class User{
private String id;
private String code;
private String name;
}List list；這么個(gè)列表，我想單獨(dú)取出code，假設(shè)有5個(gè)數(shù)據(jù)，有三個(gè)code是1，兩個(gè)code是2，我想用java8的stream的方法操作取出一個(gè)列表或者set，例如List這樣，里面放了一個(gè)1和一個(gè)2，就是同時(shí)去重，怎么寫誒
2 回答
慕田峪9158850
TA貢獻(xiàn)1794條經(jīng)驗(yàn) 獲得超8個(gè)贊
public static void main(String[] args) {
List<User> users = new ArrayList<>();
users.add(new User("1","1","張三"));
users.add(new User("2","1","李四"));
users.add(new User("3","2","王五"));
users.add(new User("4","2","小明"));
users.add(new User("5","1","小三"));
Set<String> codeExists = new HashSet<>();
users = users.stream().filter((V)->{
String code = V.getCode();
if(codeExists.contains(code)){
return false;
}else{
codeExists.add(code);
return true;
}
}).collect(Collectors.toList());
System.out.println(users);
POPMUISE
TA貢獻(xiàn)1765條經(jīng)驗(yàn) 獲得超5個(gè)贊
class User{
String code;
public String getCode() {
return code;
}
}
public class Test {
public static void main(String args[]){
List<User> users = new ArrayList<>();
users.stream()
.collect(Collectors.groupingBy(User::getCode))
.keySet();
}
}先分組,分完組后只拿keySet就行了
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