Java 中 List 的 7 种遍历方式 及 性能对比

# for i 循环
for (int i = 0; i < list.size(); i++) {
    
    
    list.get(i);
}

# 增强for循环
for (int item : list) {
    
    
}

# iterator for 循环
for (Iterator<Integer> iterator = list.iterator(); iterator.hasNext(); ) {
    
    
    iterator.next();
}

# iterator while 循环
Iterator<Integer> iterator = list.iterator();
while (iterator.hasNext()) {
    
    
    iterator.next();
}

# list.forEach 循环
list.forEach(item -> {
    
    
});

# list.stream().forEach 循环
list.stream().forEach(item -> {
    
    
});

# list.parallelStream().forEach 循环
 list.parallelStream().forEach(item -> {
    
    
 });

性能比较

每种循环各遍历10000_0000次 total cost time : 699 ms
for i 循环                                 : 63 ms, 9.01%
iterator for 循环                          : 89 ms, 12.73%
iterator while 循环                        : 86 ms, 12.30%
for Boost 循环                             : 161 ms, 23.03%
list.forEach 循环                          : 115 ms, 16.45%
list.stream().forEach 循环                 : 115 ms, 16.45%
list.parallelStream().forEach 循环         : 66 ms, 9.44%