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Junit��试

Sun, 23 Jan 2011 02:20:00 GMT

Junit是由 Erich Gamma �?span lang="EN-US"> Kent Beck �~�写的一个回归测试框�Ӟ��regression testing framework�Q��?span lang="EN-US">Junit是一套框�Ӟ��l�承TestCase�c�，��可以用Junit�q�行自动��试了�?/p>

1 junit�Ҏ�?span lang="EN-US">

junit

Junit是一个开放源代码�?span lang="EN-US">Java��试框架�Q�用于编写和�q�行可重复的��试。他是用于单元测试框架体�p?span lang="EN-US">xUnit的一个实例（用于java语言�Q�。它包括以下�Ҏ��：

　　�?用于��试期望�l�果的断�a��Q?span lang="EN-US">Assertion�Q?span lang="EN-US">

　　�?用于�׃�n共同��试数据的测试工�?span lang="EN-US">

　　�?用于方便的组�l�和�q�行��试的测试套�?span lang="EN-US">

�?囑�Ş和文本的��试�q�行�?span lang="EN-US">

2 Eclipse中配�|?span lang="EN-US">Junit

叛_��要��用的junit的项目，点击properties—java bulid path-libraries�Q�点�?span lang="EN-US">Add External JARs,加上JUNIT包�?span lang="EN-US">

3 用法

- 创徏�Q�从junit.framework.TestCase�z��nuit test需要的test case.

- 书写��试�Ҏ��

- �~�译书写�?span lang="EN-US">test case后，�~�译所写的test case�c?span lang="EN-US">

- �q�行�Q�启�?span lang="EN-US">junit test runnner 来运行这�?span lang="EN-US">test case�?span lang="EN-US">

实例代码�Q?span lang="EN-US">

package com.dr.test;

import java.util.List;

import junit.framework.TestCase;

import com.dr.dao.StudentDao;

import com.dr.dao.impl.StudentDaoImpl;

import com.dr.vo.Student;

public class StudentDaoImplTest extends TestCase{

StudentDao dao;

protected void setUp() throws Exception{

dao=new StudentDaoImpl();

}

protected void tearDown() throws Exception{

}

public void testAdd(){

Student stu=new Student();

stu.setName("ling");

stu.setAge(1);

stu.setEmail("ling@126.com");

dao.addStudent(stu);

}

public void testListStudent(){

List list=dao.getStudentList();

System.out.println(list.size());

}

Junit中的两个函数�Q?span lang="EN-US">setUp�?span lang="EN-US">tearDown,�?span lang="EN-US">junit framework中提供初始化金额反初始化每个��试�Ҏ��的�?span lang="EN-US">setUp在每个测试方法调用前被调用，负责初始化测试方法所需要的��试环境�Q?span lang="EN-US">teardown在每个测试方法被调用之后被调用，负责撤销��试环境�?span lang="EN-US">

��试�l�果�Q?br />

�?/span>JUnit的窗口中昄��了一个绿条，�l�条证明��试成功�?/span>

向日�?/a> 2011-01-23 10:20 发表评论

Tue, 18 Jan 2011 13:39:00 GMT

Listener�?/span>Servlet的监听器�Q�它可以监听客户端的��h��、服务端的操作等。通过监听器，可以自动�Ȁ发一些操作，比如监听在线的用��L��数量。当增加一�?/span>HttpSession�Ӟ��激�?/span>sessionCreated(HttpSessionEvent se)�Ҏ��Q�这样就可以�l�在�U��h数加1。常用的监听接口有以下几个：

ServletContextListener监听ServletContext。当创徏ServletContext�Ӟ��Ȁ�?/span> contextInitialized(ServletContextEvent sce)�Ҏ��Q�当销�?/span>ServletContext�Ӟ��Ȁ�?/span>contextDestroyed(ServletContextEvent sce)�Ҏ��?/span>

ServletContextAttributeListener监听�?/span>ServletContext属性的操作�Q�比如增加、删除、修改属性�?/span>

