Java StringBuilder trimToSize()用法及代码示例

StringBuilder类的trimToSize()方法是一种内置方法，用于修剪用于StringBuilder对象的字符序列的容量。如果StringBuilder对象使用的缓冲区大于保留其当前字符序列所需的缓冲区，则将调用此方法以调整StringBuilder对象的大小，以将该对象转换为更节省空间的对象。调用此方法可能会(但不是必须)影响以后对capacity()方法的调用返回的值。

用法:

public void trimToSize()

返回值：此方法不返回任何内容。

以下示例程序旨在说明StringBuilder.trimToSize()方法：

范例1：

// Java program to demonstrate 
// the trimToSize() Method. 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a StringBuilder object 
        // with a String pass as parameter 
        StringBuilder str 
            = new StringBuilder("GeeksForGeeks"); 
  
        // add more string to StringBuilder 
        str.append("Contribute"); 
  
        // print capacity 
        System.out.println("Capacity before "
                           + "applying trimToSize() = "
                           + str.capacity()); 
  
        // applying trimToSize() Method 
        str.trimToSize(); 
  
        // print string 
        System.out.println("String = " + str.toString()); 
  
        // print capacity 
        System.out.println("Capacity after"
                           + " applying trimToSize() = "
                           + str.capacity()); 
    } 
}

输出：

Capacity before applying trimToSize() = 29
String = GeeksForGeeksContribute
Capacity after applying trimToSize() = 23

范例2：

// Java program to demonstrate 
// the trimToSize() Method. 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a StringBuilder object 
        // with a String pass as parameter 
        StringBuilder str 
            = new StringBuilder(); 
  
        // add more string to StringBuilder 
        str.append("GeeksForGeeks classes"); 
  
        // print capacity 
        System.out.println("Capacity before"
                           + " applying trimToSize() = "
                           + str.capacity()); 
  
        // applying trimToSize() Method 
        str.trimToSize(); 
  
        // print string 
        System.out.println("String = " + str.toString()); 
  
        // print capacity 
        System.out.println("Capacity after "
                           + "applying trimToSize() = "
                           + str.capacity()); 
    } 
}

输出：

Capacity before applying trimToSize() = 34
String = GeeksForGeeks classes
Capacity after applying trimToSize() = 21

参考文献：
https://docs.oracle.com/javase/10/docs/api/java/lang/StringBuilder.html#trimToSize()

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注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 StringBuilder trimToSize() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。