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This article mainly introduces "Java how to save login CAPTCHA to redis". In daily operation, I believe that many people have doubts about how to save login CAPTCHA to redis in Java. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the question of "how to save login CAPTCHA to redis". Next, please follow the editor to study!

Introduce redis dependency

Org.springframework.boot

Spring-boot-starter-data-redis

CAPTCHA generation class

Package com.yishang.yspay.util

Import org.springframework.beans.factory.annotation.Autowired

Import org.springframework.data.redis.core.RedisTemplate

Import java.awt.*

Import java.util.Random

/ * *

* CAPTCHA generation class

, /

Public class RandomValidateCode {

Public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY"; / / key in session

/ / private String randString = "0123456789"; / / randomly generate the string private String with only numbers

/ / private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; / / randomly generate a string with only letters

Private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; / / randomly generates a string of numbers and letters

Private int width = 95 position / picture width

Private int height = 25umbnail / picture high

Private int lineSize = 10 / number of interference lines

Private int stringNum = 4 characters / number of characters randomly generated

/ * *

* redis tool

, /

@ Autowired

Private RedisTemplate redisTemplate

Private Random random = new Random ()

/ *

* get the font

, /

Private Font getFont () {

Return new Font ("Fixedsys", Font.CENTER_BASELINE, 24)

}

/ *

* get the color

, /

Public Color getRandColor (int fc, int bc) {

If (fc > 255)

Fc = 255,

If (bc > 255)

Bc = 255,

Int r = fc + random.nextInt (bc-fc-16)

Int g = fc + random.nextInt (bc-fc-14)

Int b = fc + random.nextInt (bc-fc-18)

Return new Color (r, g, b)

}

/ *

* draw string

, /

Public String drowString (Graphics g, String randomString, int I) {

G.setFont (getFont ())

G.setColor (new Color (random.nextInt, random.nextInt), random

.nextInt (121)

String rand = String.valueOf (getRandomString (random.nextInt (randString)

.length ()

RandomString + = rand

G.translate (random.nextInt (3), random.nextInt (3))

G.drawString (rand, 13 * I, 16)

Return randomString

}

/ *

* draw interference lines

, /

Public void drowLine (Graphics g) {

Int x = random.nextInt (width)

Int y = random.nextInt (height)

Int xl = random.nextInt (13)

Int yl = random.nextInt (15)

G.drawLine (x, y, x + xl, y + yl)

}

/ *

* get random characters

, /

Public String getRandomString (int num) {

Return String.valueOf (randString.charAt (num))

}

}

Interface

@ RequestMapping (value = "/ getVerify")

Public void getVerify (HttpServletRequest request, HttpServletResponse response) {

Response.setContentType ("image/jpeg"); / / set the corresponding type and tell the browser that the output is an image.

Response.setHeader ("Pragma", "No-cache"); / / set the response header information, telling the browser not to cache this content

Response.setHeader ("Cache-Control", "no-cache")

Response.setDateHeader ("Expire", 0)

RandomValidateCode randomValidateCode = new RandomValidateCode ()

/ / the BufferedImage class is an Image class with a buffer, and the Image class is a class used to describe image information.

BufferedImage image = new BufferedImage (95,25, BufferedImage.TYPE_INT_BGR)

Graphics g = image.getGraphics (); / / generate the Graphics object of the Image object, which can perform various drawing operations on the image

G.fillRect (0,0,95,25)

G.setFont (new Font ("Times New Roman", Font.ROMAN_BASELINE, 18))

G.setColor (randomValidateCode.getRandColor 110,133)

/ / draw interference lines

For (int I = 0; I

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