log4j输出到文件和数据库
官方API地址：http://logging.apache.org/log4j/1.2/apidocs/index.html?org/apache/log4j/PatternLayout.html
控制台的实现就不说了，这里提供两种实例的配置，一种是输出为文件的（每天输出一个文件），一种为输出到数据库的配置。
1、输出到文件：
log4j.rootCategory=WARN, CONSOLE, FILE log4j.logger.com.surfilter.bt=FATAL,TOFILE log4j.appender.TOFILE=org.apache.log4j.DailyRollingFileAppender log4j.appender.TOFILE.Threshold=FATAL log4j.appender.TOFILE.File=E:/javascpace/bt/logs/union.html log4j.appender.TOFILE.Append=true log4j.appender.TOFILE.ImmediateFlush=true log4j.appender.TOFILE.DatePattern='.'yyyy-MM-dd'.html' log4j.appender.TOFILE.layout=com.surfilter.bt.util.FormatHTMLLayout
这里的com.surfilter.bt.util.FormatHTMLLayout是重写了log4j提供的HTMLLayout类，具体代码如下：
import java.text.SimpleDateFormat;
import java.util.Map;
import org.apache.log4j.HTMLLayout;
import org.apache.log4j.Layout;
import org.apache.log4j.Level;
import org.apache.log4j.helpers.Transform;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.spi.LoggingEvent;
import com.opensymphony.xwork2.ActionContext;
import com.surfilter.core.Constants;
import com.surfilter.security.domain.User;
public class FormatHTMLLayout extends HTMLLayout {
public FormatHTMLLayout() {
}
protected final int BUF_SIZE = 256;
protected final int MAX_CAPACITY = 1024;
static String TRACE_PREFIX = "<br> ";
// output buffer appended to when format() is invoked
private StringBuffer sbuf = new StringBuffer(BUF_SIZE);
String title="系统操作日志";
/**
* A string constant used in naming the option for setting the the HTML
* document title. Current value of this string constant is <b>Title</b>.
*/
public static final String TITLE_OPTION = "Title";
// Print no location info by default
boolean locationInfo = true;
public String format(LoggingEvent event) {
if (sbuf.capacity() > MAX_CAPACITY) {
sbuf = new StringBuffer(BUF_SIZE);
} else {
sbuf.setLength(0);
}
sbuf.append(Layout.LINE_SEP + "<tr>" + Layout.LINE_SEP);
/* sbuf.append("<td>");
sbuf.append(String.valueOf(i));
sbuf.append("</td>" + Layout.LINE_SEP);
*/
sbuf.append("<td>");
sbuf.append(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new java.util.Date()));
sbuf.append("</td>" + Layout.LINE_SEP);
/* String escapedThread = Transform.escapeTags(event.getThreadName());
sbuf.append("<td title=\"" + escapedThread + " thread\">");
sbuf.append(escapedThread);
sbuf.append("</td>" + Layout.LINE_SEP);
*/
sbuf.append("<td title=\"级别\">");
if (event.getLevel().equals(Level.FATAL)) {
sbuf.append("<font color=\"#339933\">");
sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
sbuf.append("</font>");
} else if (event.getLevel().isGreaterOrEqual(Level.WARN)) {
sbuf.append("<font color=\"#993300\"><strong>");
sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
sbuf.append("</strong></font>");
} else {
sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
}
sbuf.append("</td>" + Layout.LINE_SEP);
/* String escapedLogger = Transform.escapeTags(event.getLoggerName().substring(event.getLoggerName().lastIndexOf(".")));
sbuf.append("<td title=\"类名\">");
sbuf.append(escapedLogger);
sbuf.append("</td>" + Layout.LINE_SEP);
*/
if (locationInfo) {
LocationInfo locInfo = event.getLocationInformation();
sbuf.append("<td title=\"行号\">");
sbuf.append(Transform.escapeTags(locInfo.getFileName()));
sbuf.append(':');
sbuf.append(locInfo.getLineNumber());
sbuf.append("</td>" + Layout.LINE_SEP);
}
Map session = ActionContext.getContext().getSession();
if(session!=null){
User user = (User) session.get(Constants.USER_IN_SESSION);
sbuf.append("<td>"+user.getName()+"</td>");
}else{
sbuf.append("<td> </td>");
}
sbuf.append("<td title=\"日志信息\">");
sbuf.append(Transform.escapeTags(event.getRenderedMessage()));
sbuf.append("</td>" + Layout.LINE_SEP);
sbuf.append("</tr>" + Layout.LINE_SEP);
if (event.getNDC() != null) {
sbuf.append("<tr><td bgcolor=\"#EEEEEE\" style=\"font-size : xx-small;\" colspan=\"6\" title=\"Nested Diagnostic Context\">");
sbuf.append("NDC: " + Transform.escapeTags(event.getNDC()));
sbuf.append("</td></tr>" + Layout.LINE_SEP);
}
String[] s = event.getThrowableStrRep();
if (s != null) {
sbuf.append("<tr><td bgcolor=\"#993300\" style=\"color:White; font-size : xx-small;\" colspan=\"4\">");
appendThrowableAsHTML(s, sbuf);
sbuf.append("</td></tr>" + Layout.LINE_SEP);
}
return sbuf.toString();
}
private void appendThrowableAsHTML(String[] s, StringBuffer sbuf) {
if (s != null) {
int len = s.length;
if (len == 0)
return;
sbuf.append(Transform.escapeTags(s[0]));
sbuf.append(Layout.LINE_SEP);
for (int i = 1; i < len; i++) {
sbuf.append(TRACE_PREFIX);
sbuf.append(Transform.escapeTags(s[i]));
sbuf.append(Layout.LINE_SEP);
}
}
}
/**
* Returns appropriate HTML headers.
