[Java][j2ee]log4j初試

注：省略了很多其他東西，按部就班照搬問題多多。僅做自己備忘及給需要的朋友參考

使用log4j在web項目中進行日誌記錄。
1.添加一個用於log4j初始化（指定屬性文件等）的servlet

package addrbook.servlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.*;

public class Log4jInitServlet extends HttpServlet {

public void init() {

String prefix = getServletContext().getRealPath("/");

String file = getInitParameter("log4j-init-file");

if (file != null) {

PropertyConfigurator.configure(prefix + file);

}

public void doGet(HttpServletRequest req, HttpServletResponse res) {

}

2.配置web.xml，讓project啓動就讓log4j初始化（project啓動即運行上面的servlet）

<servlet-name>Log4jInitServlet</servlet-name>

<servlet-class>addrbook.servlet.Log4jInitServlet</servlet-class>

<init-param>

<param-name>log4j-init-file</param-name>

<param-value>/WEB-INF/classes/log4j.properties</param-value>

</init-param>

<load-on-startup>1</load-on-startup>

</servlet>

3.編寫log4j.properties,（演示在一個配置文件中控制多個logger的輸出）

#log4j.rootLogger=fatal

log4j.logger.DB = debug,R

log4j.logger.LOGON = debug,R2

log4j.appender.R=org.apache.log4j.DailyRollingFileAppender

log4j.appender.R.layout=org.apache.log4j.PatternLayout

log4j.appender.R.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %c %p%n %m%n

log4j.appender.R.File=../webapps/addressbook1/WEB-INF/log/event.log

log4j.appender.R2=org.apache.log4j.DailyRollingFileAppender

log4j.appender.R2.layout=org.apache.log4j.PatternLayout

log4j.appender.R2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %c %p%n %m%n

log4j.appender.R2.File=../webapps/addressbook1/WEB-INF/log/event.log

一個是用於控制數據庫操作日誌的DB（R），一個是用於登陸信息日誌的LOGON（R2），在一個properties一起配置。指定了日誌輸出的路徑“log4j.appender.R.File=../webapps/addressbook1/WEB-INF/log/event.log”。
如果直接爲log4j.appender.R.File=event.log, 則日誌文件將位域tomcat/bin/eveng.log

4.在代碼中添加日誌操作代碼

package addrbook.model;

import java.sql.*;

import org.apache.log4j.*;

public class DBUtil {

private final static String DRIVER_NAME = "com.mysql.jdbc.Driver";

private final static String DBURL = "jdbc:mysql://";

private final static String DBNAME = "struts_addr";

private final static String DB_USER_NAME = "feng";

private final static String DB_USER_PWD = "";

public static Logger logger = Logger.getLogger("DB"); //獲取一個Logger，名字與properties文件裏的對應

public DBUtil() {

}

public static java.sql.Connection connectToDb(String hostName,

String databaseName) throws Exception {

Connection connection = null;

String connName = DBURL + hostName + ":3306" + "/" + databaseName;

logger.debug("connName: "+connName); //日誌輸出

Class.forName(DRIVER_NAME).newInstance();

connection = DriverManager.getConnection(connName, DB_USER_NAME,

DB_USER_PWD);

return connection;

}

public static Connection connectToDb(String databaseName) throws Exception {

return (connectToDb("localhost", databaseName));

}

public static Connection connectToDb() throws Exception {

return (connectToDb("localhost", DBNAME));

}

package addrbook.action;

import java.util.Locale;

import javax.servlet.http.*;

import org.apache.struts.action.*;

import org.apache.struts.util.MessageResources;

import addrbook.form.InsertForm;

import addrbook.model.AddressBookBean;

import addrbook.model.DBUtil;

import addrbook.Constants;

/**

* <strong>InsertAction</strong> inserts a new record into the database.

public final class InsertAction extends AbstActionBase {

public ActionForward execute(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response)

throws Exception {

Locale locale = getLocale(request);

MessageResources messages = getResources(request);

String name = null;

String phone = null;

String address = null;

ActionMessages errors = new ActionMessages();

name = ((InsertForm) form).getName();

phone = ((InsertForm) form).getPhone();

address = ((InsertForm) form).getAddress();

try {

AddressBookBean bean = new AddressBookBean(name, phone, address);

bean.insert();

