util
千次阅读

2021-02-26 20:52:44

Util是utiliy的缩写，是一个多功能、基于工具的包。

java.util是包含集合框架、遗留的 collection 类、事件模型、日期和时间设施、国际化和各种实用工具类(字符串标记生成器、随机数生成器和位数组、日期Date类、堆栈Stack类、向量Vector类等)。集合类、时间处理模式、日期时间工具等各类常用工具包。

Java的实用工具类库java.util包。在这个包中，Java提供了一些实用的方法和数据结构。例如，Java提供日期(Data)类、日历(Calendar)类来产生和获取日期及时间，提供随机数(Random)类产生各种类型的随机数，还提供了堆栈(Stack)、向量(Vector) 、位集合(Bitset)以及哈希表(Hashtable)等类来表示相应的数据结构。

Java是一门面向对象编程语言，不仅吸收了C++语言的各种优点，还摒弃了C++里难以理解的多继承、指针等概念，因此Java语言具有功能强大和简单易用两个特征。Java语言作为静态面向对象编程语言的代表，极好地实现了面向对象理论，允许程序员以优雅的思维方式进行复杂的编程。

Java具有简单性、面向对象、分布式、健壮性、安全性、平台独立与可移植性、多线程、动态性等特点。Java可以编写桌面应用程序、Web应用程序、分布式系统和嵌入式系统应用程序等。

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java.util.concurrent.ExecutionException 错误解决。

千次阅读 2022-04-19 10:22:09

java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/recommender]] at java....

错误：

java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/recommender]]
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:943)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/recommender]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	... 6 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.webresources.StandardRoot@5a3ef48a]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4968)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5101)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 6 more
Caused by: org.apache.catalina.LifecycleException: Failed to initialize component [org.apache.catalina.webresources.JarResourceSet@725c6763]
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:107)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:135)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:722)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 9 more
Caused by: java.lang.IllegalArgumentException: java.util.zip.ZipException: invalid LOC header (bad signature)
	at org.apache.catalina.webresources.AbstractSingleArchiveResourceSet.initInternal(AbstractSingleArchiveResourceSet.java:142)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	... 12 more
Caused by: java.util.zip.ZipException: invalid LOC header (bad signature)
	at java.util.zip.ZipFile.read(Native Method)
	at java.util.zip.ZipFile.access$1400(Unknown Source)
	at java.util.zip.ZipFile$ZipFileInputStream.read(Unknown Source)
	at java.util.zip.ZipFile$ZipFileInflaterInputStream.fill(Unknown Source)
	at java.util.zip.InflaterInputStream.read(Unknown Source)
	at sun.misc.IOUtils.readFully(Unknown Source)
	at java.util.jar.JarFile.getBytes(Unknown Source)
	at java.util.jar.JarFile.getManifestFromReference(Unknown Source)
	at java.util.jar.JarFile.getManifest(Unknown Source)
	at org.apache.catalina.webresources.AbstractSingleArchiveResourceSet.initInternal(AbstractSingleArchiveResourceSet.java:140)
	... 13 more

一月 22, 2018 4:27:58 下午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:943)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:789)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:630)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:349)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:483)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:951)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 6 more

一月 22, 2018 4:27:58 下午 org.apache.catalina.startup.Catalina start
严重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:630)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:349)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:483)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:789)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 9 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:951)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 11 more

解决方法：找到 tomcat下的 server.xml，打开后删除以下的东东。

造成此错误，是项目迁移时出现的错。
自己也找了很久，找到这个大神的博客。https://www.cnblogs.com/yidan621/p/5252075.html

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java 后端

java.util.concurrent.RejectedExecutionException异常

万次阅读 2021-01-18 20:30:02

java.util.concurrent.RejectedExecutionException异常报错。具体看了下代码，里面的执行逻辑也不难，没有外部依赖都是内存多线程cpu类型计算的逻辑。下面是报错的线程池状态变化，由上到下，按照时间增长，最后...

场景

业务一切正常，突然收到一堆告警，发现全是
java.util.concurrent.RejectedExecutionException异常报错。
具体看了下代码，里面的执行逻辑也不难，没有外部依赖都是内存多线程cpu类型计算的逻辑。
下面是报错的线程池状态变化，由上到下，按照时间增长，最后达到饱和。

java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 99, active threads = 75, queued tasks = 5000, completed tasks = 1595259]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 101, active threads = 74, queued tasks = 4999, completed tasks = 1595298]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 90, active threads = 70, queued tasks = 4998, completed tasks = 1595354]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 93, active threads = 75, queued tasks = 5000, completed tasks = 1595378]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 85, active threads = 72, queued tasks = 5000, completed tasks = 1595443]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 83, active threads = 70, queued tasks = 5000, completed tasks = 1595447]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 90, active threads = 81, queued tasks = 5000, completed tasks = 1595476]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 85, active threads = 74, queued tasks = 4994, completed tasks = 1595574]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 91, active threads = 80, queued tasks = 4999, completed tasks = 1595678]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 95, active threads = 85, queued tasks = 5000, completed tasks = 1595696]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 95, active threads = 87, queued tasks = 5000, completed tasks = 1595721]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 93, active threads = 85, queued tasks = 4999, completed tasks = 1595727]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 94, active threads = 85, queued tasks = 4998, completed tasks = 1595737]
...
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 109, active threads = 96, queued tasks = 4999, completed tasks = 1596150]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 113, active threads = 102, queued tasks = 4998, completed tasks = 1596191]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 109, queued tasks = 5000, completed tasks = 1596355]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 110, queued tasks = 5000, completed tasks = 1596517]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 119, active threads = 110, queued tasks = 4999, completed tasks = 1596519]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 113, active threads = 105, queued tasks = 5000, completed tasks = 1596553]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 122, active threads = 109, queued tasks = 4999, completed tasks = 1596602]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]
java.util.concurrent.ThreadPoolExecutor@57b5ea0f[Running, pool size = 120, active threads = 120, queued tasks = 5000, completed tasks = 1597061]

因为cpu4核，所以coresize = 40,maxsize = 120，都正常。

    private static BlockingQueue<Runnable> executorQueue = new LinkedBlockingQueue<>(5000);
    private static ExecutorService executorService = new ThreadPoolExecutor(
            Runtime.getRuntime().availableProcessors() * 10,
            Runtime.getRuntime().availableProcessors() * 30,
            60, TimeUnit.SECONDS, executorQueue);

通过对ThreadPoolExecutor类分析，引发java.util.concurrent.RejectedExecutionException主要有两种原因：

线程池显示的调用了shutdown()之后，再向线程池提交任务的时候，如果你配置的拒绝策略是ThreadPoolExecutor.AbortPolicy的话，这个异常就被会抛出来。
当你的排队策略为有界队列，并且配置的拒绝策略是ThreadPoolExecutor.AbortPolicy，当线程池的线程数量已经达到了maximumPoolSize的时候，你再向它提交任务，就会抛出ThreadPoolExecutor.AbortPolicy异常。

排查

因为全机房、只有一个节点报错，而其他机器都正常，在这个一定保证正确的前提下。
1、看了线上的请求量、并没有突增，所以排除外部因素
2、看了代码逻辑，逻辑内部并没有打印报错日志，说明不是线程执行耗时导致后面的其他线程排队
3、排除线程池是否提前关闭。并没有，因为手动没有显示关闭，另外看日志也知道里面的线程数还在变化，所以不存在关闭的说法。

考虑是否是机器本身的原因，后面经过排查，看到那个点线上的cpu使用率突然升高、系统负载突然飙升，网卡流出、流入报文数目、tcp连接数也突然为0。具体干了什么，已经让运营去看了。至少说明我们代码没有问题。

如下图，可以感受下：
在这里插入图片描述

解决

线上第一时间出现这个问题，没想2秒，看了下报错代码逻辑，然后重启了这个节点实例（当时重启完后，观察又没问题了，带着疑惑然后才去排查）

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JavaScript工具类：util.js用法实例

千次阅读 2019-03-04 15:30:59

_util.isEmpty() console.log(_util.isEmpty(undefined)); // true console.log(_util.isEmpty(null)); // true console.log(_util.isEmpty('')); // true console.log(_util.isEmpty([])); /...

缓存方法

_util.cookie.set()

_util.cookie.set('user_name', 'guang');         // 关闭浏览器后失效。注：单独打开 demo.html 是没法缓存的，需要启动本地服务
_util.cookie.set('user_id', '12', 1);           // 保存一天
_util.cookie.set('user_type', 'admin', 1/24);   // 保存一个小时
_util.cookie.set('is_login', '1', 1/24/60);     // 保存一分钟

_util.cookie.get()

console.log(_util.cookie.get('user_name'));     // guang
console.log(_util.cookie.get('user_id'));       // 12
console.log(_util.cookie.get('user_type'));     // admin
console.log(_util.cookie.get('is_login'));      // '1'

_util.cookie.remove()

_util.cookie.remove('user_name');
_util.cookie.remove('user_id');
_util.cookie.remove('user_type');
_util.cookie.remove('is_login');

本地储存方法

_util.storage.set()

_util.storage.set('user', { name: 'guang', age: '25'}); // 'obj-{"name":"guang","age":"25"}'
_util.storage.set('lang', 'zh-cn');                     // 'zh-cn'

_util.storage.get()

console.log(_util.storage.get('user'));     // { name: 'guang', age: '25'}
console.log(_util.storage.get('lang'));     // 'zh-cn'

_util.storage.remove()

_util.storage.remove('user');	// 删除 user 及对应的值

_util.storage.clear()

_util.storage.clear();	// 清空所有 localStorage

数据类型通用方法

_util.isEmpty()

console.log(_util.isEmpty(undefined));  // true
console.log(_util.isEmpty(null));   // true
console.log(_util.isEmpty(''));     // true
console.log(_util.isEmpty([]));     // true
console.log(_util.isEmpty({}));     // true

_util.isString()

console.log(_util.isString('q'));  // true

_util.isArray()

console.log(_util.isArray('q'));    // false
console.log(_util.isArray(['q']));  // true

_util.isObject()

console.log(_util.isObject('q'));       // false
console.log(_util.isObject(['q']));     // false
console.log(_util.isObject({id:'q'}));  // true

_util.isFunction()

var fn = function(){};

console.log(_util.isFunction(fn));  // true

_util.length()

var obj = {
    id: 'a',
    status: '0'
};
var arr = ['p','o','i'];
var str = 'yeah';

console.log(_util.length(obj));     // 2
console.log(_util.length(arr));     // 3
console.log(_util.length(str));     // 4

_util.forEach()

var source = [
    { id: 'c', status: '3', count: '46' },
    { id: 'd', status: '1', count: '41' }
];
_util.forEach(source, function(i, item){
    console.log(i);
    console.log(item);  
    // 0
    // { id: 'c', status: '3', count: '46' }
    // 1
    // { id: 'd', status: '1', count: '41' }
});

var source = {
    id: 'c',
    status: '3'
};
_util.forEach(source, function(key, value){
    console.log(key);
    console.log(value);  
    // 'id'
    // 'c'
    // 'status'
    // '3'
});

_util.isEqual()

var source1 = [
    'qw',
    ['q','w'],
    { id: 'a', status: '2', count: '19' },
];
var source2 = [
    'qw',
    ['q','w'],
    { id: 'a', status: '2', count: '19' },
];
var source3 = [
    'qw',
    ['q','w'],
    { id: 'b', status: '2', count: '19' },
];

console.log(_util.isEqual(source1, source2));     // true
console.log(_util.isEqual(source1, source3));     // false

_util.copy()

var s1 = { id: 'a' };
var s2 = s1;
s2.status = '2';
console.log(s1);    // {id: "a", status: "2"}

var s1 = { id: 'a' };
var s2 = _util.copy(s1);
s2.status = '2';
console.log(_util.copy(s1));    // {id: "a"}

var s1 = [{ id: 'a' }];
var s2 = s1;
s2.push({ id: 'b' });
console.log(_util.copy(s1));    // [{id: "a"}, {id: "b"}]

var s1 = [{ id: 'a' }];
var s2 = _util.copy(s1);
s2.push({ id: 'b' });
console.log(_util.copy(s1));    // [{id: "a"}]

字符串方法

_util.trim()

var str = '  qwe  rty ';

console.log(_util.trim(str));       // 'qwe  rty'

_util.trimAll()

var str = '  qwe  rty ';

console.log(_util.trimAll(str));    // 'qwerty'

_util.string.format()

var str = '确定要{0}单据【{1}】吗？';

console.log(_util.string.format(str, '删除', 'QZYDYJZB201901300002'));   // '确定要删除单据【QZYDYJZB201901300002】吗？'

_util.string.isStartWith()

var str = 'qwerty';
var startStr = 'qw';

console.log(_util.string.isStartWith(str, startStr'));   // true

_util.string.isEndWith()

var str = 'qwerty';
var endStr = 'ty';

console.log(_util.string.isEndWith(str, endStr));   // true

_util.string.firstUpperCase()

var str = 'qwerty';

console.log(_util.string.firstUpperCase(str));   // 'Qwerty'

_util.string.reverse()

var str = 'qwerty';

console.log(_util.string.reverse(str));   // 'ytrewq'

_util.string.split()

var str = 'a,s,d';

console.log(_util.string.split(str, ','));   // ["a", "s", "d"]

_util.string.getNext()

console.log(_util.string.getNext('0001'));     // '0002'
console.log(_util.string.getNext('XM0001'));   // 'XM0002'

数字方法

_util.number.parseInt()

console.log(_util.number.parseInt('25.36'));   // 25

_util.number.parseFloat()

console.log(_util.number.parseFloat('25.36'));   // 25.36

_util.number.toFixed()

console.log(_util.number.toFixed('25.3682', 2));   // '25.37'

_util.number.round()

console.log(_util.number.round('25.3682', 2));   // 25.37

_util.number.ceil()

console.log(_util.number.ceil('25.3612', 2));   // 25.37

_util.number.floor()

console.log(_util.number.floor('25.3682', 2));   // 25.36

_util.number.mul()

var n1 = 1.2;
var n2 = 2.3;
var n3 = 3.45;

console.log(_util.number.mul(n1, n2 ,n3));   // 9.522

_util.number.add()

var n1 = 1.2;
var n2 = 2.3;
var n3 = 3.45;

console.log(_util.number.add(n1, n2 ,n3));   // 6.95

_util.number.random()

console.log(_util.number.random(1, 100));   // 55

数组方法

_util.array.indexOf()

var arr = [
    'qwert',
    ['q', 'w', 'e'],
    { id: 'a', name: '光' }
];

console.log(_util.array.indexOf(arr, 'qwert'));         // 0
console.log(_util.array.indexOf(arr, ['q', 'w', 'e'])); // 1
console.log(_util.array.indexOf(arr, {id: 'a'}));       // 2。当检索数组中的对象时，只用匹配该对象的某一个（几个）属性即可查询到。

_util.array.push()

var arr = ['q'];
var len = _util.array.push(arr, ['w','e']);

console.log(arr);   // ["q", "w", "e"]
console.log(len);   // 4

_util.array.sort()

var arr = [
    { billNo: 'CGAPD20190301000002', date: '2019-03-01', count: '22' },
    { billNo: 'CGAPD20190228000001', date: '2019-02-28', count: '14' },
    { billNo: 'CGAPD20190301000001', date: '2019-03-01', count: '36' },
];

console.log(_util.array.sort(arr, 'billNo'));   // 输出结果为：  
// [
//    { billNo: 'CGAPD20190228000001', date: '2019-02-28', count: '14' },
//    { billNo: 'CGAPD20190301000001', date: '2019-03-01', count: '36' },
//    { billNo: 'CGAPD20190301000002', date: '2019-03-01', count: '22' },
// ];

_util.array.unique()

var arr = [
    'qw',
    'qw',
    ['q','w'],
    ['w','q'],
    { id: 'a', status: '1', count: '22' },
    { id: 'a', status: '2', count: '19' },
];

console.log(_util.array.unique(arr));   // 输出结果为：
// [
//     'qw',
//     ['q','w'],
//     ['w','q'],
//     { id: 'a', status: '1', count: '22' },
//     { id: 'a', status: '2', count: '19' },
// ]

console.log(_util.array.unique(arr, 'id')); // 输出结果为：
// [
//     'qw',
//     ['q','w'],
//     ['w','q'],
//     { id: 'a', status: '1', count: '22' },
// ]

console.log(_util.array.unique(arr, 'id', true));   // 输出结果为：
// [
//     'qw',
//     ['q','w'],
//     { id: 'a', status: '1', count: '22' },
// ]