HttpSessionListener监听HttpSession的操作。当创徏一�?/span>Session�Ӟ��Ȁ�?/span>session Created(HttpSessionEvent se)�Ҏ��Q�当销毁一�?/span>Session�Ӟ��Ȁ�?/span>sessionDestroyed (HttpSessionEvent se)�Ҏ��?/span>

HttpSessionAttributeListener监听HttpSession中的属性的操作。当�?/span>Session增加一个属性时�Q�激�?/span> attributeAdded(HttpSessionBindingEvent se) �Ҏ��Q�当�?/span>Session删除一个属性时�Q�激�?/span>attributeRemoved(HttpSessionBindingEvent se)�Ҏ��Q�当�?/span>Session属性被重新讄��Ӟ��Ȁ�?/span>attributeReplaced(HttpSessionBindingEvent se) �Ҏ��?/span>

下面我们开发一个具体的例子�Q�这个监听器能够�l�计在线的�h数�?br />

�E�序源代码：

package com.dr.web.listener;

import javax.servlet.ServletContext;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

import javax.servlet.http.HttpSessionEvent;

import javax.servlet.http.HttpSessionListener;

publicclass UserCountListener implements ServletContextListener,

HttpSessionListener {

//每个web应用都有且仅有一�?/span>ServletContext对象�Q�这个对象在所有的Servlet都可以��用�?/span>

/**

* 因�ؓ一�?/span>web应用��׃��?/span>ServletContext 对象�Q�因此可以��?/span>ServletContext 来做一些全局性的属性设�|�等�?/span>

* 比如�|�站讉K��计数器等�{?/span>

* ServletContext 是一个应用程序与Web容器(tomcat之类)交互的接�?/span>,同时它也是管理应用程序资源的对象�Q?/span>

通过它可以读�?/span>web.xml中一些配�|�，�?/span>param>中的信息�Q�读取应用中的资源等�?/span>

Session 是一个会话对象，也就是说当客��L��讉K��服务器页面时�Q�它才��生，

原理是服务器�Ҏ��个客��L��产生一�?/span>sessionid�?/span>,�q�把它也保存在客��L��Q?/span>

每次��h��旉��证这�?/span>sessionid是否是创��Z��sessionid的客��L��Q�在服务器端对应�q�个sessionid会创��Z��个缓存区�Q?/span>

存储一些相关信�?/span>,�E�序员可以操作，如被用于购物车，存储用户信息�{�，�q�个区域只有对特定用��h��讉K��权限�Q�对其他客户是拒�l�访问的�Q�这��是一个会话�?/span>

Request 是一个请求对象，也就是说它的生命很短暂，只在一个请求中存在�Q�如一个页面到另一个页面，

一个页面到servlet�?/span>action,一�?/span>servlet�?/span>action�?/span>jsp��面�{?/span>,你可以用它的setAttribute�Ҏ��传递需要的信息(对象),验证��h��方的信息,获得��h��方发�q�来的文件内容等�?/span>

private ServletContext sc;

publicvoid contextDestroyed(ServletContextEvent arg0) {

}

publicvoid contextInitialized(ServletContextEvent event) {

ServletContext sc = event.getServletContext();

sc.setAttribute("Users", new Integer(0));

this.sc = sc;

}

publicvoid sessionCreated(HttpSessionEvent event) {//在线

System.out.println("new user login our web site");

Integer users = (Integer)sc.getAttribute("Users");

sc.setAttribute("Users", ++users);

}

publicvoid sessionDestroyed(HttpSessionEvent event) {

Integer users = (Integer)sc.getAttribute("Users");

sc.setAttribute("Users", --users);

