通过easycsv组件可以方便处理csv文本内容的写入与读取功能，大数据量也不会导致系统OOM异常
<dependency>
<groupId>com.github.aifeinik</groupId>
<artifactId>easycsv</artifactId>
<version>1.0</version>
</dependency>
public class CsvTest {
CampaignModel m1 = new CampaignModel("2019-01-01", 10000000L, "campaign1", 12.21d, 300L, 0.12d);
CampaignModel m2 = new CampaignModel("2019-01-02", 12000001L, "campaign2", 13.01d, 80L, 0.13d);
CampaignModel m3 = new CampaignModel("2019-01-03", 13000002L, "campaign3", 14.11d, 100L, 0.14d);
CampaignModel m4 = new CampaignModel("2019-01-04", 15000002L, "campaign4", 10.11d, 99L, 0.16d);
ArrayList<CampaignModel> data1 = Lists.newArrayList(m1, m2);
ArrayList<CampaignModel> data2 = Lists.newArrayList(m3, m4);
private String writeFilePath = "G:/tmp/campaign.csv";
/**
* 小数据量写入
*/
public void writeSmallData() {
CsvWriter writer = null;
try {
writer = CsvFactory.getWriter(writeFilePath, Charset.forName("GBK"));
CsvUtil.write(writer, data1, true, null);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (writer != null) {
writer.close();
}
}
}
/**
* 大数据量通过分批写入，不至于导致OOM问题
*/
@Test
public void writeLargeData() {
CsvWriter writer = null;
try {
writer = CsvFactory.getWriter(writeFilePath, Charset.forName("GBK"));
//首次写入数据包含写入head行
CsvUtil.write(writer, data1, true, null);
//下一批数据写入不在写入head行
CsvUtil.write(writer, data2, false, null);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (writer != null) {
writer.close();
}
}
}
/**
* 小数据量读取
* @throws Exception
*/
@Test
public void readSmallData() throws Exception {
final InputStream is = FileUtil.getResourcesFileInputStream("campaign.csv");
List<CampaignModel> models = CsvUtil.read(is, CampaignModel.class, 1, Charset.forName("GBK"), null);
print(models);
}
/**
* 大数据量读取
* @throws Exception
*/
@Test
public void readLargeData() throws Exception {
final InputStream is = FileUtil.getResourcesFileInputStream("campaign.csv");
CsvUtil.readOnListener(is, CampaignModel.class, 1, Charset.forName("GBK"), null , new CampaignDataListener());
}
public static class CampaignDataContext implements CsvContext {
@Override
public void initWriter(CsvWriter writer) {}
@Override
public void initReader(CsvReader reader) {
//通过这里设置headers可灵活设置具体csv文件解析对应的head顺序，可通过将headers参数配置化（如：通过配置中心读取）
reader.setHeaders(new String[]{"日期", "广告系列 ID", "广告系列", "费用", "点击次数", "点击率"});
}
}
public void print(List<CampaignModel> objects) {
for (CampaignModel object : objects) {
System.out.println(object);
}
}
}