*/
public String getHeader() {
StringBuffer sbuf = new StringBuffer();
sbuf.append("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">" + Layout.LINE_SEP);
sbuf.append("<html>" + Layout.LINE_SEP);
sbuf.append("<head>" + Layout.LINE_SEP);
// sbuf.append("<meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">");
sbuf.append("<title>" + title + "</title>" + Layout.LINE_SEP);
sbuf.append("<style type=\"text/css\">" + Layout.LINE_SEP);
sbuf.append("<!--" + Layout.LINE_SEP);
sbuf.append("body, table {font-family: '宋体',arial,sans-serif; font-size: 12px;}" + Layout.LINE_SEP);
sbuf.append("th {background: #336699; color: #FFFFFF; text-align: left;}" + Layout.LINE_SEP);
sbuf.append("-->" + Layout.LINE_SEP);
sbuf.append("</style>" + Layout.LINE_SEP);
sbuf.append("</head>" + Layout.LINE_SEP);
sbuf.append("<body bgcolor=\"#FFFFFF\" topmargin=\"6\" leftmargin=\"6\">" + Layout.LINE_SEP);
// sbuf.append("<hr size=\"1\" noshade>" + Layout.LINE_SEP);
// sbuf.append("Log session start time " + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new java.util.Date()) + "<br>" + Layout.LINE_SEP);
// sbuf.append("<p>" + Layout.LINE_SEP);
sbuf.append("<table cellspacing=\"0\" cellpadding=\"4\" border=\"1\" bordercolor=\"#224466\" width=\"100%\">" + Layout.LINE_SEP);
sbuf.append("<tr>" + Layout.LINE_SEP);
// sbuf.append("<th>序列</th>" + Layout.LINE_SEP);
sbuf.append("<th>执行时间</th>" + Layout.LINE_SEP);
sbuf.append("<th>级别</th>" + Layout.LINE_SEP);
// sbuf.append("<th>所在类</th>" + Layout.LINE_SEP);
if (locationInfo) {
sbuf.append("<th>所在行</th>" + Layout.LINE_SEP);
}
sbuf.append("<th>操作人</th>");
sbuf.append("<th>信息</th>" + Layout.LINE_SEP);
sbuf.append("</tr>" + Layout.LINE_SEP);
sbuf.append("<br></br>" + Layout.LINE_SEP);
return sbuf.toString();
}
}
注，上面输出里包含了从当前session里取到的用户信息，只需要重写getHeader，format，appendThrowableAsHTML三个方法就可以了。LoggingEvent 提供的方法可以获取各种日志信息。
2、输入到数据库，现在配置是将日志信息同时输出到文件和数据库
log4j.rootCategory=WARN, CONSOLE, FILE log4j.logger.com.surfilter.bt=FATAL,TOFILE,JDBC log4j.appender.TOFILE=org.apache.log4j.DailyRollingFileAppender log4j.appender.TOFILE.Threshold=FATAL log4j.appender.TOFILE.File=E:/javascpace/bt/logs/union.html log4j.appender.TOFILE.Append=true log4j.appender.TOFILE.ImmediateFlush=true log4j.appender.TOFILE.DatePattern='.'yyyy-MM-dd'.html' log4j.appender.TOFILE.layout=com.surfilter.bt.util.FormatHTMLLayout
log4j.appender.JDBC=org.apache.log4j.jdbc.JDBCAppender
#log4j.appender.JDBC=com.surfilter.bt.util.Log4jToDBAppender
log4j.appender.JDBC.Threshold=FATAL
log4j.appender.JDBC.URL=jdbc:oracle:thin:@127.0.0.1:1521:orcl
log4j.appender.JDBC.driver=oracle.jdbc.driver.OracleDriver
log4j.appender.JDBC.user=db_user
log4j.appender.JDBC.password=db_password
log4j.appender.JDBC.sql=insert into sys_log(id,loginid,PRIORITY,LOGDATE,CLASS,METHOD,MSG) values (seq_sys_log.nextval,'0','%p','%d{yyyy-MM-dd HH:mm:ss}','%c{1}','%-10.50l','%m')
log4j.appender.JDBC.layout=org.apache.log4j.PatternLayout
以上配置将会同时输出到文件和数据库，注意这里有一行注释掉的实现com.surfilter.bt.util.Log4jToDBAppender，如果你要使用连接池可以继承JDBCAppender重写实现，下面是JDBCAppender的实现源码，可以从log4j官网上down到：
package org.apache.log4j.jdbc;
import org.apache.log4j.spi.*;
import org.apache.log4j.PatternLayout;
import java.util.ArrayList;
import java.util.Iterator;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.SQLException;
public class JDBCAppender extends org.apache.log4j.AppenderSkeleton
implements org.apache.log4j.Appender {
protected String databaseURL = "jdbc:odbc:myDB";