}

Web.xml中配�|�如下：

<listener-class>com.dr.web.listener.UserCountListenerlistener-class>

listener>

�?/span>UserCountListener里，�?/span>users代表当前在线的�h敎ͼ�UserCountListener��在Web服务器启动时自动执行。当UserCountListener构造好后，�?/span>users讄��?/span> 0。每增加一�?/span>Session�Q?/span>UserCountListener会自动调�?/span>sessionCreated(HttpSessionEvent event)�Ҏ��Q�每销毁一�?/span>Session�Q?/span>UserCountListener会自动调�?/span> sessionDestroyed(HttpSessionEvent se)�Ҏ��。当调用sessionCreated(HttpSessionEvent event)�Ҏ��Ӟ��说明又有一个客户在��h��Q�此时��在线的�h敎ͼ�users�Q�加1�Q��ƈ且把user写到ServletContext中�?/span> ServletContext的信息是所有客��L��׃�n的，�q�样�Q�每个客��L��都可以读取到当前在线的�h数�?/span>

�q�行�l�果�Q?br />

向日�?/a> 2011-01-18 21:39 发表评论

Tue, 14 Dec 2010 02:35:00 GMT

摘要: MVC是三个单词的�~�写,分别为：模型(Model),视图(View)和控制Control)�?MVC模式的目的就是实现Web�pȝ��的职能分工�?Model层实现系�l�中的业务逻辑�Q�通常可以用JavaBean或EJB来实现�?View层用于与用户的交互，通常用JSP来实现�?Control层是Model与View之间沟通的桥梁�Q�它可以分派用户的请求�ƈ选择恰当的视图以用于昄��Q�同时它也可... 阅读全文

向日�?/a> 2010-12-14 10:35 发表评论

�q��o器—防止未��d��直接讉K��|�站内部

Tue, 14 Dec 2010 02:26:00 GMT

有些�|�站需要登录以后才能访问网站内部资源，�q�就需要我们做一个过滤器�Q�当用户讉K��|�站内部资源�Ӟ��要先�l�过�q��o器，�q��o器判断是否有�q�个用户�Q�有则蟩转进入网站内部页面，没有则返回登录页面�?/span>

�q��o器代码：

package com.dr.course;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import com.dr.common.Global;

import com.dr.vo.User;

public class IsLoginFilter implements Filter {

public void destroy() {

}

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain filterChain) throws IOException, ServletException {

System.out.println("every request pass here");

HttpServletRequest hrequest=(HttpServletRequest)request;

HttpSession session=hrequest.getSession();

User user = (User)session.getAttribute(Global.USER);

if(user == null){

//跌��{到登陆页�?/span>

hrequest.getRequestDispatcher("/index.jsp").forward(request,response);

}

filterChain.doFilter(request, response);

}

public void init(FilterConfig filterConfig) throws ServletException {

}

LoginServlet�c�，�q�行��d��之后的处理：

package com.dr.course;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import com.dr.common.Global;

import com.dr.vo.User;

public class LoginServlet extends HttpServlet{

public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{

String userName=request.getParameter("username");

String passWord=request.getParameter("password");

System.out.println("userName | " + userName);

System.out.println("passWord | " + passWord);

User user = new User();

user.setUserName(userName);

user.setPassWord(passWord);

HttpSession session = request.getSession();

//��d��成功�Q�把User攑ֈ�session�Q�然后在拦截器中判断

//key--value

session.setAttribute(Global.USER, user);

request.getRequestDispatcher("/admin/main.jsp").forward(request, response);

}

web.xml中配�|�如下：

- <filter>

<filter-name>isLoginfilter-name>

<filter-class>com.dr.course.IsLoginFilterfilter-class>

filter>

- <filter-mapping>

<filter-name>isLoginfilter-name>

<url-pattern>/admin/*url-pattern>

filter-mapping>

- <servlet>

<servlet-name>loginservlet-name>

<servlet-class>com.dr.course.LoginServletservlet-class>

servlet>

- <servlet-mapping>

<servlet-name>loginservlet-name>

<url-pattern>/loginurl-pattern>

servlet-mapping>

未登录界面：

成功��d��的界面：

向日�?/a> 2010-12-14 10:26 发表评论

邮箱自动��d��

Mon, 13 Dec 2010 10:54:00 GMT

cookie为用��L��陆服务器后，服务器写在客��L��的文件�?/span>

我们在登�?/span>126邮箱�Ӟ��如果��N��上两周内自动登录，两周内不用输入用户名和密码邮��׃��自动��d��Q�这是因为第一�ơ登录时服务器将用户名和密码写入cookie中，�q�返回给客户端�?/span>

