集合转换为数组
public static void main(String
[] args
) {
Collection
<String> collection
= new ArrayList<String>();
collection
.add("aaa");
collection
.add("bbb");
collection
.add("ccc");
collection
.add("ddd");
collection
.add("eee");
Object
[] o
= collection
.toArray();
for(int i
=0;i
<o
.length
;i
++){
System
.out
.print(o
[i
]+"--");
}
String
[] arr
= new String[collection
.size()];
collection
.toArray(arr
);
for(int i
=0;i
<arr
.length
;i
++){
System
.out
.print(arr
[i
]+"--");
}
}
数组转换为集合
public static void main(String
[] args
) {
String
[] arr
= {"aaa","bbb","ccc","ddd","eee"};
List
<String> list
= Arrays
.asList(arr
);
System
.out
.println(list
);
list
.add("1");
}
排序与乱序
public static void main(String
[] args
) {
ArrayList
<String> list
= new ArrayList<String>();
list
.add("jsbj");
list
.add("dsvsd");
list
.add("sdv");
list
.add("agfd");
list
.add("agfw");
list
.add("agfww");
list
.add("argd");
Collections
.sort(list
);
System
.out
.println(list
);
Collections
.sort(list
, new Comparator<String>() {
@Override
public int compare(String o1
, String o2
) {
return o1
.length()-o2
.length();
}
});
System
.out
.println(list
);
Collections
.shuffle(list
);
System
.out
.println(list
);
}
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