Java的Set、List、Map、JSON、XML之间的转换

r囧r小猫 2023-10-12 19:33 17阅读 0赞

#### 1. Java的Set转List、Set转Map、Set转JSON、Set转XML ####

##### Set转List #####

Set<String> set = new HashSet<>();
    set.add("A");
    set.add("B");
    set.add("C");
    
    List<String> list = new ArrayList<>(set);

##### Set转Map #####

Set<String> set = new HashSet<>();
    set.add("A");
    set.add("B");
    set.add("C");
    
    Map<Integer, String> map = new HashMap<>();
    int index = 0;
    for (String str : set) {
        
        map.put(index++, str);
    }

##### Set转JSON #####

Set<String> set = new HashSet<>();
    set.add("A");
    set.add("B");
    set.add("C");
    
    String json = new Gson().toJson(set);

##### Set转XML #####

Set<String> set = new HashSet<>();
    set.add("A");
    set.add("B");
    set.add("C");
    
    Document document = DocumentHelper.createDocument();
    Element root = document.addElement("Set");
    for (String str : set) {
        
        Element element = root.addElement("Item");
        element.setText(str);
    }

#### 2. Java的List转Set、List转Map、List转JSON、List转XML ####

##### List转Set #####

List<String> list = new ArrayList<>();
    list.add("A");
    list.add("B");
    list.add("C");
    
    Set<String> set = new HashSet<>(list);

##### List转Map #####

List<String> list = new ArrayList<>();
    list.add("A");
    list.add("B");
    list.add("C");
    
    Map<Integer, String> map = new HashMap<>();
    for (int i = 0; i < list.size(); i++) {
        
        map.put(i, list.get(i));
    }

##### List转JSON #####

List<String> list = new ArrayList<>();
    list.add("A");
    list.add("B");
    list.add("C");
    
    String json = new Gson().toJson(list);

##### List转XML #####

List<String> list = new ArrayList<>();
    list.add("A");
    list.add("B");
    list.add("C");
    
    Document document = DocumentHelper.createDocument();
    Element root = document.addElement("List");
    for (String str : list) {
        
        Element element = root.addElement("Item");
        element.setText(str);
    }

#### 3. Java的Map转List、Map转Set、Map转JSON、Map转XML ####

##### Map转List #####

Map<Integer, String> map = new HashMap<>();
    map.put(1, "A");
    map.put(2, "B");
    map.put(3, "C");
    
    List<String> list = new ArrayList<>(map.values());

##### Map转Set #####

Map<Integer, String> map = new HashMap<>();
    map.put(1, "A");
    map.put(2, "B");
    map.put(3, "C");
    
    Set<Map.Entry<Integer, String>> set = map.entrySet();

##### Map转JSON #####

Map<Integer, String> map = new HashMap<>();
    map.put(1, "A");
    map.put(2, "B");
    map.put(3, "C");
    
    String json = new Gson().toJson(map);

##### Map转XML #####

Map<Integer, String> map = new HashMap<>();
    map.put(1, "A");
    map.put(2, "B");
    map.put(3, "C");
    
    Document document = DocumentHelper.createDocument();
    Element root = document.addElement("Map");
    for (Map.Entry<Integer, String> entry : map.entrySet()) {
        
        Element element = root.addElement("Item");
        element.addAttribute("Key", entry.getKey().toString());
        element.setText(entry.getValue());
    }

#### 4. Java的JSON转List、JSON转Map、JSON转Set、JSON转XML ####

##### JSON转List #####

String json = "[\"A\", \"B\", \"C\"]";
    Type listType = new TypeToken<List<String>>() {
        }.getType();
    List<String> list = new Gson().fromJson(json, listType);

##### JSON转Map #####

String json = "{\"1\":\"A\",\"2\":\"B\",\"3\":\"C\"}";
    Type mapType = new TypeToken<Map<Integer, String>>() {
        }.getType();
    Map<Integer, String> map = new Gson().fromJson(json, mapType);

##### JSON转Set #####

String json = "[\"A\", \"B\", \"C\"]";
    Type setType = new TypeToken<Set<String>>() {
        }.getType();
    Set<String> set = new Gson().fromJson(json, setType);

##### JSON转XML #####

String json = "{\"A\":\"1\",\"B\":\"2\",\"C\":\"3\"}";
    JSONObject jsonObject = new JSONObject(json);
    Document document = DocumentHelper.createDocument();
    Element root = document.addElement("JSON");
    for (String key : jsonObject.keySet()) {
        
        Element element = root.addElement(key);
        element.setText(jsonObject.getString(key));
    }

#### 5. Java的XML转List、XML转Map、XML转Set、XML转JSON ####

##### XML转List #####

String xml = "<List><Item>A</Item><Item>B</Item><Item>C</Item></List>";
    Document document = DocumentHelper.parseText(xml);
    Element root = document.getRootElement();
    List<String> list = new ArrayList<>();
    for (Element element : root.elements("Item")) {
        
        list.add(element.getText());
    }

##### XML转Map #####

String xml = "<Map><Item Key=\"1\">A</Item><Item Key=\"2\">B</Item><Item Key=\"3\">C</Item></Map>";
    Document document = DocumentHelper.parseText(xml);
    Element root = document.getRootElement();
    Map<Integer, String> map = new HashMap<>();
    for (Element element : root.elements("Item")) {
        
        int key = Integer.parseInt(element.attributeValue("Key"));
        String value = element.getText();
        map.put(key, value);
    }

##### XML转Set #####

String xml = "<Set><Item>A</Item><Item>B</Item><Item>C</Item></Set>";
    Document document = DocumentHelper.parseText(xml);
    Element root = document.getRootElement();
    Set<String> set = new HashSet<>();
    for (Element element : root.elements("Item")) {
        
        set.add(element.getText());
    }

##### XML转JSON #####

String xml = "<XML><A>1</A><B>2</B><C>3</C></XML>";
    Document document = DocumentHelper.parseText(xml);
    Element root = document.getRootElement();
    JSONObject jsonObject = new JSONObject();
    for (Element element : root.elements()) {
        
        jsonObject.put(element.getName(), element.getText());
    }
    String json = jsonObject.toString();