blocks|key|780697|text|看看java.util.LinkedList或java.util.ArrayList|type|unstyled|depth|inlineStyleRanges|entityRanges|data|780698|List<Integer>+x+=+new+ArrayList<Integer>();
x.add(1);
x.add(2);|code-block|syntax|javascript|780699|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Look at java.util.LinkedList or java.util.ArrayList

<pre><code>List&lt;Integer&gt; x = new ArrayList&lt;Integer&gt;();
x.add(1);
x.add(2);
</code></pre>

blocks|key|995078|text|为此，您可能需要使用ArrayList+--用于像structure这样的动态大小的数组。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995079|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You probably want to use an ArrayList for this -- for a dynamically sized array like structure.

blocks|key|995109|text|您可以先使用ArrayList，然后再使用toArray()方法。但根据您所做的工作，您甚至可能根本不需要数组。看看Lists是不是更符合你的需求。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|995110|请参阅：Java+List+Tutorial|995111|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/tutorial/collections/interfaces/list.html^0|6|9|L|9|1M|5|0|4|I|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|H|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

You can use an <code>ArrayList</code> and then use the <code>toArray()</code> method. But depending on what you are doing, you might not even need an array at all. Look into seeing if <code>Lists</code> are more what you want.

See: <a href="http://download.oracle.com/javase/tutorial/collections/interfaces/list.html" rel="noreferrer">Java List Tutorial</a>

blocks|key|780781|text|使用ArrayList或切换到数组可自动增加数组大小。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|780782|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Use an ArrayList or juggle to arrays to auto increment the array size.

blocks|key|995208|text|Apache+Commons有一个ArrayUtils实现，可以在新数组的末尾添加一个元素：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|995209|/**+Copies+the+given+array+and+adds+the+given+element+at+the+end+of+the+new+array.+*/
public+static+<T>+T[]+add(T[]+array,+T+element)|code-block|syntax|javascript|995210|entityMap|0|LINK|mutability|MUTABLE|url|http://commons.apache.org/proper/commons-lang/javadocs/api-3.1/org/apache/commons/lang3/ArrayUtils.html#add%2528T%255b%255d,%2520T%2529^0|H|A|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Apache Commons has an <a href="http://commons.apache.org/proper/commons-lang/javadocs/api-3.1/org/apache/commons/lang3/ArrayUtils.html#add%28T%5b%5d,%20T%29">ArrayUtils</a> implementation to add an element at the end of the new array:

<pre><code>/** Copies the given array and adds the given element at the end of the new array. */
public static &lt;T&gt; T[] add(T[] array, T element)
</code></pre>

blocks|key|995263|text|您可以使用JAVA中的Collection框架将元素动态添加到数组中。集合框架不适用于原始数据类型。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995264|此集合框架将在"java.util.*“包中提供|995265|例如，如果您使用ArrayList，|995266|在其中创建一个对象，然后添加一些元素(任何类型，如String、Integer+...etc)|995267|ArrayList+a+=+new+ArrayList();
a.add("suman");
a.add(new+Integer(3));
a.add("gurram");|code-block|syntax|javascript|995268|现在，您已将3个元素添加到数组中。|995269|如果要删除任何已添加的元素|995270|a.remove("suman");|995271|同样，如果您想要添加任何元素|995272|a.add("Gurram");|995273|因此数组大小是动态增加/减少的。|995274|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|13|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|J|7|17|8|@]|9|@]|A|$K|L]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|J|7|19|8|@]|9|@]|A|$K|L]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

You can dynamically add elements to an array using Collection Frameworks in JAVA. collection Framework doesn't work on primitive data types.

This Collection framework will be available in "java.util.*" package

For example if you use ArrayList, 

Create an object to it and then add number of elements (any type like String, Integer ...etc)

<pre><code>ArrayList a = new ArrayList();
a.add("suman");
a.add(new Integer(3));
a.add("gurram");
</code></pre>

Now you were added 3 elements to an array.

if you want to remove any of added elements

<pre><code>a.remove("suman");
</code></pre>

again if you want to add any element

<pre><code>a.add("Gurram");
</code></pre>

So the array size is incresing / decreasing dynamically..

blocks|key|995321|text|记录您在原始数组中所处的位置|type|unstyled|depth|inlineStyleRanges|entityRanges|data|995322|class+recordStuff+extends+Thread
{
++++double[]+aListOfDoubles;
++++int+i+=+0;

++++void+run()
++++{
++++++++double+newData;
++++++++newData+=+getNewData();+//+gets+data+from+somewhere

++++++++aListofDoubles[i]+=+newData;+//+adds+it+to+the+primitive+array+of+doubles
++++++++i%2B%2B+//+increments+the+counter+for+the+next+pass

