变量“结果”可能尚未初始化答案

【问题标题】：Variable 'result' might not have been initialized变量“结果”可能尚未初始化
【发布时间】：2015-06-28 23:14:04
【问题描述】：

public class MonthName {
  public static String month_name(int month) {
    String result;

    if (month == 1) {
      result = "January";
    } else if (month == 2) {
      result = "February";
    } else if (month == 3) {
      result = "February";
    } else if (month == 4) {
      result = "February";
    } else if (month == 5) {
      result = "February";
    } else if (month == 6) {
      result = "February";
    } else if (month == 7) {
      result = "February";
    } else if (month == 8) {
      result = "February";
    } else if (month == 9) {
      result = "February";
    } else if (month == 10) {
      result = "February";
    } else if (month == 11) {
      result = "February";
    } else if (month == 12) {
      result = "February";
    }

    return result;
  }


  public static void main(String[] args) {
    System.out.println("Month 1: " + month_name(1));
    System.out.println("Month 2: " + month_name(2));
    System.out.println("Month 3: " + month_name(3));
    System.out.println("Month 4: " + month_name(4));
    System.out.println("Month 5: " + month_name(5));
    System.out.println("Month 6: " + month_name(6));
    System.out.println("Month 7: " + month_name(7));
    System.out.println("Month 8: " + month_name(8));
    System.out.println("Month 9: " + month_name(9));
    System.out.println("Month 10: " + month_name(10));
    System.out.println("Month 11: " + month_name(11));
    System.out.println("Month 12: " + month_name(12));
    System.out.println("Month 43: " + month_name(43));
  }
}

所以我已经在结果中声明了相关字符串的值，但它仍然说我的变量“结果”可能没有被初始化。

我正在尝试实现类似于this 的输出。任何人都可以帮助我吗？谢谢！

【问题讨论】：

标签： java

【解决方案1】：

如果您的变量月份可能为空或 12，则可能会发生这种情况。您可以通过简单地删除 if-else 树中的最后一个 if 来解决这个问题，例如：

public class MonthName {
  public static String month_name(int month) {
    String result = "";

    if (month == 1) {
      result = "January";
    } else if (month == 2) {
      result = "February";
    } else if (month == 3) {
      result = "February";
    } else if (month == 4) {
      result = "February";
    } else if (month == 5) {
      result = "February";
    } else if (month == 6) {
      result = "February";
    } else if (month == 7) {
      result = "February";
    } else if (month == 8) {
      result = "February";
    } else if (month == 9) {
      result = "February";
    } else if (month == 10) {
      result = "February";
    } else if (month == 11) {
      result = "February";
    } else {
      result = "February";
    }

    return result;
  }


  public static void main(String[] args) {
    System.out.println("Month 1: " + month_name(1));
    System.out.println("Month 2: " + month_name(2));
    System.out.println("Month 3: " + month_name(3));
    System.out.println("Month 4: " + month_name(4));
    System.out.println("Month 5: " + month_name(5));
    System.out.println("Month 6: " + month_name(6));
    System.out.println("Month 7: " + month_name(7));
    System.out.println("Month 8: " + month_name(8));
    System.out.println("Month 9: " + month_name(9));
    System.out.println("Month 10: " + month_name(10));
    System.out.println("Month 11: " + month_name(11));
    System.out.println("Month 12: " + month_name(12));
    System.out.println("Month 43: " + month_name(43));
  }
}

这意味着您的变量必须介于 1 和 12 之间，否则您应该抛出异常。但无论如何，我不会一直使用那些 if-else 树。反正冗余太多了。

改为这个：

switch (month) {
case 1:  result = "January";
         break;
case 2:  result = "February";
         break;
case 3:  result = "March";
         break;
case 4:  result = "April";
         break;
case 5:  result = "May";
         break;
case 6:  result = "June";
         break;
case 7:  result = "July";
         break;
case 8:  result = "August";
         break;
case 9:  result = "September";
         break;
case 10: result = "October";
         break;
case 11: result = "November";
         break;
case 12: result = "December";
         break;
default: result = "Invalid month";
         break;
}

【讨论】：

【解决方案2】：

局部变量应在使用前初始化。它们没有默认值

初始化

String result="";

【讨论】：

【解决方案3】：

由于month 只是一个int，它可以采用1-12 以外的值（您的if/else/if 结构处理的内容）。

要消除错误，您可以将其初始化为空的String，但是，您可能需要考虑错误情况。

例如，如果传递了不在1-12 范围内的东西，该方法应该做什么？

【讨论】：

【解决方案4】：

变量result 尚未初始化。 result 只会在输入介于 1 和 12 之间时包含一个值。

你可以在声明变量的时候试试这个

String result = "";

这样您就不需要添加另一行来将结果设置为错误。

String result = "error";

【讨论】：