java 数组复制的方法

1，for循环，效率一般

2，使用克隆，效率最差

3，使用System.arraycopy()方法，效率最高

public class ArrayCopyDemo

{

static class Student
{
public String
name = null;

public Student()
{
name = "zhangsan";
}
}

/**
* @param args
*/
public static void main( String[] args )
{
// TODO Auto-generated method stub

Student[] data = new Student[ 1024000 ];
for( int i = 0; i < data.length; i++ )
{
data[ i ] = new Student();

}

Student[] a = new Student[ data.length ];
long startTime = System.currentTimeMillis();
for( int i = 0; i < a.length; i++ )
{
a[ i ] = data[ i ];
}
long endTime = System.currentTimeMillis();
System.out.println( "消耗时间: " + ( endTime - startTime ) + " ms." );

Student[] b = new Student[ data.length ];
startTime = System.currentTimeMillis();
System.arraycopy( data, 0, b, 0, b.length );
endTime = System.currentTimeMillis();
System.out.println( "消耗时间: " + ( endTime - startTime ) + " ms." );
startTime = System.currentTimeMillis();
Student[] c = data.clone();
endTime = System.currentTimeMillis();
System.out.println( "消耗时间: " + ( endTime - startTime ) + " ms." );

}

}