++++++++System.out.println("mode:+"+%2B+doStuff());
++++}

++++void+doStuff()
++++{
++++++++//+Calculate+the+mode+of+the+double[]+array

++++++++for+(int+i+=+0;+i+<+aListOfDoubles.length;+i%2B%2B)+
++++++++{
++++++++++++int+count+=+0;
++++++++++++for+(int+j+=+0;+j+<+aListOfDoubles.length;+j%2B%2B)
++++++++++++{
++++++++++++++++if+(a[j]+==+a[i])+count%2B%2B;
++++++++++++}
++++++++++++if+(count+>+maxCount)+
++++++++++++{
++++++++++++++++maxCount+=+count;
++++++++++++++++maxValue+=+aListOfDoubles[i];
++++++++++++}
++++++++}
++++++++return+maxValue;
++++}
}|code-block|syntax|javascript|995323|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

keep a count of where you are in the primitive array

<pre><code>class recordStuff extends Thread
{
 double[] aListOfDoubles;
 int i = 0;

 void run()
 {
 double newData;
 newData = getNewData(); // gets data from somewhere

 aListofDoubles[i] = newData; // adds it to the primitive array of doubles
 i++ // increments the counter for the next pass

 System.out.println("mode: " + doStuff());
 }

 void doStuff()
 {
 // Calculate the mode of the double[] array

 for (int i = 0; i &lt; aListOfDoubles.length; i++) 
 {
 int count = 0;
 for (int j = 0; j &lt; aListOfDoubles.length; j++)
 {
 if (a[j] == a[i]) count++;
 }
 if (count &gt; maxCount) 
 {
 maxCount = count;
 maxValue = aListOfDoubles[i];
 }
 }
 return maxValue;
 }
}
</code></pre>

blocks|key|781054|text|这是在java中添加数组的一种简单方法。我使用了第二个数组来存储我的原始数组，然后又向其中添加了一个元素。之后，我将该数组传递回原来的数组。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|781055|++++int+[]+test+=+{12,22,33};
++++int+[]+test2=+new+int[test.length%2B1];
++++int+m=5;int+mz=0;
++++for+(+int+test3:+test)++++++++
++++{++++++++++
++++test2[mz]=test3;+mz%2B%2B;++++++++
++++}+
++++test2[mz%2B%2B]=m;
++++test=test2;

++++for+(+int+test3:+test)

++++{
++++++System.out.println(test3);
++++}|code-block|syntax|javascript|781056|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is a simple way to add to an array in java. I used a second array to store my original array, and then added one more element to it. After that I passed that array back to the original one.

<pre><code> int [] test = {12,22,33};
 int [] test2= new int[test.length+1];
 int m=5;int mz=0;
 for ( int test3: test) 
 { 
 test2[mz]=test3; mz++; 
 } 
 test2[mz++]=m;
 test=test2;

 for ( int test3: test)

 {
 System.out.println(test3);
 }
</code></pre>

blocks|key|781083|text|在Java中，数组的大小是固定的，但您可以使用其索引和for循环将元素动态添加到固定大小的数组中。请看下面的例子。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|781084|package+simplejava;

import+java.util.Arrays;

/**
+*
+*+@author+sashant
+*/
public+class+SimpleJava+{

++++/**
+++++*+@param+args+the+command+line+arguments
+++++*/
++++public+static+void+main(String[]+args)+{
++++++++//+TODO+code+application+logic+here

++++++++try{
++++++++++++String[]+transactions;
++++++++++++transactions+=+new+String[10];

++++++++++++for(int+i+=+0;+i+<+transactions.length;+i%2B%2B){
++++++++++++++++transactions[i]+=+"transaction+-+"%2BInteger.toString(i);++++++++++++
++++++++++++}

++++++++++++System.out.println(Arrays.toString(transactions));

++++++++}catch(Exception+exc){
++++++++++++System.out.println(exc.getMessage());
++++++++++++System.out.println(Arrays.toString(exc.getStackTrace()));
++++++++}
++++}

}|code-block|syntax|javascript|781085|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In Java size of array is fixed , but you can add elements dynamically to a fixed sized array using its index and for loop. Please find example below.

<pre><code>package simplejava;

import java.util.Arrays;

/**
 *
 * @author sashant
 */
public class SimpleJava {

 /**
 * @param args the command line arguments
 */
 public static void main(String[] args) {
 // TODO code application logic here

 try{
 String[] transactions;
 transactions = new String[10];

 for(int i = 0; i &lt; transactions.length; i++){
 transactions[i] = "transaction - "+Integer.toString(i); 
 }

 System.out.println(Arrays.toString(transactions));

 }catch(Exception exc){
 System.out.println(exc.getMessage());
 System.out.println(Arrays.toString(exc.getStackTrace()));
 }
 }

}
</code></pre>

In PHP, you can dynamically add elements to arrays by the following:

<pre><code>$x = new Array();
$x[] = 1;
$x[] = 2;
</code></pre>

After this, <code>$x</code> would be an array like this: <code>{1,2}</code>.

Is there a way to do something similar in Java?

How can I dynamically add items to a Java array?

在PHP中，您可以通过以下方式向数组中动态添加元素：$x = new Array();$x[] = 1;$x[] = 2;在此之后，$x将是如下所示的数组：{1,2}。有没有办法在Java中做类似的事情？

问如何将项动态添加到Java数组中？
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何将项动态添加到Java数组中？EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何将项动态添加到Java数组中？
EN