由于项目要做一个统计分析与记录的功能，为了后期分析用户的一些行为，同时记录的东西要同时输出多处，并且可配置输出
想到了使用log4j，知道他是可以同时指定多个输出目的地，并且如有变更，直接修改配置文件。
关于log4j的基本概论及使用，见http://www.iteye.com/topic/378077，这个帖子讲的很细，归纳了很多东西
问题一：把登录用户每次访问的ip地址 时间等记录下来，存放到日志文件里，再存一份到数据库
第一步:记录用户访问，写一个filter如下，里面MDC是一个类似map的东西，只不过做了线程方式的封装使用，每个线程会有自己的一份map
public class UserLogFilter implements Filter {
private Logger logger;
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest httpRequest = (HttpServletRequest) request;
Object user = httpRequest.getSession().getAttribute(
Constants.User.LOGIN_USER);
if (user != null) {
Integer usr_id = (Integer) ReflectionUtils.invokeGetterMethod(user, "usrId");
String log_ip = request.getLocalAddr();
SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date now=new Date(System.currentTimeMillis());
MDC.put("usr_id", usr_id);
MDC.put("log_title", "网站访问记录");
MDC.put("log_type", "记录");
MDC.put("log_title", "网站访问记录");
MDC.put("log_datetime", format.format(now));
MDC.put("log_ip", log_ip);
logger.info(MDC.getContext());
}
chain.doFilter(request, response);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
logger=Logger.getLogger(UserLogFilter.class);
}
}
第二部：配置log4j.properties，输出到文件与数据库
引用
#不懂的话，参考给出的第一个连接地址一样，j2EE项目详细控制
log4j.logger.com.bhaman.yiyaosou.util.web=INFO,,project-util,project-util-db
#project-util-web file appender
log4j.appender.project-util=org.apache.log4j.DailyRollingFileAppender
log4j.appender.project-util.file=${user.home}/logs/project-util.log
log4j.appender.project-util.layout=org.apache.log4j.PatternLayout
log4j.appender.project-util.threshold=INFO
log4j.appender.project-util.layout.conversionPattern=%d [%X{usr_id}/%X{log_ip}/%X{req.id} - %X{entranceMethod} - %X{req.requestURIWithQueryString}] %-5p %c - %m%n
log4j.appender.project-util-db=com.log4j.service.DBAppender
log4j.appender.project-util-db.bufferSize=16
log4j.appender.project-util-db.threshold=INFO
#此处对应filter里面的MDC里面的键值对，你懂的
log4j.appender.project-util-db.sql=insert into user_log (usr_id,log_title,log_category,log_type,log_datetime,log_ip) VALUES ('%X{usr_id}','%X{log_title}','%X{log_type}','%X{log_title}','%X{log_datetime}','%X{log_ip}')
第三部：由于log4j里面给出的输出JDBCappender，是有问题的，首先面对业务需求，他是用JDBC，性能上问题很大，特别是现在这个应用。log4j支持自己写appender，自己写得要知道怎么写才行啊。
直接看JDBCAppender的源码
如下里面提到有做了缓冲，看源码会更清晰，两个ArrayList，一个来存东西，一个来控制清零后默认的缓冲大小不变，具体看源码关于这两个list，里面执行的sql就是配置文件里面那个，会在调用的时候set进来，
引用
<p>Each append call adds to an <code>ArrayList</code> buffer. When
the buffer is filled each log event is placed in a sql statement
(configurable) and executed.
<b>BufferSize</b>, <b>db URL</b>, <b>User</b>, & <b>Password</b> are
configurable options in the standard log4j ways.
