Java如何提取指定列的内容，并可以对其相应的操作
我的报错信息为java.lang.NumberFormatException: For input string: ""SMX""
    
private void Encode() {
        try {
                    BufferedReader reader = new BufferedReader(new FileReader("待加密坐标.csv"));
                    //reader.readLine();//第一行信息，为标题信息
                    String line = null;
                    BufferedWriter writer = new BufferedWriter(new FileWriter("已加密坐标.csv"));
                  
                    while((line=reader.readLine())!=null){
                        String item[] = line.split(",");//CSV格式文件为逗号分隔符文件，这里根据逗号切分
                      
                        String a = item[item.length-4];//提取首列
                        String x = item[item.length-3];//提取经度
                        String y = item[item.length-2];//提取纬度
                        String b = item[item.length-1];//提取末列

                        double X = Double.parseDouble(x);//将字符串转成双精度型
                        double Y = Double.parseDouble(y);
                        double[][] outXY = null;//声明局部变量并初始化
                        outXY[0] = encrypt(X,Y);
                        outXY[1] = encrypt(X,Y);
                        this.jTextArea2.append(a +","+ outXY[0]+","+ outXY[1] +","+ b + "," + "\r\n");
                        writer.write(a +","+ outXY[0]+","+ outXY[1] +","+ b + "," + "\r\n");
                       
                    }
                    reader.close();
                    writer.close(); 
                    } catch (Exception e) { 
                    e.printStackTrace();
                    }
}
------解决方案--------------------
"SMX" 无法转成数字， 

检查下你的数据文件，是否有不符合规范的数据
------解决方案--------------------
你试图吧
"SMX"转化成数据，所以报错。
 String a = item[item.length-4];//提取首列
                        String x = item[item.length-3];//提取经度
                        String y = item[item.length-2];//提取纬度