60 lines
1.9 KiB
Java
60 lines
1.9 KiB
Java
package chapter5;
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public class Example09 {
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private static final int TIMES = 100000;
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public static void main(String[] args) {
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testString();
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testStringBuffer();
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testStringBuilder();
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test();
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}
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// String时间效率
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public static void testString() {
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long start = System.currentTimeMillis();
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String str = "";
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for (int i = 0; i < TIMES; i++) {
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str += "test";
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}
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long end = System.currentTimeMillis();
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System.out.println("String测试耗时：" + (end - start) + "ms");
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}
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// StringBuffer时间效率（线程安全）
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public static void testStringBuffer() {
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long start = System.currentTimeMillis();
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StringBuffer sb = new StringBuffer();
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for (int i = 0; i < TIMES; i++) {
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sb.append("test");
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}
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long end = System.currentTimeMillis();
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System.out.println("StringBuffer测试耗时：" + (end - start) + "ms");
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}
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// StringBuilder时间效率（非线程安全）
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public static void testStringBuilder() {
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long start = System.currentTimeMillis();
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StringBuilder sb = new StringBuilder("hello");
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for (int i = 0; i < TIMES; i++) {
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sb.append("test");
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}
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long end = System.currentTimeMillis();
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System.out.println("StringBuilder测试耗时：" + (end - start) + "ms");
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}
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public static void test() {
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String s1 = new String("abc");
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String s2 = new String("abc");
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System.out.println(s1.equals(s2)); // 打印结果为true
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StringBuffer sb1 = new StringBuffer("abc");
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StringBuffer sb2 = new StringBuffer("abc");
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System.out.println(sb1.equals(sb2)); // 打印结果为false
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StringBuilder sbr1=new StringBuilder("abc");
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StringBuilder sbr2=new StringBuilder("abc");
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System.out.println(sbr1.equals(sbr2)); // 打印结果为false
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}
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}
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