[英]Spring MVC - Create a ZIP file in memory and let user download
我有一个网络项目
请注意,在下载之前,我不会创建物理文件。
我完成了1-3。 我似乎找不到下载部分的解决方案。 我正在使用纯Spring MVC(尽我所能),Hibernate,MySQL。
HomeController.java
@RequestMapping(value="/doretrieve", method=RequestMethod.POST, produces="application/zip")
@ResponseBody
public ZipOutputStream doRetrieve(@RequestParam(value="calcgrouplist") String selectedCalcGroups, @RequestParam(value="env") String currentEnv){
ZipOutputStream zipCalgGroups = null;
try {
String[] cgs = calcGroupService.insertToArray(selectedCalcGroups);
for(String cg:cgs){
System.out.println("Calculation Group: " + cg);
}
Map startRetrieve = calcGroupService.startRetrieve(currentEnv, cgs);
if (startRetrieve != null ){
zipCalgGroups = calcGroupService.zipCalcGroups(currentEnv, startRetrieve);
} else {
return null;
}
} catch (NullPointerException e) {
e.printStackTrace();
}
return zipCalgGroups;
}
CalcGroupService.java代码来创建xml文件的zip文件
public ZipOutputStream zipCalcGroups(String database, Map startRetrieve) {
//Sort
//SortCalcGroupParameters sort = new SortCalcGroupParameters();
//sort.run(new File("\\" + database));
Map<String, byte[]> mapXmlFiles = startRetrieve;
try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos))
{
for (Map.Entry<String, byte[]> mapXmlFile:mapXmlFiles.entrySet()){
ZipEntry entry = new ZipEntry(mapXmlFile.getKey());
zos.putNextEntry(entry);
zos.write(mapXmlFile.getValue());
zos.closeEntry();
}
return zos;
} catch (IOException e) {
e.printStackTrace();
}
return null;
我能够解决自己的问题。 下面是编辑后的方法:
HomeController的:
@RequestMapping(value="/doretrieve", method=RequestMethod.POST, produces="application/zip")
@ResponseBody
public byte[] doRetrieve(HttpServletResponse response, @RequestParam(value="calcgrouplist")
String selectedCalcGroups, @RequestParam(value="env") String currentEnv){
try {
String[] cgs = calcGroupService.insertToArray(selectedCalcGroups);
for(String cg:cgs){
System.out.println("Calculation Group: " + cg);
}
//returns map of file name and xml
Map startRetrieve = calcGroupService.startRetrieve(currentEnv, cgs);
//set file name of the zipped calc group/s using selected environment
response.setHeader("Content-Disposition", "attachment; filename=" + currentEnv + ".zip");
if (startRetrieve != null ){
byte[] zipped = calcGroupService.zipCalcGroupsFromMemory(currentEnv, startRetrieve);
return zipped;
} else {
return null;
}
} catch (NullPointerException e) {
e.printStackTrace();
}
return null;
}
CalcGroupService :
public byte[] zipCalcGroupsFromMemory(String database, Map startRetrieve) {
Map<String, byte[]> mapXmlFiles = startRetrieve;
HttpServletRequest request = null;
try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos)) {
for (Map.Entry<String, byte[]> mapXmlFile : mapXmlFiles.entrySet()) {
byte[] xml = sortCalcGroup(mapXmlFile.getKey(), mapXmlFile.getValue());
zos.putNextEntry(new ZipEntry(mapXmlFile.getKey()));
//zos.write(mapXmlFile.getValue());
zos.write(xml);
zos.closeEntry();
}
zos.close();
return baos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
上面的代码生成了一个不错的压缩xml文件。
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