Java verification code tool instance code

Tools:

VerifyCodeServlet：

LoginServlet:

login. jsp:

loginsuccess：

Welcome, warm welcome, welcome <% = username% > leaders to guide the work!

Profile:

Suggestion: it is better to set the servlet generating the verification code not to cache, so that there is no need to add a time stamp when the page requests the verification code image. Adding a time stamp is to deceive the browser to prevent the browser from reading the verification code image in the cache, and there is no response after clicking to change one. This is not very good. Each time you click to change one, the browser will cache the newly obtained image locally. If you set no cache in the servlet, it will not be cached locally.

summary

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