下次��d��?/span>Http协议会带着用户�?/span>cookie��L��务器验证�Q�因为服务器已经存储用户的信息，所以会自动��d��?/span>

��d��代码�Q?/span>

package com.dr.course;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

this.doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String username=request.getParameter("username");

String password=request.getParameter("password");

String savetime=request.getParameter("saveTime");

if(CheckLogin.login(username, password)){

if(null!=savetime){

int saveTime=Integer.parseInt(savetime);//�q�里接受的表单��gؓ天来计算�?/span>

int seconds=saveTime*24*60*60;

Cookie cookie = new Cookie("user", username+"=="+password);

cookie.setMaxAge(seconds);

response.addCookie(cookie);

}

request.setAttribute("username",username);

request.getRequestDispatcher("/main126.jsp").forward(request,response);

}else{

request.getRequestDispatcher("/failure.jsp").forward(request,response);

}

验证代码�Q?/span>

package com.dr.course;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class IndexFilter implements Filter {

public void destroy() {

// TODO Auto-generated method stub

}

public void doFilter(ServletRequest arg0, ServletResponse arg1,

FilterChain arg2) throws IOException, ServletException {

System.out.println("every request pass here haha");

HttpServletRequest request = (HttpServletRequest) arg0;

HttpServletResponse response = (HttpServletResponse) arg1;

Cookie[] cookies = request.getCookies();

String[] cooks = null;

String username = null;

String password = null;

if (cookies != null) {

for (Cookie coo : cookies) {

String aa = coo.getValue();

cooks = aa.split("==");

if (cooks.length == 2) {

username = cooks[0];

password = cooks[1];

}

System.out.println("cookie username | " + username);

System.out.println("cookie password | " + password);

if (CheckLogin.login(username, password)) {

System.err.println("check successfully cookie data ");

request.getSession().setAttribute("username",username);

request.getRequestDispatcher("/main126.jsp").forward(request, response);

}else{

arg2.doFilter(request,response );

}

public void init(FilterConfig arg0) throws ServletException {

// TODO Auto-generated method stub

}

package com.dr.course;

public class CheckLogin {

public static boolean login(String username, String password) {

if ("admin".equals(username) && "123456".equals(password)) {

return true;

} else {

return false;

}

web.xml中配�|�如下：

- <filter>

<filter-name>loginFilterfilter-name>

<filter-class>com.dr.course.IndexFilterfilter-class>

filter>

- <filter-mapping>

<filter-name>loginFilterfilter-name>

<url-pattern>/main126.jspurl-pattern>

filter-mapping>

- <servlet>

<servlet-name>LoginServletservlet-name>

<servlet-class>com.dr.course.LoginServletservlet-class>

servlet>

- <servlet-mapping>

<servlet-name>LoginServletservlet-name>

<url-pattern>/login.dourl-pattern>

servlet-mapping>

��目录加入到Tomcat中，开�?/span>Tomcat�Q�打开��览器输入网址:http://127.0.0.1:8080/AutoLogin/login.do�q�行��试�?/span>

向日�?/a> 2010-12-13 18:54 发表评论

Mon, 13 Dec 2010 10:44:00 GMT

Http协议中默认的�~�码字符集和�q�_��字符集都不是中文的，所�?/span>Web��目中经�怼�遇到中文��q��问题�?/span>

为防止中文�ؕ码出玎ͼ�首先我们要把��目中每个网��늚��~�码形式�Ҏ��中文的，HTML�|�页中的charset�Ҏ��UTF-8�Q?/span>JSP�|�页中的pageEncoding�Ҏ��UTF-8�?/span>

