double d = -5.0 / 0.0;
		if (d == Double.NEGATIVE_INFINITY) {
			System.out.println("d 的值为负无穷");
		}

Vector v = new Vector(10);
		for (int i = 0; i < 100; i++) {
			Object o = new Object();
			v.add(o);
			o = null;
		}

SortedMap<String,String> map = new TreeMap<String, String>();

LinkedHashMap<String,String> map = new LinkedHashMap<String,String>();

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<servlet>
        <servlet-name>action</servlet-name>
        <servlet-class>com.allcom.base.util.AutoActionServlet</servlet-class>
        <init-param>
            <param-name>config</param-name>
            <param-value>/WEB-INF/struts-*.xml</param-value>
        </init-param>
        <init-param>
            <param-name>debug</param-name>
            <param-value>3</param-value>
        </init-param>
        <init-param>
            <param-name>detail</param-name>
            <param-value>3</param-value>
        </init-param>
        <load-on-startup>5</load-on-startup>
    </servlet>

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set JAVA_OPTS=%JAVA_OPTS% -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port="9004"
set JAVA_OPTS=%JAVA_OPTS% -Dcom.sun.management.jmxremote.authenticate="false" -Dcom.sun.management.jmxremote.ssl="false"

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PrintWriter out;
			try {
				out = response.getWriter();
				out.println("该服务已被发布，不能再发布！");
			} catch (IOException e) {
				e.printStackTrace();
			}

return null;

request.setAttribute("message", "<script type=\"text/javascript\" language=\"javascript\">parent.leftFrame.location.reload();</script>");

<logic:present name="message">
        	<bean:write name="message" filter="false"/>
        </logic:present>

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<DefaultContext reloadable="true" crossContext="true">
			<Resource name="jdbc/juddiDB" scope="Shareable" type="javax.sql.DataSource"/>
			<ResourceParams name="jdbc/juddiDB">
				<parameter>
					<name>url</name>
					<value>jdbc:mysql://localhost/juddi</value>
				</parameter>
				<parameter>
					<name>driverClassName</name>
					<value>org.gjt.mm.mysql.Driver</value>
				</parameter>
				<parameter>
					<name>username</name>
					<value>juddi</value>
				</parameter>
				<parameter>
					<name>password</name>
					<value>juddi</value>
				</parameter>
			</ResourceParams>
		</DefaultContext>

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE weblogic-web-app PUBLIC "-//BEA Systems, Inc.//DTD Web Application 6.0//EN" "http://www.bea.com/servers/wls600/dtd/weblogic-web-jar.dtd">
<Context path="/juddi" docBase="juddi" debug="5" reloadable="true" crossContext="true">
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_juddiDB_log" suffix=".txt" timestamp="true"/>
<Resource name="jdbc/juddiDB" auth="Container" type="javax.sql.DataSource" username="juddi" password="juddi" url="jdbc:mysql://localhost/juddi" driverClassName="org.gjt.mm.mysql.Driver" />
</Context>

<?xml version="1.0" encoding="UTF-8"?>
<juddi-users>
  <user userid="sviens" password="password" />
  <user userid="juddi" password="juddi" />
</juddi-users>

jUDDI DataSource Validation 
+ Got a JNDI Context! 
+ Got a JDBC DataSource (dsname=java:comp/env/jdbc/juddiDB) 
+ Got a JDBC Connection! 
+ SELECT COUNT(*) FROM PUBLISHER = 1

*********** Running SaveBusinessExample *********** 
Get authtoken 
Returned authToken:authToken:60BDF210-6641-11DB-A066-BC0BE7D6EEB5 
Save 'Sample Business' 
Returned businessKey:60DF35B0-6641-11DB-A066-A0B53CE33E0E 
Listing businesses starting with S after we publish 
Sample Business 
Sample Business 
Sample Business 

*********** Running FindBusinessExample *********** 
Sample Business 
Sample Business 
Sample Business

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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

	<context-param>
	    <param-name>contextConfigLocation</param-name>
	    <param-value>/WEB-INF/applicationContext.xml
	    classpath:org/codehaus/xfire/spring/xfire.xml</param-value>
	</context-param>
	
