commons-logging 分析之: org.apache.commons.logging.impl.SimpleLog
弓玉书
分析info 日志
public class Main {
public static void main(String[] args) {
Log logger = LogFactory.getLog(Main.class);
//**重点**
logger.info("message");
}
}SimpleLog初始化
SimpleLog静态初始化
触发初始化的地方:
//org.apache.commons.logging.impl.LogFactoryImpl::createLogFromClass
c = Class.forName(logAdapterClassName, true, currentCL);
// Initialize class attributes.
// Load properties file, if found.
// Override with system properties.
static {
// Add props from the resource simplelog.properties
// 从simplelog.properties 载入属性到 simpleLogProps 中
InputStream in = getResourceAsStream("simplelog.properties");
if(null != in) {
try {
simpleLogProps.load(in);
in.close();
} catch(java.io.IOException e) {
// ignored
}
}
// static protected final String systemPrefix = "org.apache.commons.logging.simplelog.";
// 是否显示日志：org.apache.commons.logging.simplelog.showlogname, 默认值：false
showLogName = getBooleanProperty( systemPrefix + "showlogname", showLogName);
// org.apache.commons.logging.simplelog.showShortLogname 是否显示短日志名称 默认值：true
showShortName = getBooleanProperty( systemPrefix + "showShortLogname", showShortName);
// org.apache.commons.logging.simplelog.showdatetime 是否显示时间 默认值：false
showDateTime = getBooleanProperty( systemPrefix + "showdatetime", showDateTime);
if(showDateTime) {
//static protected final String DEFAULT_DATE_TIME_FORMAT = "yyyy/MM/dd HH:mm:ss:SSS zzz";
//static protected String dateTimeFormat = DEFAULT_DATE_TIME_FORMAT;
//org.apache.commons.logging.simplelog.dateTimeFormat 时间格式化， 默认值： yyyy/MM/dd HH:mm:ss:SSS zzz
dateTimeFormat = getStringProperty(systemPrefix + "dateTimeFormat",
dateTimeFormat);
try {
dateFormatter = new SimpleDateFormat(dateTimeFormat);
} catch(IllegalArgumentException e) {
// If the format pattern is invalid - use the default format
dateTimeFormat = DEFAULT_DATE_TIME_FORMAT;
dateFormatter = new SimpleDateFormat(dateTimeFormat);
}
}
}SimpleLog 构造初始化
public SimpleLog(String name) {
logName = name;
// Set initial log level
// Used to be: set default log level to ERROR
// IMHO it should be lower, but at least info ( costin ).
//设置默认级别为 info
setLevel(SimpleLog.LOG_LEVEL_INFO);
// static protected final String systemPrefix = "org.apache.commons.logging.simplelog.";
// Set log level from properties
//org.apache.commons.logging.simplelog.log.com.aya.Main
String lvl = getStringProperty(systemPrefix + "log." + logName);
int i = String.valueOf(name).lastIndexOf(".");
// 遍历用户包：找到对应的日志级别
//org.apache.commons.logging.simplelog.log.com.aya
//org.apache.commons.logging.simplelog.log.com
while(null == lvl && i > -1) {
name = name.substring(0,i);
lvl = getStringProperty(systemPrefix + "log." + name);
i = String.valueOf(name).lastIndexOf(".");
}
// org.apache.commons.logging.simplelog.defaultlog 用户配置的默认级别
if(null == lvl) {
lvl = getStringProperty(systemPrefix + "defaultlog");
}
if("all".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_ALL);
} else if("trace".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_TRACE);
} else if("debug".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_DEBUG);
} else if("info".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_INFO);
} else if("warn".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_WARN);
} else if("error".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_ERROR);
} else if("fatal".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_FATAL);
} else if("off".equalsIgnoreCase(lvl)) {
setLevel(SimpleLog.LOG_LEVEL_OFF);
}
}获取属性
- 从系统环境变量中获取，不为null就返回
- 从simpleLogProps 中获取（从simplelog.properties 载入的）
private static String getStringProperty(String name) {
String prop = null;
try {
prop = System.getProperty(name);
} catch (SecurityException e) {
; // Ignore
}
return (prop == null) ? simpleLogProps.getProperty(name) : prop;
}SimpleLog 属性总结
复制配置: https://blog.csdn.net/gxmark/article/details/7338253
新建配置文件：simplelog.properties
org.apache.commons.logging.simplelog.defaultlog=trace
org.apache.commons.logging.simplelog.log.XXXXXX=debug
org.apache.commons.logging.simplelog.showlogname=true
org.apache.commons.logging.simplelog.showShortLogname=true
org.apache.commons.logging.simplelog.showdatetime=true
org.apache.commons.logging.simplelog.dateTimeFormat=yyyy-MM-dd hh:mm:ss
日志打印分析
public final void info(Object message) {
if (isLevelEnabled(SimpleLog.LOG_LEVEL_INFO)) {
log(SimpleLog.LOG_LEVEL_INFO,message,null);
}
}是否启用日志级别 isLevelEnabled
/**
* Is the given log level currently enabled?
*
* @param logLevel is this level enabled?
*/
protected boolean isLevelEnabled(int logLevel) {
// log level are numerically ordered so can use simple numeric
// comparison
// 日志级别是否大于等于当前日志级别
return (logLevel >= currentLogLevel);
}打印日志
- 拼接日志内容
- showDateTime（时间）
- type（日志级别）
- showShortName（用户类的简单名称）
- t (异常信息)
- 打印
protected void log(int type, Object message, Throwable t) {
// Use a string buffer for better performance
StringBuffer buf = new StringBuffer();
// Append date-time if so configured
if(showDateTime) {
Date now = new Date();
String dateText;
synchronized(dateFormatter) {
dateText = dateFormatter.format(now);
}
buf.append(dateText);
buf.append(" ");
}
// Append a readable representation of the log level
switch(type) {
case SimpleLog.LOG_LEVEL_TRACE: buf.append("[TRACE] "); break;
case SimpleLog.LOG_LEVEL_DEBUG: buf.append("[DEBUG] "); break;
case SimpleLog.LOG_LEVEL_INFO: buf.append("[INFO] "); break;
case SimpleLog.LOG_LEVEL_WARN: buf.append("[WARN] "); break;
case SimpleLog.LOG_LEVEL_ERROR: buf.append("[ERROR] "); break;
case SimpleLog.LOG_LEVEL_FATAL: buf.append("[FATAL] "); break;
}
// Append the name of the log instance if so configured
if( showShortName) {
if( shortLogName==null ) {
// Cut all but the last component of the name for both styles
shortLogName = logName.substring(logName.lastIndexOf(".") + 1);
shortLogName =
shortLogName.substring(shortLogName.lastIndexOf("/") + 1);
}
buf.append(String.valueOf(shortLogName)).append(" - ");
} else if(showLogName) {
buf.append(String.valueOf(logName)).append(" - ");
}
// Append the message
buf.append(String.valueOf(message));
// Append stack trace if not null
if(t != null) {
buf.append(" <");
buf.append(t.toString());
buf.append(">");
java.io.StringWriter sw= new java.io.StringWriter(1024);
java.io.PrintWriter pw= new java.io.PrintWriter(sw);
t.printStackTrace(pw);
pw.close();
buf.append(sw.toString());
}
// Print to the appropriate destination
write(buf);
}打印
protected void write(StringBuffer buffer) {
// 系统错误输出
System.err.println(buffer.toString());
}控制台输出
2018-06-19 04:37:01 [INFO] Main - message
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