Java框架学习顺序是什么

public class LoggingEvent {
 public long timestamp;//日志时间戳
 private int level;//日志级别
 private Object message;//日志主题
 private String threadName;//线程名称
 private long threadId;//线程id
 private String loggerName;//日志名称
 
 //getter and setters...
 
 @Override
 public String toString() {
  return "LoggingEvent{" +
    "timestamp=" + timestamp +
    ", level=" + level +
    ", message=" + message +
    ", threadName='" + threadName + '\'' +
    ", threadId=" + threadId +
    ", loggerName='" + loggerName + '\'' +
    '}';
 }
}

public interface Appender {
 void append(LoggingEvent event);
}

public class ConsoleAppender implements Appender {
 private OutputStream out = System.out;
 private OutputStream out_err = System.err;

 @Override
 public void append(LoggingEvent event) {
  try {
   out.write(event.toString().getBytes(encoding));
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}

public enum Level {
 ERROR(40000, "ERROR"), WARN(30000, "WARN"), INFO(20000, "INFO"), DEBUG(10000, "DEBUG"), TRACE(5000, "TRACE");

 private int levelInt;
 private String levelStr;

 Level(int i, String s) {
  levelInt = i;
  levelStr = s;
 }

 public static Level parse(String level) {
  return valueOf(level.toUpperCase());
 }

 public int toInt() {
  return levelInt;
 }

 public String toString() {
  return levelStr;
 }

 public boolean isGreaterOrEqual(Level level) {
  return levelInt>=level.toInt();
 }

}

public class LoggingEvent {
 public long timestamp;//日志时间戳
 private Level level;//替换后的日志级别
 private Object message;//日志主题
 private String threadName;//线程名称
 private long threadId;//线程id
 private String loggerName;//日志名称
 
 //getter and setters...
}

public interface Logger{
 void trace(String msg);
 void info(String msg);
 void debug(String msg);
 void warn(String msg);
 void error(String msg);
 String getName();
}

public class LogcLogger implements Logger{
 private String name;
 private Appender appender;
 private Level level = Level.TRACE;//当前Logger的级别，默认最低
 private int effectiveLevelInt;//冗余级别字段，方便使用
 
 @Override
 public void trace(String msg) {
  filterAndLog(Level.TRACE,msg);
 }

 @Override
 public void info(String msg) {
  filterAndLog(Level.INFO,msg);
 }

 @Override
 public void debug(String msg) {
  filterAndLog(Level.DEBUG,msg);
 }

 @Override
 public void warn(String msg) {
  filterAndLog(Level.WARN,msg);
 }

 @Override
 public void error(String msg) {
  filterAndLog(Level.ERROR,msg);
 }
 
 /**
  * 过滤并输出，所有的输出方法都会调用此方法
  * @param level 日志级别
  * @param msg 输出内容
  */
 private void filterAndLog(Level level,String msg){
  LoggingEvent e = new LoggingEvent(level, msg,getName());
  //目标的日志级别大于当前级别才可以输出
  if(level.toInt() >= effectiveLevelInt){
   appender.append(e);
  }
 }
 
 @Override
 public String getName() {
  return name;
 }
 
 //getters and setters...
}

private LogcLogger parent;//先给增加一个parent属性

private void filterAndLog(Level level,String msg){
 LoggingEvent e = new LoggingEvent(level, msg,getName());
 //循环向上查找可用的logger进行输出
 for (LogcLogger l = this;l != null;l = l.parent){
  if(l.appender == null){
   continue;
  }
  if(level.toInt()>effectiveLevelInt){
   l.appender.append(e);
  }
  break;
 }
}

/**
 * 一个全局的上下文对象
 */
public class LoggerContext {

 /**
  * 根logger
  */
 private Logger root;

 /**
  * logger缓存，存放解析配置文件后生成的logger对象，以及通过程序手动创建的logger对象
  */
 private Map<String,Logger> loggerCache = new HashMap<>();

 public void addLogger(String name,Logger logger){
  loggerCache.put(name,logger);
 }

 public void addLogger(Logger logger){
  loggerCache.put(logger.getName(),logger);
 }
 //getters and setters...
}

public interface ILoggerFactory {
 //通过class获取/创建logger
 Logger getLogger(Class<?> clazz);
 //通过name获取/创建logger
 Logger getLogger(String name);
 //通过name创建logger
 Logger newLogger(String name);
}

public class StaticLoggerFactory implements ILoggerFactory {

 private LoggerContext loggerContext;//引用LoggerContext

 @Override
 public Logger getLogger(Class<?> clazz) {
  return getLogger(clazz.getName());
 }