	<listener>
	    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	
	<servlet>
	    <servlet-name>xfire</servlet-name>
	    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
	</servlet>
	
	<servlet-mapping>
	    <servlet-name>xfire</servlet-name>
	    <url-pattern>*.ws</url-pattern><!-- 
	    <url-pattern>/*</url-pattern> -->
	</servlet-mapping>
    
    <servlet>
         <servlet-name>XFireServlet</servlet-name>
         <servlet-class>
                 org.codehaus.xfire.transport.http.XFireConfigurableServlet
         </servlet-class>
     </servlet>
     
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
         <url-pattern>/servlet/XFireServlet/*</url-pattern>
     </servlet-mapping>
 
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
          <url-pattern>/services/*</url-pattern>
     </servlet-mapping>

</web-app>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>
	<import resource="classpath:org/codehaus/xfire/spring/xfire.xml" />
	<bean id="userDao" class="com.zhuweisky.xfireDemo.UserDaoImpl"/>
	
	<bean id="userServiceTarget" class="com.zhuweisky.xfireDemo.UserServiceImpl">
		<property name="userDao" ref="userDao"/>
	</bean>
	
	<!-- 使用XFire导出器 -->
	<bean id="baseWebService" class="org.codehaus.xfire.spring.remoting.XFireExporter" lazy-init="false" abstract="true">
	<!-- 引用xfire.xml中定义的工厂 -->
		<property name="serviceFactory" ref="xfire.serviceFactory" />
		<!-- 引用xfire.xml中的xfire实例 -->
		<property name="xfire" ref="xfire" />
	</bean>
	
	<!-- Declare a parent bean with all properties common to both services -->
	<bean id="userService" parent="baseWebService">
	    <property name="serviceBean">
	        <ref bean="userServiceTarget"/>
	    </property>
	    <property name="serviceClass">
	        <value>com.zhuweisky.xfireDemo.UserService</value>
	    </property>
	</bean>
</beans>

public static void main(String[] args)
	{
    	ApplicationContext ctx = new FileSystemXmlApplicationContext("WebRoot/WEB-INF/applicationContext.xml");
    	
		try{
			XFireExporter xfe = (XFireExporter) ctx.getBean("userService");
//			System.out.println(o.toString());
			UserService srvc = (UserService) xfe.getServiceBean();
			System.out.println(srvc.getUser("tom").getAge());
			List users=srvc.getUsers();
			for (Iterator iter = users.iterator(); iter.hasNext();) {
				User user = (User) iter.next();
				System.out.println(user.getName());
			}
		}catch (Exception e){
			e.printStackTrace();
		}
	}

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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <servlet>
         <servlet-name>XFireServlet</servlet-name>
         <servlet-class>
                 org.codehaus.xfire.transport.http.XFireConfigurableServlet
         </servlet-class>
     </servlet>
     
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
         <url-pattern>/servlet/XFireServlet/*</url-pattern>
     </servlet-mapping>
 
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
          <url-pattern>/services/*</url-pattern>
     </servlet-mapping>
</web-app>

package com.zhuweisky.xfireDemo;

import java.io.Serializable;

public class User implements Serializable {
	private String name;
	private int age;
	
	public User() {
		super();
		// TODO Auto-generated constructor stub
	}
	
	public User(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

package com.zhuweisky.xfireDemo;

import java.util.List;

public interface UserService {
	public User getUser();
	public List<User> getUsers();
}

package com.zhuweisky.xfireDemo;

import java.util.List;
import java.util.Vector;

public class UserServiceImpl implements UserService {
	public List<User> getUsers(){
		List list=new Vector();
		User user1 = new User("tom",23);
		User user2 = new User("jerry",26);
		list.add(user1);
		list.add(user2);
		return list;
	}
	
	public User getUser(){
		User user = new User("tom",23);
		return user;
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xfire.codehaus.org/config/1.0">
    <service>
      <name>UserService</name>
      <namespace>http://com.zhuweisky.xfireDemo/UserService</namespace>
      <serviceClass>com.zhuweisky.xfireDemo.UserService</serviceClass>
      <implementationClass>com.zhuweisky.xfireDemo.UserServiceImpl</implementationClass>
    </service>
</beans>

