我有一个问题，我想从树中打印JSONObjects和JSONArrays。当我想打印孩子时会出现问题。
public class program {
public static void main(String[] args) throws IOException {
File file = new File("");
File outputfile = new File("");
PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(outputfile, true)));
JSONParser parser = new JSONParser();
try {
Object object = parser.parse(new FileReader(file));
JSONObject jsonObject = (JSONObject) object;
JSONArray jsonArray = (JSONArray) jsonObject.get("declaration-list");
try {
Iterator iterator = jsonArray.iterator();
while (iterator.hasNext()) {
JSONObject jo = (JSONObject) iterator.next();
String variableName = (String) jo.get("declared-variable");
MyTreeNode<String> root = new MyTreeNode<>(variableName);
try {
long value = (long) jo.get("value");
MyTreeNode<Long> child1 = new MyTreeNode(value);
System.out.println(root.getData());
root.addChild(child1);
for (MyTreeNode node : root.getChildren()) {
System.out.println(node.getData());
}
} catch (Exception e) {
final JSONObject jsonValue = (JSONObject) jo.get("value");
final String operator = (String) jsonValue.get("operator");
final JSONArray arguments = (JSONArray) jsonValue.get("arguments");
if (operator.equals("set")) {
MyTreeNode<JSONArray> test1 = new MyTreeNode(arguments);
root.addChild(test1);
for (MyTreeNode node : root.getChildren()) {
System.out.print(root.getData() + " = ");
System.out.println(node.getData());
}
}
if (operator.equals("pair")) {
MyTreeNode<JSONArray> test2 = new MyTreeNode(arguments);
root.addChild(test2);
for (MyTreeNode node : root.getChildren()) {
System.out.print(root.getData() + " = ");
System.out.println(node.getData());
}
}
}
}
} catch (Exception e) {
System.out.println("Oops for now");
}
} catch (FileNotFoundException e) {
System.out.println("Input file not found");
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParseException e) {
System.out.println("File was not parsed");
e.printStackTrace();
}
pw.flush();
pw.close();
}
}
这只是我一直在使用的标准树实现。
class MyTreeNode<T> {
private T data = null;
private List<MyTreeNode> children = new ArrayList<>();
private MyTreeNode parent = null;
public MyTreeNode(T data) {
this.data = data;
}
public void addChild(MyTreeNode child) {
child.setParent(this);
this.children.add(child);
}
public void addChild(T data) {
MyTreeNode<T> newChild = new MyTreeNode<>(data);
newChild.setParent(this);
children.add(newChild);
}
public void addChildren(List<MyTreeNode> children) {
for (MyTreeNode t : children) {
t.setParent(this);
}
this.children.addAll(children);
}
public List<MyTreeNode> getChildren() {
return children;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
private void setParent(MyTreeNode parent) {
this.parent = parent;
}
public MyTreeNode getParent() {
return parent;
}
}
当我打印根节点的子节点时，我会得到这样的结果：[0,4]。理想情况下，我想将孩子打印为（0,4），因为这表示一组。我知道我需要覆盖.toString，但是当我不在树类中传递参数时，我怎么能这样做呢。
以下是JSON文件的示例：
{
"declaration-list" : [
{
"declared-variable" : "x0",
"value" : 1
},
{
"declared-variable" : "x212",
"value" : {
"operator" : "pair",
"arguments" : [
1,
2
]
}
},
{
"declared-variable" : "x213",
"value" : {
"operator" : "pair",
"arguments" : [
3,
4
]
}
},
{
"declared-variable" : "x3",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x212"
},
{
"variable" : "x213"
}
]
}
},
{
"declared-variable" : "x214",
"value" : {
"operator" : "pair",
"arguments" : [
0,
4
]
}
},
{
"declared-variable" : "x215",
"value" : {
"operator" : "pair",
"arguments" : [
1,
6
]
}
},
{
"declared-variable" : "x10",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x214"
},
{
"variable" : "x215"
}
]
}
},
{
"declared-variable" : "x216",
"value" : {
"operator" : "set",
"arguments" : [
8
]
}
},
{
"declared-variable" : "x8",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x216"
}
]
}
},
{
"declared-variable" : "x217",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x8"
}
]
}
},
{
"declared-variable" : "x8",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x8"
},
{
"variable" : "x217"
}
]
}
},
{
"declared-variable" : "x17",
"value" : {
"operator" : "set",
"arguments" : [
1,
2,
{
"variable" : "x8"
}
]
}
},
{
"declared-variable" : "x218",
"value" : {
"operator" : "pair",
"arguments" : [
1,
{
"variable" : "x17"
}
]
}
},
{
"declared-variable" : "x18",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x17"
},
{
"variable" : "x218"
}
]
}
},
{
"declared-variable" : "x19",
"value" : {
"operator" : "pair",
"arguments" : [
{
"variable" : "x18"
},
{
"variable" : "x17"
}
]
}
},
{
"declared-variable" : "x219",
"value" : {
"operator" : "set",
"arguments" : [
0
]
}
},
{
"declared-variable" : "x221",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x219"
},
{
"variable" : "x220"
}
]
}
},
{
"declared-variable" : "x224",
"value" : {
"operator" : "set",
"arguments" : [
2,
1
]
}
},
{
"declared-variable" : "x225",
"value" : {
"operator" : "set",
"arguments" : [
{
"variable" : "x19"
}
]
}
},
]
}
答案 0 :(得分：0)
很抱歉，如果这是一个粗略的答案，但您可以添加以下方法或类似于MyTreeNode类的方法。如果你知道任何类型T的类在调用getData（）时将采用“[x，y]”的格式，这将有效：
void printData() {
String t = (String)getData();
t.replace("[", "(");
t.replace("]", ")");
System.out.println(t);
}
编辑：更新了评论澄清的代码：
void printData() {
String t = (String)getData();
if(t.startsWith("{") && t.endsWith("}")) {
t.replace("{", "(");
t.replace("}", ")");
}
else if(t.startsWith("[") && t.endsWith("]")) {
t.replace("[", "(");
t.replace("]", ")");
}
System.out.println(t);
}
答案 1 :(得分：0)
实现此目的的一种方法是使用自定义toString（）方法编写包装类，您可以在其中定义如何输出JSONArray的元素。
这看起来像这样：
public class MyArrayNode {
private JSONArray array;
public MyArrayNode(JSONArray array) {
this.array = array;
}
public JSONArray getArray() {
return array;
}
@Override
public String toString() {
StringJoiner sj = new StringJoiner(",", "(", ")");
array.forEach(a -> sj.add(a.toString()));
return sj.toString();
}
}
如果你想打印出这样的JSONArray，只需制作你的MyTreeNode即可 包含MyArrayNode类型元素：
final JSONArray arguments = (JSONArray) jsonValue.get("arguments");
if (operator.equals("set")) {
MyTreeNode<MyArrayNode> test1 = new MyTreeNode(new MyArrayNode(arguments));