package com.data.agg.csv.main;
import com.data.agg.csv.bean.CsvBean;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* @Author 赵超
* @Date 2022/5/30 14:32
* @Version 1.0
*/
@Slf4j
public class CsvReader {
String csvFilePath;
/**
* csv文件的读入流
*/
FileInputStream csvFileInputStream;
/**
* csv文件的读取指针
*/
BufferedReader csvFileBufferReader;
/**
* 缓冲行
*/
String bufferedLineForCsvFile;
CsvBean csvBean = new CsvBean();
/**
* 初始化方法
*
* @param csvFilePath csv文件的绝对路径
*/
public CsvReader(String csvFilePath) throws IOException {
this.csvFilePath = csvFilePath;
Charset charset = Charset.forName("gbk");
csvFileInputStream = new FileInputStream(csvFilePath);
csvFileBufferReader = new BufferedReader(new InputStreamReader(csvFileInputStream, charset));
/**
* 读取csv文件的文件表头
*/
String s = csvFileBufferReader.readLine();
//保存csv表头
List<String> header = new ArrayList<>();
String[] columns = s.split(",");
String columnStr = StringUtils.join(columns, ",");
header.add(columnStr);
csvBean.setHeaders(header);
}
public boolean hasNext() throws IOException {
if ("EOF".equals(bufferedLineForCsvFile)) return false;
else return true;
}
/**
* 读取数据中的一行
*
* @return <字段名, 值>形式
* @throws IOException
*/
public Map<String, Object> getLine() throws IOException {
/**
* 读取mid数据中的一行，按照mif数据文件头中的分隔符对其进行分割
*/
String csvColumns = csvFileBufferReader.readLine();
if (csvColumns == null || csvColumns.isEmpty()) {
bufferedLineForCsvFile = "EOF";
return null;
}
String[] columnData = csvColumns.split(",");
/**
* 将数据以<字段名, 值>的形式进行组装
*/
Map<String, Object> oneLineData = new HashMap<>();
String[] headerArr = csvBean.getHeaders().get(0).split(",");
for (int i = 0; i < headerArr.length; i++) {
oneLineData.put(headerArr[i], columnData[i]);
}
// 若缓冲区内存放着EOF标记则直接返回null
if ("EOF".equals(bufferedLineForCsvFile)) {
return null;
}
return oneLineData;
}
/**
* 关闭reader缓冲区
*/
public void close() {
if (csvFileBufferReader != null) {
try {
csvFileBufferReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (csvFileInputStream != null) {
try {
csvFileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