package com.zhuweisky.xfireDemo.test;

import java.net.MalformedURLException;   
import java.net.URL;   
import java.util.Iterator;
import java.util.List;
import java.util.Vector;
  
import org.codehaus.xfire.XFireFactory;
import org.codehaus.xfire.client.Client; 
import org.codehaus.xfire.client.XFireProxyFactory;
import org.codehaus.xfire.service.Service;
import org.codehaus.xfire.service.binding.ObjectServiceFactory;
import org.w3c.dom.Document;


import com.sun.org.apache.xerces.internal.dom.DocumentImpl;

import com.zhuweisky.xfireDemo.User;
import com.zhuweisky.xfireDemo.UserService;

public class TestCallWebService {

    public static void main(String[] args)
	{
		Service srvcModel = new ObjectServiceFactory().create(UserService.class);
		XFireProxyFactory factory = new XFireProxyFactory(XFireFactory.newInstance().getXFire());
		String helloWorldURL = "http://localhost:8080/XFireZhuweiTest/services/UserService";
		try{
			UserService srvc = (UserService) factory.create(srvcModel, helloWorldURL);
			System.out.println(srvc.getUser().getName());
			List users=srvc.getUsers();
			for (Iterator iter = users.iterator(); iter.hasNext();) {
				User user = (User) iter.next();
				System.out.println(user.getName());
			}
		}catch (MalformedURLException e){
			e.printStackTrace();
		}
	}

}

<?xml version="1.0" encoding="UTF-8"?>
<mappings>
  <mapping>
    <method name="getUsers">
      <return-type componentType="com.zhuweisky.xfireDemo.User"/>
    </method>
  </mapping>
</mappings>

public Map getUsersMap(int count);

<mapping>
		<method name="getUsersMap">
			<parameter index="0" mappedName="count" keyType="java.lang.Integer" />
			<return-type mappedName="UserMap"
				keyType="java.lang.Integer"
				componentType="com.zhuweisky.xfireDemo.User" ignore="true" />
		</method>
	</mapping>

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package com.xxx.services;

import java.io.Serializable;

public class User implements Serializable {
	private String name;
	private int age;
	
	public int getAge() {
		return age;
	}
	......//getter() or setter();
}

package com.xxx.services;

import java.util.List;

import javax.jws.WebMethod;
import javax.jws.WebService;

@WebService(name="UserServiceIntf", targetNamespace="http://www.webservicex.net")
public interface UserService {
	@WebMethod
	public User getUser();
	@WebMethod
	public List getUsers();
}

package com.xxx.services;

import java.util.List;
import java.util.Vector;

import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
@WebService(endpointInterface="org.codehaus.xfire.jaxb.UserService", serviceName="UserService")
@SOAPBinding(parameterStyle=SOAPBinding.ParameterStyle.BARE)
public class UserServiceImpl implements UserService {
	public User getUser(){
		User user = new User("tom",23);
		return user;
	}
	public List getUsers(){
		List list=new Vector();
		User user1 = new User("tom",23);
		User user2 = new User("jerry",26);
		list.add(user1);
		list.add(user2);
		return list;
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xfire.codehaus.org/config/1.0">
    <service>
    	<name>UserService</name>
    	<namespace>http://com.xxx.services/UserService</namespace>
    	<serviceBean>com.xxx.services.UserServiceImpl</serviceBean>
		<serviceFactory>#jaxbServiceFactory</serviceFactory>
    </service>
    
    <bean name="jaxbServiceFactory" class="org.codehaus.xfire.jaxb2.JaxbServiceFactory">
    	<constructor-arg ref="xfire.transportManager"/>
  	</bean>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

	<servlet>
         <servlet-name>XFireServlet</servlet-name>
         <servlet-class>
                 org.codehaus.xfire.transport.http.XFireConfigurableServlet
         </servlet-class>
     </servlet>
     
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
         <url-pattern>/servlet/XFireServlet/*</url-pattern>
     </servlet-mapping>
 
