java如何实现图形验证码呢?

Java生成图形验证码的方法

图形验证码实现思路:
   1.引入相应的jar包 easy-captcha

   2.调用 CaptchaUtil.out即可生成验证码
      同时验证码会存储在session(captcha)中

注意事项:
    生成的验证码会存储到Session中,如下源码所示

easy-captcha部分源码分析

public class CaptchaUtil {
...
	
 public static void out(Captcha captcha, HttpServletRequest request, HttpServletResponse response) throws IOException {
	setHeader(response);
	request.getSession().setAttribute("captcha", captcha.text().toLowerCase());
 	captcha.out(response.getOutputStream());
  } 
...
}

//引入相应依赖

pom.xml
<dependency>
  <groupId>com.github.whvcse</groupId>
  <artifactId>easy-captcha</artifactId>
  <version>1.6.2</version>
</dependency>

//springmvc中使用
@Controller
public class CaptchaController {
    
    @RequestMapping("/captcha")
    public void captcha(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //生成图形验证码
		CaptchaUtil.out(request, response);
    }
} 


//前端html代码
<img src="/captcha" width="130px" height="48px" />