我是Apache POI的新手。
我编写了一个用于从excel文件中删除重复记录的小代码。我成功地能够识别表格中的重复记录，但在删除记录后写入新文件时，不会生成任何输出。
请帮助我出错的地方？
我写得好吗？或者我错过了什么？
public static void main(String args[]) {
DataFormatter formatter = new DataFormatter();
HSSFWorkbook input_workbook;
HSSFWorkbook workbook_Output_Final;
HSSFSheet input_workbook_sheet;
HSSFRow row_Output;
HSSFRow row_1_index;
HSSFRow row_2_index;
String value1 = "";
String value2 = "";
int count;
//main try catch block starts
try {
FileInputStream input_file = new FileInputStream("E:\\TEST\\Output.xls"); //reading from input file
input_workbook = new HSSFWorkbook(new POIFSFileSystem(input_file));
for (int sheetnum = 0; sheetnum < input_workbook.getNumberOfSheets(); sheetnum++) { //traversing sheets
input_workbook_sheet = input_workbook.getSheetAt(sheetnum);
int input_workbook_sheet_total_row = input_workbook_sheet.getLastRowNum(); //fetching last row nmber
for (int input_workbook_sheet_row_1 = 0; input_workbook_sheet_row_1 <= input_workbook_sheet_total_row; input_workbook_sheet_row_1++) { //traversing row 1
for (int input_workbook_sheet_row_2 = 0; input_workbook_sheet_row_2 <= input_workbook_sheet_total_row; input_workbook_sheet_row_2++) {
row_1_index = input_workbook_sheet.getRow(input_workbook_sheet_row_1); //fetching one iteration row index
row_2_index = input_workbook_sheet.getRow(input_workbook_sheet_row_2); //fetching sec iteration row index
if (row_1_index != row_2_index) {
count = 0;
value1 = "";
value2 = "";
for (int row_1_index_cell = 0; row_1_index_cell < row_1_index.getLastCellNum(); row_1_index_cell++) { //traversing cell for each row
try {
value1 = value1 + formatter.formatCellValue(row_1_index.getCell(row_1_index_cell)); //fetching row cells value
value2 = value2 + formatter.formatCellValue(row_2_index.getCell(row_1_index_cell)); //fetching row cells value
} catch (NullPointerException e) {
}
count++;
if (count == row_1_index.getLastCellNum()) {
if (value1.hashCode() == value2.hashCode()) { //remove the duplicate logic
System.out.println("deleted : " + row_2_index);
System.out.println("------------------");
input_workbook_sheet.removeRow(row_2_index);
}
}
}
}
}
}
}
FileOutputStream fileOut = new FileOutputStream("E:\\TEST\\workbook.xls");
input_workbook.write(fileOut);
fileOut.close();
input_file.close();
} catch (Exception e) {
//e.printStackTrace();
}
//main try catch block ends
}
答案 0 :(得分：1)
有几点需要注意：
你吞下任何一种例外; Igotsome nullpointers与我的测试数据，这将阻止编写工作簿
删除行时，向后移动行号是一个老技巧，因为您不必调整刚刚删除的行号
代码清空行，但它不会向上移动所有行（=删除后有一个间隙）。如果您想消除这种差距，可以使用shiftRows
你通过哈希码比较事物，这是可能的（在某些用例中），但我觉得.equals（）就是你想要做的。另请参阅Relationship between hashCode and equals method in Java
这里有一些适用于我的测试数据的代码，如果某些内容无法处理您的数据，请随时发表评论：
public static void main(String args[]) throws IOException {
DataFormatter formatter = new DataFormatter();
HSSFWorkbook input_workbook;
HSSFWorkbook workbook_Output_Final;
HSSFSheet input_workbook_sheet;
HSSFRow row_Output;
HSSFRow row_1_index;
HSSFRow row_2_index;
String value1 = "";
String value2 = "";
int count;
FileInputStream input_file = new FileInputStream("c:\\temp\\test.xls");
input_workbook = new HSSFWorkbook(new POIFSFileSystem(input_file));
for (int sheetnum = 0; sheetnum < input_workbook.getNumberOfSheets(); sheetnum++) {
input_workbook_sheet = input_workbook.getSheetAt(sheetnum);
int input_workbook_sheet_total_row = input_workbook_sheet.getLastRowNum();
for (int input_workbook_sheet_row_1 = input_workbook_sheet_total_row; input_workbook_sheet_row_1 >=0; input_workbook_sheet_row_1--) { // traversing
for (int input_workbook_sheet_row_2 = input_workbook_sheet_total_row; input_workbook_sheet_row_2 >= 0 ; input_workbook_sheet_row_2--) {
row_1_index = input_workbook_sheet.getRow(input_workbook_sheet_row_1);
row_2_index = input_workbook_sheet.getRow(input_workbook_sheet_row_2);
if (row_1_index != null && row_2_index != null && row_1_index != row_2_index) {
count = 0;
value1 = "";
value2 = "";
int row_1_max = row_1_index.getLastCellNum() - 1;
for (int row_1_index_cell = 0; row_1_index_cell < row_1_max; row_1_index_cell++) {
try {
value1 = value1 + formatter.formatCellValue(row_1_index.getCell(row_1_index_cell));
value2 = value2 + formatter.formatCellValue(row_2_index.getCell(row_1_index_cell));
} catch (NullPointerException e) {
e.printStackTrace();
}
count++;
if (value1.equals(value2)) {
System.out.println("deleted : " + row_2_index.getRowNum());
System.out.println("------------------");
input_workbook_sheet.removeRow(row_2_index);
input_workbook_sheet.shiftRows(
row_2_index.getRowNum() + 1,
input_workbook_sheet_total_row,
-1,
true,
true);
}
}
}
}
}
}
FileOutputStream fileOut = new FileOutputStream("c:\\temp\\workbook.xls");
input_workbook.write(fileOut);
fileOut.close();
input_file.close();
input_workbook.close();
}