<dependency>
       <groupId>com.opencsv</groupId>
       <artifactId>opencsv</artifactId>
       <version>5.7.0</version>
   </dependency>

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    private String userId;
    private String userName;
    private String sex;
}

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User1 {
    @CsvBindByPosition(position = 0)
    public String userId;
    @CsvBindByPosition(position = 1)
    public String userName;
    @CsvBindByPosition(position = 2)
    public String sex;
}

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User2 {
    @CsvBindByName(column = "用户ID")
    public String userId;
    @CsvBindByName(column = "用户名")
    public String userName;
    @CsvBindByName(column = "性别")
    public String sex;
}

/**
   * 简单的写入
   * @throws Exception
   */
  private static void csvWriter() throws Exception {
      // 写入位置
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
      // 标题行
      String[] titleRow = {"用户ID", "用户名", "性别"};
      // 数据行
      ArrayList<String[]> dataRows = new ArrayList<>();
      String[] dataRow1 = {"1", "张三", "男"};
      String[] dataRow2 = {"2", "李四", "男"};
      String[] dataRow3 = {"3", "翠花", "女"};
      dataRows.add(dataRow1);
      dataRows.add(dataRow2);
      dataRows.add(dataRow3);
 
      OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
      // 1. 通过new CSVWriter对象的方式直接创建CSVWriter对象
      // CSVWriter csvWriter = new CSVWriter(writer);
      // 2. 通过CSVWriterBuilder构造器构建CSVWriter对象
      CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
              .build();
      // 写入标题行
      csvWriter.writeNext(titleRow, false);
      // 写入数据行
      csvWriter.writeAll(dataRows, false);
      csvWriter.close();
  }

用户ID,用户名,性别 
1,张三,男 
2,李四,男 
3,翠花,女 

/**
   * 基于位置映射的写入
   * @throws Exception
   */
  private static void beanToCsvByPosition() throws Exception {
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
 
      List<User> list = new ArrayList<>();
      list.add(new User("1", "张三", "男"));
      list.add(new User("2", "李四", "男"));
      list.add(new User("3", "翠花", "女"));
 
      OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
      ColumnPositionMappingStrategy<User> strategy = new ColumnPositionMappingStrategy();
      // 未指定的列不写入
      String[] columns = new String[] { "userId", "userName", "sex"};
      strategy.setColumnMapping(columns);
      strategy.setType(User.class);
      // 如果需要标题行，可这样写入
      // CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
      //         .build();
      // String[] titleRow = {"用户ID", "用户名", "性别"};
      // csvWriter.writeNext(titleRow, false);
 
      StatefulBeanToCsv<User> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User>(writer)
              .withMappingStrategy(strategy)
              .withApplyQuotesToAll(false)
              .build();
      statefulBeanToCsv.write(list);
      writer.close();
  }

1,张三,男
2,李四,男
3,翠花,女

/**
     * 基于CsvBindByPosition注解映射的写入
     * @throws Exception
     */
    private static void beanToCsvByPositionAnnotation() throws Exception {
        String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
        String fileName = classpath+"test/demo.csv";
 
        List<User1> list = new ArrayList<>();
        list.add(new User1("1", "张三", "男"));
        list.add(new User1("2", "李四", "男"));
        list.add(new User1("3", "翠花", "女"));
        // 未使用@CsvBindByPosition注解的列不写入
        OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
 
        // 如果需要标题行，可这样写入
        // CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
        //         .build();
        // String[] titleRow = {"用户ID", "用户名", "性别"};
        // csvWriter.writeNext(titleRow, false);
 
        StatefulBeanToCsv<User1> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User1>(writer)
                .withApplyQuotesToAll(false)
                .build();
        statefulBeanToCsv.write(list);
        writer.close();
    }

1,张三,男
2,李四,男
3,翠花,女

/**
    * 基于列名映射的写入
    * @throws Exception
    */
   private static void beanToCsvByName() throws Exception {
       String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
       String fileName = classpath+"test/demo.csv";

