ColumnPositionMappingStrategy＃generateHeader返回空数组
@Overridepublic String[] generateHeader() { return new String[0];}如果从BeanToCsv构建器中删除MappingStrategy
// replace StatefulBeanToCsv<Product> beanWriter = builder.withMappingStrategy(mappingStrategy).build();// withStatefulBeanToCsv<Product> beanWriter = builder.build();
它将产品的类成员写为CSV标头
如果您的产品类成员名称是
"productCode", "MFD", "EXD"
这应该是正确的解决方案
否则，添加@CsvBindByName批注
import com.opencsv.bean.CsvBindByName;import com.opencsv.bean.StatefulBeanToCsv;import com.opencsv.bean.StatefulBeanToCsvBuilder;import java.io.FileWriter;import java.io.Writer;import java.util.ArrayList;import java.util.List;public class CsvTest { public static void main(String[] args) throws Exception { Writer writer = new FileWriter(fileName); StatefulBeanToCsvBuilder<Product> builder = new StatefulBeanToCsvBuilder<>(writer); StatefulBeanToCsv<Product> beanWriter = builder.build(); List<Product> products = new ArrayList<>(); products.add(new Product("1", "11", "111")); products.add(new Product("2", "22", "222")); products.add(new Product("3", "33", "333")); beanWriter.write(products); writer.close(); } public static class Product { @CsvBindByName(column = "productCode") String id; @CsvBindByName(column = "MFD") String member2; @CsvBindByName(column = "EXD") String member3; Product(String id, String member2, String member3) { this.id = id; this.member2 = member2; this.member3 = member3; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getMember2() { return member2; } public void setMember2(String member2) { this.member2 = member2; } public String getMember3() { return member3; } public void setMember3(String member3) { this.member3 = member3; } }}输出：
“ EXD”，“ MFD”，“ PRODUCTCODE”
“ 111”，“ 11”，“ 1”
“ 222”，“ 22”，“ 2”
“ 333”，“ 33”，“ 3”
请注意; 班级，由于OpenCSV库使用了Reflection，所以getter和setter程序需要公开
