牛客网项目-第一章

环境配置

java
maven
idea

Spring Intializr

搜索jar包的网站：https://mvnrepository.com/
https://start.spring.io/
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缺少的aop包，手动在pom.xml中加入依赖

    	<dependency>
      		<groupId>org.springframework.boot</groupId>
      		<artifactId>spring-boot-starter-aop</artifactId>
    	</dependency>

另外评论区中有人提到JPA底层也是aop实现的，可以导入这个用来代替aop。

下载解压后用idea打开

Spring boot 入门示例

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一开始运行时有报错：

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2023-09-09T15:40:08.281+08:00 ERROR 34354 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
	If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
	If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).


Process finished with exit code 0

原因

这是因为spring boot 会默认加载org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration 这个类DataSourceAutoConfiguration类使用了@Configuration注解向spring注入了dataSource bean。因为工程中没有关于dataSource相关的配置信息，当spring创建dataSource bean因缺少相关的信息就会报错。