       List<User> list = new ArrayList<>();
       list.add(new User("1", "张三", "男"));
       list.add(new User("2", "李四", "男"));
       list.add(new User("3", "翠花", "女"));

       OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
       // 可通过比较器指定列的顺序
       // 标题行的列名默认为bean的字段名大写
       HeaderColumnNameMappingStrategy<User> strategy = new HeaderColumnNameMappingStrategy<>();
       HashMap<String, Integer> columnOrderMap = new HashMap<>();
       columnOrderMap.put("USERID", 1);
       columnOrderMap.put("SEX", 10);
       columnOrderMap.put("USERNAME", 100);
       strategy.setColumnOrderOnWrite(Comparator.comparingInt(column -> (columnOrderMap.getOrDefault(column, 0))));
       strategy.setType(User.class);

       StatefulBeanToCsv<User> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User>(writer)
               .withMappingStrategy(strategy)
               .withApplyQuotesToAll(false)
               .build();
       statefulBeanToCsv.write(list);
       writer.close();
   }

USERID,SEX,USERNAME
1,男,张三
2,男,李四
3,女,翠花

/**
   * 基于CsvBindByName注解映射的写入
   * @throws Exception
   */
  private static void beanToCsvByNameAnnotation() throws Exception {
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
 
      List<User2> list = new ArrayList<>();
      list.add(new User2("1", "张三", "男"));
      list.add(new User2("2", "李四", "男"));
      list.add(new User2("3", "翠花", "女"));
 
      OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
      // 可通过比较器指定列的顺序
      // 通过CsvBindByName注解的column属性，指定标题行的列名
      HeaderColumnNameMappingStrategy<User2> strategy = new HeaderColumnNameMappingStrategy<>();
      // 注意这里的key是指的标题行的列名
      HashMap<String, Integer> columnOrderMap = new HashMap<>();
      columnOrderMap.put("用户ID", 1);
      columnOrderMap.put("用户名", 10);
      columnOrderMap.put("性别", 100);
      strategy.setColumnOrderOnWrite(Comparator.comparingInt(column -> (columnOrderMap.getOrDefault(column, 0))));
      strategy.setType(User2.class);
 
      StatefulBeanToCsv<User2> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User2>(writer)
              .withMappingStrategy(strategy)
              .withApplyQuotesToAll(false)
              .build();
      statefulBeanToCsv.write(list);
      writer.close();
  }

用户ID,用户名,性别
1,张三,男
2,李四,男
3,翠花,女

/**
   * 简单的读取
   * @throws Exception
   */
  private static void csvReader() throws Exception {
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
      InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
      CSVReader csvReader = new CSVReaderBuilder(reader).build();
      List<String[]> list = csvReader.readAll();
      for (String[] strings : list) {
          System.out.println(JSON.toJSONString(strings));
      }
      csvReader.close();
  }

["用户ID","用户名","性别"]
["1","张三","男"]
["2","李四","男"]
["3","翠花","女"]

/**
    * 基于位置映射的读取
    * @throws Exception
    */
   private static void csvToBeanByPosition() throws Exception {
       String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
       String fileName = classpath+"test/demo.csv";
       InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
       // 不需要标题行，列的顺序通过列位置映射指定
       ColumnPositionMappingStrategy<User> strategy = new ColumnPositionMappingStrategy();
       String[] columns = new String[] { "userId", "userName", "sex"};
       strategy.setColumnMapping(columns);
       strategy.setType(User.class);
       CsvToBean<User> csvToBean = new CsvToBeanBuilder<User>(reader)
               .withMappingStrategy(strategy)
               .build();
       List<User> list = csvToBean.parse();
       for (User user : list) {
           System.out.println(JSON.toJSONString(user));
       }
       reader.close();
   }

