ItemWriter怎么输出数据到Excel?
时间: 2024-03-25 15:40:58 浏览: 21
要将数据输出到Excel中,可以使用Spring Batch提供的一些现成的ItemWriter实现,例如JdbcBatchItemWriter和JpaItemWriter。但是,如果想将数据输出到Excel中,需要自定义一个ItemWriter来实现。以下是一个简单的实现方式:
1.添加依赖
在项目的pom.xml文件中,添加以下依赖:
```
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.0</version>
</dependency>
```
2.自定义ExcelItemWriter
```
public class ExcelItemWriter<T> implements ItemWriter<T> {
private String filePath;
private String sheetName;
private List<String> headers;
private List<String> columns;
private boolean overwrite;
public ExcelItemWriter(String filePath, String sheetName, List<String> headers, List<String> columns, boolean overwrite) {
this.filePath = filePath;
this.sheetName = sheetName;
this.headers = headers;
this.columns = columns;
this.overwrite = overwrite;
}
@Override
public void write(List<? extends T> items) throws Exception {
Workbook workbook;
if (overwrite) {
workbook = new XSSFWorkbook();
} else {
FileInputStream fis = new FileInputStream(filePath);
workbook = new XSSFWorkbook(fis);
fis.close();
}
Sheet sheet = workbook.getSheet(sheetName);
if (sheet == null) {
sheet = workbook.createSheet(sheetName);
}
int rowNum = sheet.getLastRowNum();
if (rowNum == 0) {
Row headerRow = sheet.createRow(0);
for (int i = 0; i < headers.size(); i++) {
headerRow.createCell(i).setCellValue(headers.get(i));
}
}
for (int i = 0; i < items.size(); i++) {
Row dataRow = sheet.createRow(++rowNum);
T item = items.get(i);
for (int j = 0; j < columns.size(); j++) {
String column = columns.get(j);
Field field = item.getClass().getDeclaredField(column);
field.setAccessible(true);
Object value = field.get(item);
dataRow.createCell(j).setCellValue(value.toString());
}
}
FileOutputStream fos = new FileOutputStream(filePath);
workbook.write(fos);
fos.close();
}
}
```
3.在Job配置中使用ExcelItemWriter
```
@Bean
public Step myStep() {
return stepBuilderFactory.get("myStep")
.<MyData, MyData>chunk(100)
.reader(myDataReader())
.processor(myDataProcessor())
.writer(new ExcelItemWriter<>("data.xlsx", "Sheet1", Arrays.asList("Header1", "Header2"), Arrays.asList("field1", "field2"), true))
.build();
}
```
在ExcelItemWriter中,我们使用了Apache POI库来操作Excel文件,通过调用Workbook、Sheet和Row等类的方法,实现了将数据写入到Excel文件中的功能。在Job配置中,我们将ExcelItemWriter作为Step的writer,这样在Step执行时,就会将数据写入到Excel文件中。
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