Echarts在java中使用

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">

<title>This is my JSP page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<link href="assets/css/bootstrap.min.css" rel="stylesheet">
<style type="text/css">

html,body,#wrapper{
width: 100%;
height: 100%;
}

.navbar-inverse{
border-radius:0;
margin-bottom: 0;
}
.navbar-inverse .navbar-header{
width: 180px;
text-align: center;
border-right: 1px solid rgba(255,255,255,0.4);
}
.navbar-inverse .navbar-header .navbar-brand{
float: none;
display: inline-block;
}
.slider{
width: 180px;
min-width:180px;
top:52px;
bottom: 0;
position: absolute;
background-color: rgba(0,0,0,0.00);
box-shadow:3px 0 6px rgba(0,0,0,0.3)
}
.slider .nav li a:hover,
.slider .nav li.active > a{
background-color: rgba(0,0,0,0.2)!important;
}
.slider .sub-menu li a{
padding-left:40px;
}
.slider .sub-menu{
/* border-bottom:1px solid #e5e5e5; */
border-top:1px solid #e5e5e5;
}
#wrap{
margin: 0 0 0 180px;
}

#wrap .wrap{
padding:5px 10px;
}

.panel .panel-footer{
background-color: #ffffff;
padding: 0 15px;
}

.panel-footer .pagination{
margin: 5px;
}

</style>
</head>

<body>
<div id="wrapper">
<nav class="navbar navbar-inverse">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<a class="navbar-brand" href="#">后台系统</a>
</div>

<ul class="nav navbar-nav">
<li class="active"><a href="#">首 页 <span class="sr-only">(current)</span></a></li>
<li><a href="views/login.jsp">登 录</a></li>
<li class="dropdown"><a href="#" class="dropdown-toggle"
data-toggle="dropdown" role="button" aria-haspopup="true"
aria-expanded="false">更 多 <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="#">注 册</a></li>
<li><a href="#">Another action</a></li>
<li><a href="#">Something else here</a></li>
<li role="separator" class="divider"></li>
<li><a href="#">Separated link</a></li>
<li role="separator" class="divider"></li>
<li><a href="#">One more separated link</a></li>
</ul>
</li>
</ul>
<ul class="nav navbar-nav pull-right">
<li><a href="logout" title="安全退出">安全退出</a></li>
</ul>
</nav>
<div class="slider">
<ul class="nav">
<li class="active">
<a href="javascript:void(0);" onclick="openOrClose(this)"><i class="glyphicon glyphicon-user"></i> 用户管理 <i class="glyphicon glyphicon-chevron-down pull-right"></i></a>
<ul class="nav sub-menu">
<li><a href="users/usersController?_method=findAll"><i class="glyphicon glyphicon-list"></i> 用户列表</a></li>
<li class="active"><a href="#"><i class="glyphicon glyphicon-plus"></i> 用户添加</a></li>
</ul>
</li>
<li>
<a href="javascript:void(0);" onclick="openOrClose(this)"><i class="glyphicon glyphicon-th-list"></i> 地址管理 <i class="glyphicon glyphicon-chevron-left pull-right"></i></a>
<ul class="nav sub-menu hidden">
<li ><a href="#"><i class="glyphicon glyphicon-list"></i> 地址列表</a></li>
<li><a href="#"><i class="glyphicon glyphicon-plus"></i> 地址添加</a></li>
</ul>
</li>

</ul>
</div>

<div id="wrap">
<div class="wrap">
<div class="panel panel-info">
<div class="panel-heading">
用户列表