protected String databaseUser = "me";
protected String databasePassword = "mypassword";
protected Connection connection = null;
protected String sqlStatement = "";
protected int bufferSize = 1;
protected ArrayList buffer;
protected ArrayList removes;
public JDBCAppender() {
super();
buffer = new ArrayList(bufferSize);
removes = new ArrayList(bufferSize);
}
public void append(LoggingEvent event) {
buffer.add(event);
if (buffer.size() >= bufferSize)
flushBuffer();
}
protected String getLogStatement(LoggingEvent event) {
return getLayout().format(event);
}
protected void execute(String sql) throws SQLException {
Connection con = null;
Statement stmt = null;
try {
con = getConnection();
stmt = con.createStatement();
stmt.executeUpdate(sql);
} catch (SQLException e) {
if (stmt != null)
stmt.close();
throw e;
}
stmt.close();
closeConnection(con);
//System.out.println("Execute: " + sql);
}
protected void closeConnection(Connection con) {
}
protected Connection getConnection() throws SQLException {
if (!DriverManager.getDrivers().hasMoreElements())
setDriver("sun.jdbc.odbc.JdbcOdbcDriver");
if (connection == null) {
connection = DriverManager.getConnection(databaseURL, databaseUser,
databasePassword);
}
return connection;
}
public void close()
{
flushBuffer();
try {
if (connection != null && !connection.isClosed())
connection.close();
} catch (SQLException e) {
errorHandler.error("Error closing connection", e, ErrorCode.GENERIC_FAILURE);
}
this.closed = true;
}
public void flushBuffer() {
//Do the actual logging
removes.ensureCapacity(buffer.size());
for (Iterator i = buffer.iterator(); i.hasNext();) {
try {
LoggingEvent logEvent = (LoggingEvent)i.next();
String sql = getLogStatement(logEvent);
execute(sql);
removes.add(logEvent);
}
catch (SQLException e) {
errorHandler.error("Failed to excute sql", e,
ErrorCode.FLUSH_FAILURE);
}
}
// remove from the buffer any events that were reported
buffer.removeAll(removes);
// clear the buffer of reported events
removes.clear();
}
public void finalize() {
close();
}
public boolean requiresLayout() {
return true;
}
public void setSql(String s) {
sqlStatement = s;
if (getLayout() == null) {
this.setLayout(new PatternLayout(s));
}
else {
((PatternLayout)getLayout()).setConversionPattern(s);
}
}
public String getSql() {
return sqlStatement;
}
public void setUser(String user) {
databaseUser = user;
}
public void setURL(String url) {
databaseURL = url;
}
public void setPassword(String password) {
databasePassword = password;
}
public void setBufferSize(int newBufferSize) {
bufferSize = newBufferSize;
buffer.ensureCapacity(bufferSize);
removes.ensureCapacity(bufferSize);
}
public String getUser() {
return databaseUser;
}
public String getURL() {
return databaseURL;
}
public String getPassword() {
return databasePassword;
}
public int getBufferSize() {
return bufferSize;
}
public void setDriver(String driverClass) {
try {
Class.forName(driverClass);
} catch (Exception e) {
errorHandler.error("Failed to load driver", e,
ErrorCode.GENERIC_FAILURE);
}
}
}
然后说一下PatternLayout里的ConversionPattern主要的格式化输开形式，Log4J采用类似C语言中的printf函数的打印，格式化日志信息，打印参数如下：
%m 输出代码中指定的消息
%p 输出优先级，即DEBUG，INFO，WARN，ERROR，FATAL
%r 输出自应用启动到输出该log信息耗费的毫秒数
%c 输出所属的类目，通常就是所在类的全名，例%c{1}： 类名"a.b.c" 时输出 "c"
%t 输出产生该日志事件的线程名
%n 输出一个回车换行符，Windows平台为“rn”，Unix平台为“n”
%d 输出日志时间点的日期或时间，默认格式为ISO8601，也可以在其后指定格式，比 如：%d{yyyy MMM dd HH:mm:ss,SSS}，输出类似：2002年10月18日 22：10：28，921
%l 输出日志事件的发生位置，包括类目名、发生的线程，以及在代码中的行数。