页面接收String 怎样转换成List<Integer>
时间: 2024-01-21 13:18:09 浏览: 27
要将一个字符串转换为一个整数列表,需要将字符串分割为整数字符串,然后将每个整数字符串转换为整数并添加到列表中。下面是一个Java示例代码:
```java
String input = "1,2,3,4,5";
List<Integer> output = new ArrayList<>();
for (String str : input.split(",")) {
output.add(Integer.parseInt(str.trim()));
}
System.out.println(output);
```
这段代码将字符串“1,2,3,4,5”转换为一个整数列表,并输出结果:[1, 2, 3, 4, 5]。
相关问题
public DataResult<Integer> deleteByIds(@RequestBody List<Integer> ids) { ObjectMapper mapper = new ObjectMapper(); ids = mapper.readValue(jsonString, new TypeReference<List<Integer>>(){}); return DataResult.success(bisTaskService.deleteByIds(ids)); }检查一下有什么错误并修改
在该方法中,您已经使用了 `@RequestBody` 注解来接收请求主体中的 JSON 字符串并将其映射到给定的 `List<Integer>` 对象。因此,您不需要再使用 `ObjectMapper` 对象来读取 JSON 字符串并将其转换为 `List<Integer>` 对象。
因此,您可以删除以下行:
```
ObjectMapper mapper = new ObjectMapper();
ids = mapper.readValue(jsonString, new TypeReference<List<Integer>>(){});
```
修改后的代码如下:
```
public DataResult<Integer> deleteByIds(@RequestBody List<Integer> ids) {
return DataResult.success(bisTaskService.deleteByIds(ids));
}
```
public class DFALexer { public static boolean dfaRecognize(Map<String, Object> dfa, String inputStr) { return true } public static Map<String, Object> json_file2map(String fileName) { JSONParser parser = new JSONParser(); Map<String, Object> dfa = new HashMap<>(); try { Object obj = parser.parse(new FileReader(fileName)); JSONObject dfaJson = (JSONObject) obj; List<Integer> endStates = new ArrayList<>(); JSONArray endStatesJson = (JSONArray) dfaJson.get("end"); for (Object stateObj : endStatesJson) { endStates.add(((Long) stateObj).intValue()); } List<String> symbols = new ArrayList<>(); JSONArray symbolsJson = (JSONArray) dfaJson.get("syms"); for (Object symbolObj : symbolsJson) { symbols.add((String) symbolObj); } List<List<Integer>> transitions = new ArrayList<>(); JSONArray transitionsJson = (JSONArray) dfaJson.get("transfer"); for (Object transitionObj : transitionsJson) { JSONArray transitionJson = (JSONArray) transitionObj; List<Integer> transition = new ArrayList<>(); for (Object valueObj : transitionJson) { if (valueObj instanceof String) { transition.add((int) ((String) valueObj).charAt(0)); } else { transition.add(((Long) valueObj).intValue()); } } transitions.add(transition); } dfa.put("end", endStates); dfa.put("start", ((Long) dfaJson.get("start")).intValue()); dfa.put("syms", symbols); dfa.put("transfer", transitions); } catch (Exception e) { e.printStackTrace(); } return dfa; }在这段代码实现DFA识别方法,要求:inpuStr被成功接收则返回true,不成功接收则返回false
public class DFALexer {
public static boolean dfaRecognize(Map<String, Object> dfa, String inputStr) {
int currentState = (int)dfa.get("start");
List<List<Integer>> transitions = (List<List<Integer>>)dfa.get("transfer");
List<Integer> endStates = (List<Integer>)dfa.get("end");
List<String> symbols = (List<String>)dfa.get("syms");
for (int i = 0; i < inputStr.length(); i++) {
char c = inputStr.charAt(i);
int symbolIndex = symbols.indexOf(String.valueOf(c));
if (symbolIndex == -1) {
return false;
}
currentState = transitions.get(currentState).get(symbolIndex);
}
return endStates.contains(currentState);
}
public static Map<String, Object> json_file2map(String fileName) {
JSONParser parser = new JSONParser();
Map<String, Object> dfa = new HashMap<>();
try {
Object obj = parser.parse(new FileReader(fileName));
JSONObject dfaJson = (JSONObject) obj;
List<Integer> endStates = new ArrayList<>();
JSONArray endStatesJson = (JSONArray) dfaJson.get("end");
for (Object stateObj : endStatesJson) {
endStates.add(((Long) stateObj).intValue());
}
List<String> symbols = new ArrayList<>();
JSONArray symbolsJson = (JSONArray) dfaJson.get("syms");
for (Object symbolObj : symbolsJson) {
symbols.add((String) symbolObj);
}
List<List<Integer>> transitions = new ArrayList<>();
JSONArray transitionsJson = (JSONArray) dfaJson.get("transfer");
for (Object transitionObj : transitionsJson) {
JSONArray transitionJson = (JSONArray) transitionObj;
List<Integer> transition = new ArrayList<>();
for (Object valueObj : transitionJson) {
if (valueObj instanceof String) {
transition.add((int) ((String) valueObj).charAt(0));
} else {
transition.add(((Long) valueObj).intValue());
}
}
transitions.add(transition);
}
dfa.put("end", endStates);
dfa.put("start", ((Long) dfaJson.get("start")).intValue());
dfa.put("syms", symbols);
dfa.put("transfer", transitions);
} catch (Exception e) {
e.printStackTrace();
}
return dfa;
}
}
需要注意的是,这里的DFA是由一个JSON文件转换而来的,JSON文件应该包含以下属性:
- start:DFA的起始状态
- end:DFA的终止状态
- syms:DFA的输入字符集
- transfer:DFA的转移函数,用二维数组表示
如果JSON文件格式有误,会抛出异常并返回空的DFA。
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