void ensureCapacity(int minimumCapacity)
描述 (Description)
java.lang.StringBuilder.ensureCapacity()方法确保容量至少等于指定的最小值。 如果当前容量小于参数，则分配具有更大容量的新内部阵列。 新容量更大 -
- minimumCapacity参数。
- 旧容量的两倍加2。
如果minimumCapacity参数是非正的，则此方法不执行任何操作，只返回。
声明 (Declaration)
以下是java.lang.StringBuilder.ensureCapacity()方法的声明
public void ensureCapacity(int minimumCapacity)
参数 (Parameters)
minimumCapacity - 这是所需的最小容量。
返回值 (Return Value)
此方法不返回任何值。
异常 (Exception)
NA
例子 (Example)
以下示例显示了java.lang.StringBuilder.ensureCapacity（）方法的用法。
package com.iowiki;
import java.lang.*;
public class StringBuilderDemo {
public static void main(String[] args) {
StringBuilder str1 = new StringBuilder("tuts point");
System.out.println("string1 = " + str1);
// returns the current capacity of the string Builder 1
System.out.println("Old Capacity = " + str1.capacity());
/* increases the capacity, as needed, to the specified amount in the
given StringBuilder object */
// returns twice the capacity plus 2
str1.ensureCapacity(28);
System.out.println("New Capacity = " + str1.capacity());
StringBuilder str2 = new StringBuilder("compile online");
System.out.println("string2 = " + str2);
// returns the current capacity of string Builder 2
System.out.println("Old Capacity = " + str2.capacity());
/* returns the old capacity as the capacity ensured is less than the
old capacity */
str2.ensureCapacity(29);
System.out.println("New Capacity = " + str2.capacity());
}
}
让我们编译并运行上面的程序，这将产生以下结果 -
string1 = tuts point
Old Capacity = 26
New Capacity = 54
string2 = compile online
Old Capacity = 30
New Capacity = 30
