Java for循环常见优化方法案例详解

List<String> list = new ArrayList<String>();

for (int i = 0; i < list.size(); i++) {
 System.out.println(list.get(i));
}

int m = list.size();
for (int i = 0; i < m; i++) {
      System.out.println(list.get(i));
}

for (int i = 0, n = list.size(); i < n; i++) {
    System.out.println(list.get(i));
}

for (int i = list.size() - 1; i >= 0; i--) {
System.out.println(list.get(i));
}

for (Iterator<String> it = list.iterator(); it.hasNext();) {
      System.out.println(it.next());
}

for (Object o : list) {
     System.out.println(o);
}

for (int i = 0; i < 10; i++) {
   for (int j = 0; j < 10000; j++) {
   }
}

 //前：
 int a = 10, b = 11;
  for (int i = 0; i < 10; i++) {
               i = i * a * b;
   } 
 
 
//后：
 int c = a * b;
 for (int i = 0; i < 10; i++) {
         i = i * c;
  }

for (int i = 0; i < 10; i++) {
     try {
 
     } catch (Exception e) {
 
     }
}

try {
   for (int i = 0; i < 10; i++) {
   }
} catch (Exception e) {
 
}
 catch (Exception e) {
 
     }
}

try {
   for (int i = 0; i < 10; i++) {
   }
} catch (Exception e) {
 
}