Question

我正在用Java编写一个函数，但我无法编译代码。我没有看到语法错误;你能救我吗？

public String getUserInput(String prompt){
    String inputLine = null;
    System.out.print(prompt + " ");
    try(
        BufferedReader is = new BufferedReader(new InputStreamReader(System.in));
        inputLine = is.readLine();
        if (inputLine.length() == 0 ) 
            return null;
        ) 
    catch (IOException e) {
            System.out.println("IOException: " + e);
        }
    return inputLine.toLowerCase();
}

它无法编译。

Answer 1

将(和)替换为try - 阻止{和}

Answer 2

检查try块括号，其()在java中是不允许的，并为方法保留。对于块使用{}

正确答案

public String getUserInput(String prompt){
    String inputLine = null;
    System.out.print(prompt + " ");
    try
    //( this is wrong
    {
        BufferedReader is = new BufferedReader(new InputStreamReader(System.in));
        inputLine = is.readLine();
        if (inputLine.length() == 0 ) 
            return null;
        //)
    } 
    catch (IOException e) {
            System.out.println("IOException: " + e);
        }
return inputLine.toLowerCase();
}

Answer 3

您是否想要try-with-resource（Java 7 +）？

try (BufferedReader is = new BufferedReader(new InputStreamReader(System.in))) {

    inputLine = is.readLine();

    if (inputLine.length() == 0)
        return null;

} catch (IOException e) {
    System.out.println("IOException: " + e);
}

如果没有，那么请回想一下标准try-catch块采用以下形式：

try {
    ...
} catch (...) {

}

请注意{}括号。

令牌错误，语法

3 个答案: