<dependency>
    <groupId>com.opencsv</groupId>
    <artifactId>opencsv</artifactId>
    <version>5.6</version>
</dependency>

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    public String userId;
    public String userName;
    public 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 = "用戶ID")
    public String userId;
    @CsvBindByName(column = "用戶名")
    public String userName;
    @CsvBindByName(column = "性別")
    public String sex;
}

    /**
     * 簡(jiǎn)單的寫入
     * @throws Exception
     */
    private static void csvWriter() throws Exception {
        // 寫入位置
        String classpath = Thread.currentThread().getContextClassLoader().getResource("").getPath();
        String fileName = classpath+"test/demo.csv";
        // 標(biāo)題行
        String[] titleRow = {"用戶ID", "用戶名", "性別"};
        // 數(shù)據(jù)行
        ArrayList<String[]> dataRows = new ArrayList<>();
        String[] dataRow1 = {"1", "張三", "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. 通過new CSVWriter對(duì)象的方式直接創(chuàng)建CSVWriter對(duì)象
        // CSVWriter csvWriter = new CSVWriter(writer);
        // 2. 通過CSVWriterBuilder構(gòu)造器構(gòu)建CSVWriter對(duì)象
        CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
                .build();
        // 寫入標(biāo)題行
        csvWriter.writeNext(titleRow, false);
        // 寫入數(shù)據(jù)行
        csvWriter.writeAll(dataRows, false);
        csvWriter.close();
    }

    /**
     * 基于位置映射的寫入
     * @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", "張三", "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();
        // 未指定的列不寫入
        String[] columns = new String[] { "userId", "userName", "sex"};
        strategy.setColumnMapping(columns);
        strategy.setType(User.class);
        // 如果需要標(biāo)題行，可這樣寫入
        // CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
        //         .build();
        // String[] titleRow = {"用戶ID", "用戶名", "性別"};
        // csvWriter.writeNext(titleRow, false);
        StatefulBeanToCsv<User> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User>(writer)
                .withMappingStrategy(strategy)
                .withApplyQuotesToAll(false)
                .build();
        statefulBeanToCsv.write(list);
        writer.close();
    }

    /**
     * 基于CsvBindByPosition注解映射的寫入
     * @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", "張三", "男"));
        list.add(new User1("2", "李四", "男"));
        list.add(new User1("3", "翠花", "女"));
        // 未使用@CsvBindByPosition注解的列不寫入
        OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(fileName), Charset.forName("UTF-8"));
        // 如果需要標(biāo)題行，可這樣寫入
        // CSVWriter csvWriter = (CSVWriter) new CSVWriterBuilder(writer)
        //         .build();
        // String[] titleRow = {"用戶ID", "用戶名", "性別"};
        // csvWriter.writeNext(titleRow, false);
        StatefulBeanToCsv<User1> statefulBeanToCsv = new StatefulBeanToCsvBuilder<User1>(writer)
                .withApplyQuotesToAll(false)
                .build();
        statefulBeanToCsv.write(list);
        writer.close();
    }

    /**
     * 基于列名映射的寫入
     * @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", "張三", "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"));
        // 可通過比較器指定列的順序
        // 標(biāo)題行的列名默認(rèn)為bean的字段名大寫
        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();
    }

    /**
     * 基于CsvBindByName注解映射的寫入
     * @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", "張三", "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"));
        // 可通過比較器指定列的順序
        // 通過CsvBindByName注解的column屬性，指定標(biāo)題行的列名
        HeaderColumnNameMappingStrategy<User2> strategy = new HeaderColumnNameMappingStrategy<>();
        // 注意這里的key是指的標(biāo)題行的列名
        HashMap<String, Integer> columnOrderMap = new HashMap<>();
        columnOrderMap.put("用戶ID", 1);
        columnOrderMap.put("用戶名", 10);
        columnOrderMap.put("性別", 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();
    }

    /**
     * 簡(jiǎn)單的讀取
     * @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();
    }

    /**
     * 基于位置映射的讀取
     * @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"));
        // 不需要標(biāo)題行，列的順序通過列位置映射指定
        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();
    }

    /**
     * 基于CsvBindByPosition注解映射的讀取
     * @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"));
        // 不需要標(biāo)題行，列的順序通過CsvBindByPosition注解的position屬性指定
        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();
    }

    /**
     * 基于列名映射的讀取
     * @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的字段名稱大寫為標(biāo)題列名
        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();
    }

    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屬性為標(biāo)題列名
        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();
    }

public class MyCsvToBeanFilter implements CsvToBeanFilter {
    @Override
    public boolean allowLine(String[] line) {
        // 過濾掉用戶名為李四的行
        if("李四".equals(line[1])){
            return false;
        }
        return true;
    }
}

    /**
     * 基于列名轉(zhuǎn)換映射的讀取
     * @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"));
        // 指定標(biāo)題列名和bean列名映射關(guān)系
        HeaderColumnNameTranslateMappingStrategy<User> strategy = new HeaderColumnNameTranslateMappingStrategy<>();
        // key：標(biāo)題列名，value：bean的屬性名
        HashMap<String, String> columnMappingMap = new HashMap<>();
        columnMappingMap.put("用戶ID", "userId");
        columnMappingMap.put("性別", "sex");
        columnMappingMap.put("用戶名", "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u(píng)serId屬性
                .build();
        List<User> list = csvToBean.parse();
        for (User user : list) {
            System.out.println(JSON.toJSONString(user));
        }
        reader.close();
    }

{"sex":"男","userName":"張三"}
{"sex":"女","userName":"翠花"}