Java Vector setSize()
Java Vector类的
setSize()方法用于设置Vector 的大小。如果新大小大于当前大小，则将空项目添加到向量的末尾。否则，将丢弃索引为newSize或更高的所有组件。
语法
以下是
setSize()方法的声明:
Public void setSize(int newSize)
参数
| 参数 |
说明 |
必需/可选 |
| newSize |
它是向量的新大小。 |
必需 |
返回
setSize()方法不返回任何内容。
异常
ArrayIndexOutOfBoundsException -如果新大小为，则此方法将引发异常。向量为负，即newSize <0。
兼容版本
Java 1.2及更高版本
示例1
import java.util.*;
public class VectorSetSizeExample1 {
public static void main(String arg[]) {
//Create an empty vector
Vector<Integer> vec = new Vector<>();
//Add elements in the vector
vec.add(1);
vec.add(2);
vec.add(3);
System.out.println("Components of the vector: "+vec);
//Set the new size of the vector
vec.setSize(6);
//Displaying the vector elements after setting new size
System.out.println("Components of the vector after setting new size: ");
for (Integer num : vec) {
System.out.println("Number = " +num);
}
}
}
输出:
Components of the vector: [1, 2, 3]
Components of the vector after setting new size:
Number = 1
Number = 2
Number = 3
Number = null
Number = null
Number = null
示例2
import java.util.*;
public class VectorSetSizeExample2 {
public static void main(String arg[]) {
//Create an empty vector
Vector < String > colors = new Vector < String > ();
//Add elements in the vector
colors.add("White");
colors.add("Green");
colors.add("Black");
//Displaying the vector elements
System.out.println("Components of a vector: "+colors);
//Set the new size for the vector
colors.setSize(6);
//Displaying the vector elements after setting new size
System.out.print("Components of a vector after setting new size: "+colors);
}
}
输出:
Components of a vector: [White, Green, Black]
Components of a vector after setting new size: [White, Green, Black, null, null, null]
示例3
import java.util.*;
public class VectorSetSizeExample3 {
public static void main(String arg[]) {
//Create an empty vector
Vector<Integer> vec = new Vector<>();
//Add elements in the vector
vec.add(10);
vec.add(20);
vec.add(30);
//Set the new size of the vector
vec.setSize(-15);
//Displaying the vector element
System.out.println("Vector element after setSize(): " +vec);
}
}
输出:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -15
at java.base/java.util.Vector.setSize(Vector.java:314)
at myPackage.VectorSetSizeExample3.main(VectorSetSizeExample3.java:12)
