我尝试完成有关 Java 日志记录 API 的教程:
www.vogella.com/articles/Logging/article.html
但生成的文件是空的(在 Netbeans、Eclipse 以及从 cmd 运行 jar 中测试)。日志消息仅显示在控制台中。
以下是项目中使用的文件。这种行为的原因可能是什么？
项目:de.vogella.logger
MyHtmlFormatter.java
package de.vogella.logger;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;
//This custom formatter formats parts of a log record to a single line
class MyHtmlFormatter extends Formatter {
// This method is called for every log records
public String format(LogRecord rec) {
StringBuffer buf = new StringBuffer(1000);
// Bold any levels >= WARNING
buf.append("<tr>");
buf.append("<td>");
if (rec.getLevel().intValue() >= Level.WARNING.intValue()) {
buf.append("<b>");
buf.append(rec.getLevel());
buf.append("</b>");
} else {
buf.append(rec.getLevel());
}
buf.append("</td>");
buf.append("<td>");
buf.append(calcDate(rec.getMillis()));
buf.append(' ');
buf.append(formatMessage(rec));
buf.append('\n');
buf.append("<td>");
buf.append("</tr>\n");
return buf.toString();
}
private String calcDate(long millisecs) {
SimpleDateFormat date_format = new SimpleDateFormat("MMM dd,yyyy HH:mm");
Date resultdate = new Date(millisecs);
return date_format.format(resultdate);
}
// This method is called just after the handler using this
// formatter is created
public String getHead(Handler h) {
return "<HTML>\n<HEAD>\n" + (new Date())
+ "\n</HEAD>\n<BODY>\n<PRE>\n"
+ "<table width=\"100%\" border>\n "
+ "<tr><th>Level</th>" +
"<th>Time</th>" +
"<th>Log Message</th>" +
"</tr>\n";
}
// This method is called just after the handler using this
// formatter is closed
public String getTail(Handler h) {
return "</table>\n </PRE></BODY>\n</HTML>\n";
}
}
MyLogger.java
package de.vogella.logger;
import java.io.IOException;
import java.util.logging.FileHandler;
import java.util.logging.Formatter;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;
public class MyLogger {
static private FileHandler fileTxt;
static private SimpleFormatter formatterTxt;
static private FileHandler fileHTML;
static private Formatter formatterHTML;
static public void setup() throws IOException {
// Get the global logger to configure it
Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
logger.setLevel(Level.INFO);
fileTxt = new FileHandler("Logging.txt");
fileHTML = new FileHandler("Logging.html");
// Create txt Formatter
formatterTxt = new SimpleFormatter();
fileTxt.setFormatter(formatterTxt);
logger.addHandler(fileTxt);
// Create HTML Formatter
formatterHTML = new MyHtmlFormatter();
fileHTML.setFormatter(formatterHTML);
logger.addHandler(fileHTML);
}
}
UseLogger.java
package de.vogella.logger.test;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import de.vogella.logger.MyLogger;
public class UseLogger {
// Always use the classname, this way you can refactor
private final static Logger LOGGER = Logger.getLogger(UseLogger.class
.getName());
public void doSomeThingAndLog() {
// Image here some real work
// Now we demo the logging
// Set the LogLevel to Severe, only severe Messages will be written
LOGGER.setLevel(Level.SEVERE);
LOGGER.severe("Info Log");
LOGGER.warning("Info Log");
LOGGER.info("Info Log");
LOGGER.finest("Really not important");
// Set the LogLevel to Info, severe, warning and info will be written
// Finest is still not written
LOGGER.setLevel(Level.INFO);
LOGGER.severe("Info Log");
LOGGER.warning("Info Log");
LOGGER.info("Info Log");
LOGGER.finest("Really not important");
}
public static void main(String[] args) {
UseLogger tester = new UseLogger();
try {
MyLogger.setup();
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException("Problems with creating the log files");
}
tester.doSomeThingAndLog();
}
}
最佳答案
更改以下行(在方法 de.vogella.logger.MyLogger.setup() 中):
// Get the global logger to configure it
Logger logger = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
与:
// Get the global logger to configure it
Logger logger = Logger.getLogger("");
查看更多:
关于生成空日志文件的 Java Logging API，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16641633/