需要引入commons-lang包，Maven配置如下：
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.6</version>
</dependency>
测试代码如下：
import org.apache.commons.lang3.time.FastDateFormat;
import java.text.SimpleDateFormat;
import java.util.*;
/**
* Discribe:Test
* 2015/11/12 23:16
*/
public class DateTest {
public static void main(String[] args) {
/**
* testDateFormat
*/
int cont = 200000;
String pattern = "yyyy-MM-dd HH:mm:ss";
/**
* 测试10次
*/
for(int i=1;i<=10;i++){
testDateFormat(cont,i,pattern);
}
}
/**
* testDateFormat
*/
public static void testDateFormat(int cont,int num,String pattern){
System.out.println("执行第"+num+"次");
long l1 = System.currentTimeMillis();
for(int i=0;i<=cont;i++){
SimpleDateFormat s = new SimpleDateFormat(pattern);
Date date = new Date(System.currentTimeMillis());
String string = s.format(date);
}
long l2 = System.currentTimeMillis();
System.out.println("SimpleDateFormat covert time:"+(l2-l1));
for(int i=0;i<=cont;i++){
FastDateFormat s = FastDateFormat.getInstance(pattern, TimeZone.getDefault(), Locale.getDefault());
Date date = new Date(System.currentTimeMillis());
String string = s.format(date);
//System.out.println(string);
}
long l3 = System.currentTimeMillis();
System.out.println("FastDateFormat covert time:"+(l3-l2));
}
}
多次运行结果如下：
执行第1次 SimpleDateFormat covert time:1183 FastDateFormat covert time:441 执行第2次 SimpleDateFormat covert time:566 FastDateFormat covert time:155 执行第3次 SimpleDateFormat covert time:322 FastDateFormat covert time:132 执行第4次 SimpleDateFormat covert time:323 FastDateFormat covert time:140 执行第5次 SimpleDateFormat covert time:331 FastDateFormat covert time:130 执行第6次 SimpleDateFormat covert time:292 FastDateFormat covert time:93 执行第7次 SimpleDateFormat covert time:245 FastDateFormat covert time:96 执行第8次 SimpleDateFormat covert time:249 FastDateFormat covert time:98 执行第9次 SimpleDateFormat covert time:246 FastDateFormat covert time:98 执行第10次 SimpleDateFormat covert time:242 FastDateFormat covert time:103
从运行结果来看，FastDateFormat效率明 SimpleDateFormat