学习材料：

001  Java 前端加密传输后端解密以及验证码功能：

http://blog.tingyun.com/web/article/detail/1046

002  spring framework核心框架体系结构 

003http://fangjian0423.github.io/

https://www.kailing.pub/article/index/arcid/153.html  ，

003,slf4J----使用,【slf4j 不指定具体的日志类，方便需要替换时可以快速替换】

<!--

import org.slf4j.LoggerFactory;

import org.slf4j.Logger;

private static final Logger logger = LoggerFactory.getLogger(Tips.class);

-->
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>