eclipse 中的项目无法解析 Maven 依赖项中存在的 jars
Project in eclipse not resolving jars present in Maven dependency
我在使用 eclipse 和 maven 时变得非常困惑。我正在尝试创建一个具有如下包结构的项目:
现在在 DbSIngleton.java
文件中我引用了 EmbeddedDriver
class org.apache.derby.jdbc
包。但它无法解决这个问题,这很奇怪,因为 jar 存在于 Maven 依赖项中,如图所示。还有另一个 jar twitter4j
被引用而没有任何错误。为什么这个 derby jar 失败了?我错过了什么吗?
代码:
private DbSingleton() {
try {
DriverManager.registerDriver(new org.apache.derby.jdbc.EmbeddedDriver());
} catch (SQLException e) {
e.printStackTrace();
}
if(conn != null) {
throw new RuntimeException("Use getConnection() method to create");
}
if(instance != null) {
throw new RuntimeException("Use getInstance() method to create");
}
}
pom.xml:
<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>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.twitter4j</groupId>
<artifactId>twitter4j-core</artifactId>
<version>[4.0,)</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.derby/derby -->
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
请删除测试范围
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
<scope>test</scope>
</dependency>
应该是
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
</dependency>
Twitter 依赖项在默认范围内。因此,它正在得到解决。
我在使用 eclipse 和 maven 时变得非常困惑。我正在尝试创建一个具有如下包结构的项目:
现在在 DbSIngleton.java
文件中我引用了 EmbeddedDriver
class org.apache.derby.jdbc
包。但它无法解决这个问题,这很奇怪,因为 jar 存在于 Maven 依赖项中,如图所示。还有另一个 jar twitter4j
被引用而没有任何错误。为什么这个 derby jar 失败了?我错过了什么吗?
代码:
private DbSingleton() {
try {
DriverManager.registerDriver(new org.apache.derby.jdbc.EmbeddedDriver());
} catch (SQLException e) {
e.printStackTrace();
}
if(conn != null) {
throw new RuntimeException("Use getConnection() method to create");
}
if(instance != null) {
throw new RuntimeException("Use getInstance() method to create");
}
}
pom.xml:
<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>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.twitter4j</groupId>
<artifactId>twitter4j-core</artifactId>
<version>[4.0,)</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.derby/derby -->
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
请删除测试范围
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
<scope>test</scope>
</dependency>
应该是
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.11.1.1</version>
</dependency>
Twitter 依赖项在默认范围内。因此,它正在得到解决。