    <h3>Your details:</h3>
    <ul>
        <li><%= username %></li>
        <li><%= email %></li>
        <li><%= qn %></li>
        <li><%= ans %></li>
        <li><%= pass %></li>
        <li><img src="<%= outputfile%>" alt="Image not found" /></li>
    </ul>
    <a href="<%= request.getRequestURI() %>">BACK</a>
<%
}
%>
</body>
</html>

references.java（单独工作，能够生成）

package convert;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.util.Random;
import java.util.Scanner;

public class references {

    private final int stringLength = 10;

    public BufferedImage stringToImage(){
            //reference from: http://stackoverflow.com/questions/18800717/convert-text-content-to-image
            Scanner reader = new Scanner(System.in);            
            String imageText = "";
            for(int count = 0; count < stringLength; count++){                      //consisting of 8 value
                Random rand = new Random();                                         //randomly selected
                int randomNumber = rand.nextInt(10);                                //of 1-9
                imageText += randomNumber;                                          //one number at a time for 8 times
            }
            BufferedImage img = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = img.createGraphics();
            Font font = new Font("Arial", Font.PLAIN, 48);
            g2d.setFont(font);
            FontMetrics fm = g2d.getFontMetrics();
            int width = fm.stringWidth(imageText);
            int height = fm.getHeight();
            g2d.dispose();

            img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
            g2d = img.createGraphics();
            g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
            g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
            g2d.setFont(font);
            fm = g2d.getFontMetrics();
            g2d.setColor(Color.BLACK);
            g2d.drawString(imageText, 0, fm.getAscent());
            g2d.dispose();
            /*try{
                File outputfile = new File("saved.png");
                ImageIO.write(img, "png", outputfile);
            } catch (IOException e) {}*/
            return img;
        }
}

在jsp上生成图像并显示的任何其他方法？

Answer 1

您可以在jsp中使用<img src="saved.png">。只要saved.png位于您的Web应用程序上下文根目录中。

另一种方法是创建一个servlet，它将处理即时图像生成（无需保存到硬盘驱动器）。然后在jsp中你将servlet引用为图像的src。

生成BufferedImage后，JSP在html中显示图像

1 个答案: