我为 Spring Controller 创建了一个实用程序类,用于调用它以使用 SuperCSV 库 ( http://supercsv.sourceforge.net/ ) 从 bean 集合生成 CSV
实用程序类非常基本:
public static void export2CSV(HttpServletResponse response,
String[] header, String filePrefix, List<? extends Object> dataObjs) {
try{
response.setContentType("text/csv;charset=utf-8");
response.setHeader("Content-Disposition","attachment; filename="+filePrefix+"_Data.csv");
OutputStream fout= response.getOutputStream();
OutputStream bos = new BufferedOutputStream(fout);
OutputStreamWriter outputwriter = new OutputStreamWriter(bos);
ICsvBeanWriter writer = new CsvBeanWriter(outputwriter, CsvPreference.EXCEL_PREFERENCE);
// the actual writing
writer.writeHeader(header);
for(Object anObj : dataObjs){
writer.write(anObj, header);
}
}catch (Exception e){
e.printStackTrace();
}
};
问题是,我从这个操作中得到了不同的行为,但我不知道为什么。当我从一个 Controller (我们将其称为“A”)调用它时,我得到了预期的数据输出。
当我从另一个 Controller (“B”)调用它时,我得到了一小段无法识别的二进制数据,OO Calc 无法打开这些数据。在 Notepad++ 中打开它会产生一行不可读的乱码,我只能假设这是读者试图向我显示二进制流。
Controller “A”调用(有效的)
@RequestMapping(value="/getFullReqData.html", method = RequestMethod.GET)
public void getFullData(HttpSession session, HttpServletRequest request, HttpServletResponse response) throws IOException{
logger.info("INFO: ******************************Received request for full Req data dump");
String projName= (String)session.getAttribute("currentProject");
int projectID = ProjectService.getProjectID(projName);
List<Requirement> allRecords = reqService.getFullDataSet(projectID);
final String[] header = new String[] {
"ColumnA",
"ColumnB",
"ColumnC",
"ColumnD",
"ColumnE"
};
CSVExporter.export2CSV(response, header, projName+"_reqs_", allRecords);
};
...这是 Controller “B”调用(失败的那个):
@RequestMapping(value="/getFullTCData.html", method = RequestMethod.GET)
public void getFullData(HttpSession session, HttpServletRequest request, HttpServletResponse response) throws IOException{
logger.info("INFO: Received request for full TCD data dump");
String projName= (String)session.getAttribute("currentProject");
int projectID = ProjectService.getProjectID(projName);
List<TestCase> allRecords = testService.getFullTestCaseList(projectID);
final String[] header = new String[] {
"ColumnW",
"ColumnX",
"ColumnY",
"ColumnZ"
};
CSVExporter.export2CSV(response, header, projName+"_tcs_", allRecords);
}
观察结果:
- 我首先调用哪个 Controller 并不重要。 “A”总是有效,而“B”总是产生乱码
- 对此函数的两次调用都有一个标题列列表,这些标题列是传递给 CSVWriter 的 bean 中定义的全部操作集的子集
- 简单的异常 printStackTrace 正在努力检测 bean 的反射字段何时与定义不匹配(即找不到 get() 以编程方式获取值),表明所有列/变量匹配都成功。<
- 在调试器中,我已根据传递的对象数量验证了 writer.write(Object, header) 调用的命中次数达到了预期,并且这些对象具有预期数据
任何建议或见解将不胜感激。我真的很困惑如何更好地隔离问题......
最佳答案
您没有关闭 writer。此外,CsvBeanWriter 会将编写器包装在 BufferedWriter 中,因此您也可以简化您的 outputwriter
。
public static void export2CSV(HttpServletResponse response,
String[] header, String filePrefix, List<? extends Object> dataObjs) {
ICsvBeanWriter writer;
try{
response.setContentType("text/csv;charset=utf-8");
response.setHeader("Content-Disposition",
"attachment; filename="+filePrefix+"_Data.csv");
OutputStreamWriter outputwriter =
new OutputStreamWriter(response.getOutputStream());
writer = new CsvBeanWriter(outputwriter, CsvPreference.EXCEL_PREFERENCE);
// the actual writing
writer.writeHeader(header);
for(Object anObj : dataObjs){
writer.write(anObj, header);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
writer.close(); // closes writer and underlying stream
} catch (Exception e){}
}
};
Super CSV 2.0.0-beta-1现在出来了!除了添加许多其他功能(包括 Maven 支持和新的 Dozer 扩展)之外,CSV 编写器现在还公开了一个 flush()
方法。
关于java - SuperCSV 的输出不可读?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12358184/