intellij idea springboot无法读取配置文件的解决方法

问题描述

Spring Boot项目中运行之后，出现如下的错误：

***************************
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).

或者出现@Value注解的值无法导入的时候，

 Could not resolve placeholder 'elasticsearch.host' in value "${elasticsearch.host}"

可以用以下的解决方案

问题分析及解决方案

问题原因: Mybatis没有找到合适的加载类,其实是大部分spring - datasource - url没有加载成功,分析原因如下所示.

DataSourceAutoConfiguration会自动加载.
没有配置spring - datasource - url 属性.
spring - datasource - url 配置的地址格式有问题.
配置 spring - datasource - url的文件没有加载.

网上给出了这几种解决方案.

方案一 (解决原因1)

排除此类的autoconfig。启动以后就可以正常运行。

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})

方案二 (解决原因2)

在application.properties/或者application.yml文件中没有添加数据库配置信息.

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/read_data?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver

方案三 (解决原因3)

在spring xml配置文件中引用了数据库地址所以需要对:等进行转义处理.但是在application.properties/或者application.yml文件并不需要转义,错误和正确方法写在下面了.

#错误示例
spring.datasource.url = jdbc:mysql\://192.168.0.20\:1504/f_me?setUnicode=true&characterEncoding=utf8
#正确示例
spring.datasource.url = jdbc:mysql://192.168.0.20:1504/f_me?setUnicode=true&char

方案四 (解决原因4)

要在pom文件中<build></build>添加如下.来保证yml或者properties文件能被正常扫描到且加载成功.（intellij idea 运行时，扫描不到src文件夹（java文件夹）里面的配置文件）

<resources>
   <resource>
      <directory>src/main/java</directory>
      <includes>
         <include>**/*.yml</include>
         <include>**/*.properties</include>
      </includes>
      <filtering>false</filtering>
   </resource>
   <resource>
      <directory>src/main/resources</directory>
      <includes>
         <include>**/*.yml</include>
         <include>**/*.properties</include>
      </includes>
      <filtering>false</filtering>
   </resource>
</resources>