然后我们做一个过滤器�Q�每�ơ对�|�页的请求都会进入到�q��o器，�q�且�?/span>request�?/span>response都改�?/span>UTF-8�~�码形式�Q�这样防止了中文��q��的出现�?/span>

源代码如下：

package com.dr.servletform;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.jsp.jstl.core.Config;

public class MyFilter implements Filter{

String encoding="";

public void destroy() {

}

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException, ServletException {

System.out.println("pass here-------");

request.setCharacterEncoding(encoding);

response.setCharacterEncoding(encoding);

chain.doFilter(request, response);

}

public void init(FilterConfig config) throws ServletException {

String encoding=config.getInitParameter("encoding");

this.encoding=encoding;

System.out.println(encoding);

}

web.xml中配�|�如下：

<filter-name>MyFilterfilter-name>

<filter-class>com.dr.servletform.MyFilterfilter-class>

- <init-param>

<param-name>encodingparam-name>

<param-value>UTF-8param-value>

init-param>

filter>

- <filter-mapping>

<filter-name>MyFilterfilter-name>

<url-pattern>/*url-pattern>

filter-mapping>

向日�?/a> 2010-12-13 18:44 发表评论

JDBC

Wed, 08 Dec 2010 11:54:00 GMT

JDBC�?/span>Java语言提供讉K��和操作数据库的一�U�途径�Q�通过使用JDBC可以操作��L��?/span>SQL语句�Q�来讉K��和操作数据库

JDBC�~�程步骤�Q?/span>

加蝲数据库驱动（jar 文�g�Q?/span>

获得数据库连�?/span>

创徏语句 (SQL)

执行查询

遍历�l�果�?/span>

关闭数据库连�?/span>

�C�Z��程序：

package com.dr.jdbc;

/**

* DriverManager 驱动�E�序��理�?/span> 在数据库和相应驱动程序之间徏立连�?/span>

* Connection 对象代表与数据库的连接，也就是在已经加蝲�?/span>Driver和数据库之间建立�q�接

* Statement 提供在基层连接上�q�行SQL语句�Q��ƈ且访问结�?/span>

* ResultSet �?/span>Statement执行SQL语句�Ӟ��有时会返�?/span>ResultSet�l�果集，包含的是查询的结果集

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public class Test {

public static void main(String[] args) {

query();

}

public static void query(){

Connection conn = null;

try {

//1.加蝲数据库驱�?/span>

Class.forName("com.mysql.jdbc.Driver");

//2.获得数据库连�?/span>

//DriverManager 驱动�E�序��理�?/span> 在数据库和相应驱动程序之间徏立连

conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/jdbc_db", "root", "1234");

//3.创徏语句

String sql = "select * from UserTbl";

//�q�回一个执�?/span>SQL的句�?/span>

Statement stmt = conn.createStatement();

//�q�回查询�?/span>

//4.执行语句

ResultSet rs = stmt.executeQuery(sql);

//5.遍历�l�果�?/span>

while(rs.next()){

int id = rs.getInt(1);

String username = rs.getString(2);

String password = rs.getString(3);

int age = rs.getInt(4);

System.out.println(id+":"+username+":"+password+":"+age);

}

} catch (Exception e) {

e.printStackTrace();

}finally{

if(conn!=null){

try { //关闭数据库连�?/span>

conn.close();

} catch (SQLException e) {

conn = null;

e.printStackTrace();