_util.array.filter()

arr = [
    { id: 'a', status: '1', count: '22' },
    { id: 'b', status: '2', count: '19' },
    { id: 'c', status: '3', count: '46' },
    { id: 'd', status: '1', count: '41' },
];

console.log(_util.array.filter(arr, { status: '1'}));   // 输出结果为：
// [
//     { id: 'a', status: '1', count: '22' },
//     { id: 'd', status: '1', count: '41' }
// ]

console.log(_util.array.filter(arr, { status: '1', id: 'a'}));      // 输出结果为：
// [
//     { id: 'a', status: '1', count: '22' }
// ]

console.log(_util.array.filter(arr, { status: ['1', '2']}));        // 输出结果为：
// [
//     { id: 'a', status: '1', count: '22' },
//     { id: 'b', status: '2', count: '19' },
//     { id: 'd', status: '1', count: '41' }
// ]

console.log(_util.array.filter(arr, { status: ['1', '2']}, true));  // 输出结果为：
// [
//     { id: 'c', status: '3', count: '46' },
// ]

_util.array.select()

var arr = [
    { id: 'a', status: '1', count: '22' },
    { id: 'b', status: '2', count: '19' },
    { id: 'c', status: '3', count: '46' },
];

console.log(_util.array.select(arr, 'count'));    // ["22", "19", "46"]
console.log(_util.array.select(arr, ['status', 'count']));    // 输出结果为：
// [
//     { status: '1', count: '22' },
//     { status: '2', count: '19' },
//     { status: '3', count: '46' }
// ]

_util.array.concat()

var arr1 = ['q','w'];
var arr2 = ['q','a'];

console.log(_util.array.concat(arr1, arr2));    // ["q", "w", "a"]

_util.array.group()

var arr = [
    { size: 'S', color: '红色', price: '199' },
    { size: 'M', color: '蓝色', price: '299' },
    { size: 'M', color: '黄色', price: '159' },
    { size: 'S', color: '绿色', price: '168' },
];

console.log(_util.array.group(arr, 'size'));    // 输出结果为：
// [
//     {
//         "size":"S",
//         "group":[
//             {
//                 "size":"S",
//                 "color":"红色",
//                 "price":"199"
//             },
//             {
//                 "size":"S",
//                 "color":"绿色",
//                 "price":"168"
//             }
//         ]
//     },
//     {
//         "size":"M",
//         "group":[
//             {
//                 "size":"M",
//                 "color":"蓝色",
//                 "price":"299"
//             },
//             {
//                 "size":"M",
//                 "color":"黄色",
//                 "price":"159"
//             }
//         ]
//     }
// ]

_util.array.remove()

var arr = ['s', 'g', '', null, undefined, { id:'q', status: '1'} ];

_util.array.remove(arr);
console.log(arr);   // ["s", "g", { id:'q', status: '1'}]

_util.array.remove(arr, ['s', { id:'q' }]);
console.log(arr);   // ["g"]

_util.array.clear()

var arr = ['s', 'h', 'i'];
_util.array.clear(arr);

console.log(arr);   // []

对象方法

_util.object.keys()

var obj = {
    name: 'guang',
    age: '25'
};

console.log(_util.object.keys(obj));    // ["name", "age"]

_util.object.values()

var obj = {
    name: 'guang',
    age: '25'
}

console.log(_util.object.values(obj));  // ["guang", "25"]

_util.object.assign()

var obj2 = {
    type: 'admin',
    age: '26'
};
_util.object.assign(obj, obj2);

console.log(obj);   // { name: "guang", age: "26", type: "admin" }

_util.object.select()

var obj = {
    name: 'guang',
    email: '123456@qq.com',
    phone: '13566668888'
};

console.log(_util.object.select(obj, ['name', 'phone'])); // {name: "guang", phone: "13566668888"}

