java生成随机验证码

java生成随机验证码

用到的主要类：

Random 生成随机数

BufferedImage 图片缓冲区

Graphics2D 画笔

ImagerIO(RenderedImage image,String formatName,outputStream os)

Color new Color(int r,int g,int b)

Font new Font(String name, int style, int size) 根据指定名称、样式和磅值大小，创建一个新 Font。

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;
/*
* 生成随机验证码
*/
public class VerifiCode {
private int width = 60;   //图片宽度
private int height = 25;    //图片高度
private Random rm = new Random();
private String text;        //验证码文本
private String codes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";//验证码
private String[] fontNames = {"宋体","华文楷体", "黑体", "微软雅黑", "楷体_GB2312"}; //字体名称
/*
*获取随机字体
*/
public Font randomFont(){
int style = rm.nextInt(4);  //字体样式：0是无样式，1是加粗，2是斜体，3是加粗加斜体
int size = rm.nextInt(4)+20;    //字体大小
int index = rm.nextInt(fontNames.length);
String fontName = fontNames[index];
Font font = new Font(fontName,style,size);
return font;
}
/*
* 获取随机颜色
*/
public Color randomColor(){
int r = rm.nextInt(150);
int g = rm.nextInt(150);
int b = rm.nextInt(150);
Color color = new Color(r,g,b);
return color;
}
/*
*对验证码图片画干扰线，防止暴力破解
*/
public BufferedImage drawLine(BufferedImage image){
Graphics2D g = image.createGraphics();
for(int i=0;i<3;i++){               //三条干扰线
int x1 = rm.nextInt(width);
int y1 = rm.nextInt(height);
int x2 = rm.nextInt(width);
int y2 = rm.nextInt(height);
g.drawLine(x1,y1,x2,y2);
}
return image;
}
/*
*生成验证码图片
*/
public BufferedImage drawImage(){
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 4; i++) {
int index = rm.nextInt(codes.length());
String s= codes.charAt(index)+"";
sb.append(s);
float x = 1.0f*width/5*(i+1);
g.setFont(randomFont());
g.setColor(randomColor());
g.drawString(s,x,height-5);
}
this.text = sb.toString();
drawLine(image);
return image;
}

public String getText() {
return text;
}

public static void input(BufferedImage image,OutputStream os) throws IOException{
ImageIO.write(image,"JPEG",os);     //将获取的image写入到输出流os中
}
}