} catch (Exception ex) {

//ex.printStackTrace(System.out);

DBUtil.logger.debug("exception!!", ex); //記錄數據庫操作異常日誌

errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage(

"error.insert.failed"));

}

if (!errors.isEmpty()) {

saveErrors(request, errors);

return (new ActionForward(mapping.getInput()));

}

// If we had no errors, then add a confirmation message

ActionMessages actionMessages = new ActionMessages();

actionMessages.add(ActionMessages.GLOBAL_MESSAGE, new ActionMessage(

"record.inserted"));

saveMessages(request, actionMessages);

return (mapping.findForward(Constants.FORWARD_CONFIRMATION));

}

package addrbook;

import addrbook.model.*;

import java.util.*;

import java.io.*;

import javax.servlet.ServletException;

import javax.servlet.http.*;

import javax.servlet.*;

import org.apache.commons.digester.Digester;

import org.apache.log4j.*;

public final class UserDatabaseServlet extends HttpServlet {

private Hashtable<String, UserBean> database = null;

//private int debug = 0;

private String pathname = "/WEB-INF/userdatabase.xml";

private static Logger logger = Logger.getLogger("LOGON");//獲取logger，名字與properties文件對應

public void destroy(){

getServletContext().removeAttribute(Constants.DATABASE_KEY);

}

/*public int getDebug(){

return this.debug;

}*/

public void addUser(UserBean user){

database.put(user.getUserName(), user);

}

public void init() throws ServletException{

String value = getServletConfig().getInitParameter("pathname");

if(value != null)

pathname = value;

try{

load();

getServletContext().setAttribute(Constants.DATABASE_KEY, database);

}catch(Exception e){

//log("Database load exception",e);

logger.debug("Database load exception", e);

throw new UnavailableException("Cannot load database from '"+pathname+"' "+e.getMessage());

}

private synchronized void load() throws Exception{

database = new Hashtable<String, UserBean>();

//記錄loon信息

logger.info("Loading database from '"+pathname+"'");

InputStream is = getServletContext().getResourceAsStream(pathname);

if(is == null){

//記錄logon信息

logger.info("No such resource available - loading empty database");

return;

}

BufferedInputStream bis = new BufferedInputStream(is);

Digester digester = new Digester();

digester.push(this);

//digester.setDebug(1);

digester.setValidating(false);

digester.addObjectCreate("database/user", "addrbook.model.UserBean");

digester.addSetProperties("database/user");

digester.addSetNext("database/user","addUser");

digester.parse(bis);

bis.close();

}

一個日誌輸出event.log

08-04-13 17:19:17 LOGON INFO

Loading database from '/WEB-INF/userdatabase.xml'

2008-04-13 17:19:30 DB DEBUG

connName: jdbc:mysql://localhost:3306/struts_addr

2008-04-13 17:19:31 DB DEBUG

exception!!

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.ConnectException

MESSAGE: Connection refused: connect

STACKTRACE:

java.net.ConnectException: Connection refused: connect

at java.net.PlainSocketImpl.socketConnect(Native Method)

at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)

at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)

at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)

at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)

at java.net.Socket.connect(Socket.java:519)

at java.net.Socket.connect(Socket.java:469)

at java.net.Socket.<init>(Socket.java:366)

at java.net.Socket.<init>(Socket.java:209)

at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)

at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)

at com.mysql.jdbc.Connection.createNewIO(Connection.java:2744)

at com.mysql.jdbc.Connection.<init>(Connection.java:1553)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)

at java.sql.DriverManager.getConnection(DriverManager.java:582)

at java.sql.DriverManager.getConnection(DriverManager.java:185)

at addrbook.model.DBUtil.connectToDb(DBUtil.java:26)

at addrbook.model.DBUtil.connectToDb(DBUtil.java:36)

at addrbook.model.AddressBookBean.insert(AddressBookBean.java:57)

at addrbook.action.InsertAction.execute(InsertAction.java:55)

at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)

at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)

at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)

at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)

at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)

at java.lang.Thread.run(Thread.java:619)

** END NESTED EXCEPTION **

Last packet sent to the server was 0 ms ago.

at com.mysql.jdbc.Connection.createNewIO(Connection.java:2820)