java学习记录

# 第一个SpringBoot项目

https://www.jb51.net/article/223251.htm#_label0

# pom用阿里云源

<repositories>
    <repository>
        <id>public</id>
        <name>aliyun nexus</name>
        <url>https://maven.aliyun.com/repository/public</url>
        <releases>
            <enabled>true</enabled>
        </releases>
    </repository>
</repositories>

<pluginRepositories>
    <pluginRepository>
        <id>public</id>
        <name>aliyun nexus</name>
        <url>https://maven.aliyun.com/repository/public</url>
        <releases>
            <enabled>true</enabled>
        </releases>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </pluginRepository>
</pluginRepositories>

 

# java中controller，service，serviceImpl，mapper，xml等几个文件的作用理解

https://blog.csdn.net/congweijing/article/details/82499627

https://blog.csdn.net/u011397981/article/details/113106817

https://www.cnblogs.com/heroljy/p/15724043.html

# idea直接跳转到mapper xml插件 mybatisx 

 

# mybitplus无法插入null和0，非空解决方法

https://zhuanlan.zhihu.com/p/649109650

 

 

# java map,list对应json关系

 

// map
Map<String,String> map666 = new HashMap<>();
map666.put("xixi1","111");
map666.put("xixi2","222");

// 创建一个List对象，用于存储字符串类型的元素
List<String> list555 = new ArrayList<>();
list555.add("Apple");
list555.add("Banana");
list555.add("Orange");

List<Map<String,String>> list666 = new ArrayList<>();
// List<Object> list666 = new ArrayList<>(); 同上面效果一样
list666.add(map666);
list666.add(map666);

ajax.put("myMap", map666);  // { myMap: {xixi1:"111" },{xixi2:"222"} }
ajax.put("myListString", list555); // { myListString: ["Apple", "Banana", "Orange"] }
ajax.put("myListMap", list666); // { myListMap:[ {xixi1:"111",xixi2:"222"}  {xixi1:"111",xixi2:"222"} ] }