public class StringJudgeController {public static void main(String[] args) {// 当测试的次数从10000  变为100000.结果差异很大！！！JudgeString1("This is the test data", 10000);JudgeString2("This is the test data", 10000);JudgeString3("This is the test data", 10000);JudgeString4("This is the test data", 10000);JudgeString5("This is the test data", 10000);}/*** 方法一: 最多人使用的一个方法, 直观, 方便, 但效率很低;* 方法二: 比较字符串长度, 效率高, 是最好的一个方法;* 方法三: Java SE 6.0 才开始提供的方法, 效率和方法二几乎相等, 但出于兼容性考虑, 推荐使用方法二;* 方法四: 这是一种比较直观,简便的方法,而且效率也非常的高,与方法二、三的效率差不多;* 方法五: 这是java自己封装的方法，方便调用；但是效率最低*/public static void JudgeString1(String str, long num) {long startTiem = System.currentTimeMillis();for (int i = 0; i < num; i++) {for (int j = 0; j < num; j++) {if (str == null || "".equals(str)) {}}}long endTime = System.currentTimeMillis();System.out.println("function1耗时：" + (endTime - startTiem) + "ms");}public static void JudgeString2(String str, long num) {long startTiem = System.currentTimeMillis();for (int i = 0; i < num; i++) {for (int j = 0; j < num; j++) {if (str == null || str.length() <= 0) {}}}long endTime = System.currentTimeMillis();System.out.println("function2耗时：" + (endTime - startTiem) + "ms");}public static void JudgeString3(String str, long num) {long startTiem = System.currentTimeMillis();for (int i = 0; i < num; i++) {for (int j = 0; j < num; j++) {if (str == null || str.isEmpty()) {}}}long endTime = System.currentTimeMillis();System.out.println("function3耗时：" + (endTime - startTiem) + "ms");}public static void JudgeString4(String str, long num) {long startTiem = System.currentTimeMillis();for (int i = 0; i < num; i++) {for (int j = 0; j < num; j++) {if (str == null || str == "") {}}}long endTime = System.currentTimeMillis();System.out.println("function4耗时：" + (endTime - startTiem) + "ms");}public static void JudgeString5(String str, long num) {long startTiem = System.currentTimeMillis();for (int i = 0; i < num; i++) {for (int j = 0; j < num; j++) {if (StringUtils.isBlank(str)) {}}}long endTime = System.currentTimeMillis();System.out.println("function5耗时：" + (endTime - startTiem) + "ms");}
}