java - 更新 CSV 文件中的特定行

Question

我想更新 .CSV 文件中的特定行(满足预定义条件)。

这是我的代码:

ProductID,ProductName,price,availability,type
12345,abc,300,yes,medicine
23456,def,400,yes,testing
34567,ghi,200,no,medicine
45678,jkl,500,no,testing

这是代码

    CsvReader products = new CsvReader("D:\\sample.csv");
            CsvWriter csvOutput = new CsvWriter(new FileWriter("D:\\sample.csv", true), ',');
            products.readHeaders();
            products.getRawRecord();
            while (products.readRecord())
            {
                String productID = products.get("ProductID");
                String productName = products.get("ProductName");
                String supplierID = products.get("price");
                String categoryID = products.get("availability");
                String quantityPerUnit = products.get("type");

                if(productID.equals("roche123")){
                    csvOutput.replace(productName, "12", "newproductName");
                    csvOutput.replace(supplierID , "12", "newsupplierID ");
                }

但是这不起作用。有人可以帮忙吗？

Answer 1

方法 CsvWriter.replace 不是实例方法，并且不会对当前记录进行内联替换。

相反，它应该用作

String replace = CsvWriter.replace(
    inputString, // somefoobar
    substringToReplace, // foobar
    substringSubstitute); // candy
// replace will be "somecandy"

以下代码片段应演示其原理。

假设sample_in.csv为

ProductID,ProductName,price,availability,type
12345,abc,300,yes,medicine
23456,def,400,yes,testing
34567,ghi,200,no,medicine
45678,jkl,500,no,testing
roche123,product 12,supplier 12,no,foobar

代码片段

CsvReader products = new CsvReader("sample_in.csv");
CsvWriter csvOutput = new CsvWriter(new FileWriter("sample_out.csv", true), ',');
products.readHeaders();

csvOutput.writeRecord(products.getHeaders());

String[] outValues = new String[5];
while (products.readRecord()) {
    String productID = products.get("ProductID");
    String productName = products.get("ProductName");
    String supplierID = products.get("price"); // is this correct?
    String categoryID = products.get("availability");
    String quantityPerUnit = products.get("type");

    if (productID.equals("roche123")) {
        productName = CsvWriter.replace(productName, "12", "newproductName");
        supplierID = CsvWriter.replace(supplierID, "12", "newsupplierID");
    }

    outValues[0] = productID;
    outValues[1] = productName;
    outValues[2] = supplierID;
    outValues[3] = categoryID;
    outValues[4] = quantityPerUnit;
    csvOutput.writeRecord(outValues);
}

将生成 sample_out.csv 为

ProductID,ProductName,price,availability,type
12345,abc,300,yes,medicine
23456,def,400,yes,testing
34567,ghi,200,no,medicine
45678,jkl,500,no,testing
roche123,product newproductName,supplier newsupplierID,no,foobar

从输入行

roche123,product 12,supplier 12,no,foobar

• 列 ProductName 从 product 12 更新为 product newproductName
• price 列从 supplier 12 更新为 supplier newsupplierID

编辑该代码段正在使用 JavaCSV 库。