[code="java"]
SqlSession session=sqlSessionFactory.openSession();
try {
UserMapper userMapper= session.getMapper(UserMapper.class);
List users = userMapper.getUsersByName("999");
System.out.println(users);
if(users==null){
System.out.println("not found result.");
return ;
}
for (User user2 : users) {
System.out.println(user2.getId()+"/"+user2.getName()+"/"+user2.getAge());
}
} catch (Exception e) {
System.out.println("get failed");
e.printStackTrace();
}finally{
session.close();
}
[/code]
请问myBatis返回值为[]是一个什类型 ,if(users==null)这样判断也不行,那应该怎样判断为空呢??
[code="java"] List users = userMapper.getUsersByName("999");
System.out.println(users);
if(users==null||users.isEmpty()){
System.out.println("not found result.");
return ;
} [/code]
这是个list,可以这样判断
[code="java"]if(users==null||users.size()==0)[/code]
[]:空list对象返回的String对象
可以用这个判断if(list.isEmpty()||list.size()==0)