{"sex":"男","userId":"1","userName":"张三"}
{"sex":"男","userId":"2","userName":"李四"}
{"sex":"女","userId":"3","userName":"翠花"}

/**
   * 基于CsvBindByPosition注解映射的读取
   * @throws Exception
   */
  private static void csvToBeanByPositionAnnotation() throws Exception {
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
      InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
      // 不需要标题行，列的顺序通过CsvBindByPosition注解的position属性指定
      CsvToBean<User1> csvToBean = new CsvToBeanBuilder<User1>(reader)
              .withType(User1.class)
              .build();
      List<User1> list = csvToBean.parse();
      for (User1 user : list) {
          System.out.println(JSON.toJSONString(user));
      }
      reader.close();
  }

{"sex":"男","userId":"1","userName":"张三"}
{"sex":"男","userId":"2","userName":"李四"}
{"sex":"女","userId":"3","userName":"翠花"}

/**
   * 基于列名映射的读取
   * @throws Exception
   */
  private static void csvToBeanByName() throws Exception {
      String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
      String fileName = classpath+"test/demo.csv";
      InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
      // bean的字段名称大写为标题列名
      CsvToBean<User> csvToBean = new CsvToBeanBuilder<User>(reader)
              .withType(User.class)
              .build();
      List<User> list = csvToBean.parse();
      for (User user : list) {
          System.out.println(JSON.toJSONString(user));
      }
      reader.close();
  }

{"sex":"男","userId":"1","userName":"张三"}
{"sex":"男","userId":"2","userName":"李四"}
{"sex":"女","userId":"3","userName":"翠花"}

private static void csvToBeanByNameAnnotation() throws Exception {
        String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
        String fileName = classpath+"test/demo.csv";
        InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
        // CsvBindByName注解的column属性为标题列名
        CsvToBean<User2> csvToBean = new CsvToBeanBuilder<User2>(reader)
                .withType(User2.class)
                .build();
        List<User2> list = csvToBean.parse();
        for (User2 user : list) {
            System.out.println(JSON.toJSONString(user));
        }
        reader.close();
    }

{"sex":"男","userId":"1","userName":"张三"}
{"sex":"男","userId":"2","userName":"李四"}
{"sex":"女","userId":"3","userName":"翠花"}

public class MyCsvToBeanFilter implements CsvToBeanFilter {
 
    @Override
    public boolean allowLine(String[] line) {
        // 过滤掉用户名为李四的行
        if("李四".equals(line[1])){
            return false;
        }
        return true;
    }
}

 
    /**
     * 基于列名转换映射的读取
     * @throws Exception
     */
    private static void csvToBeanByColumnNameTranslateMapping() throws Exception {
        String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
        String fileName = classpath+"test/demo.csv";
        InputStreamReader reader = new InputStreamReader(new FileInputStream(fileName), Charset.forName("UTF-8"));
        // 指定标题列名和bean列名映射关系
        HeaderColumnNameTranslateMappingStrategy<User> strategy = new HeaderColumnNameTranslateMappingStrategy<>();
        // key：标题列名，value：bean的属性名
        HashMap<String, String> columnMappingMap = new HashMap<>();
        columnMappingMap.put("用户ID", "userId");
        columnMappingMap.put("性别", "sex");
        columnMappingMap.put("用户名", "userName");
        strategy.setColumnMapping(columnMappingMap);
        strategy.setType(User.class);
        CsvToBean<User> csvToBean = new CsvToBeanBuilder<User>(reader)
                .withMappingStrategy(strategy)
                .withFilter(new MyCsvToBeanFilter())
                .withIgnoreField(User2.class, User2.class.getField("userId"))// 忽略userId属性
                .build();
        List<User> list = csvToBean.parse();
        for (User user : list) {
            System.out.println(JSON.toJSONString(user));
        }
        reader.close();
    }

{"sex":"男","userName":"张三"}
{"sex":"女","userName":"翠花"}