Question

我在数组中有24个元素，我希望写入要在Excel中打开的CSV文件。

当我运行程序时，它会在我的Netbeans项目文件夹中创建一个CSV文件。但是，当我打开CSV文件时 - 它是空白的。

在我的main方法中，我向用户显示数组，然后调用writeCSV方法，如下所示：

    //show the user the sorted array
    System.out.println( "The sorted array is: ");
    for ( int i=0; i<24; i++)      
        System.out.println( "\t" + course2[i].toString() );

    //write the data from the duplicate array to a CSV file
    System.out.println("\nWriting data from Course array to CSV File.");
    writeCSV(course2, count);

writeCSV方法粘贴在下面：

    //write from duplicate array of courses to a CSV file
    public static void writeCSV(Course[] courseArray, int count) throws Exception {

    //create a File class object and give the file the name employees.csv
    java.io.File courseCSV = new java.io.File("courses.csv");

    //Create a Printwriter text output stream and link it to the CSV File
    java.io.PrintWriter outfile = new java.io.PrintWriter(courseCSV);

    //Iterate the elements actually being used
    for (int i=0; i < count ; i++) {
        outfile.write(courseArray[i].toCSVString());

    }//end for

    outfile.close();
    } //end writeCSV()

上面的writeCSV方法调用toCSVString方法，该方法在我创建的名为Course的类中定义。我在下面贴了这个方法：

// method to return properties as a CSV string on one line
//public String toCSVString(Course c){
public String toCSVString() {
    String record = campus + ","
                  + course + ","
                  + section + ","
                  + crn + ","
                  + credits + ","
                  + time + ","
                  + days + "\n";

    return record;
} //end toCSVString()

我的代码运行完美，直到我必须将数组写入CSV文件。这是在创建空白CSV文件时。这让我相信我的toCSVString方法或者我认为的writeCSV方法中有错误。任何提示或帮助将不胜感激。感谢。

Answer 1

对于刚刚收听的人......

将writeCSV方法更改为：

//write from duplicate array of courses to a CSV file
public static void writeCSV(Course[] courseArray) throws Exception {

    //create a File class object and give the file the name employees.csv
    java.io.File courseCSV = new java.io.File("courses.csv");

    //Create a Printwriter text output stream and link it to the CSV File
    java.io.PrintWriter outfile = new java.io.PrintWriter(courseCSV);

    //Iterate the elements actually being used
    for (int i=0; i < courseArray.length ; i++) {
        outfile.write(courseArray[i].toCSVString());

    }//end for

    outfile.close();
} //end writeCSV()

从这个函数中删除count参数，除非你真的打算在CSV文件中写入不同数量的元素。从你的主要方法来看，情况并非如此。
将for循环中的count更改为courseArray.length

然后，在您的main方法中，将调用更改为：

writeCSV(course2);

始终确保初始化变量，如有疑问，请使用调试器。这可以帮助你发现这一点。

希望这有帮助。

将数组写入CSV文件 - Java

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