<form action="users/usersController" style="display:inline;">
<div class="col-sm-4 pull-right" style="margin-top: -7px;">
<div class="input-group">
<input type="text" class="form-control" name="keyword" placeholder="搜索..." value="${page.keywords[‘username‘] }">
<input type="hidden" name="_method" value="findAll">
<span class="input-group-btn">
<button class="btn btn-default" type="submit">搜 索</button>
</span>
</div>
</div>
</form>
<button type="button" class="btn btn-default btn-sm pull-right" style="margin-top:-5px;" data-toggle="modal" data-target="#gridSystemModalLabel">年龄分析</button>
</div>
<table class="table table-bordered table-hover" style="margin-bottom: 0">
<tr>
<th>ID</th>
<th>用户名</th>
<th>密码</th>
<th>年龄</th>
<th>邮箱</th>
<th>操作</th>
</tr>
<c:forEach items="${page.data }" var="user">
<tr>
<td>${user.id }</td>
<td>${user.username }</td>
<td>${user.password }</td>
<td>${user.age }</td>
<td>${user.email }</td>
<td>
<a href="#" class="btn btn-info">详情</a>
<a href="users/usersController?_method=findById&id=${user.id }" class="btn btn-warning">修改</a>
<a href="users/usersController?_method=deleteById&id=${user.id }" onclick="return confirm(‘确认删除?‘);" class="btn btn-danger">删除</a>
</td>
</tr>
</c:forEach>
</table>
<div class="panel-footer text-right">
<ul class="pagination">
<li><span>${page.curr } / ${page.pageCount }</span></li>
<li ${(page.curr eq page.first)?‘class="disabled"‘:‘‘ }>
<a href="users/usersController?_method=findAll&keyword=${page.keywords[‘username‘] }&curr=${page.first }" title="首页">首页</a>
</li>
<li ${(page.curr eq page.first)?‘class="disabled"‘:‘‘ }>
<a href="users/usersController?_method=findAll&keyword=${page.keywords[‘username‘] }&curr=${page.prev }" title="上一页">上一页</a>
</li>

<c:forEach begin="${page.start }" end="${page.end }" var="num">
<c:choose>
<c:when test="${page.curr == num }">
<li class="active"><a title="第${num }页">${num }</a></li>
</c:when>
<c:otherwise>
<li><a href="users/usersController?_method=findAll&keyword=${page.keywords[‘username‘] }&curr=${num }" title="第${num }页">${num }</a></li>
</c:otherwise>
</c:choose>
</c:forEach>

<li ${(page.curr eq page.last)?‘class="disabled"‘:‘‘ }>
<a href="users/usersController?_method=findAll&keyword=${page.keywords[‘username‘] }&curr=${page.next }" title="下一页">下一页</a>
</li>
<li ${(page.curr eq page.last)?‘class="disabled"‘:‘‘ }>
<a href="users/usersController?_method=findAll&keyword=${page.keywords[‘username‘] }&curr=${page.last }" title="尾页">尾页</a>
</li>
</ul>
</div>
</div>
</div>
</div>

<div class="modal fade" role="dialog" aria-labelledby="gridSystemModalLabel" id="gridSystemModalLabel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
<h4 class="modal-title" id="gridSystemModalLabel">用户年龄分析</h4>
</div>
<div class="modal-body">
<div class="container-fluid">
<div class="row">
<div class="col-lg-12">
<div id="charts" style="width: 100%;height:60%;"></div>
</div>
</div>
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">关闭</button>
</div>
</div><!-- /.modal-content -->
</div><!-- /.modal-dialog -->
</div><!-- /.modal -->

</body>
<script type="text/javascript" src="assets/js/jquery-1.11.3.min.js"></script>
<script type="text/javascript" src="assets/js/bootstrap.min.js"></script>
<script type="text/javascript" src="assets/js/echarts.min.js"></script>
<script type="text/javascript" src="assets/js/Utils.js"></script>
<script type="text/javascript">

