Java实现读取TXT和CSV文件内容

<!--csv文件操作-->
        <dependency>
            <groupId>net.sourceforge.javacsv</groupId>
            <artifactId>javacsv</artifactId>
            <version>2.0</version>
        </dependency>

package util;
import com.csvreader.CsvReader;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.ArrayList;
 
public class ReadFileTool {
 
    //读取文件
    public static String readTextFile(String jsonFile) {
        StringBuilder stringBuilder = new StringBuilder();
        try {
            //01.FileInputStream（字节流） 实现了InputStream接口，用来读取文件中的字节流，参数是文件或者文件路径+文件名称
            FileInputStream fileInputStream = new FileInputStream(jsonFile);
            //02.将 fileInputStream（字节流） 流作为参数，转为InputStreamReader（字符流）
            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
            //03.将 字符流（参数）转为字符串流，带缓冲的流读取，默认缓冲区8k
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String tempString;
            while ((tempString = bufferedReader.readLine()) != null)
            {
                // 将字符串 添加到 stringBuilder中
                stringBuilder.append(tempString);
            }
            bufferedReader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return stringBuilder.toString();
    }
 
    //通过BufferedReader读取CSV
    public static ArrayList readCsvFileFromJava(String csvFile,String encoding) {
 
        ArrayList<String[]> csvArrList=new ArrayList<String[]>();
        StringBuilder stringBuilder = new StringBuilder();
        try {
            //01.FileInputStream（字节流） 实现了InputStream接口，用来读取文件中的字节流，参数是文件或者文件路径+文件名称
            FileInputStream fileInputStream = new FileInputStream(csvFile);
            //02.将 fileInputStream（字节流） 流作为参数，转为InputStreamReader（字符流）
            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, encoding);
            //03.将 字符流（参数）转为字符串流，带缓冲的流读取，默认缓冲区8k
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String line;
            while ((line = bufferedReader.readLine()) != null)
            {
               // System.out.println(line);
                String item[] = line.split(",",-1);//CSV格式文件为逗号分隔符文件，这里根据逗号切分,-1表示获取所有空值
                csvArrList.add(item);
            }
            bufferedReader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return csvArrList;
    }
 
//通过com.csvreader.CsvReader 读取CSV
    public static ArrayList readCsvFileFromCsvReader(String csvFile,String encoding) {
        ArrayList<String[]> csvArrList=new ArrayList<String[]>();
        try {
            CsvReader reader = new CsvReader(csvFile, ',', Charset.forName(encoding));
            reader.readHeaders();
            String[] headArray = reader.getHeaders();//获取标题
            for(String a:headArray){
                System.out.print(a);
            }
            System.out.println();
            System.out.println("---------");
          
            while (reader.readRecord()) {
                // System.out.println(Arrays.asList(reader.getValues()));
                // 按行读取，并把每一行的数据添加到list集合
                csvArrList.add(reader.getValues());
            }
            reader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return csvArrList;
    }
 
    //测试
    public static void main(String[] args) {
 
        String userDir = System.getProperty("user.dir");
        String fileDir = userDir + File.separator + "sourceFile" + File.separator;
        String cfgFileName = "dwd_op_event.csv";
        String  csvFullFileName = fileDir + cfgFileName;
        ArrayList<String []> csvArrList =readCsvFileFromCsvReader(csvFullFileName,"GBK");
 
    }
    
}