java - 如何将换行符添加到多树的toString

Question

有这样一个结构:

public class TreeNode {

private String key;
private List<TreeNode> children;
    ....

我覆盖了 toString() 函数

@Override
public String toString() {
    String treeStructure = "TreeNode [key=" + key +  "]";
    if(children!=null){
        for(TreeNode child:children){
        treeStructure = treeStructure+"--- >"+children.toString()+"/n";
        }
    }
    return treeStructure;
}

然后我测试结果:

public static void main(String[] args) {
    TreeNode node = new TreeNode();
    node.setKey("root");
    List<TreeNode> children = new ArrayList<TreeNode>();
    TreeNode child1 = new TreeNode();
    child1.setKey("child1");
    TreeNode child2 = new TreeNode();
    child2.setKey("child2");
    children.add(child1);
    children.add(child2);
    List<TreeNode> grandchildren = new ArrayList<TreeNode>();
    TreeNode grandchild = new TreeNode();
    grandchild.setKey("grandchild");
    grandchildren.add(grandchild);

    node.setChildren(children);
    child1.setChildren(grandchildren);

    System.out.println(node);

}

但是当我运行它时输出是:

TreeNode [key=root]--->[TreeNode [key=child1]--->[TreeNode [key=grandchild]]/n, TreeNode [key=child2]]/n--->[TreeNode [key=child1]--->[TreeNode [key=grandchild]]/n, TreeNode [key=child2]]/n

我怎样才能像这样在输出中添加换行符:

TreeNode [key=root]--->TreeNode [key=child1]--->TreeNode [key=grandchild]
                   --->TreeNode [key=child2]

但是现在 child1 显示了两次，结果中没有添加换行符。

================================我改了功能:

@Override
public String toString() {
    String treeStructure = "TreeNode [key=" + key +  "]";
    if(children!=null){
        for(TreeNode child:children){
        treeStructure = treeStructure+"\n"+"-->"+children.toString()+"\n";
        }
    }
    return treeStructure;
}

那么输出是:

TreeNode [key=root]
--->[TreeNode [key=child1]
--->[TreeNode [key=grandchild]]
, TreeNode [key=child2]]

--->[TreeNode [key=child1]
--->[TreeNode [key=grandchild]]
, TreeNode [key=child2]]

为什么 child 重复两次，“，”从哪里来？

Answer 1

使用\n代替/n

treeStructure = treeStructure + "--- >" + children.toString() + "\n";