今天新建一個前端demo專案，需要引入thymeleaf依賴，專案執行和測試都正常，但是打包的時候卻報以下錯誤：

D:\Server\Java\jdk1.8.0_231\bin\java.exe -Dmaven.multiModuleProjectDirectory=E:\Private\homework-parent\template-layui -Dmaven.home=E:\Tools\Maven\apache-maven-3.6.3 -Dclassworlds.conf=E:\Tools\Maven\apache-maven-3.6.3\bin\m2.conf "-Dmaven.ext.class.path=D:\Software\JetBrains\IntelliJ IDEA 2019.3.3\plugins\maven\lib\maven-event-listener.jar" "-javaagent:D:\Software\JetBrains\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=14887:D:\Software\JetBrains\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath E:\Tools\Maven\apache-maven-3.6.3\boot\plexus-classworlds-2.6.0.jar;E:\Tools\Maven\apache-maven-3.6.3\boot\plexus-classworlds.license org.codehaus.classworlds.Launcher -Didea.version2019.3.3 -s E:\Tools\Maven\apache-maven-3.6.3\conf\settings.xml -Dmaven.repo.local=E:\Tools\Repository package
[INFO] Scanning for projects...
[INFO] 
[INFO] --------------------< org.dandelion:template-layui >--------------------
[INFO] Building template-layui 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ template-layui ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.171 s
[INFO] Finished at: 2021-06-14T07:55:24+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:3.2.0:resources (default-resources) on project template-layui: Input length = 1 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

 

根據網上獲取到的資訊說是pom檔案中沒有引入maven-resources-plugin外掛，於是我把pom檔案修改為如下，但還是不行。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>org.dandelion</groupId>
    <artifactId>template-layui</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <java.version>1.8</java.version>
        <mybatis.version>1.3.2</mybatis.version>
        <mysql.version>5.1.48</mysql.version>
        <nekohtml.version>1.9.22</nekohtml.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
            <version>${nekohtml.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>${mybatis.version}</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>
 

根據報錯資訊得知引入maven外掛maven-resources-plugin時版本可能衝突，我用的springboot版本時2.4.4，而這裡用到的maven外掛是3.2.0。

嘗試將maven外掛改為3.1.0，再次打包成功。

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>3.1.0</version>
        </plugin>
    </plugins>
</build>
 

所以問題是使用springboot2.4.x版本引入maven的resource外掛時需要指定3.1.0版本。