将CSV文件转换为Java中的JSON对象 [英] Converting an CSV file to a JSON object in Java

查看:1033
本文介绍了将CSV文件转换为Java中的JSON对象的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

有没有开放源代码的Java库将CSV(或XLS)文件转换为JSON对象?我尝试使用json.cdl( http:// bethecoder。 com / applications / tutorials / json / json-java / csv-to-jsonarray.html ),但不知为什么它似乎不适用于大的CSS字符串。我试图找到像 http://www.cparker15.com/ code / utilities / csv-to-json / ,但用java编写。任何帮助是赞赏。谢谢!

Is there an open source java library to convert a CSV (or XLS) file to a JSON object? I tried using json.cdl (http://bethecoder.com/applications/tutorials/json/json-java/csv-to-jsonarray.html) but somehow it does not seem to work for large CSS strings. I'm trying to find something like http://www.cparker15.com/code/utilities/csv-to-json/, but written in java. Any help is appreciated. Thanks!

推荐答案

这是我的Java程序,希望有人觉得它有用。

Here is my Java program and hope somebody finds it useful.

格式必须是这样:

SYMBOL,DATE,CLOSE_PRICE,OPEN_PRICE,HIGH_PRICE,LOW_PRICE, VOLUME,ADJ_CLOSE

"SYMBOL,DATE,CLOSE_PRICE,OPEN_PRICE,HIGH_PRICE,LOW_PRICE,VOLUME,ADJ_CLOSE

AAIT,2015-02-26 00:00:00.000,-35.152,0,35.152,35.12,679,0

AAIT,2015-02-26 00:00:00.000,-35.152,0,35.152,35.12,679,0

AAL,2015-02-26 00:00:00.000,49.35,50.38,50.38,49.02,7572135,0

AAL,2015-02-26 00:00:00.000,49.35,50.38,50.38,49.02,7572135,0"

第一行是列标题。任何地方都没有引号。用逗号分隔,而不是分号。

First line is the column headers. No quotation marks anywhere. Separate with commas and not semicolons. You get the deal.

/* Summary: Converts a CSV file to a JSON file.*/

//import java.util.*;
import java.io.*;

import javax.swing.*;
import javax.swing.filechooser.FileNameExtensionFilter;

public class CSVtoJSON extends JFrame{
    private static final long serialVersionUID = 1L;
    private static File CSVFile;
    private static BufferedReader read;
    private static BufferedWriter write;

    public CSVtoJSON(){
        FileNameExtensionFilter filter = new FileNameExtensionFilter("comma separated values", "csv");
        JFileChooser choice = new JFileChooser();
        choice.setFileFilter(filter); //limit the files displayed

        int option = choice.showOpenDialog(this);
        if (option == JFileChooser.APPROVE_OPTION) {
            CSVFile = choice.getSelectedFile();
        }
        else{
            JOptionPane.showMessageDialog(this, "Did not select file. Program will exit.", "System Dialog", JOptionPane.PLAIN_MESSAGE);         
            System.exit(1);
        }
    }

    public static void main(String args[]){
        CSVtoJSON parse = new CSVtoJSON();
        parse.convert();

        System.exit(0);
    }

    private void convert(){
        /*Converts a .csv file to .json. Assumes first line is header with columns*/
        try {
            read = new BufferedReader(new FileReader(CSVFile));

            String outputName = CSVFile.toString().substring(0, 
                    CSVFile.toString().lastIndexOf(".")) + ".json"; 
            write = new BufferedWriter(new FileWriter(new File(outputName)));

            String line;
            String columns[]; //contains column names
            int num_cols;
            String tokens[];

            int progress = 0; //check progress

            //initialize columns
            line = read.readLine(); 
            columns = line.split(",");
            num_cols = columns.length;


            write.write("["); //begin file as array
            line = read.readLine();


            while(true) {
                tokens = line.split(",");

                if (tokens.length == num_cols){ //if number columns equal to number entries
                    write.write("{");

                    for (int k = 0; k < num_cols; ++k){ //for each column 
                        if (tokens[k].matches("^-?[0-9]*\\.?[0-9]*$")){ //if a number
                            write.write("\"" + columns[k] + "\": " + tokens[k]);
                            if (k < num_cols - 1) write.write(", ");                                                }
                        else { //if a string
                            write.write("\"" + columns[k] + "\": \"" + tokens[k] + "\"");
                            if (k < num_cols - 1) write.write(", ");
                        }
                    }

                    ++progress; //progress update
                    if (progress % 10000 == 0) System.out.println(progress); //print progress           


                    if((line = read.readLine()) != null){//if not last line
                        write.write("},");
                        write.newLine();
                    }
                    else{
                        write.write("}]");//if last line
                        write.newLine();
                        break;
                    }
                }
                else{
                    //line = read.readLine(); //read next line if wish to continue parsing despite error 
                    JOptionPane.showMessageDialog(this, "ERROR: Formatting error line " + (progress + 2)
                     + ". Failed to parse.", 
                            "System Dialog", JOptionPane.PLAIN_MESSAGE);                    
                    System.exit(-1); //error message
                }
            }

            JOptionPane.showMessageDialog(this, "File converted successfully to "     + outputName, 
                    "System Dialog", JOptionPane.PLAIN_MESSAGE);

            write.close();
            read.close();
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }       
    }
    }

需要Swing,漂亮的小GUI,所以那些谁知道绝对没有Java可以使用它一旦打包成可执行文件。随意改进它。谢谢StackOverflow帮助我这些年。

Requires Swing but comes with a nifty little GUI so those who know absolutely no Java can use it once packaged into an executable .jar. Feel free to improve upon it. Thank you StackOverflow for helping me out all these years.

这篇关于将CSV文件转换为Java中的JSON对象的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

查看全文
登录 关闭
扫码关注1秒登录
发送“验证码”获取 | 15天全站免登陆