_util.object.remove()

var obj = {
    name: 'guang',
    email: '123456@qq.com',
    phone: '13566668888',
    wrong: '',
    wrong2: undefined,
};

console.log(_util.object.remove(obj)); // {name: "guang", email: "123456@qq.com", phone: "13566668888"}
console.log(_util.object.remove(obj, ['name', 'phone'])); // {email: "123456@qq.com"}

_util.object.getValue()

var obj = {
    name: 'guang',
    child: {
        name: 'lan'
    }
};

console.log(_util.object.getValue(obj, 'child.name'));  // lan

_util.object.serialize()

var obj = {
    id: 'a',
    billNo: 'CGDD20190228000001'
};

console.log(_util.object.serialize(obj));   // id=a&billNo=CGDD20190228000001

_util.object.clear()

var obj = {
    id: 'a',
    billNo: 'CGDD20190228000001'
};
_util.object.clear(obj);

console.log(obj);  // {id: "", billNo: ""}

json数据方法

_util.json.toTreeData()

var data = [
    { "id": "1", "level": "1", "name": "基础平台", "parentId": null },
    { "id": "2", "level": "1", "name": "财务平台", "parentId": null },
    { "id": "101", "level": "2", "name": "设置", "parentId": "1" },
    { "id": "102", "level": "2", "name": "系统", "parentId": "1" },
    { "id": "10101", "level": "3", "name": "参数设置", "parentId": "101" },
    { "id": "10201", "level": "3", "name": "权限设置", "parentId": "102" }
];

console.log(_util.json.toTreeData(data, 'id', 'parentId', 'children')); // 输出结果为：
// [
//     {
//         "id":"1",
//         "level":"1",
//         "name":"基础平台",
//         "parentId":null,
//         "children":[
//             {
//                 "id":"101",
//                 "level":"2",
//                 "name":"设置",
//                 "parentId":"1",
//                 "children":[
//                     {
//                         "id":"10101",
//                         "level":"3",
//                         "name":"参数设置",
//                         "parentId":"101"
//                     }
//                 ]
//             },
//             {
//                 "id":"102",
//                 "level":"2",
//                 "name":"系统",
//                 "parentId":"1",
//                 "children":[
//                     {
//                         "id":"10201",
//                         "level":"3",
//                         "name":"权限设置",
//                         "parentId":"102"
//                     }
//                 ]
//             }
//         ]
//     },
//     {
//         "id":"2",
//         "level":"1",
//         "name":"财务平台",
//         "parentId":null
//     }
// ]

时间方法

_util.date.format()

console.log(_util.date.format());
console.log(_util.date.format('', 'YYYY月MM年DD日'));
console.log(_util.date.format('', 'YYYY-MM-DD hh:mm:ss 星期WW'));

_util.date.otherMonth()

console.log(_util.date.otherMonth(-1, '2019-03-04'));	// 2019-02-04
console.log(_util.date.otherMonth(1, '2019-03-04'));	// 2019-04-04

_util.date.startOfMonth()

console.log(_util.date.startOfMonth(0, '2019-03-04'));	// '2019-03-01'
console.log(_util.date.startOfMonth(-1, '2019-03-04'));	// '2019-02-01'

_util.date.endOfMonth()

console.log(_util.date.endOfMonth(0, '2019-03-04'));	// '2019-03-31'
console.log(_util.date.endOfMonth(-1, '2019-03-04'));	// '2019-02-28'

_util.date.startOfWeek()

console.log(_util.date.startOfWeek(0, '2019-03-04'));		// '2019-03-04'

_util.date.endOfWeek()

console.log(_util.date.endOfWeek(0, '2019-03-04'));		// '2019-03-10'

_util.date.otherDate()

console.log(_util.date.otherDate(-6, '2019-03-04'));	// '2019-02-26'

_util.date.howManyDays()

console.log(_util.date.howManyDays('2019-01-12', '2019-02-01'));    // 20

_util.date.howManyMonths()

console.log(_util.date.howManyMonths('2019-01', '2018-05'));    // 8

_util.date.getDatesBetween()

console.log(_util.date.getDatesBetween('2019-01-25', '2019-02-01'));    // ["2019-01-25", "2019-01-26", "2019-01-27", "2019-01-28", "2019-01-29", "2019-01-30", "2019-01-31", "2019-02-01"]
console.log(_util.date.getDatesBetween('2019-01-25', '2019-02-01', 'YYYY-MM')); // ["2019-01", "2019-02"]