<p>The <code>setSql(String sql)</code> sets the SQL statement to be
used for logging -- this statement is sent to a
<code>PatternLayout</code> (either created automaticly by the
appender or added by the user). Therefore by default all the
conversion patterns in <code>PatternLayout</code> can be used
inside of the statement. (see the test cases for examples)
那么我自己写的appender继承它就好了，直接使用它的缓冲及sql执行，那么唯一要变的就是连接了，我要从连接池里面取出，怎么做看下面注释
引用
<li>Override <code>getConnection()</code> to pass any connection
you want. Typically this is used to enable application wide
connection pooling.
<li>Override <code>closeConnection(Connection con)</code> -- if
you override getConnection make sure to implement
<code>closeConnection</code> to handle the connection you
generated. Typically this would return the connection to the
pool it came from.
<li>Override <code>getLogStatement(LoggingEvent event)</code> to
produce specialized or dynamic statements. The default uses the
sql option value.
我不需要覆写getLogStatement，我想改变的只是连接的获取方式罢了，如上分析后，直接写我的appender，里面用到了高效的BoneCP连接池，在spring里面本来是有配置这个的，但log4j是独立于spring的，是无法获取到，只能自己再来一份
public class DBAppender extends org.apache.log4j.jdbc.JDBCAppender {
private BoneCP connectionPool = null;
private Connection connection = null;
private static Logger logger=Logger.getLogger(DBAppender.class);
public DBAppender() {
// 设置连接池配置信息
BoneCPConfig config = new BoneCPConfig();
PropetiesUtil p;
try {
Properties P = new Properties();
P.load(DBAppender.class.getClassLoader().getResourceAsStream("application.properties"));
// 数据库的JDBC URL
config.setJdbcUrl(P.getProperty("jdbc.url"));
// 数据库用户名
config.setUsername(P.getProperty("jdbc.username"));
// 数据库用户密码
config.setPassword(P.getProperty("jdbc.password"));
// 数据库连接池的最小连接数
config.setMinConnectionsPerPartition(5);
// 数据库连接池的最大连接数
config.setMaxConnectionsPerPartition(10);
config.setPartitionCount(1);
// 设置数据库连接池
connectionPool = new BoneCP(config);
} catch (SQLException e) {
// TODO Auto-generated catch block
logger.error("连接池配置加载异常",e);
} catch (IOException e) {
// TODO Auto-generated catch block
logger.error("加载配置文件IO异常",e);
}
// fetch a connection
}
@Override
protected Connection getConnection() throws SQLException {
if(connection==null||connection.isClosed()){
connection = connectionPool.getConnection();
}
return connection;
}
@Override
protected void closeConnection(Connection con) {
// TODO Auto-generated method stub
try {
connection.close();
connection=null;
} catch (SQLException e) {
// TODO Auto-generated catch block
logger.error("连接没正常关闭",e);
}
}
}
第四步：一切OK，然后就测试
日志文件：
引用
2011-07-21 11:07:01,125 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:01, log_title=网站访问记录, usr_id=282}
2011-07-21 11:07:03,640 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:03, log_title=网站访问记录, usr_id=282}
2011-07-21 11:07:04,796 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:04, log_title=网站访问记录, usr_id=282}
2011-07-21 11:07:08,906 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:08, log_title=网站访问记录, usr_id=282}
2011-07-21 11:07:09,281 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:09, log_title=网站访问记录, usr_id=282}
2011-07-21 11:07:14,531 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:07:14, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:10,984 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:10, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:11,796 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:11, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:22,078 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:22, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:22,875 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:22, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:28,562 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:28, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:30,250 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:30, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:31,390 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:31, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:32,750 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:32, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:33,781 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:33, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:36,156 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:36, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:41,578 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:41, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:43,156 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:43, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:44,968 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:44, log_title=网站访问记录, usr_id=282}
2011-07-21 11:11:48,765 [282/127.0.0.1/ - - ] INFO com.bhaman.yiyaosou.util.web.UserLogFilter - {log_type=记录, log_ip=127.0.0.1, log_datetime=2011-07-21 11:11:48, log_title=网站访问记录, usr_id=282}
数据库：
