Java 默认构造函数无法处理隐式超级构造函数引发的异常类型IOException。必须定义显式构造函数

我有两个java类Configuration.java和login.java

Configuration.java

login.java

有人能帮我解决这个错误吗

还可以按如下方式更改配置文件：

public class Configuration {
    public Configuration() {}

    public String[] getparams() throws IOException {
        Properties properties = new Properties();
        FileInputStream fileStream = new FileInputStream("C:/.../Desktop/configuration.txt");
        try {
            properties.load(fileStream);
            String ip = (String) properties.get("IP");
            String port = (String) properties.get("Port");
            return new String[]{ip, port};

        } finally {
            try {
                fileStream.close();
            } catch (IOException ex) {
                Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
            }

        }
    }
}

---

为什么不将getParam的签名更改为不抛出错误呢。我看到您这样做部分是为了调用properties.load（）

比如：

公共类配置{

public Configuration() {}

public String getparams() {
    Properties properties = new Properties();
    FileInputStream fileStream = null;
    try {

        fileStream = new FileInputStream("C:/.../Desktop/configuration.txt");

        properties.load(fileStream);
        String ip = (String) properties.get("IP");
        String port = (String) properties.get("Port");
        return ip + port;

    } 
    catch(IOException ex)
    {
        return null;
    }
   finally {
        try {
            fileStream.close();
        } catch (IOException ex) {
            Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
        }

    }
}

}

---

如果try块也可以抛出，您可能希望将新属性移动到try块中。

您从哪里得到消息？我在Login中调用getparams（）时出错。java您可以向Kushtrim显示

Login.java

？p：我必须将您的建议放在方法中吗？getparams（）方法会抛出IOException，因此无论您在哪里调用它，您应该用try-catch语句将其包围起来。因此，只需将try-catch添加到login.java中的代码中，因为我知道try-catch bloc必须在methode中，因为当我在没有methode的情况下执行该操作时，在标记“；”，{在该标记之后应为“”，是的，您应该在onCreate（…）上初始化变量方法谢谢你的回复只是一个提示：在我剩下的代码中，LOGIN_URL无法解析为变量！你是指getParam返回的URL吗？

   public class Login extends Activity implements OnClickListener {

    Configuration cfg;
    String ip;
    String port;
    private String LOGIN_URL;
    //other variables

    protected void onCreate(Bundle savedInstanceState) {
        //here you initialize your variables
        try {
            cfg = new Configuration();
            String[] params = cfg.getparams();
            ip = params[0];
            port = params[1];
            LOGIN_URL = "http://"+ ip +":"+port+"/webservice/login.php";
        } catch (IOException e) {
            //handle the exception
        }
        //.. your other code ...
    }
    //... your other methods ...

   }  

public class Configuration {
    public Configuration() {}

    public String[] getparams() throws IOException {
        Properties properties = new Properties();
        FileInputStream fileStream = new FileInputStream("C:/.../Desktop/configuration.txt");
        try {
            properties.load(fileStream);
            String ip = (String) properties.get("IP");
            String port = (String) properties.get("Port");
            return new String[]{ip, port};

        } finally {
            try {
                fileStream.close();
            } catch (IOException ex) {
                Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
            }

        }
    }
}

public Configuration() {}

public String getparams() {
    Properties properties = new Properties();
    FileInputStream fileStream = null;
    try {

        fileStream = new FileInputStream("C:/.../Desktop/configuration.txt");

        properties.load(fileStream);
        String ip = (String) properties.get("IP");
        String port = (String) properties.get("Port");
        return ip + port;

    } 
    catch(IOException ex)
    {
        return null;
    }
   finally {
        try {
            fileStream.close();
        } catch (IOException ex) {
            Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
        }

    }
}