$(‘#gridSystemModalLabel‘).on(‘shown.bs.modal‘,function(){
var charts = echarts.init(document.getElementById("charts"));

var option = {
title: {
text: ‘用户年龄分析‘,
left:‘center‘
},
tooltip: {},
legend: {
orient:‘vertical‘,
left:‘left‘,
data: ["衬衫","羊毛衫","雪纺衫","裤子","高跟鞋","袜子"]
},
series: [{
name: ‘用户年龄分析‘,
type: ‘pie‘,
radius:‘65%‘,
data: []
}]
};
charts.showLoading();
utils.ajax({
url:‘users/usersController‘,
data:{"_method":"analyzeAge"},
success:function(data){
charts.hideLoading();
eval("data = "+data);
//为了得到名字
var names = [];
for(var i in data){
names.push(data[i][‘name‘]);
}
//设置值
option.legend.data = names;
option.series[0].data = data;
charts.setOption(option);
}
});

});
//打开或是关闭菜单
function openOrClose(_dom){
var sub_menu = getNextSilbing(_dom);
var flag = _dom.querySelector(".pull-right");
//如果包含某些样式 则做一些事情
if(hasClass(sub_menu,"hidden")){
//去掉 关于隐藏的class
removeClass(sub_menu,"hidden");
//去掉菜单上的向左的箭头
removeClass(flag,"glyphicon-chevron-left");
//添加上向下的箭头
addClass(flag,"glyphicon-chevron-down");
}else{
//添加是 隐藏的class
addClass(sub_menu,"hidden");
//移除向下的箭头
removeClass(flag,"glyphicon-chevron-down");
//添加上向左的箭头
addClass(flag,"glyphicon-chevron-left");
}
//console.log();

}
//得到下一个兄弟节点
function getNextSilbing(_dom){
_dom = _dom.nextSibling;
while(_dom.nodeType!=1){
_dom = _dom.nextSibling;
}
return _dom;
}
//判断是否包含没有个class样式
function hasClass(_dom,_className){
if(_dom.className.indexOf(_className)!=-1){
return true;
}
return false;
}
//给指定的元素添加指定的样式
function addClass(_dom,_className){
_dom.className = _dom.className+" "+_className;
}
//给指定的元素移除指定的样式
function removeClass(_dom,_className){
_dom.className = _dom.className.replace(_className,"");
//将每次添加上的多余的空格去掉
_dom.className = _dom.className.replace(/\s+/ig," ");
}
</script>
</html>

UsersController.java

package com.huawei.controller;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import com.huawei.common.Page;
import com.huawei.po.Users;
import com.huawei.service.UsersService;

/**
* Servlet implementation class UsersController
*/
public class UsersController extends HttpServlet {
private static final long serialVersionUID = 1L;

private UsersService usersService = new UsersService();

/**
* @see HttpServlet#HttpServlet()
*/
public UsersController() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
/**
* 将 当前的doPost方法 当作中专站
*/
String _method = request.getParameter("_method");

if("findAll".equalsIgnoreCase(_method)){
this.findAll(request, response);
}else if("deleteById".equalsIgnoreCase(_method)){
this.deleteById(request, response);
}else if("register".equalsIgnoreCase(_method)){
this.register(request, response);
}else if("findById".equalsIgnoreCase(_method)){
this.findById(request, response);
}else if("update".equalsIgnoreCase(_method)){
this.update(request, response);
}else if("analyzeAge".equalsIgnoreCase(_method)){
this.analyzeAge(request, response);
}
}

private void analyzeAge(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
// TODO Auto-generated method stub
response.getWriter().write(this.usersService.analyzeAge());

}

private void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{

Users curr = (Users) request.getSession().getAttribute("admin");

if(ServletFileUpload.isMultipartContent(request)){
Map<String, FileItem> map = new HashMap<String, FileItem>();
//创建工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
//得到JVM提供的缓存目录
ServletContext context = this.getServletContext();
File repository = (File)context.getAttribute("javax.servlet.context.tempdir");
factory.setRepository(repository);
//创建ServletFileUpload
ServletFileUpload upload = new ServletFileUpload(factory);

//解析请求
try {
List<FileItem> items = upload.parseRequest(request);
//users = new Users();

for(FileItem item:items){
//form表单里面的每一个字段
map.put(item.getFieldName(), item);
}

Users u = new Users();

u.setId(Integer.parseInt(map.get("id").getString()));
u.setUsername(map.get("username").getString());
u.setPassword(map.get("password").getString());
u.setEmail(map.get("email").getString());
//u.setImage(Integer.parseInt(map.get("id").getString()));
u.setAge(Integer.parseInt(map.get("age").getString()));

//处理 前一步的数据没有顺序的问题
//for(String key:map.keySet()){
//FileItem item = map.get(key);

//if(item.isFormField()){

//没有顺序

//}else{
//得到跟路径
String path = context.getRealPath("/");
//得到附件目录
File attachment = new File(path,"attachment/"+map.get("username").getString());
//如果没有 就创建目录
System.out.println(attachment.getAbsolutePath());
System.out.println(attachment.exists());
if(!attachment.exists()){
attachment.mkdirs();
}

FileItem image = map.get("image");

File output = new File(attachment,System.currentTimeMillis()+"."+getSuffix(image.getName()));

image.write(output);
u.setImage("attachment/"+map.get("username").getString()+"/"+output.getName());
//System.currentTimeMillis()
this.usersService.update(u);
this.findAll(request, response);
//}
//}
//map.get("id");
} catch (Exception e) {
e.printStackTrace();
}
}

}

private String getSuffix(String name){
if(name!=null){
String[] suffixs = name.split("\\.");
if(suffixs.length>1){
return suffixs[suffixs.length-1];
}
}
return "";
}

private void findById(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
if(id!=null && id.trim()!=""){
Users users = this.usersService.findById(Integer.parseInt(id));
request.setAttribute("users", users);
request.getRequestDispatcher("/views/update.jsp").forward(request, response);
return ;
}
}

private void register(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
Users users = null;
//判断是否有文件上传
if(ServletFileUpload.isMultipartContent(request)){
//创建工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
//得到JVM提供的缓存目录
ServletContext context = this.getServletContext();
File repository = (File)context.getAttribute("javax.servlet.context.tempdir");
factory.setRepository(repository);
//创建ServletFileUpload
ServletFileUpload upload = new ServletFileUpload(factory);

//解析请求
try {
List<FileItem> items = upload.parseRequest(request);
users = new Users();

for(FileItem item:items){
//form表单里面的每一个字段

}
//得到跟路径
String path = context.getRealPath("/");
//得到附件目录
File attachment = new File(path,"attachment");
//如果没有 就创建目录
if(!attachment.exists()){
attachment.mkdirs();
}

} catch (FileUploadException e) {
e.printStackTrace();
}
}

}

protected void deleteById(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
String id = request.getParameter("id");
this.usersService.deleteById(Integer.parseInt(id));
response.sendRedirect("usersController?_method=findAll");

}

protected void findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//List<Users> users = this.usersService.findAll();
//request.setAttribute("users", users);

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

if(keyword==null){
keyword = "";
}

Page page = new Page();
String curr = request.getParameter("curr");
if(curr ==null || curr.trim().equals("")){
curr ="1";
}
page.getKeywords().put("username", keyword);
page.setCurr(Integer.parseInt(curr));
page = this.usersService.find4Page(page);
request.setAttribute("page", page);
request.getRequestDispatcher("/views/index.jsp").forward(request, response);
return;
}