}

向日�?/a> 2010-12-08 19:54 发表评论

Fri, 12 Nov 2010 10:14:00 GMT

1.包含客户端和服务器两部分�E�序�Q��ƈ且两个程序能分开独立�q�行�?br /> 2.客户端可以输入服务器地址和端口，�q�接服务器�?br /> 3..服务器能接受客户端连接，�q�向客户端输出发送的字符丌Ӏ?br />
代码如下�Q?br /> 服务器端�Q?br />

package com.dr.Demo01;

import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;

public class ServerSocket01 {

public static void main(String[] args) {
  ServerSocket server=null;
  try{
   //服务器在9999端口开辟了服务
   server=new ServerSocket(9999);
  }catch(Exception e){}
  //对于服务器而言�Q�所有用��L��h��都是通过SeverSocket实现
  Socket client=null;
  try{
   //服务器在此等待用��L��链接
   System.out.println("�{�待客户端链接、、�?);
   client=server.accept();//服务端接收到一个client
  }catch(Exception e){}
  //要向客户端打��C��?br />   PrintStream out=null;
  //得到向客��L��输出信息的能�?br />   try{
   out=new PrintStream(client.getOutputStream());
  }catch(Exception e){}
  out.println("Hi,how do you do?");
  try{
   client.close();
   server.close();
  }catch(Exception e){}
  System.out.println("客户端回应完毕、、�?);
}

}

客户端：

package com.dr.Demo01;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;

public class ClientSocket01 {

public static void main(String[] args) {

  Socket client=null;
  try{
   //实际上表�C��链接到服务器上去�?br />    client=new Socket("192.168.1.23",9999);
  }catch(Exception e){}
  //�{�待服务器端的回�?br />   String str=null;
  //如果直接使用InputStream接受会比较麻�?br />   //最好的�Ҏ��是可以把内容攑օ�发哦�~�冲��之中进行读�?br />   BufferedReader buf=null;

  try{
   buf=new BufferedReader(new InputStreamReader(client.getInputStream()));
      str=buf.readLine();
  }catch(Exception e){}
  System.out.println(str);
}

}

向日�?/a> 2010-11-12 18:14 发表评论

Wed, 10 Nov 2010 10:48:00 GMT

�U�程间通信�Q�一个线�E�向数据存储�I�间��d��数据�Q?/span>Benz�Q�，另一个线�E�从数据存储�I�间取出数据�Q?/span>BMW�Q��?/span>

�E�序有两�U�以外需要考虑�Q?/span>

1�?span style="font: 7pt 'Times New Roman'"> 假设Benz�U�程刚向数据存储�I�间��d��了一辆�R的名字。还没有加入�q�辆车的颜色�Q?/span>CPU��切换到�?/span>BMW�U�程�Q?/span>Benz�U�程��把�q�辆车的名字和上辆�R的颜色联�p�d��了一赗��?/span>

2�?span style="font: 7pt 'Times New Roman'"> Benz放了若干�ơ的数据�?/span>BMW才开始取数据�Q�或者是�Q?/span>BMW取完了一个数据后�Q�还没等�?/span>Benz攑օ�新的数据�Q�又重复取出已取�q�的数据�?/span>

可能出现的问题：

1�?span style="font: 7pt 'Times New Roman'"> Benz�?/span>BMW快时�Q?/span>BMW会漏掉一些数据没有取到�?/span>

2�?span style="font: 7pt 'Times New Roman'"> BMW�?/span>Benz快时�Q?/span>BMW取相同的数据�?/span>

多个�U�程�׃�n同一资源的时候，必须�q�行同步�Q�采用同步方法，解决�W�一个问题�?/span>

�U�程的等待和唤醒机制�Q?/span>

wait()�Q�告诉当前线�E�放弃监视器�q�进入睡眠状态，直到其他�U�程�q�入同一监视器�ƈ调用notify为止�?/span>

notify()�Q�唤醒同一对象监视器中调用wait的第一个线�E��?/span>

�E�序中采用线�E�的�{�待和唤醒机�Ӟ��当发�?/span>BMW没有取走内容�Ӟ��Benz应该�{�待�Q�当BMW把内容取��C��后，Benz才可以放。这栯��决了�W�二个问题�?/span>

