Java Examples - String Optimization
Java ExamplesThe following example demonstrates optimizing strings using the String.intern() method:
StringOptimization.java file
public class StringOptimization {
public static void main(String[] args){
String variables[] = new String[50000];
for( int i=0;i <50000;i++){
variables[i] = "s"+i;
}
long startTime0 = System.currentTimeMillis();
for(int i=0;i<50000;i++){
variables[i] = "hello";
}
long endTime0 = System.currentTimeMillis();
System.out.println("Directly using strings:"+ (endTime0 - startTime0) + " ms" );
long startTime1 = System.currentTimeMillis();
for(int i=0;i<50000;i++){
variables[i] = new String("hello");
}
long endTime1 = System.currentTimeMillis();
System.out.println("Using the new keyword:" + (endTime1 - startTime1) + " ms");
long startTime2 = System.currentTimeMillis();
for(int i=0;i<50000;i++){
variables[i] = new String("hello");
variables[i] = variables[i].intern();
}
long endTime2 = System.currentTimeMillis();
System.out.println("Using the intern() method of string objects:"
+ (endTime2 - startTime2)
+ " ms");
}
}
The output of the above code example is:
直接使用字符串： 3 ms 使用 new 关键字：5 ms 使用字符串对象的 intern() 方法: 10 msOther extensions