我需要在我的 Maven 專案中決議一個 json 檔案。為此，我從我的 java 檔案 ( App.java )中的一個簡單匯入開始
package com.mycompany.app;
import com.fasterxml.jackson.*;// <-------- HERE
public class App
{
public static void main( String[] args )
{
}
}
然后，我嘗試通過 using 編譯專案，mvn package但出現錯誤：
[INFO] Scanning for projects...
[INFO]
[INFO] ----------------------< com.mycompany.app:my-app >----------------------
[INFO] Building my-app 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.0.2:resources (default-resources) @ my-app ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /tmp/my-app/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ my-app ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /tmp/my-app/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /tmp/my-app/src/main/java/com/mycompany/app/App.java:[2,1] package com.fasterxml.jackson does not exist
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.628 s
[INFO] Finished at: 2022-05-10T15:31:39 02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project my-app: Compilation failure
[ERROR] /tmp/my-app/src/main/java/com/mycompany/app/App.java:[2,1] package com.fasterxml.jackson does not exist
[ERROR]
[ERROR] -> [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/MojoFailureException
以下是我構建 maven 專案的方式：
- 我創建了我的 Maven 專案：
mvn -B archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4
- 我修改了檔案 App.java（由上一個命令創建）以匹配我的檔案。
- 我修改了 pom.xml 以添加依賴項：
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.13.2</version>
</dependency>
你知道如何解決這個錯誤嗎？
uj5u.com熱心網友回復：
我最近已經回答了一個類似的問題：問題是com.fasterxml.jackson不是一個包，有一個檔案夾com/fasterxml/jackson （參見源代碼），但不是一個包。在 Java 中，package是包含至少一個類的命名空間。Asterix import以非遞回方式匯入包中的所有類。所以，如果你需要，比如說，使用 classesJsonParser.java和JacksonException.javafrom package com.fasterxml.jackson.core，你可以像這樣添加一個 asterix 匯入：com.fasterxml.jackson.core.*
轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/472446.html