Java 在 IntelliJ IDEA 13 中设置 Log4J
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Setting Up Log4J in IntelliJ IDEA 13
提问by user3748486
I'm building a simple app in IntelliJ IDEA 13 and can't seem to figure out how to get log4j working. My app is a simple demo that I made to make sure I could build something functional, all it does is multiply two random numbers and uses apache tomcat to put it on a localhost that I can access via my browser.
我正在 IntelliJ IDEA 13 中构建一个简单的应用程序，但似乎无法弄清楚如何让 log4j 工作。我的应用程序是一个简单的演示，我用来确保我可以构建一些功能性的东西，它所做的只是将两个随机数相乘并使用 apache tomcat 将它放在我可以通过浏览器访问的本地主机上。
Here is the class code:
这是类代码：
package Sample;
log4j-api-2.0.jar;
log4j-core-2.0.jar;
import org.apache.log4j.Logger;
import org.apache.log4j.LogManager;
public class HelloWorld {
public static double getMessage() {
return Math.random()* Math.random();
}
private static Logger log = LogManager.getRootLogger();
log.debug("Debugging Message");
log.info("Informational message");
log.warn("Warning Message");
System.in.read();
}
I'm getting the error "class or interface expected" at the import lines and jar file lines so I don't think I've placed the corresponding files in the right directory. That's also causing the rest of the logging lines (from private static Logger... on) to generate errors.
我在导入行和 jar 文件行收到错误“预期的类或接口”，所以我认为我没有将相应的文件放在正确的目录中。这也会导致其余的日志记录行（来自私有静态 Logger ... on）生成错误。
回答by Dave Newton
1.The following isn't valid Java:
1.以下是无效的 Java：
log4j-api-2.0.jar;
log4j-core-2.0.jar;
You onlyneed the importlines, e.g.,
你只需要import线条，例如，
import org.apache.log4j.Logger;
import org.apache.log4j.LogManager;
2.The .jarfiles must be associated with your project.
2.该.jar文件必须与项目有关。
You can:
你可以：
- Right-click the "External Libraries" section and add them that way, or...
- Use Maven and add them as project dependencies, or...
- Use some other dependency management and/or build tool, e.g., Ant + Ivy, Gradle, etc.
- 右键单击“外部库”部分并以这种方式添加它们，或者...
- 使用 Maven 并将它们添加为项目依赖项，或者...
- 使用其他一些依赖管理和/或构建工具，例如 Ant + Ivy、Gradle 等。
3.You need to move the logging statements into a place where code is valid, like in a method:
3.您需要将日志语句移动到代码有效的地方，例如在方法中：
package sample;
import org.apache.log4j.Logger;
import org.apache.log4j.LogManager;
public class HelloWorld {
private static final Logger log = LogManager.getRootLogger();
public static void main(String[] args) {
log.debug("Debugging Message");
log.info("Informational message");
log.warn("Warning Message");
}
}
