java代码测试集合,数组等最大存储大小

其实java里面的集合，数组等他们的存储容量我们是可以预估的。1、存储原始类型，这种存储大小是固定的。2、存储对象，由于内容大小有变化，但是我们可以通过测试获取到大慨存储容量。

还有就是我们扩容内存，会影响集合或数组存储大小。

1、List<Integer>

int judgeListmaxCount = 0;

try {

for (int i = 0; i <= 50000000; i++) {

judgeListmaxCount = i;

dataList.add(i);

}

} catch (Exception e) {

System.out.println("judgeListmaxCount:" + judgeListmaxCount);

} finally {

System.out.println("judgeListmaxCount:" + judgeListmaxCount);

}

异常消息:

Exception in thread "main" judgeListmaxCount:38647475

java.lang.OutOfMemoryError: Java heap space

at java.util.ArrayList.ensureCapacity(ArrayList.java:169)

at java.util.ArrayList.add(ArrayList.java:351)

at com.yxie.test.CreateDichotoSearchData.main(CreateDichotoSearchData.java:21)

xieyun@xieyun-OptiPlex-760:~/work/dichotomy/bin$ java -Xms1024m -Xmx1024m com.yxie.test.CreateDichotoSearchData

judgeListmaxCount:38647475

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

at java.util.Arrays.copyOf(Arrays.java:2760)

at java.util.Arrays.copyOf(Arrays.java:2734)

at java.util.ArrayList.ensureCapacity(ArrayList.java:167)

at java.util.ArrayList.add(ArrayList.java:351)

at com.yxie.test.CreateDichotoSearchData.main(CreateDichotoSearchData.java:21)

2、int[]

int intSize = 0;

try {

for (int i = 191059999; i <= 191160000; i++) {

intSize = i;

int[] allInt = new int[i];

System.out.println("allInt:" + allInt.length);

}

} catch (Exception e) {

} finally {

System.out.println("intSize:" + intSize);

}

异常消息:

intSize:191060000

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

at com.yxie.test.CreateDichotoSearchData.main(CreateDichotoSearchData.java:54)

改变java虚拟机内存大小，会影响int[]数组大小。

xieyun@xieyun-OptiPlex-760:~/work/dichotomy/bin$ java -Xms1024m -Xmx1024m com.yxie.test.CreateDichotoSearchData

Integer max:2147483647

fileSize:4000000000

spareFileSize:1852516353

intSize:191059999

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

at com.yxie.test.CreateDichotoSearchData.main(CreateDichotoSearchData.java:54)

xieyun@xieyun-OptiPlex-760:~/work/dichotomy/bin$

xieyun@xieyun-OptiPlex-760:~/work/dichotomy/bin$ java -Xms2024m -Xmx2024m com.yxie.test.CreateDichotoSearchData

Integer max:2147483647

fileSize:4000000000

spareFileSize:1852516353

allInt:191059999

allInt:191060000

allInt:191060001