可怕的Java反射错误_Java_Excel_Reflection

可怕的Java反射错误

java excel reflection

可怕的Java反射错误,java,excel,reflection,Java,Excel,Reflection,所以，问题出在这里。我试图使用Java中的反射来定义一种“视图”类型，以便通过有序的方法声明输出到excel工作表。（按数字顺序排列）从理论上讲，这应该很好，而且在一定程度上是这样的问题是，反射方法似乎随机决定有时有效，而不是其他方法。它不会抛出异常，它会毫不费力地找到方法名，但一旦它点击布尔值检查方法是否以适当的标记开始，它有时会在j=5处停止。以下是澄清方法的代码： public boolean objectWriter(List<Object> input, String

所以，问题出在这里。我试图使用Java中的反射来定义一种“视图”类型，以便通过有序的方法声明输出到excel工作表。（按数字顺序排列）

从理论上讲，这应该很好，而且在一定程度上是这样的

问题是，反射方法似乎随机决定有时有效，而不是其他方法。它不会抛出异常，它会毫不费力地找到方法名，但一旦它点击布尔值检查方法是否以适当的标记开始，它有时会在j=5处停止。以下是澄清方法的代码：

public boolean objectWriter(List<Object> input, String sheetName, int startingRow, String tag){
    ArrayList<Object> myList = new ArrayList<>();
    jxl.write.Number number;
    Label label;

    //This is just an internal counter since we're using a for-each loop. 
    int j;
    try{
        for (int i = 0; i < input.size(); i++){
            j = 0;
            //we want to iterate over all of the available methods in the given class with reflection
            for (Method m: input.get(i).getClass().getMethods()){
                //Check to see if the method name has our requested tag, plus the appropriate counter
                //tacked on, and ZERO parameters, in our case.
                myLog.debug("this is our boolean check: " + m.getName().startsWith((tag + j)));
                if (m.getName().startsWith((tag + j))){
                    myLog.debug("m.getname inside: " + m.getName());
                    //Invoke the method, give it's return value to r (return)
                    final Object r = m.invoke(input.get(i));
                    //Since we defined in the requirements of this class that it must be a string
                    //those types of methods returned, this works just fine, just case it to
                    //String (Since String extends object) and call it a day. 
                    if (isNumeric((String)r)){
                        //if it's a number, make a number object out of it. 
                        number = new jxl.write.Number(j, startingRow + i
                        , Double.parseDouble((String)r)
                        , buildNumberFormat((String)r));

                        myList.add(number);
                    }else{
                        label = new Label(j,startingRow + i,(String)r);
                        myList.add(label);
                    }
                    j++;
                }
            }
        }
    }catch(IllegalAccessException | IllegalArgumentException | InvocationTargetException ex){
        myLog.error("There was an error working through the point class with reflection.", ex);
        return false;
    }
    boolean successfulWrite = myExcelWriter.writeInformation(myList, sheetName);
    myExcelWriter.resizeColumns(18, sheetName);
    return successfulWrite;