 @Override
 public Logger getLogger(String name) {
  Logger logger = loggerContext.getLoggerCache().get(name);
  if(logger == null){
   logger = newLogger(name);
  }
  return logger;
 }
 
 /**
  * 创建Logger对象
  * 匹配logger name，拆分类名后和已创建（包括配置的）的Logger进行匹配
  * 比如当前name为com.aaa.bbb.ccc.XXService，那么name为com/com.aaa/com.aaa.bbb/com.aaa.bbb.ccc
  * 的logger都可以作为parent logger，不过这里需要顺序拆分，优先匹配“最近的”
  * 在这个例子里就会优先匹配com.aaa.bbb.ccc这个logger，作为自己的parent
  *
  * 如果没有任何一个logger匹配，那么就使用root logger作为自己的parent
  *
  * @param name Logger name
  */
 @Override
 public Logger newLogger(String name) {
  LogcLogger logger = new LogcLogger();
  logger.setName(name);
  Logger parent = null;
  //拆分包名，向上查找parent logger
  for (int i = name.lastIndexOf("."); i >= 0; i = name.lastIndexOf(".",i-1)) {
   String parentName = name.substring(0,i);
   parent = loggerContext.getLoggerCache().get(parentName);
   if(parent != null){
    break;
   }
  }
  if(parent == null){
   parent = loggerContext.getRoot();
  }
  logger.setParent(parent);
  logger.setLoggerContext(loggerContext);
  return logger;
 }
}

public class LoggerFactory {

 private static ILoggerFactory loggerFactory = new StaticLoggerFactory();

 public static ILoggerFactory getLoggerFactory(){
  return loggerFactory;
 }

 public static Logger getLogger(Class<?> clazz){
  return getLoggerFactory().getLogger(clazz);
 }

 public static Logger getLogger(String name){
  return getLoggerFactory().getLogger(name);
 }
}

<configuration>

 <appender name="std_plain" class="cc.leevi.common.logc.appender.ConsoleAppender">
 </appender>

 <logger name="cc.leevi.common.logc">
  <appender-ref ref="std_plain"/>
 </logger>

 <root level="trace">
  <appender-ref ref="std_pattern"/>
 </root>
</configuration>

public interface Configurator {
 void doConfigure();
}

public class XMLConfigurator implements Configurator{
 
 private final LoggerContext loggerContext;
 
 public XMLConfigurator(URL url, LoggerContext loggerContext) {
  this.url = url;//文件url
  this.loggerContext = loggerContext;
 }
 
 @Override
 public void doConfigure() {
  try{
   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
   DocumentBuilder documentBuilder = factory.newDocumentBuilder();
   Document document = documentBuilder.parse(url.openStream());
   parse(document.getDocumentElement());
   ...
  }catch (Exception e){
   ...
  }
 }
 private void parse(Element document) throws IllegalAccessException, ClassNotFoundException, InstantiationException {
  //do parse...
 }
}

public class ContextInitializer {
 final public static String AUTOCONFIG_FILE = "logc.xml";//默认使用xml配置文件
 final public static String YAML_FILE = "logc.yml";

 private static final LoggerContext DEFAULT_LOGGER_CONTEXT = new LoggerContext();
 
 /**
 * 初始化上下文
 */
 public static void autoconfig() {
  URL url = getConfigURL();
  if(url == null){
   System.err.println("config[logc.xml or logc.yml] file not found!");
   return ;
  }
  String urlString = url.toString();
  Configurator configurator = null;

  if(urlString.endsWith("xml")){
   configurator = new XMLConfigurator(url,DEFAULT_LOGGER_CONTEXT);
  }
  if(urlString.endsWith("yml")){
   configurator = new YAMLConfigurator(url,DEFAULT_LOGGER_CONTEXT);
  }
  configurator.doConfigure();
 }

 private static URL getConfigURL(){
  URL url = null;
  ClassLoader classLoader = ContextInitializer.class.getClassLoader();
  url = classLoader.getResource(AUTOCONFIG_FILE);
  if(url != null){
   return url;
  }
  url = classLoader.getResource(YAML_FILE);
  if(url != null){
   return url;
  }
  return null;
 }
 
 /**
 * 获取全局默认的LoggerContext
 */
 public static LoggerContext getDefautLoggerContext(){
  return DEFAULT_LOGGER_CONTEXT;
 }
}

public class StaticLoggerFactory implements ILoggerFactory {

 private LoggerContext loggerContext;

 public StaticLoggerFactory() {
  //构造StaticLoggerFactory时，直接调用配置解析的方法，并获取loggerContext
  ContextInitializer.autoconfig();
  loggerContext = ContextInitializer.getDefautLoggerContext();
 }
}