java.util.logging 日志文件或输出到哪里去了？

Question

更新我犯了一个我一直忽略的错误。我的 logging.properties 文件在文件名中有一个我不知道的尾随 space。我不知道它是如何进入那里的，但是一旦我删除了 space 一切正常。我的问题是我提供了错误的名称，即没有尾随 space.

的文件名

我不明白 java.util.logging 是如何工作的。我正在尝试复制以下位置提供的示例代码： Java Practices -> Logging messages

我首先在 Eclipse 中创建了一个空的 Java 项目。 我在包 myapp.business 中创建了一个 class SimpleLogger.java .在resources下面，我放了logging.properties。我没有任何编译问题，我可以单步执行代码，但我不知道输出到哪里去了？

SimpleLogger.java 看起来像：

package myapp.business;

import java.util.logging.Level;
import java.util.logging.Logger;

public final class SimpleLogger {

  public static void main(String... args) {
    SimpleLogger thing = new SimpleLogger();
    thing.doSomething();
  }

  public void doSomething() {
    // Log messages, one for each level
    // The actual logging output depends on the configured
    // level for this package. Calls to "inapplicable"
    // messages are inexpensive.
    fLogger.finest("this is finest");
    fLogger.finer("this is finer");
    fLogger.fine("this is fine");
    fLogger.config("this is config");
    fLogger.info("this is info");
    fLogger.warning("this is a warning");
    fLogger.severe("this is severe");

    // In the above style, the name of the class and
    // method which has generated a message is placed
    // in the output on a best-efforts basis only.
    // To ensure that this information is always
    // included, use the following "precise log"
    // style instead :
    fLogger.logp(Level.INFO, this.getClass().toString(), "doSomething", "blah");

    // For the very common task of logging exceptions, there is a
    // method which takes a Throwable :
    Throwable ex = new IllegalArgumentException("Some exception text");
    fLogger.log(Level.SEVERE, "Some message", ex);

    // There are convenience methods for exiting and
    // entering a method, which are at Level.FINER :
    fLogger.exiting(this.getClass().toString(), "doSomething");

    // Display user.home directory, if desired.
    // (This is the directory where the log files are generated.)
    // System.out.println("user.home dir: " +
    // System.getProperty("user.home") );
  }

  // PRIVATE

  // This style has no hard-coded literals, and requires the logger
  // to be non-static.
  private final Logger fLogger = Logger.getLogger(this.getClass().getPackage().getName());

  // This style lets the logger be static, but hard-codes a class literal.
  // private static final Logger fLogger =
  // Logger.getLogger(SimpleLogger.class.getPackage().getName())
  // ;

  // This style uses a hard-coded literal and should likely be avoided:
  // private static final Logger fLogger = Logger.getLogger("myapp.business");
}

我的 logging.properties 位于 resources 目录中，如下所示：

# Properties file which configures the operation of the JDK 
# logging facility.

# The system will look for this config file, first using 
# a System property specified at startup: 
# 
# >java -Djava.util.logging.config.file=myLoggingConfigFilePath 
# 
# If this property is not specified, then the config file is 
# retrieved from its default location at: 
# 
# JDK_HOME/jre/lib/logging.properties

# Global logging properties. 
# ------------------------------------------ 
# The set of handlers to be loaded upon startup. 
# Comma-separated list of class names. 
# (? LogManager docs say no comma here, but JDK example has comma.) 
handlers=java.util.logging.FileHandler, java.util.logging.ConsoleHandler

# Default global logging level. 
# Loggers and Handlers may override this level 
.level=INFO

# Loggers 
# ------------------------------------------ 
# Loggers are usually attached to packages. 
# Here, the level for each package is specified. 
# The global level is used by default, so levels 
# specified here simply act as an override. 
myapp.ui.level=ALL 
myapp.business.level=CONFIG 
myapp.data.level=SEVERE

# Handlers 
# -----------------------------------------

# --- ConsoleHandler --- 
# Override of global logging level 
java.util.logging.ConsoleHandler.level=SEVERE 
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter

# --- FileHandler --- 
# Override of global logging level 
java.util.logging.FileHandler.level=ALL

# Naming style for the output file: 
# (The output file is placed in the directory 
# defined by the "user.home" System property.) 
java.util.logging.FileHandler.pattern=%h/java%u.log

# Limiting size of output file in bytes: 
java.util.logging.FileHandler.limit=50000

# Number of output files to cycle through, by appending an 
# integer to the base file name: 
java.util.logging.FileHandler.count=1

# Style of output (Simple or XML): 
java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter

在 Eclipse 中的运行配置中，我的 Main class 为 myapp.business.SimpleLogger，我的 VM 参数为 -Djava.util.logging.config.file=resources/logging.properties

我在控制台上没有看到任何内容，也找不到任何 *.log 文件。如果有帮助，我会在 Ubuntu 16.10 运行发布。

编辑： 回应 pvg 我试图将 Eclipse 中的 VM 参数更改为：-Djava.util.logging.config.file=/home/myusername/EclipseWorkspace/Temp/resources/logging.properties

我也试过在bin目录下通过命令行调用它：

java -Djava.util.logging.config.file=/home/myusername/EclipseWorkspace/Temp/resources/logging.properties -cp . myapp.business.SimpleLogger

这也不起作用，即我没有看到任何输出，也没有在任何地方看到 *.log 文件。

Answer 1

对我来说，只有当我将整个路径放在 Eclipse VM 参数中时它才有效：

-Djava.util.logging.config.file=/whole/path/of/logging.properties

然后，将根据 logging.properties 文件中的配置创建输出文件。在这种情况下：

# Naming style for the output file: 
# (The output file is placed in the directory 
# defined by the "user.home" System property.) 
java.util.logging.FileHandler.pattern=%h/java%u.log

输出文件将创建在您用户的主目录中。在我的例子中，创建的文件名是 java0.log - %u 表示 "unique number to resolve conflicts" （a.k.a。一个自动生成的数字，以避免具有相同名称的文件；在我的例子中，它是 0).

Answer 2

...but I cannot figure out where does the output go?

使用以下代码获取工作目录并列出可以告诉您主目录的环境。此示例还尝试使用 LogManager 设置创建文件处理程序。

public static void main(String[] args) throws IOException {
    System.out.println("Working directory=" + new File(".").getCanonicalPath());
    for (Map.Entry<String, String> e : System.getenv().entrySet()) {
        System.out.println(e);
    }
    new FileHandler().close();
}

java.util.logging 日志文件或输出到哪里去了？

Where does the java.util.logging log file or output go?

java

eclipse

logging

java.util.logging