Existing a database tables, in accordance with the requirements, the need will be displayed in the table in a tree, only have these three fields, can't add the parent id, how to use the code to handle, please give a little advice

CodePudding user response:

 class TreeNode {
Private String dar. 

Private String treeName; 

Private String treeCode; 

Private List The children; 

Public TreeNode (String dar, String treeName, String treeCode) {
This. TId=dar; 
Enclosing treeName=treeName; 
Enclosing treeCode=treeCode; 
} 

Public String gettId () {
Return dar; 
} 

Public void settId (String dar) {
This. TId=dar; 
} 

Public String getTreeName () {
Return treeName; 
} 

Public void setTreeName (String treeName) {
Enclosing treeName=treeName; 
} 

Public String getTreeCode () {
Return treeCode; 
} 

Public void setTreeCode (String treeCode) {
Enclosing treeCode=treeCode; 
} 

Public List GetChildren () {
Return the children==null? New ArrayList<> () : the children; 
} 

Public void setChildren (List The list) {
This. The children=list; 
} 
} 

 public List TreeBin (List The list) {
TreeNode root=new TreeNode (" root ", "root", "root"); 
//by treecode order, also can use SQL directly order 
List. Sort ((a, b) - & gt; Atul gawande etTreeCode (). CompareTo (b.g etTreeCode ())); 
Map The map=new HashMap<> (a); 
For (TreeNode node: list) {
if (! Map. Either containsKey (node. GetTreeCode ())) {
The map. The put (node. GetTreeCode (), the node). 
} 
String parentCode=node. GetTreeCode (). The substring (0, node. GetTreeCode (). The length () - 3); 
If (parentCode. Length ()==0) {
Root. GetChildren (). The add (node); 
} 
If (map. Either containsKey (parentCode)) {
The map. The get (parentCode). GetChildren (). The add (node); 
} 
} 
Return a root. The getChildren (); 
} 

CodePudding user response:

If you are familiar with pid method is how to operate, so also is very simple,

Private String dar.
Private String parentTreeCode;
Private String treeCode;

Public String getParentTreeCode () {
If (StringUtils. IsNotBlank (enclosing treeCode)) {
Return parentTreeCode. Substring (0, dar. Length () - 3);
}
return null;
}

Attention to Mr Itself into the root node, the root node treeCode="", the tree is generated in the pid way

CodePudding user response:

reference 1/f, a handsome and forced response:

 class TreeNode {
Private String dar. 

Private String treeName; 

Private String treeCode; 

Private List The children; 

Public TreeNode (String dar, String treeName, String treeCode) {
This. TId=dar; 
Enclosing treeName=treeName; 
Enclosing treeCode=treeCode; 
} 

Public String gettId () {
Return dar; 
} 

Public void settId (String dar) {
This. TId=dar; 
} 

Public String getTreeName () {
Return treeName; 
} 

Public void setTreeName (String treeName) {
Enclosing treeName=treeName; 
} 

Public String getTreeCode () {
Return treeCode; 
} 

Public void setTreeCode (String treeCode) {
Enclosing treeCode=treeCode; 
} 

Public List GetChildren () {
Return the children==null? New ArrayList<> () : the children; 
} 

Public void setChildren (List The list) {
This. The children=list; 
} 
} 

 public List TreeBin (List The list) {
TreeNode root=new TreeNode (" root ", "root", "root"); 
//by treecode order, also can use SQL directly order 
List. Sort ((a, b) - & gt; Atul gawande etTreeCode (). CompareTo (b.g etTreeCode ())); 
Map The map=new HashMap<> (a); 
For (TreeNode node: list) {
if (! Map. Either containsKey (node. GetTreeCode ())) {
The map. The put (node. GetTreeCode (), the node). 
} 
String parentCode=node. GetTreeCode (). The substring (0, node. GetTreeCode (). The length () - 3); 
If (parentCode. Length ()==0) {
Root. GetChildren (). The add (node); 
} 
If (map. Either containsKey (parentCode)) {
The map. The get (parentCode). GetChildren (). The add (node); 
} 
} 
Return a root. The getChildren (); 
} 

This way generated is empty, what all have no

CodePudding user response:

refer to the second floor RockeyCui response:

if you are familiar with pid method is how to operate, so also is very simple,

Private String dar.
Private String parentTreeCode;
Private String treeCode;

Public String getParentTreeCode () {
If (StringUtils. IsNotBlank (enclosing treeCode)) {
Return parentTreeCode. Substring (0, dar. Length () - 3);
}
return null;
}

Note Mr Itself into the root node, the root node treeCode="", the tree is generated in the pid way.

The basic have no what relation and pid, although use recursion, method is totally different

CodePudding user response:

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