arraylist

问题 Following is the structure of the document i have in a collection in MongoDB { "_id": { "$oid": "5f48e358d43721376c397f53" }, "heading": "this is heading", "tags": ["tag1","tag2","tag3"], "categories": ["projA", "projectA2"], "content": ["This", "is", "the", "content", "of", "the", "document"], "timestamp": 1598612312.506219, "lang": "en" } When i am importing data in PDI using the mongodb input step the system is putting each array of the "content" element in a different field I want to

问题 I'm new to Java, so apologies if any of this is unclear - I want to convert a list of four-digit integers into a list of integer arrays - i.e if I have an integer that is 4567, I want to convert that into an array of four separate integers [4, 5, 6, 7]. So I want to convert each line/index of the list into it's own array (rather than converting the entire list into an array). I'm currently reading a file that has four-digit integers (each on a new line) and adding them to a list, which is

问题 I'm new to Java, so apologies if any of this is unclear - I want to convert a list of four-digit integers into a list of integer arrays - i.e if I have an integer that is 4567, I want to convert that into an array of four separate integers [4, 5, 6, 7]. So I want to convert each line/index of the list into it's own array (rather than converting the entire list into an array). I'm currently reading a file that has four-digit integers (each on a new line) and adding them to a list, which is

问题 I'm new to Java, so apologies if any of this is unclear - I want to convert a list of four-digit integers into a list of integer arrays - i.e if I have an integer that is 4567, I want to convert that into an array of four separate integers [4, 5, 6, 7]. So I want to convert each line/index of the list into it's own array (rather than converting the entire list into an array). I'm currently reading a file that has four-digit integers (each on a new line) and adding them to a list, which is

问题 I'm getting data from database model Income. This is how it looks @Table(name = "Income") public class Income extends Model { @Column(name = "AmountDate") public String amountDate; @Column(name = "Amount") public Double amount; @Column(name = "Day") public int day; @Column(name = "Month") public int month; @Column(name = "Year") public int year; } In my fragment I'm getting all Income data from database. In my BaseAdapter I would like to create ArrayList with month and year in it. It would

问题 I'm passing an arraylist from servlet by setting it in the attribute and forwarding it to the jsp Servlet: ArrayList <String> mylist = new ArrayList <String>(); mylist.add("Superman"); mylist.add("batman"); mylist.add("flash"); request.setAttribute("mylist", mylist); request.getRequestDispatcher("Welcome.jsp").forward(request, response); response.sendRedirect("Index.jsp"); Index.jsp function doPopulateList(obj) { alert("HELLO"+obj.id +obj.name+obj.value); var select = document

问题 Why I can initialize ArrayList, like this: ArrayList<Integer> x = new ArrayList<Integer>(Arrays.asList(1,2)); But got Error when using: ArrayList<Long> x = new ArrayList<Long>(Arrays.asList(1,2)); 回答1: Explanation Java automatically transforms int to long if needed. However, Java does not do the same if a transformation from Integer to Long is needed. The function Arrays.asList(...) returns a List<E> with E being the type used as parameters. As you use 1, 2, 3 the type is int . However the

问题 Why I can initialize ArrayList, like this: ArrayList<Integer> x = new ArrayList<Integer>(Arrays.asList(1,2)); But got Error when using: ArrayList<Long> x = new ArrayList<Long>(Arrays.asList(1,2)); 回答1: Explanation Java automatically transforms int to long if needed. However, Java does not do the same if a transformation from Integer to Long is needed. The function Arrays.asList(...) returns a List<E> with E being the type used as parameters. As you use 1, 2, 3 the type is int . However the

问题 I want to do 2D dynamic ArrayList example: [1][2][3] [4][5][6] [7][8][9] and i used this code: ArrayList<ArrayList<Integer>> group = new ArrayList<ArrayList<Integer>>(); group.add(new ArrayList<Integer>(1, 2, 3)); how should i initialize this arraylist? 回答1: If it is not necessary for the inner lists to be specifically ArrayList s, one way of doing such initialization in Java 7 would be as follows: ArrayList<List<Integer>> group = new ArrayList<List<Integer>>(); group.add(Arrays.asList(1, 2,

问题 I want to do 2D dynamic ArrayList example: [1][2][3] [4][5][6] [7][8][9] and i used this code: ArrayList<ArrayList<Integer>> group = new ArrayList<ArrayList<Integer>>(); group.add(new ArrayList<Integer>(1, 2, 3)); how should i initialize this arraylist? 回答1: If it is not necessary for the inner lists to be specifically ArrayList s, one way of doing such initialization in Java 7 would be as follows: ArrayList<List<Integer>> group = new ArrayList<List<Integer>>(); group.add(Arrays.asList(1, 2,