}

UsersService.java

package com.huawei.service;

import java.util.List;

import com.huawei.common.Page;
import com.huawei.dao.UsersDAO;
import com.huawei.po.Users;

public class UsersService {

private UsersDAO usersDAO = new UsersDAO();

public List<Users> findAll(){
return this.usersDAO.findAll();
}

public void deleteById(Integer id) {
// TODO Auto-generated method stub
this.usersDAO.delete(id);
}

public Page find4Page(Page page){
return this.usersDAO.find4Page(page);
}

public Users findByUsername(String username) {
List<Users> users = this.usersDAO.findBy("username",username);
return users.size()>0?users.get(0):null;
}

public Users findById(Integer id){
return this.usersDAO.findById(id);
}

public void update(Users users){
this.usersDAO.update(users);
}

public String analyzeAge(){
return this.usersDAO.analyzeAge();
}
}

UsersDAO.java

package com.huawei.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import com.huawei.base.BaseDAO;
import com.huawei.common.CallBack;
import com.huawei.common.Page;
import com.huawei.po.Users;
import com.huawei.utils.BeanUtil;

public class UsersDAO extends BaseDAO<Users, Integer>{

@Override
public Page find4Page(Page page) {
//构建sql语句
String sql = "SELECT * FROM "+BeanUtil.getTableName(clazz)+" WHERE username LIKE ? LIMIT ?,?";
String count = "SELECT COUNT(1) FROM "+BeanUtil.getTableName(clazz)+" WHERE username LIKE ?";
//得到数据
List<Users> data = this.find(sql, new Object[]{"%"+page.getKeywords().get("username")+"%",(page.getCurr()-1)*page.getPageSize(),page.getPageSize()});
page.setRowCount(this.getCount(count,new Object[]{"%"+page.getKeywords().get("username")+"%"}));
page.setData(data);
return page;
}

public String analyzeAge(){

final StringBuilder sb = new StringBuilder("[");

String sql = "SELECT "+
"CASE "+
"WHEN age>0 && age<11 THEN ‘十岁以下‘ "+
"WHEN age>10 && age<21 THEN ‘11-20‘ "+
"WHEN age>20 && age<31 THEN ‘21-30‘ "+
"WHEN age>30 && age<41 THEN ‘31-40‘ "+
"WHEN age>40 && age<51 THEN ‘41-50‘ "+
"WHEN age>50 && age<61 THEN ‘51-60‘ "+
"WHEN age>60 && age<71 THEN ‘61-70‘ "+
"WHEN age>70 && age<81 THEN ‘71-80‘ "+
"WHEN age>80 && age<91 THEN ‘81-90‘ "+
"WHEN age>90 && age<101 THEN ‘91-100‘ "+
"WHEN age>100 THEN ‘一百岁以上‘ "+
"END as ‘label‘,count(age) as ‘value‘ "+
"FROM "+
"users "+
"GROUP BY label ";

this.executeQuery(sql, null, new CallBack() {

@Override
public void execute(ResultSet rs) throws SQLException {
//处理数据
//"{\"name\":\"\",\"value\":\"\"}"
while(rs.next()){
sb.append("{").append("\"name\":\"").append(rs.getString("label")+"\",\"value\":\"").append(rs.getInt("value")+"\"").append("},");
}
}
});

if(sb.length()>1){
sb.deleteCharAt(sb.length()-1);
}

sb.append("]");
return sb.toString();
}

}

时间： 2024-08-03 19:23:15

Echarts在java中使用的相关文章

【实例教程】Echarts 的 Java 封装类库

Echarts 的 Java 封装类库:http://www.oschina.net/p/echarts-java 没想到喜欢Echarts 的 Java 封装类库的人还挺多,在源码中的测试例子一般目的只是构造官网例子的结构,这里写个比较实际的简单例子来演示如何写出一个图表. 首先看看Option的提示. Option说明 Option正式代码中使用,不需要任何依赖. GsonOption正式代码中可以使用,需要引入Gson包,使用toString()方法可以转换为JSON结构的数据(支持fun

java中的三元运算符详解

最近在带领实习生中遇到很多新手问与三元运算符有关的java题目,多数为代码结果题,少数为应用题.鉴于很多资料上对于java三元运算的讲解过于简单,网上的资料与题目也不是很完善,对于结果答案分析不一,故在此总结,当然仅为个人观点,水平有限,不足之处,还请大家多多指出,互相交流学习. 什么是java三元运算符呢?无疑其操作元有三个,第一个是条件表达式,剩余两个为值,条件表达式为真时运算取第一个值,为假时取第二个值. 其示例代码如下:boolean a = 20 < 45 ? true : false