}

等等，等等，我给了这个方法一个标签“get”，它将按照指定的顺序拉出所有三个方法。另外，它是在使用这个特殊方法的要求中定义的，返回值都是字符串，所以我很确定这不是问题所在。奇怪的是，如果（m.getName（）.startsWith（（tag+j））在j=5时开始失败，我不明白为什么行
上的布尔检查有时会失败无论如何，如果有人有任何想法，我会非常感激。我被困在这里了同样值得注意的是，对于我给出的数据集，每次j=5都将是'else'子句。对我来说，这不仅仅是巧合，但我看不出有什么不对编辑如果我在布尔检查之前对“m”运行一个操作，那么它完全按照预期工作（拉出所有正确枚举的方法等）的概率会显著增加（接近99%工作），这也毫无意义。比如我如何在实际语句之前打印出布尔语句？这使得它几乎每次都能工作。但这肯定不是一个解决办法编辑#2 根据要求，我继续将println移到调试日志中，这是一个截断的版本，但它实际上在29次内重复了该模式，同样有趣的是，如果我将输出发送到日志记录器而不是控制台，那么前面提到的成功概率会回到没有它的情况下。。。奇怪 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,881 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet0Label 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet1MD 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet2Easting 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet3Northing 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet4TVD 09:02:45,882 DEBUG [root] this is our boolean check: true 09:02:45,882 DEBUG [root] m.getname inside: xGet5Date 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,882 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,883 DEBUG [root] this is our boolean check: false 09:02:45,884 DEBUG [root] this is our boolean check: false 09:02:45,884 DEBUG [root] this is our boolean check: false 09:02:45,884 DEBUG [root] this is our boolean check: false 09:02:45,884 DEBUG [root] this is our boolean check: false 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet0Label 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet1MD 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet2Easting 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet3Northing 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet4TVD 09:02:45,884 DEBUG [root] this is our boolean check: true 09:02:45,884 DEBUG [root] m.getname inside: xGet5Date 明白了！因此，在我处理被检查方法的“排序”时，存在一个固有的缺陷。虽然我预期“getMethods（）”会以不特定的顺序返回类的方法，但如果其中一个方法的顺序错误，它就不会被重新检查只是由于偶然事件，有时数字顺序的第一种方法会出现在后面的方法之前，从而导致正确的行为。通常情况下，编号为0-5的方法出现在6-14之后（这是该数据集中的范围）因此，我的解决方案是创建一个被拒绝方法名称的“池”，然后每次检查失败时，迭代拒绝池，并确保其中一个不符合要求。如果不是这些，那就不是我们关心的方法这会减慢触摸的速度，但在毫秒范围内解决方案代码： public boolean objectWriter(List<Object> input, String sheetName, int startingRow, String tag){ ArrayList<Object> myList = new ArrayList<>(); ArrayList<Method> methodList = new ArrayList<>(); jxl.write.Number number; Label label; //This is just an internal counter since we're using a for-each loop. int j; try{ for (int i = 0; i < input.size(); i++){ j = 0; //we want to iterate over all of the available methods in the given class with reflection for (Method m: input.get(i).getClass().getDeclaredMethods()){ //Check to see if the method name has our requested tag, plus the appropriate counter //tacked on, and ZERO parameters, in our case. if (m.getName().startsWith((tag + j))){ //Invoke the method, give it's return value to r (return) final Object r = m.invoke(input.get(i)); //Since we defined in the requirements of this class that it must be a string //those types of methods returned, this works just fine, just case it to //String (Since String extends object) and call it a day. if (isNumeric((String)r)){ //if it's a number, make a number object out of it. number = new jxl.write.Number(j, startingRow + i , Double.parseDouble((String)r) , buildNumberFormat((String)r)); myList.add(number); }else{ label = new Label(j,startingRow + i,(String)r); myList.add(label); } j++; }else{ methodList.add(m); for (int x = 0; x < methodList.size(); x++){ if (methodList.get(x).getName().startsWith((tag + j))){ //Invoke the method, give it's return value to r (return) final Object r = methodList.get(x).invoke(input.get(i)); //Since we defined in the requirements of this class that it must be a string //those types of methods returned, this works just fine, just case it to //String (Since String extends object) and call it a day. if (isNumeric((String)r)){ //if it's a number, make a number object out of it. number = new jxl.write.Number(j, startingRow + i , Double.parseDouble((String)r) , buildNumberFormat((String)r)); myList.add(number); }else{ label = new Label(j,startingRow + i,(String)r); myList.add(label); } j++; //methodList.remove(x); break; } } } } } }catch(IllegalAccessException | IllegalArgumentException | InvocationTargetException ex){ myLog.error("There was an error working through the point class with reflection.", ex); return false; } boolean successfulWrite = myExcelWriter.writeInformation(myList, sheetName); myExcelWriter.resizeColumns(18, sheetName); return successfulWrite; } public boolean objectWriter（列表输入、字符串sheetName、int startingRow、字符串标记）{ ArrayList myList=新的ArrayList（）； ArrayList methodList=新的ArrayList（）； jxl.write.Number；标签； //这只是一个内部计数器，因为我们对每个循环使用一个。 int j；试一试{ 对于（int i=0；ipublic boolean objectWriter(List<Object> input, String sheetName, int startingRow, String tag){ ArrayList<Object> myList = new ArrayList<>(); ArrayList<Method> methodList = new ArrayList<>(); jxl.write.Number number; Label label; //This is just an internal counter since we're using a for-each loop. int j; try{ for (int i = 0; i < input.size(); i++){ j = 0; //we want to iterate over all of the available methods in the given class with reflection for (Method m: input.get(i).getClass().getDeclaredMethods()){ //Check to see if the method name has our requested tag, plus the appropriate counter //tacked on, and ZERO parameters, in our case. if (m.getName().startsWith((tag + j))){ //Invoke the method, give it's return value to r (return) final Object r = m.invoke(input.get(i)); //Since we defined in the requirements of this class that it must be a string //those types of methods returned, this works just fine, just case it to //String (Since String extends object) and call it a day. if (isNumeric((String)r)){ //if it's a number, make a number object out of it. number = new jxl.write.Number(j, startingRow + i , Double.parseDouble((String)r) , buildNumberFormat((String)r)); myList.add(number); }else{ label = new Label(j,startingRow + i,(String)r); myList.add(label); } j++; }else{ methodList.add(m); for (int x = 0; x < methodList.size(); x++){ if (methodList.get(x).getName().startsWith((tag + j))){ //Invoke the method, give it's return value to r (return) final Object r = methodList.get(x).invoke(input.get(i)); //Since we defined in the requirements of this class that it must be a string //those types of methods returned, this works just fine, just case it to //String (Since String extends object) and call it a day. if (isNumeric((String)r)){ //if it's a number, make a number object out of it. number = new jxl.write.Number(j, startingRow + i , Double.parseDouble((String)r) , buildNumberFormat((String)r)); myList.add(number); }else{ label = new Label(j,startingRow + i,(String)r); myList.add(label); } j++; //methodList.remove(x); break; } } } } } }catch(IllegalAccessException | IllegalArgumentException | InvocationTargetException ex){ myLog.error("There was an error working through the point class with reflection.", ex); return false; } boolean successfulWrite = myExcelWriter.writeInformation(myList, sheetName); myExcelWriter.resizeColumns(18, sheetName); return successfulWrite; }