任何人都可以推荐一个简单的API,允许我使用读取CSV输入文件,做一些简单的转换,然后写它.
一个快速的谷歌发现http://flatpack.sourceforge.net/看起来很有希望.
我只想在结合这个API之前检查其他人正在使用的内容.
我过去使用过OpenCSV.
import au.com.bytecode.opencsv.CSVReader;
String fileName = "data.csv"; CSVReader reader = new CSVReader(new FileReader(fileName ));// if the first line is the header String[] header = reader.readNext();
// iterate over reader.readNext until it returns null String[] line = reader.readNext();
在另一个问题的答案中还有其他一些选择.
更新:此答案中的代码适用于Super CSV 1.52.可以在项目网站上找到Super CSV 2.4.0的更新代码示例:http: //super-csv.github.io/super-csv/index.html
SuperCSV项目直接支持CSV单元的解析和结构化操作.从http://super-csv.github.io/super-csv/examples_reading.html你会发现例如
给一堂课
public class UserBean {
String username, password, street, town;
int zip;
public String getPassword() { return password; }
public String getStreet() { return street; }
public String getTown() { return town; }
public String getUsername() { return username; }
public int getZip() { return zip; }
public void setPassword(String password) { this.password = password; }
public void setStreet(String street) { this.street = street; }
public void setTown(String town) { this.town = town; }
public void setUsername(String username) { this.username = username; }
public void setZip(int zip) { this.zip = zip; }
}
并且您有一个带有标题的CSV文件.我们假设以下内容
username, password, date, zip, town Klaus, qwexyKiks, 17/1/2007, 1111, New York Oufu, bobilop, 10/10/2007, 4555, New York
然后,您可以创建UserBean的实例,并使用以下代码使用文件第二行的值填充它
class ReadingObjects {
public static void main(String[] args) throws Exception{
ICsvBeanReader inFile = new CsvBeanReader(new FileReader("foo.csv"), CsvPreference.EXCEL_PREFERENCE);
try {
final String[] header = inFile.getCSVHeader(true);
UserBean user;
while( (user = inFile.read(UserBean.class, header, processors)) != null) {
System.out.println(user.getZip());
}
} finally {
inFile.close();
}
}
}
使用以下"操作规范"
final CellProcessor[] processors = new CellProcessor[] {
new Unique(new StrMinMax(5, 20)),
new StrMinMax(8, 35),
new ParseDate("dd/MM/yyyy"),
new Optional(new ParseInt()),
null
};
查看Apache Common CSV.
该库读取和写入CSV的几种变体,包括标准的RFC 4180.还读取/写入制表符分隔的文件.
高强
InformixUnload
InformixUnloadCsv
MySQL的
神谕
PostgreSQLCsv
PostgreSQLText
RFC4180
TDF
阅读CSV格式的描述让我觉得使用第三方库比自己写的要少:
http://en.wikipedia.org/wiki/Comma-separated_values
维基百科列出了10个或者已知的库:
http://en.wikipedia.org/wiki/CSV_application_support
我比较了使用某种检查列表列出的库.OpenCSV对我来说是一个胜利者(YMMV),结果如下:
+ maven + maven - release version // had some cryptic issues at _Hudson_ with snapshot references => prefer to be on a safe side + code examples + open source // as in "can hack myself if needed" + understandable javadoc // as opposed to eg javadocs of _genjava gj-csv_ + compact API // YAGNI (note *flatpack* seems to have much richer API than OpenCSV) - reference to specification used // I really like it when people can explain what they're doing - reference to _RFC 4180_ support // would qualify as simplest form of specification to me - releases changelog // absence is quite a pity, given how simple it'd be to get with maven-changes-plugin // _flatpack_, for comparison, has quite helpful changelog + bug tracking + active // as in "can submit a bug and expect a fixed release soon" + positive feedback // Recommended By 51 users at sourceforge (as of now)
我们使用JavaCSV,它运行得很好
对于我工作的最后一个需要处理大量CSV的企业应用程序 - 几个月前 - 我在sourceforge 使用了SuperCSV,发现它简单,强大且无问题.
您可以使用csvreader api并从以下位置下载:
http://sourceforge.net/projects/javacsv/files/JavaCsv/JavaCsv%202.1/javacsv2.1.zip/download
要么
http://sourceforge.net/projects/javacsv/
使用以下代码:
/ ************ For Reading ***************/
import java.io.FileNotFoundException;
import java.io.IOException;
import com.csvreader.CsvReader;
public class CsvReaderExample {
public static void main(String[] args) {
try {
CsvReader products = new CsvReader("products.csv");
products.readHeaders();
while (products.readRecord())
{
String productID = products.get("ProductID");
String productName = products.get("ProductName");
String supplierID = products.get("SupplierID");
String categoryID = products.get("CategoryID");
String quantityPerUnit = products.get("QuantityPerUnit");
String unitPrice = products.get("UnitPrice");
String unitsInStock = products.get("UnitsInStock");
String unitsOnOrder = products.get("UnitsOnOrder");
String reorderLevel = products.get("ReorderLevel");
String discontinued = products.get("Discontinued");
// perform program logic here
System.out.println(productID + ":" + productName);
}
products.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
写入/附加到CSV文件
码:
/************* For Writing ***************************/
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import com.csvreader.CsvWriter;
public class CsvWriterAppendExample {
public static void main(String[] args) {
String outputFile = "users.csv";
// before we open the file check to see if it already exists
boolean alreadyExists = new File(outputFile).exists();
try {
// use FileWriter constructor that specifies open for appending
CsvWriter csvOutput = new CsvWriter(new FileWriter(outputFile, true), ',');
// if the file didn't already exist then we need to write out the header line
if (!alreadyExists)
{
csvOutput.write("id");
csvOutput.write("name");
csvOutput.endRecord();
}
// else assume that the file already has the correct header line
// write out a few records
csvOutput.write("1");
csvOutput.write("Bruce");
csvOutput.endRecord();
csvOutput.write("2");
csvOutput.write("John");
csvOutput.endRecord();
csvOutput.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
京公网安备 11010802040832号 | 京ICP备19059560号-6 