一、 ：日志，问题排查的利器

在Linux系统中，Tomcat日志记录了服务器运行过程中的各种信息，是排查问题的宝昂贵材料。只是怎么从海量的日志中飞迅速找到问题的线索，成为了许许多开发者面临的困难题。

二、 问题定位：从哪里开头

1. 查看Tomcat运行日志和报错信息

用tail命令查看Tomcat运行日志和报错信息：

cd /xxxxx/xxxxx/tomcat/logs/
tail -f catalina.out

2. 定期备份日志文件

定期备份日志文件，以防数据丢失或损恶劣：

cp /var/log/tomcat/ /var/log/tomcat/backup/

三、深厚入琢磨：怎么找到潜在问题

1. 用日志琢磨工具

通过Debian Tomcat日志找到潜在问题的步骤如下：

grep -i "error" /var/log/tomcat/
grep -i "exception" /var/log/tomcat/
grep -i "failed" /var/log/tomcat/

2. 琢磨访问日志

增有力SSL日志记录：在conf/logging.properties文件中添加以下配置，启用详细的SSL日志，以便更优良地定位问题：

java.util.logging.FileHandler.pattern = ./%u-%g-%t-%a.log
java.util.logging.FileHandler.limit = 0
java.util.logging.FileHandler.count = 0
java.util.logging.FileHandler.append = true

3. 查看关键日志文件

启用访问日志，需要修改文件。

cat /var/log/tomcat/localhost..log

四、实战案例：怎么应用这些个技巧

1. 检查配置文件

访问Tomcat日志文件：

tail -f /var/log/tomcat/

2. 检查错误和异常信息

用tail -f命令能实时查看日志文件的最新鲜内容。

tail -f /var/log/tomcat/localhost..log

3. 监控性能指标

打开日志文件/var/log/tomcat/catalina.out，会看到如下错误：

java.net.SocketException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect
at java.net.PlainSocketImpl.doConnect
at java.net.SocksSocketImpl.connect
at java.net.Socket.connect
at org.apache.catalina.connector.http/HttpClientOutputBuffer.openConnection
at org.apache.catalina.connector.http/HttpClientOutputBuffer.start
at org.apache.catalina.connector.http/HttpClientOutputBuffer.doWrite
at org.apache.catalina.connector OutputBuffer.doWrite
at org.apache.catalina.connector OutputBuffer.write
at org.apache.catalina.connector OutputBuffer.flush
at org.apache.catalina.connector OutputBuffer.endRequest
at org.apache.catalina.connector OutputBuffer finishRequest
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse
at org.apache.catalina.connector OutputBuffer finishResponse(OutputBuffer

---