浏览器判断方法

_util.browser.type()

console.log(_util.browser.type());

_util.browser.isChrome()

console.log(_util.browser.isChrome());

_util.browser.isIE()

console.log(_util.browser.isIE());

_util.browser.isEdge()

console.log(_util.browser.isEdge());

_util.browser.isSafari()

console.log(_util.browser.isSafari());

_util.browser.isFirefox()

console.log(_util.browser.isFirefox());

_util.browser.isWechat()

console.log(_util.browser.isWechat());

_util.browser.isAndroid()

console.log(_util.browser.isAndroid());

_util.browser.isIOS()

console.log(_util.browser.isIOS());

_util.browser.isMobile()

console.log(_util.browser.isMobile());

表单验证方法

_util.validate.positiveToFixed()

var input = '12.345';

console.log(_util.validate.positiveToFixed(input, 2));  // false
console.log(_util.validate.positiveToFixed(input, 3));  // true

注：其他方法直接调用即可

下载

npm i sg-utils -S

GitHub地址（记得给星哦）

https://github.com/shiguang0116/sg-utils

系列文章

JavaScript工具类（一）：util.js创建及上传
 JavaScript工具类（二）：cookie缓存
 JavaScript工具类（三）：localStorage本地储存
 JavaScript工具类（四）：数据类型
 JavaScript工具类（五）：string字符串
 JavaScript工具类（六）：number数字
 JavaScript工具类（七）：array数组
 JavaScript工具类（八）：object对象
 JavaScript工具类（九）：date日期
 JavaScript工具类（十）：base64编码、解码
 JavaScript工具类（十一）：浏览器、移动端类型
 JavaScript工具类（十二）：validate表单验证
 JavaScript工具类（十三）：url路径处理
 JavaScript工具类（十四）：json数据格式
JavaScript工具类：util.js用法实例

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展开全文

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Md5Util.java
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Md5Util.java

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android.util.Base64类

asm-util.jar

util-linux-ng-2.17源码（含fdisk）

linux：apr-util安装包 apr-util-1.5.2.tar.gz

ws-commons-util-1.0.2.jar

java.util.concurrent.ExecutionException 错误解决。

java.util.concurrent.RejectedExecutionException异常

场景

排查

解决

JavaScript工具类：util.js用法实例

缓存方法

_util.cookie.set()

_util.cookie.get()

_util.cookie.remove()

本地储存方法

_util.storage.set()

_util.storage.get()

_util.storage.remove()

_util.storage.clear()

数据类型通用方法

_util.isEmpty()

_util.isString()

_util.isArray()

_util.isObject()

_util.isFunction()

_util.length()

_util.forEach()

_util.isEqual()

_util.copy()

字符串方法

_util.trim()

_util.trimAll()

_util.string.format()

_util.string.isStartWith()

_util.string.isEndWith()

_util.string.firstUpperCase()

_util.string.reverse()

_util.string.split()

_util.string.getNext()

数字方法

_util.number.parseInt()

_util.number.parseFloat()

_util.number.toFixed()

_util.number.round()

_util.number.ceil()

_util.number.floor()

_util.number.mul()

_util.number.add()

_util.number.random()

数组方法

_util.array.indexOf()

_util.array.push()

_util.array.sort()

_util.array.unique()

_util.array.filter()

_util.array.select()

_util.array.concat()

_util.array.group()

_util.array.remove()

_util.array.clear()

对象方法

_util.object.keys()

_util.object.values()

_util.object.assign()

_util.object.select()

_util.object.remove()

_util.object.getValue()

_util.object.serialize()

_util.object.clear()

json数据方法

_util.json.toTreeData()

时间方法

_util.date.format()

_util.date.otherMonth()

_util.date.startOfMonth()

_util.date.endOfMonth()

_util.date.startOfWeek()

_util.date.endOfWeek()

_util.date.otherDate()