     <servlet-mapping>
         <servlet-name>XFireServlet</servlet-name>
          <url-pattern>/services/*</url-pattern>
     </servlet-mapping>
</web-app>

exception 

javax.servlet.ServletException: Error initializing XFireServlet.
	org.codehaus.xfire.transport.http.XFireServlet.init(XFireServlet.java:50)
	javax.servlet.GenericServlet.init(GenericServlet.java:211)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
	org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
	org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
	org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
	org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	java.lang.Thread.run(Thread.java:595)


root cause 

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.codehaus.xfire.spring.ServiceBean' defined in class path resource [META-INF/xfire/services.xml]: Initialization of bean failed; nested exception is org.codehaus.xfire.annotations.AnnotationException: Class javax.xml.namespace.QName does not have a WebService annotation
	org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:370)
	org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:226)
	org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:147)
	org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:275)
	org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:320)

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@Target({METHOD,FIELD})
	@Retention(RUNTIME)
	public @interface GeneratedValue{
		GenerationType strategy() default AUTO;
		String generator() default "";
	}

public enum GenerationType{
		TABLE,
		SEQUENCE,
		IDENTITY,
		AUTO
	}

@GeneratedValue(generator = "c-assigned")
	@GenericGenerator(name = "c-assigned", strategy = "assigned")
     private String employeeId;

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/**
Ext.get();		根据id得到该对象
Ext.select();	根据标签得到该对象
Ext.onReady();	页面加载会自动执行该方法
*/
Ext.onReady(function() {
	/**
	var myDiv = Ext.get('myDiv');
	Ext.select('p').highlight();
	myDiv.highlight();      // The element's background will highlight to yellow then fade back
	myDiv.addClass('red');  // Add a custom CSS class (defined in ExtStart.css)
	myDiv.center();         // Center the element in the viewport
	myDiv.setOpacity(.25);  // Make the element partially-transparent
	*/
	
	//Ext.get().on(事件名，执行的函数);
	Ext.get('myButton').on('click', function(){
        alert("You clicked the button");
	});
	/**
	Ext.select('p').on('click', function() {
		alert("You clicked a paragraph");
	});*/
	/**
	//paragraphClicked函数方法名
	var paragraphClicked = function() {
		alert("You clicked a paragraph");
	}
	Ext.select('p').on('click', paragraphClicked);*/
	var paragraphClicked = function(e) {
		var paragraph = Ext.get(e.target);	//e.target得到事件源对象
		paragraph.highlight();
 
		Ext.MessageBox.show({
			title: 'Paragraph Clicked',
			msg: paragraph.dom.innerHTML,
			width:400,
			buttons: Ext.MessageBox.OK,
			animEl: paragraph
		});
	}
	Ext.select('p').on('click', paragraphClicked);
	// Note: For the purposes of following along with the tutorial, all 
	// new code should be placed inside this method.  Delete the following
	// line after you have verified that Ext is installed correctly.
	
	//alert("Congratulations!  You have Ext configured correctly!");
	
});

Ext.onReady(function() {
	var myData = [		//数据源。和myReader格式对应
		['Apple',29.89,0.24,0.81,'9/1 12:00am'],
		['Ext',83.81,0.28,0.34,'9/12 12:00am'],
		['Google',71.72,0.02,0.03,'10/1 12:00am'],
		['Microsoft',52.55,0.01,0.02,'7/4 12:00am'],
		['Yahoo!',29.01,0.42,1.47,'5/22 12:00am']
	];
 
	var myReader = new Ext.data.ArrayReader({}, [		//读取数据源。和myData一一对应
		{name: 'company'},
		{name: 'price', type: 'float'},
		{name: 'change', type: 'float'},
		{name: 'pctChange', type: 'float'},
		{name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
	]);
 