java中BigDecimal的学习

干着java的活,但是看的都是一些偏底层的东西(或者我根本就没有看),有点荒废了java的学习. 最近一直在用到一个类是BigDecimal,但都是模棱两可地在那儿用,并没有深入研究这个类的细节,感觉不能再拖了. BigDecimal,从名字来看就是进行大数运算的,不光这样,还广泛用于小数的精确运算. 当你接触到和钱有关的计算的时候,这个类还是很有用滴. 先来看一个例子 1 package com.tuhooo.bigdecimal; 2 3 /** 4 * Created by tuhooo

Java 中几个重要的关键字

Java中的关键字特别多,大致如下: 访问控制 private protected public 类,方法和变量修饰符 abstract class extends final implements interface native new static strictfp synchronized transient volatile 程序控制 break continue return do while if else for instanceof switch case default 异常

深入剖析Java中的装箱和拆箱

阅读目录 一.什么是装箱?什么是拆箱?二.装箱和拆箱是如何实现的三.面试中相关的问题 自动装箱和拆箱问题是Java中一个老生常谈的问题了,今天我们就来一些看一下装箱和拆箱中的若干问题.本文先讲述装箱和拆箱最基本的东西,再来看一下面试笔试中经常遇到的与装箱.拆箱相关的问题. 回到顶部 一.什么是装箱?什么是拆箱? 我们知道 Java为每种基本数据类型都提供了对应的包装器类型,至于为什么会为每种基本数据类型提供包装器类型在此不进行阐述,有兴趣的朋友可以查阅相关资料.在Java SE5之前,如果要生成

JAVA中只有值传递

今天,我在一本面试书上看到了关于java的一个参数传递的问题: 写道 java中对象作为参数传递给一个方法,到底是值传递,还是引用传递? 我毫无疑问的回答:"引用传递!",并且还觉得自己对java的这一特性很是熟悉! 结果发现,我错了! 答案是: 值传递!Java中只有按值传递,没有按引用传递! 回家后我就迫不及待地查询了这个问题,觉得自己对java这么基础的问题都搞错实在太丢人! 综合网上的描述,我大概了解了是怎么回事,现在整理如下,如有不对之处望大神提出! 先来看一个作为程序员都熟

Java中如何优雅正确的终止线程

Java中终止线程的方式主要有三种: 1.使用stop()方法,已被弃用.原因是:stop()是立即终止,会导致一些数据被到处理一部分就会被终止,而用户并不知道哪些数据被处理,哪些没有被处理,产生了不完整的"残疾"数据,不符合完整性,所以被废弃.So, forget it! 2.使用volatile标志位 看一个简单的例子: 首先,实现一个Runnable接口,在其中定义volatile标志位,在run()方法中使用标志位控制程序运行 public class MyRunnable i

Java中I/O流之数据流

Java 中的数据流: 对于某问题:将一个 long 类型的数据写到文件中,有办法吗?    转字符串 → 通过 getbytes() 写进去,费劲,而且在此过程中 long 类型的数需要不断地转换. 现在,Java 中的数据流能够很好的解决这个问题(不需要转换,直接写进去) 1. DataInputStream 与 DataOutputStream 分别继承自 InputStream.OutputStream, 它属于处理流,需要分别套接在 InputStream.OutputStream 类

java中Random随机种子使用

在java中,通过Random生成随机数时,如果设置随机种子,则相同的种子,产生的随机数相同.若不设置则每次随机的不同. Random rnd = new Random(); rnd.setSeed(10);//用于设置种子. rnd.nextInt();// 用于产生随机数. rnd.nextInt(10); // 产生(0-9)数字.