代码如下�Q?/span>

package com.dr.test;

class Car{

private String name="奔驰";

private String color="银色";

private boolean flag=false;

public synchronized void set(String name,String color){

//如果flag的��g��?/span>true则要�{�待

if(!flag){

//�{�待

try{

wait();

}catch(Exception e){}

}

//如果向下�l�箋执行了，则表�C�可以设�|�，flag=true

this.name=name;

this.color=color;

flag=false;

notify();

}

public synchronized void get(){

//如果flag的��gؓtrue的时候，表示要等�?/span>

if(flag){

try{

wait();

}catch(Exception e){}

}

//如果向下执行了，则表�C�允许取�?/span>

System.out.println(this.name+"-->"+this.color);

//改变标志�Q�表�C�可以生产了

flag=true;

notify();

}

class Benz implements Runnable{

Car car=null;

public Benz(Car c){

this.car=c;

}

public void run(){

int i=0;

while(true){

if(i==0){

car.set("宝马", "�U�色");

i=1;

}

else{

car.set("奔驰", "银色");

i=0;

}

class BMW implements Runnable{

Car car=null;

public BMW(Car c){

this.car=c;

}

public void run(){

while(true){

car.get();

}

public class Demo01 {

public static void main(String[] args) {

Car c=new Car();

Benz benz=new Benz(c);

BMW bmw=new BMW(c);

new Thread(benz).start();

new Thread(bmw).start();

}

�q�行�l�果�Q?br />

向日�?/a> 2010-11-10 18:48 发表评论

Mon, 08 Nov 2010 09:49:00 GMT

Java�U�程的实现有两种方式�Q?/span>

1 通过�l�承Thread�c�L��实现�?/span>

每个�U�程都是通过某个特定Thread对象所对应的方�?/span>run()l来完成其操作的，�Ҏ��run()成�ؓ�U�程体�?/span>

如果惌��启动多线�E�，则肯定调�?/span>start()�Ҏ��Q?/span>start�Ҏ��可以调用被子�c�覆写过�?/span>run�Ҏ��

不过�q�种�q�种实现方式会受到单�l�承的局�?/span>

�C�Z��代码�Q?/span>

package com.dr.demo01;

//一个类只要�l�承�?/span>Thread�c�，则此�c�d��是多�U�程�c?/span>

class MyThread extends Thread{

private String name;

public MyThread(String name){

this.name=name;

}

//如果要��用多�U�程�Q�则必须有一个方法的��M��

public void run(){

//打印输出

for(int i=0;i<15;i++){

System.out.println(this.name+"--->在运行、、�?/span>");

}

public class ThreadDemo01{

public static void main(String args[]){

MyThread mt1=new MyThread("�U�程A");

MyThread mt2=new MyThread("�U�程B");

MyThread mt3=new MyThread("�U�程C");

mt1.run();

mt2.run();

mt3.run();

}

2 通过实现Runnable接口来实现�?/span>

该实现方式有以下好处�Q?/span>

�?span style="font: 7pt 'Times New Roman'"> 适合多个相干同程序代码的�U�程��d��理同一资源的情��c�?/span>

�?span style="font: 7pt 'Times New Roman'"> 可以避免�׃��Java单��承特性带来的局限�?/span>

�?span style="font: 7pt 'Times New Roman'"> 有利于程序的健壮性，代码能够被多个线�E�共享�?/span>

�C�Z��代码�Q?/span>

package com.dr.Demo05;

class MyThread implements Runnable{

public void run(){

for(int i=0;i<100;i++){

try{

Thread.sleep(1000);

}catch(Exception e){}

System.out.println(Thread.currentThread().getName()+"--�q�行�?/span>--");

}

public class Demo05 {

public static void main(String[] args) {

MyThread mt=new MyThread();

Thread t1=new Thread(mt,"�U�程A");

Thread t2=new Thread(mt,"�U�程B");

Thread t3=new Thread(mt,"�U�程C");

t1.start();

t2.start();

t3.start();

}

向日�?/a> 2010-11-08 17:49 发表评论

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