stringtokenizer_string字符串的截取_Java string 分解(2)

结果：

Token Total: 10
The
Java
platform
is
the
ideal
platform
for
network
computing

Token Total: 10
The
Java
platform
is
the
ideal
platform
for
network
computing

Token Total: 19
The
=
Java
=
platform
=
is
=
the
=
ideal
=
platform
=
for
=
network
=
computing

二、性能测试：

import java.util.Random;
import java.util.StringTokenizer;

/**
 * String测试类
 * 
 * @author xiaori.Liu
 *
 */
public class StringTest {

	public static void main(String args[]) {
		String orginStr = getOriginStr(100);
		System.out.println(orginStr);
		
		////////////// String.splic()表现//////////////////////////////////////////////
		System.out.println("使用String.splic()的切分字符串");
		long st1 = System.nanoTime();
		String[] result = orginStr.split("\\.");
		System.out.println("String.splic()截取字符串用时：" + (System.nanoTime() - st1));
		System.out.println("String.splic()截取字符串结果个数：" + result.length);
		System.out.println();

		////////////// StringTokenizer表现//////////////////////////////////////////////
		System.out.println("使用StringTokenizer的切分字符串");
		long st3 = System.nanoTime();
		StringTokenizer token = new StringTokenizer(orginStr, ".");
		System.out.println("StringTokenizer截取字符串用时:" + (System.nanoTime() - st3));
		System.out.println("StringTokenizer截取字符串结果个数：" + token.countTokens());
		System.out.println();

		//////////////////// String.substring()表现//////////////////////////////////////////

		long st5 = System.nanoTime();
		int len = orginStr.lastIndexOf(".");
		System.out.println("使用String.substring()切分字符串");
		int k = 0, count = 0;

		for (int i = 0; i <= len; i++) {
			if (orginStr.substring(i, i + 1).equals(".")) {
				if (count == 0) {
					orginStr.substring(0, i);
				} else {
					orginStr.substring(k + 1, i);
					if (i == len) {
						orginStr.substring(len + 1, orginStr.length());
					}
				}
				k = i;
				count++;
			}
		}
		System.out.println("String.substring()截取字符串用时" + (System.nanoTime() - st5));
		System.out.println("String.substring()截取字符串结果个数：" + (count + 1));
	}

	/**
	 * 构造目标字符串 eg：10.123.12.154.154
	 * 
	 * @param len
	 *            目标字符串组数(每组由3个随机数组成)
	 * @return
	 */
	private static String getOriginStr(int len) {

		StringBuffer sb = new StringBuffer();
		StringBuffer result = new StringBuffer();
		Random random = new Random();
		for (int i = 0; i < len; i++) {
			sb.append(random.nextInt(9)).append(random.nextInt(9)).append(random.nextInt(9));
			result.append(sb.toString());
			sb.delete(0, sb.length());
			if (i != len - 1)
				result.append(".");
		}

		return result.toString();
	}
}

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