java-将xlsx（excel）文件转换成json

最近在工作接触到将xlsx(excel)转换成Json文件的需求。特此写个文章总结学习。以供以后参考。

首先了解一下Json的语法
摘抄自http://www.w3school.com.cn/json/json_syntax.asp

JSON 语法是 JavaScript 对象表示法语法的子集。

• 数据在名称/值对中
• 数据由逗号分隔
• 花括号保存对象
• 方括号保存数组

JSON 值可以是：

• 数字（整数或浮点数）
• 字符串（在双引号中）
• 逻辑值（true 或 false）
• 数组（在方括号中）
• 对象（在花括号中）
• null

JSON 对象
{ “firstName”:”John” , “lastName”:”Doe” }
等价于js中
firstName = “John”；
lastName = “Doe”；

JSON 数组
[
{ “firstName”:”Bill” , “lastName”:”Gates” },
{ “firstName”:”George” , “lastName”:”Bush” },
{ “firstName”:”Thomas” , “lastName”: “Carter” }
]

JSON 文件
JSON 文件的文件类型是 “.json”
JSON 文本的 MIME 类型是 “application/json”

以下是转换代码。
excel截图如下

package XlsxToJson;

import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.sling.commons.json.JSONArray;
import org.apache.sling.commons.json.JSONObject;

import java.io.FileInputStream;
import java.io.FileWriter;
import java.util.HashMap;
import java.util.Map;

public class XlsxToJson {

    public static void main(String[] args) {
        FileInputStream inputStream = null;
        FileWriter writer = null;
        try{
            inputStream = new FileInputStream("D:\\excel\\table.xlsx");
            XSSFWorkbook workbook = new XSSFWorkbook(inputStream);
            writer = new FileWriter("D:\\excel\\test.json");
            JSONObject jsonData = transferXlsxToJson(workbook);
            jsonData.write(writer);
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (inputStream!=null){
                try {
                    inputStream.close();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
            if (writer != null){
                try{
                    writer.flush();
                    writer.close();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        }
    }

    private static JSONObject transferXlsxToJson (XSSFWorkbook workbook) throws Exception{
        //获取sheet数目，判断excel是否可用
        int sheetCount = workbook.getNumberOfSheets();
        if (sheetCount < 1) {
            throw new Exception ("Not any available sheet");
        }
        //获取第一个sheet对象
        XSSFSheet sheet = workbook.getSheetAt(0);

        //获取Upper列的值
        XSSFRow tRow = sheet.getRow(1);//索引是从0开始

        //记录索引位置
        Map indexMap = new HashMap<>();
        for (Cell cell: tRow) {
            String cellValue = cell.getStringCellValue();
            if (!(cellValue == null)|| cellValue==""){
                indexMap.put(cellValue, cell.getColumnIndex());
            }
        }

        int lastRowNum = sheet.getLastRowNum();
        JSONArray dataArr = new JSONArray();

        for (int rowIndex = 3; rowIndex <= lastRowNum; rowIndex++) {
            String incomeThreholdUpper = "";
            XSSFRow xRow = sheet.getRow(rowIndex);
            XSSFCell upperCell =  xRow.getCell(1);
            /*
            //判断值的类型是不是字符串
            if (upperCell.getCellType()==0){
                incomeThreholdUpper = String.valueOf(Math.round(upperCell.getNumericCellValue()));
                //判断值的类型是不是字符串
            }else if(upperCell.getCellType()==1){
                if (upperCell.getStringCellValue().equals("+")){
                    incomeThreholdUpper = "infinity";
                }
            }
            //获取Couple下所有列的值
            int lastCellNum = xRow.getLastCellNum();
            JSONArray CoupleArr = new JSONArray();
            int dependents = 0;
            for (int cellIndex = indexMap.get("Couple"); cellIndex "Single") ; cellIndex++) {
                XSSFCell xCell = xRow.getCell(cellIndex);                
                JSONObject jsonObj = new JSONObject().accumulate("dependents", dependents).accumulate("value", Math.round(xCell.getNumericCellValue()));
                CoupleArr.put(jsonObj);
                dependents++;
            }
            JSONObject CoupleObj = new JSONObject().accumulate("type","Couple").accumulate("this type", CoupleArr);

            //
            JSONArray SingleArr = new JSONArray();
            dependents = 0;
            for (int cellIndex = indexMap.get("Single"); cellIndex new JSONObject().accumulate("dependents", dependents).accumulate("value", Math.round(xCell.getNumericCellValue()));
                SingleArr.put(jsonObj);
                dependents++;
            }
            JSONObject SingleObj = new JSONObject().accumulate("type", "Single").accumulate("thisType", SingleArr);
            JSONObject rowObj = new JSONObject().accumulate("incomeThreholdUpper",incomeThreholdUpper).accumulate("thisIncomeLevel", new JSONArray().put(SingleObj).put(CoupleObj));
            dataArr.put(rowObj);
        }
        JSONObject Table = new JSONObject().accumulate("config", new JSONObject().accumulate("currency","$").accumulate("data", dataArr));
        return Table;
    }

}

所需的jar包如下

jar包下载地址
http://commons.apache.org/proper/commons-collections/download_collections.cgi
http://sling.apache.org/downloads.cgi
http://www.java2s.com/Code/Jar/o/Downloadorgapacheslingcommonsjson204incubatorjar.htm

如果遇到如下截图错误，是缺少commons-collections4-4.1.jar包的原因
Exception in thread “main” java.lang.NoClassDefFoundError:org/apache/commons/collections4/ListValuedMap

生成的json文件如下：
{
“config”: {
“currency”: “$”,
“data”: [
{
“incomeThreholdUpper”: “6710”,
“thisIncomeLevel”: [
{
“type”: “Single”,
“thisType”: [
{
“dependents”: 0,
“value”: 750
},
{
“dependents”: 1,
“value”: 1023
},
{
“dependents”: 2,
“value”: 2056
},
{
“dependents”: 3,
“value”: 3054
},
{
“dependents”: 4,
“value”: 4012
},
{
“dependents”: 5,
“value”: 5026
},
{
“dependents”: 6,
“value”: 6025
},
{
“dependents”: 7,
“value”: 7025
},
{
“dependents”: 8,
“value”: 8021
},
{
“dependents”: 9,
“value”: 9021
},
{
“dependents”: 10,
“value”: 10100
}
]
},
{
“type”: “Couple”,
“this type”: [
{
“dependents”: 0,
“value”: 975
},
{
“dependents”: 1,
“value”: 1459
},
{
“dependents”: 2,
“value”: 2248
},
{
“dependents”: 3,
“value”: 3158
},
{
“dependents”: 4,
“value”: 4126
},
{
“dependents”: 5,
“value”: 5458
},
{
“dependents”: 6,
“value”: 6245
},
{
“dependents”: 7,
“value”: 7569
},
{
“dependents”: 8,
“value”: 8125
},
{
“dependents”: 9,
“value”: 9506
},
{
“dependents”: 10,
“value”: 10256
}
]
}
]
},
………….

学习参考网址：
JAVA入门之如何通过 POI 读取并修改 Excel
http://jingyan.baidu.com/article/fdbd4277cbaccab89e3f48a3.html
POI读取Excel常见问题
http://www.cnblogs.com/qingxinblog/articles/3647483.html
POI操作Excel常用方法总结
http://blog.csdn.net/educast/article/details/50454810