Generating verification code image through servlet in Java Web Development

1、 Introduction to bufferedimage class

A bufferedimage class is mainly used to generate the verification code image, as follows:

Create a DrawImage servlet to generate verification code pictures

The operation results are as follows:

2、 Use captcha image in form

Operation results:

In addition to the verification code pictures of the combination of letters and numbers, the DrawImage servlet can also generate verification code pictures of Chinese characters, pure numbers and pure letters. You only need to pass the agreed generation identifier parameters to the DrawImage servlet, as shown below:

The operation results are as follows:

3、 The server handles the verification code submitted by the form

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