JavaSE8基础 StringBuffer delete trimToSize 清空字符串缓冲区与整理缓冲区的空间

Posted 2020-10-05

    os ：windows7 x64
    jdk：jdk-8u131-windows-x64
    ide：Eclipse Oxygen Release (4.7.0)
    
    
code：

package jizuiku1;

public class Demo100 {
	public static void main(String[] args) {
		StringBuffer sb = new StringBuffer();
		sb.append("cnblog");
		System.out.println(sb);
		System.out.println(sb.length());
		System.out.println(sb.capacity());
		
		System.out.println("------------------");
		
		sb.append("jizuiku jizuiku");
		System.out.println(sb);
		System.out.println(sb.length());
		System.out.println(sb.capacity());
		
		System.out.println("------------------");		
		
		sb.delete(0, sb.length()); //区间表示[0,sb.length)
		System.out.println(sb);
		System.out.println(sb.length());
		System.out.println(sb.capacity());
		System.out.println("------------------");
		
		sb.append("cnblog jizuiku jizuiku");
		System.out.println(sb);
		System.out.println(sb.length());
		System.out.println(sb.capacity());
		
		System.out.println("------------------");		
		
		sb.delete(0, sb.length()).trimToSize(); //区间表示[0,sb.length)
												//trimToSize 整理一下空间
		System.out.println(sb);
		System.out.println(sb.length());
		System.out.println(sb.capacity());
	}
}

 

result：

 

   

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