	var grid = new Ext.grid.GridPanel({
		store: new Ext.data.Store({		//数据装配
			data: myData,
			reader: myReader
		}),
		columns: [		//header:显示的标题；width:该列的宽度；sortable:可否排序；dataIndex:数据索引（从data中取）
			{header: 'Company', width: 120, sortable: true, dataIndex: 'company'},
			{header: 'Price', width: 90, sortable: true, dataIndex: 'price'},
			{header: 'Change', width: 90, sortable: true, dataIndex: 'change'},
			{header: '% Change', width: 90, sortable: true, dataIndex: 'pctChange'},
			{header: 'Last Updated', width: 120, sortable: true, 
				renderer: Ext.util.Format.dateRenderer('m/d/Y'), 	//日期格式化
	                        dataIndex: 'lastChange'}
		],
		viewConfig: {
			forceFit: true		//强制适合GridPanel（GridPanel的大小不会改变）。true:没有滚动条；fasle:有滚动条
		},
		renderTo: 'content',	//显示位置（div中的id=“content”）
		title: 'My First Grid',	//标题
		width: 500,		//GridPanel的宽度
		frame: true		//GridPanel的边框
	});
 
	grid.getSelectionModel().selectFirstRow();		//GridPanel默认选中第一行
});

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@Entity
public class Org  implements java.io.Serializable {
}

@Id
     @GeneratedValue
     private String orgId;
     private String orgName;

@Entity
public class Org  implements java.io.Serializable {


    // Fields    
	@Id
	@GeneratedValue
     private String orgId;
     private String orgName;
     @OneToMany(mappedBy = "org")
     private List<Department> departments;

    // Constructors
...
    // Property accessors
...
}

@Entity
public class Department  implements java.io.Serializable {


    // Fields    
	@Id
	@GeneratedValue
     private String id;
     private String name;
     @ManyToOne(fetch=FetchType.EAGER)
     @JoinColumn(name="org_orgId")
     private Org org;
     @OneToMany(mappedBy = "department")
     private List<Employee> employees;

    // Constructors

    public List<Employee> getEmployees() {
		return employees;
	}

	public void setEmployees(List<Employee> employees) {
		this.employees = employees;
	}

	public Org getOrg() {
		return org;
	}

	public void setOrg(Org org) {
		this.org = org;
	}

	/** default constructor */
             .
             .
             .
	
}

@Entity
public class Employee  implements java.io.Serializable {


    // Fields    
	@Id
	@GeneratedValue
     private String employeeId;
     private String employeeName;
     private String passWord;
     private Integer age;
     private Integer sex;
     @ManyToOne(fetch=FetchType.EAGER)
     @JoinColumn(name="department_id")
     private Department department;

     
    public Department getDepartment() {
		return department;
	}

	public void setDepartment(Department department) {
		this.department = department;
	}

	/** default constructor */
    ...
    // Property accessors
    ...
}

@Entity
public class Book  implements java.io.Serializable {
	@Id
	private int id;
	private String name;
	private float money;
	@ManyToMany(cascade = CascadeType.ALL)
	private List<Author> authors;
	

	public List<Author> getAuthors() {
		return authors;
	}
	public void setAuthors(List<Author> authors) {
		this.authors = authors;
	}
	
         ...
}

@Entity
public class Author  implements java.io.Serializable {
	@Id
	private int id;
	private String name;
	private int age;
	@ManyToMany(mappedBy="authors")
	private List<Book> books;
	

	public List<Book> getBooks() {
		return books;
	}

	public void setBooks(List<Book> books) {
		this.books = books;
	}

         ...
}

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• 北京: 千橡集团暨校内网诚聘软件研发工程师
• 搜狐网站诚聘Java、PHP和C++工程师

今天突然间发现一个小问题：

         为什么通过数据库备份/还原，程序操作不会报错。而通过数据导入/导出时，程序就会间断性报错。

结论：

         通过数据库备份/还原，数据库不会变化。而通过数据导入/导出时，数据库就变化了。

        导入/导出时，数据库中的表就会失去约束，并且会失去主、外键关系。

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删除集合元素,相信一提,肯定就是调用集合中的remove()方法了!

下面看个例子:

public void operate(List list){
        for (Iterator it = list.iterator(); it.hasNext();) {
            String str =  (String)it.next();
            if (str.equals("chengang")){
                list.remove(str);
            }
        }
    }

这样做可以删除元素吗?自己运行下试试!

答案一定是报错了!那么如何才可以删除正在循环的集合中的元素呢?

