关于Stringbuffer和StringBuilder
public void sds(){
StringBuffer buffer = new StringBuffer();
long l1 = System.currentTimeMillis();
for (int i = 0;i<100000;i++){
buffer.append(i).append("-");
if (i==99999){
buffer.append(i);
}
}
System.out.println(buffer);
long l2 = System.currentTimeMillis();
System.out.println(l2 - l1);
System.out.println("~~~~~~~~~~~~~~~~~~~~~~~社会人~~~~~~~~~~~~~~~~~~~~~~~");
StringBuilder builder = new StringBuilder();
long l3 = System.currentTimeMillis();
for (int j = 0;j<100000;j++){
builder.append(j).append("-");
if (j==99999){
builder.append(j);
}
}
System.out.println(builder);
long l4 = System.currentTimeMillis();
System.out.println(l4 - l3);
System.out.println(buffer.length() == builder.length());
}
打印出来的结果为什么不一样?