Java生成验证码功能实例代码

页面上输入验证码是比较常见的一个功能,实现起来也很简单.给大家写一个简单的生成验证码的示例程序,需要的朋友可以借鉴一下.

闲话少续,直接上代码.代码中的注释很详细.

package com.sm_test.utils; 
import java.awt.color;  
import java.awt.font;  
import java.awt.graphics;  
import java.awt.graphics2d;  
import java.awt.renderinghints;  
import java.awt.geom.affinetransform;  
import java.awt.image.bufferedimage;  
import java.io.file;  
import java.io.fileoutputstream;  
import java.io.ioexception;  
import java.io.outputstream;  
import java.util.arrays;  
import java.util.random;  
import javax.imageio.imageio;  
public class verifycodeutils{  
  //使用到algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符  
  public static final string verify_codes = "23456789abcdefghjklmnpqrstuvwxyz";  
  private static random random = new random();  
  /** 
   * 使用系统默认字符源生成验证码 
   * @param verifysize  验证码长度 
   * @return 
   */  
  public static string generateverifycode(int verifysize){  
    return generateverifycode(verifysize, verify_codes);  
  }  
  /** 
   * 使用指定源生成验证码 
   * @param verifysize  验证码长度 
   * @param sources  验证码字符源 
   * @return 
   */  
  public static string generateverifycode(int verifysize, string sources){  
    if(sources == null || sources.length() == 0){  
      sources = verify_codes;  
    }  
    int codeslen = sources.length();  
    random rand = new random(system.currenttimemillis());  
    stringbuilder verifycode = new stringbuilder(verifysize);  
    for(int i = 0; i < verifysize; i++){  
      verifycode.append(sources.charat(rand.nextint(codeslen-1)));  
    }  
    return verifycode.tostring();  
  }  
  /** 
   * 生成随机验证码文件,并返回验证码值 
   * @param w 
   * @param h 
   * @param outputfile 
   * @param verifysize 
   * @return 
   * @throws ioexception 
   */  
  public static string outputverifyimage(int w, int h, file outputfile, int verifysize) throws ioexception{  
    string verifycode = generateverifycode(verifysize);  
    outputimage(w, h, outputfile, verifycode);  
    return verifycode;  
  }  
  /** 
   * 输出随机验证码图片流,并返回验证码值 
   * @param w 
   * @param h 
   * @param os 
   * @param verifysize 
   * @return 
   * @throws ioexception 
   */  
  public static string outputverifyimage(int w, int h, outputstream os, int verifysize) throws ioexception{  
    string verifycode = generateverifycode(verifysize);  
    outputimage(w, h, os, verifycode);  
    return verifycode;  
  }  
  /** 
   * 生成指定验证码图像文件 
   * @param w 
   * @param h 
   * @param outputfile 
   * @param code 
   * @throws ioexception 
   */  
  public static void outputimage(int w, int h, file outputfile, string code) throws ioexception{  
    if(outputfile == null){  
      return;  
    }  
    file dir = outputfile.getparentfile();  
    if(!dir.exists()){  
      dir.mkdirs();  
    }  
    try{  
      outputfile.createnewfile();  
      fileoutputstream fos = new fileoutputstream(outputfile);  
      outputimage(w, h, fos, code);  
      fos.close();  
    } catch(ioexception e){  
      throw e;  
    }  
  }  
  /** 
   * 输出指定验证码图片流 
   * @param w 
   * @param h 
   * @param os 
   * @param code 
   * @throws ioexception 
   */  
  public static void outputimage(int w, int h, outputstream os, string code) throws ioexception{  
    int verifysize = code.length();  
    bufferedimage image = new bufferedimage(w, h, bufferedimage.type_int_rgb);  
    random rand = new random();  
    graphics2d g2 = image.creategraphics();  
    g2.setrenderinghint(renderinghints.key_antialiasing,renderinghints.value_antialias_on);  
    color[] colors = new color[5];  
    color[] colorspaces = new color[] { color.white, color.cyan,  
        color.gray, color.light_gray, color.magenta, color.orange,  
        color.pink, color.yellow };  
    float[] fractions = new float[colors.length];  
    for(int i = 0; i < colors.length; i++){  
      colors[i] = colorspaces[rand.nextint(colorspaces.length)];  
      fractions[i] = rand.nextfloat();  
    }  
    arrays.sort(fractions);  
    g2.setcolor(color.gray);// 设置边框色  
    g2.fillrect(0, 0, w, h);  
    color c = getrandcolor(200, 255);  
    g2.setcolor(c);// 设置背景色  
    g2.fillrect(0, 2, w, h-4);  
    //绘制干扰线  
    random random = new random();  
    g2.setcolor(getrandcolor(50, 255));// 设置线条的颜色  
    for (int i = 0; i < 20; i++) {  
      int x = random.nextint(w - 1);  
      int y = random.nextint(h - 1);  
      int xl = random.nextint(6) + 1;  
      int yl = random.nextint(12) + 1;  
      g2.drawline(x, y, x + xl + 40, y + yl + 20);  
    }  
    // 添加噪点  
    float yawprate = 0.05f;// 噪声率  
    int area = (int) (yawprate * w * h);  
    for (int i = 0; i < area; i++) {  
      int x = random.nextint(w);  
      int y = random.nextint(h);  
      int rgb = getrandomintcolor();  
      image.setrgb(x, y, rgb);  
    }  
    shear(g2, w, h, c);// 使图片扭曲  
//    g2.setcolor(getrandcolor(100, 160));  
    int fontsize = h-4;  
    font font = new font("algerian", font.italic, fontsize);  
    g2.setfont(font);  
    char[] chars = code.tochararray();  
    for(int i = 0; i < verifysize; i++){  
      affinetransform affine = new affinetransform();  
      affine.settorotation(math.pi / 4 * rand.nextdouble() * (rand.nextboolean() ? 1 : -1), (w / verifysize) * i + fontsize/2, h/2);  
      g2.settransform(affine); 
      g2.setcolor(getrandcolor(100, 160)); 
      g2.drawchars(chars, i, 1, ((w-10) / verifysize) * i + 5, h-(h - (int)(fontsize*0.75))/2);  
    }  
    g2.dispose();  
    imageio.write(image, "jpg", os);  
  }  
  private static color getrandcolor(int fc, int bc) {  
    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);  
  }  
  private static int getrandomintcolor() {  
    int[] rgb = getrandomrgb();  
    int color = 0;  
    for (int c : rgb) {  
      color = color << 8;  
      color = color | c;  
    }  
    return color;  
  }  
  private static int[] getrandomrgb() {  
    int[] rgb = new int[3];  
    for (int i = 0; i < 3; i++) {  
      rgb[i] = random.nextint(255);  
    }  
    return rgb;  
  }  
  private static void shear(graphics g, int w1, int h1, color color) {  
    shearx(g, w1, h1, color);  
    sheary(g, w1, h1, color);  
  }  
  private static void shearx(graphics g, int w1, int h1, color color) {  
    int period = random.nextint(2);  
    boolean bordergap = true;  
    int frames = 1;  
    int phase = random.nextint(2);  
    for (int i = 0; i < h1; i++) {  
      double d = (double) (period >> 1)  
          * math.sin((double) i / (double) period  
              + (6.2831853071795862d * (double) phase)  
              / (double) frames);  
      g.copyarea(0, i, w1, 1, (int) d, 0);  
      if (bordergap) {  
        g.setcolor(color);  
        g.drawline((int) d, i, 0, i);  
        g.drawline((int) d + w1, i, w1, i);  
      }  
    }  
  }  
  private static void sheary(graphics g, int w1, int h1, color color) {  
    int period = random.nextint(40) + 10; // 50;  
    boolean bordergap = true;  
    int frames = 20;  
    int phase = 7;  
    for (int i = 0; i < w1; i++) {  
      double d = (double) (period >> 1)  
          * math.sin((double) i / (double) period  
              + (6.2831853071795862d * (double) phase)  
              / (double) frames);  
      g.copyarea(i, 0, 1, h1, 0, (int) d);  
      if (bordergap) {  
        g.setcolor(color);  
        g.drawline(i, (int) d, i, 0);  
        g.drawline(i, (int) d + h1, i, h1);  
      }  
    }  
  }  
  public static void main(string[] args) throws ioexception{  
    file dir = new file("e:/abc");  
    int w = 200, h = 80;  
    for(int i = 0; i < 50; i++){  
      string verifycode = generateverifycode(4);  
      file file = new file(dir, verifycode + ".jpg");  
      outputimage(w, h, file, verifycode);  
    }  
  }  
}  

