无法使用Spring访问Maven属性 [英] Can't access Maven properties with Spring

问题描述

你好，我是Maven的新手，所以如果我做错了事，我想提前道歉.

我有一个带有Spring的Maven项目，在其中我还可以访问MySQL数据库.
经常无法访问MySQL数据库，因此我使用本地数据库进行测试，通过更改活动配置文件在两者之间进行交换. /p>

我通过将其放入我的POM.xml中来设置配置文件:

 <profiles>
        <profile>
            <id>Local</id>
            <dependencies>
                <dependency>
                    <groupId>org.hsqldb</groupId>
                    <artifactId>hsqldb</artifactId>
                    <version>2.3.3</version>
                    <classifier>jdk5</classifier>
                </dependency>
            </dependencies>
            <properties>
                <jdbc.url>jdbc:hsqldb:file:databaseName</jdbc.url>
                <jdbc.username>a</jdbc.username>
                <jdbc.password></jdbc.password>
                <jdbc.driver>org.hsqldb.jdbcDriver</jdbc.driver>
            </properties>
        </profile>
        <profile>
            <id>MySQL</id>
            <dependencies>
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.38</version>
                </dependency>
            </dependencies>
            <properties>
                <jdbc.url>jdbc:mysql://mysql.website.ac.uk:3306</jdbc.url>
                <jdbc.username>user</jdbc.username>
                <jdbc.password>1234</jdbc.password>
                <jdbc.driver>com.mysql.jdbc.Driver</jdbc.driver>
            </properties>
        </profile>
    </profiles>
 

当我尝试通过例如$ {jdbc.url}访问属性变量时，它们没有转换为配置文件中定义的实际值，并且出现错误.我怀疑这可能与Spring Boot有关.

解决方案

您在配置文件中指定了属性，所以有一种解决方法.诸如@Value("${name}")之类的注释引用的是外部化配置，例如来自application.yml.您应该使用此文件来加载所需的属性. @property_name@从您的Maven个人资料中加载属性.

jdbc:
  url: @jdbc.url@
  username: @jdbc.username@
and so on...

然后可以在您的代码中访问这些属性.

Hello I am new to Maven in general so I'd like to apologise in advance if I get things wrong.

I have a Maven project with spring in which I also access a MySQL database.
often the MySQL database is not accessible so I use a local database for testing, I swap between the two by changing the active profile.

I set up the profiles by putting this in my POM.xml:

<profiles>
        <profile>
            <id>Local</id>
            <dependencies>
                <dependency>
                    <groupId>org.hsqldb</groupId>
                    <artifactId>hsqldb</artifactId>
                    <version>2.3.3</version>
                    <classifier>jdk5</classifier>
                </dependency>
            </dependencies>
            <properties>
                <jdbc.url>jdbc:hsqldb:file:databaseName</jdbc.url>
                <jdbc.username>a</jdbc.username>
                <jdbc.password></jdbc.password>
                <jdbc.driver>org.hsqldb.jdbcDriver</jdbc.driver>
            </properties>
        </profile>
        <profile>
            <id>MySQL</id>
            <dependencies>
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.38</version>
                </dependency>
            </dependencies>
            <properties>
                <jdbc.url>jdbc:mysql://mysql.website.ac.uk:3306</jdbc.url>
                <jdbc.username>user</jdbc.username>
                <jdbc.password>1234</jdbc.password>
                <jdbc.driver>com.mysql.jdbc.Driver</jdbc.driver>
            </properties>
        </profile>
    </profiles>

When I try to access the properties variables through for example ${jdbc.url} they are not converted to the actual values as defined in the profile and I get errors. I suspect it might have something to do with Spring Boot.

解决方案

You specified properties in profile, so there is a workaround. Annotations such as @Value("${name}") are referencing to externalized configuration, e.g. from application.yml. You should use this file to load properties you want. @property_name@ loads property from your maven profile.

jdbc:
  url: @jdbc.url@
  username: @jdbc.username@
and so on...

Then these properties will be accessible in your code.

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