一个笨方法:

public void operate(List list){
        List removeList= new ArrayList();
        for (Iterator it = list.iterator(); it.hasNext();) {
            String str =  (String)it.next();
            if (str.equals("chengang")){
                removeList.add(str);
            }
        }
        list.removeAll(removeList);
    }

一个聪明的方法:

for (Iterator it = list.iterator(); it.hasNext();) {
            String str =  (String)it.next();
            if (str.equals("chengang")){
                it.remove();
            }
        }

你会用哪一个呢?

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原理：

          就是通过触发JavaScript事件，调用服务器程序（可以是Servlet，也可以是Action），得到所需要的值。这个值再通过载  体，返回给JavaScript，从而返回给界面，实现局部刷新！而中间的这个载体就是ActiveXObject("MSXML2.XMLHTTP")；

核心流程：
 1、HTML 中执行 JavaScript
 2、JavaScript 中去实例化 xmlHttp
 3、xmlHttp 去发出请求调用后台 Servlet
 4、Servlet 返回响应给 xmlHttp
 5、xmlHttp 拿着响应信息去更新 HTML

核心代码：

<script>
  var xmlHttp=new ActiveXObject("MSXML2.XMLHTTP");//只是IE的；

  function sendRequest(){
   //open方法用来设置请求发送，有三个参数（1、请求方式；2、请求地址；3、为true时用异步方式发送）；
   xmlHttp.open('get','http://localhost:8080/WebModule1/ajaxservlet?name='+f.uname.value,true);
   //onreadystatechange方法设置谁来接收；
   xmlHttp.onreadystatechange=getResponse;
   //send请求真正的发出；
   xmlHttp.send(null);
  }

  function getResponse(){
   //readyState判断响应的4种状态（4为响应结束）；
   if(xmlHttp.readyState==4){
    //status=200表示页面响应是正确的；400，404，500
    if(xmlHttp.status==200){
     ds.innerHTML=xmlHttp.responseText;
    }
   }
  }

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• 北京: 千橡集团暨校内网诚聘软件研发工程师

写了一个鼠标的动态提示标签：主要用来显示图片的说明信息或文字的说明信息！

问题：页面完好，可以显示提示标签，但数据只能是第一次的（得不到更新）。

问题分析：这是因为IE缓存问题，所以要有页面更新才可以。

解决方案：随便给页面上加个随机数，一切OK！

如：<script>var url="aaa.jsp?id="+id+"&time="+new Date().getTime();</script>

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最近我做了一个上传下载模块。很快就做完了，感觉还可以吧！

就是和别人的模块合起来就完了，点不了两三下就页面不动了，后台tomcat看起来象死了一样也没有什么反应！

问题：为什么自己单独跑好着呢，合起来就不行了？

解决方案：

1、怀疑filter。去掉filter，问题依旧。（排除）

2、怀疑listener。去掉listener，工程整个都死掉了，跑不了（总之很多东西都在这里，都是工程里用的）。（挂起）

3、单步跟踪。设了很多断点，跟了一会跟丢了（进了很深的底层，出不来了）。

4、打日志。没有用。感觉什么都好着呢。

5、会不会多线程，后台死锁。找了一个测试工具JProfiler，看不出来问题，也没有死锁。

天天哭呀！~~~

最后解决问题：

经：会不会是数据库死锁！

再次运行程序——死了——打开每张表（看是否有打不开的，是否发生了死锁）。结果OK，都打开了！（排除）

最后一招：每一行代码下都打印东西。终于看到了有一个service的方法执行不到（第一次可以）。在该方法中的每一行代码下继续打东西。又看到一个Dao层的方法不执行。继续。这样一层一层。终于问题浮出水面——得不到连接。因为用的是DataSource，所以忘记.close();晕！~~~加上！

问题终于解决了！一切恢复正常！

最后结论：就是一头猪！~~~

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 <body-- onload="abc()">
 <p>Hello World!</p>
 <p>Isn't this exciting?</p>
 <p>You're learning to use this Dom!</p>
 <a href="#" onClick="create()">abc</a></--body>

• 北京: 千橡集团暨校内网诚聘软件研发工程师
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以前老看别人的Blog,很是羡慕!现在自己终于也有了一个!

还是二级域名的,爽死了!

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