Java Read CSV File In Java With OpenCSV library 以及中文件亂碼解決, Mapping CSV with Java beans

sample.csv文件:

COUNTRY,CAPITAL,POPULATION
India,New Delhi, 1.21B
People's republic of China,Beijing, 1.34B
United States,Washington D.C., 0.31B

一.使用readNext()方法一行一行讀CSV文件,返回字符串數組

package com.jiangge.csv.opencsvtest;

import java.io.FileReader;
import java.io.IOException;

import au.com.bytecode.opencsv.CSVReader;

//COUNTRY,CAPITAL,POPULATION
//India,New Delhi, 1.21B
//People's republic of China,Beijing, 1.34B
//United States,Washington D.C., 0.31B

/**
 * use readNext() method of CSVReader class to read CSV file line by line. 
 * It returns a String array for each value in row.
 */
public class ReadLineByLine {
	public static void main(String[] args) throws IOException {
		String csvFilename = "C:\\sample.csv";
		CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
		String[] row = null;
		while((row = csvReader.readNext()) != null) {
		    System.out.println(row[0] + " # " + row[1] + " #  " + row[2]);
		}
		//...
		csvReader.close();
	}
}

輸出結果:

COUNTRY # CAPITAL #  POPULATION
India # New Delhi #   1.21B
People's republic of China # Beijing #   1.34B
United States # Washington D.C. #   0.31B

二 使用 readAll()方法一次讀取整個CSV文件,返回 List

package com.jiangge.csv.opencsvtest;

import java.io.FileReader;
import java.io.IOException;
import java.util.List;

import au.com.bytecode.opencsv.CSVReader;

//COUNTRY,CAPITAL,POPULATION
//India,New Delhi, 1.21B
//People's republic of China,Beijing, 1.34B
//United States,Washington D.C., 0.31B


/**
 * read full CSV file once. The readAll() method of CSVReader class comes handy for this.
 * The readAll() method returns a List of String[] for given CSV file.
 * @author jiangge
 */
public class ReadAllTest {
	public static void main(String[] args) throws IOException {
		String[] row = null;
		String csvFilename = "C:\\sample.csv";
		 
		CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
		List content = csvReader.readAll();
		 
		for (Object object : content) {
		    row = (String[]) object;
		    System.out.println(row[0] + " # " + row[1]+ " #  " + row[2]);
		}
		//...
		csvReader.close();
	}
}

輸出結果:

COUNTRY # CAPITAL #  POPULATION
India # New Delhi #   1.21B
People's republic of China # Beijing #   1.34B
United States # Washington D.C. #   0.31B

三. 使用其他的分隔符號, 和跳過某些行--具體解釋看這裏:點擊打開鏈接

CSVReader reader = new CSVReader(new FileReader(file), ';')
CSVReader reader = new CSVReader(new FileReader(file), '#')

跳過前5行,從第6行開始:

CSVReader reader = new CSVReader(new FileReader(file), ',', '\'', 5);

 
四.Mapping CSV with Java beans

1.java bean

package com.jiangge.csv.opencsvtest;

public class Country {
	private String countryName;
	private String capital;
	private String population;
	
	public String getPopulation() {
		return population;
	}
	public void setPopulation(String population) {
		this.population = population;
	}
	public String getCountryName() {
		return countryName;
	}
	public void setCountryName(String countryName) {
		this.countryName = countryName;
	}
	public String getCapital() {
		return capital;
	}
	public void setCapital(String capital) {
		this.capital = capital;
	}

}

2.關聯JavaBean,Now we can map this bean with Opencsv and read the CSV file

package com.jiangge.csv.opencsvtest;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.util.List;

import au.com.bytecode.opencsv.CSVReader;
import au.com.bytecode.opencsv.bean.ColumnPositionMappingStrategy;
import au.com.bytecode.opencsv.bean.CsvToBean;




//COUNTRY,CAPITAL,POPULATION
//India,New Delhi, 1.21B
//People's republic of China,Beijing, 1.34B
//United States,Washington D.C., 0.31B

/**
 * map this bean(Country.java) with Opencsv and read the CSV file. Check out below example:
 * @author jiangge
 */
public class JavaBeanMapWithCSV {

	public static void main(String[] args) throws FileNotFoundException {
		ColumnPositionMappingStrategy strategy = new ColumnPositionMappingStrategy();
		
		strategy.setType(Country.class); // 關聯JavaBean
		String[] columns = new String[] {"countryName", "capital"}; // the fields to bind do in your JavaBean,JavaBean裏的類變量屬性
		strategy.setColumnMapping(columns);
		CsvToBean csv = new CsvToBean();
		
		String csvFilename = "C:\\sample.csv";
		CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
		
//    	DataInputStream in = new DataInputStream(new FileInputStream(new File(csvFilename)));
//        csvReader = new CSVReader(new InputStreamReader(in,"utf-8"),',', '\'', 1); //這兩行註釋掉的內容可以解決中文亂碼問題
        
		List list = csv.parse(strategy, csvReader);
		for (Object object : list) {
			Country country = (Country) object;
			System.out.println(country.getCapital());
		}
	}
}

輸出結果:

CAPITAL
New Delhi
Beijing
Washington D.C.

OpenCSV library中文亂碼解決方法:

DataInputStream in = new DataInputStream(new FileInputStream(new File(csvFilename)));
csvReader = new CSVReader(new InputStreamReader(in,"utf-8"),',', '\'', 1); //這兩行註釋掉的內容可以解決中文亂碼問題

如果想讓 屬性爲 int類型,該如何辦呢?參考我這篇文章:http://blog.csdn.net/xiaowanggedege/article/details/17799049

參考資料:

http://viralpatel.net/blogs/java-read-write-csv-file/