上面这段代码就能生成一个验证码,略微修改就能生成各种各样的形式,main方法可以测试.

下面为大家写一下如何返回到页面

package com.sm_test.saomiao.constroller; 
import java.io.ioexception; 
import javax.servlet.http.httpservletrequest; 
import javax.servlet.http.httpservletresponse; 
import javax.servlet.http.httpsession; 
import org.springframework.stereotype.controller; 
import org.springframework.web.bind.annotation.requestmapping; 
import com.sm_test.utils.verifycodeutils; 
@controller  
public class indexconstroller { 
  @requestmapping(value = "/index") 
  public void index(httpservletrequest request,httpservletresponse response) throws ioexception{ 
    response.setheader("pragma", "no-cache");  
    response.setheader("cache-control", "no-cache");  
    response.setdateheader("expires", 0);  
    response.setcontenttype("image/jpeg");  
    //生成随机字串  
    string verifycode = verifycodeutils.generateverifycode(4);  
    //存入会话session  
    httpsession session = request.getsession(true);  
    session.setattribute("rand", verifycode.tolowercase());  
    //生成图片  
    int w = 200, h = 80;  
    verifycodeutils.outputimage(w, h, response.getoutputstream(), verifycode);  
  } 
} 

很简单,用httpservletresponse 就ok了.

需要显示验证码的地方可以直接用img标签,地址就是该controller的url就ok了

以上所述是小编给大家介绍的java生成验证码功能实例代码，希望对大家有所帮助