Java按名称替换大括号中的单词

如何解决Java按名称替换大括号中的单词

String message = "This is a message for {ID_PW}. Your result is {exam_result}. Please quote {ID_PW} if replying";

我正在从 CSV 导入数据，我想用这些数据替换大括号之间的项目。

// Using OpenCSV to read in CSV...code omitted for brevity
values = (Map<String,String>) reader.readMap();
// values has 'ID_PW','exam_result',etc keys

如何将 message 中大括号中的项替换为 values 中键的等效值？

解决方法

可能您正在寻找：

String s = "I bought {0,number,integer} mangos. From {1},the fruit seller. Out of them {2,percent} were bad.";
MessageFormat formatter = new MessageFormat(s);
Object[] argz = {22,"John",0.3};
System.out.println(formatter.format(argz));

输出：

I bought 22 mangos. From John,the fruit seller. Out of them 30% were bad.

有关详细信息，请参阅 https://docs.oracle.com/javase/8/docs/api/java/text/MessageFormat.html。

String message = "This is a message for {ID_PW}. Your result is {exam_result}. Please quote {ID_PW} if replying";

LinkedHashSet<String> fields = new LinkedHashSet<>();  // 'Automatically' handle duplicates

Pattern p = Pattern.compile("\\{([^}]*)\\}");
Matcher m = p.matcher(message);

// Find 'fields' in the message that are wrapped in curly braces and add to hash set
while (m.find()) {
    fields.add((m.group(1)));
}

// Go through CSV and parse the message with the associated fields
while (((values = (Map<String,String>) reader.readMap())) != null)
{
    Iterator itr = fields.iterator();
    String newMsg = message;
    while (itr.hasNext()) {
        String field = (String) itr.next();
        String value = values.get(field);
        if(value != null) {
            newMsg = newMsg.replaceAll("\\{" + field + "\\}",value);
        }
    }
}

使用StringBuilder。 StringBuilder 被明确设计为 String 的可变类型。接下来，不要在循环中使用正则表达式。正则表达式可能很强大，但由于您将使用循环来搜索多个模式，因此不涉及任何正则表达式（多个模式意味着多个表达式）。

我只是从左到右搜索 {，然后 } 提取 key 并在 values 地图中搜索它。类似的东西，

Map<String,String> values = new HashMap<>();
values.put("ID_PW","SimpleOne");
values.put("exam_result","84");
String message = "This is a message for {ID_PW}. Your result "
        + "is {exam_result}. Please quote {ID_PW} if replying";

StringBuilder sb = new StringBuilder(message);
int p = -1;
while ((p = sb.indexOf("{",p + 1)) > -1) {
    int e = sb.indexOf("}",p + 1);
    if (e > -1) {
        String key = sb.substring(p + 1,e);
        if (values.containsKey(key)) {
            sb.replace(p,p + key.length() + 2,values.get(key));
        }
    }
}
System.out.println(sb);

输出

This is a message for SimpleOne. Your result is 84. Please quote SimpleOne if replying