- 尽量减少对变量的重复计算
for (int i = 0; i < list.size(); i++){
...
}
//建议替换为:
for (int i = 0, length = list.size(); i < length; i++){
...
}
- 尽量采用懒加载的策略,即在需要的时候才创建
String str = "aaa";
if (i == 1){
list.add(str);
}
//建议替换为:
if (i == 1){
String str = "aaa";
list.add(str);
}
- 循环内不要不断创建对象引用
for (int i = 1; i <= count; i++){
Object obj = new Object();
}
//这种做法会导致内存中有count份Object对象引用存在,count很大的话,就耗费内存
//建议为改为:
Object obj = null;
for (int i = 0; i <= count; i++){
obj = new Object();
}
- 去掉一次性的临时变量
public int someMethod() {
int temp = getVariable();
return temp * 100;
}
//建议为改为:
public int someMethod() {
return getVariable()* 100;
}
- 避免过长参数列表
class BadExample {
public void someMethod(int i,int j,int k,int l,int m,int n){
//code
}
}
//建议为改为:
class GoodExample {
public void someMethod(Data data){
//code
}
}
class Data {
private int i;
private int j;
private int k;
private int l;
private int m;
private int n;
//getter&&setter
}