1. lib里加入3个包 slf4j-api, slf4j-log4j12， log4j

2. 在src下 创建log4j.properties  

### direct log messages to stdout ###log4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Target=System.outlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c:%L - %m%n### direct messages to file hibernate.log ####log4j.appender.file=org.apache.log4j.FileAppender#log4j.appender.file.File=hibernate.log#log4j.appender.file.layout=org.apache.log4j.PatternLayout#log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n### set log levels - for more verbose logging change 'info' to 'debug' ###log4j.rootLogger=warn, stdout#log4j.logger.org.hibernate=info#log4j.logger.org.hibernate=debuglog4j.logger.com.web.controller=debug### log schema export/update ####log4j.logger.org.hibernate.tool.hbm2ddl=debug

3. 在需要使用日志的类里添加log信息

  

package com.web.controller;import java.io.IOException;import java.io.PrintWriter;import java.util.List;import javax.annotation.Resource;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.context.support.WebApplicationContextUtils;import org.springframework.web.servlet.support.RequestContextUtils;import com.sun.xml.internal.ws.client.RequestContext;import com.web.controller.entity.Page;import com.web.controller.entity.User;import com.web.controller.service.IUserService;@Controller@RequestMapping("/user")public class UserController {	private Log log = LogFactory.getLog(this.getClass());	@Resource	private IUserService userService;			@RequestMapping("/getAllUser")	public String getAllUser(HttpServletRequest request){		List
     
       users = userService.getAllUser();		request.setAttribute("users", users);				log.fatal("this is fatal info");		return "/userController/userManager";	}}
     

 

这样， 控制台就可以输出信息了， 可以代替system.out.print功能