java map转Multipart/form-data类型body实例

我就废话不多说了，大家还是直接看代码吧！

public static String mapToTxt(Map<String,String> fieldMap, Map<String,File> fileMap,String fileName) throws Exception{
Random random = new Random();
int j;
String getLine = "\r\n";
String fileType = "Content-Type: application/octet-stream";
String doubleBar = "--";
biaoshi = "----WebKitFormBoundary";
StringBuffer sb = new StringBuffer();
for(int i = 0; i < 16;i++){
j = random.nextInt(MULTIPART_CHARS.length-2)+2;
sb.append(MULTIPART_CHARS[j]);
}
biaoshi = biaoshi + sb.toString();
StringBuffer stringBuffer = new StringBuffer();

for (Map.Entry<String,String> entity:fieldMap.entrySet()) {
String name = "Content-Disposition: form-data; name=\""+entity.getKey()+"\"";
stringBuffer.append(doubleBar+biaoshi);
stringBuffer.append(getLine);
stringBuffer.append(name);
stringBuffer.append(getLine);
stringBuffer.append(getLine);
stringBuffer.append(entity.getValue());
stringBuffer.append(getLine);
}

for (Map.Entry<String,File> entity:fileMap.entrySet()) {
String name = "Content-Disposition: form-data; name=\""+fileName+"\"; filename=\""+entity.getValue().getName()+"\"";
stringBuffer.append(doubleBar+biaoshi);
stringBuffer.append(getLine);
stringBuffer.append(name);
stringBuffer.append(getLine);
stringBuffer.append(fileType);
stringBuffer.append(getLine);
stringBuffer.append(getLine);
File f = entity.getValue();
FileInputStream fileInputStream = new FileInputStream(f);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte by[] = new byte[1024];
int k = 0;
while ((k=fileInputStream.read(by))!=-1){
byteArrayOutputStream.write(by,0,k);
}
by = byteArrayOutputStream.toByteArray();
for(int i = 0; i < by.length; i++){
stringBuffer.append(by[i]);
}
stringBuffer.append(getLine);
}
stringBuffer.append(doubleBar+biaoshi+doubleBar);
return stringBuffer.toString();
}

补充知识：java 如何取出传参数格式为form-data中的值

public Map<String, Object> Test(HttpServletRequest request,HttpServletRequest response) throws Exception {
    Map<String, String> returnMap = new HashMap<String, String>();
   String a=request.getParameter("a");//取出form-data中a的值
   String b=request.getParameter("b");//取出form-data中a的值
   //取出form-data中的二进制字段
   MultipartHttpServletRequest multipartRequest=(MultipartHttpServletRequest) request;
   MultipartFile multipartFile = multipartRequest.getFile("file");//file是form-data中二进制字段对应的name
   System.out.println(multipartFile.getSize());  
   Map<String, Object> resultMapsReturn = new HashMap<>();
   String imagePath="C:\\Users\\win\\Desktop\\1.jpg"//把取出来的二进制保存图片到本地
   if(multipartFile.getSize()<=0){
     resultMapsReturn.put("resultcode", "0");
     resultMapsReturn.put("msg", DisWebConst.ERROR_TITLE);
   }else{
     InputStream is = multipartFile.getInputStream();

OutputStream out = new FileOutputStream(imagePath);
     IOUtils.copy(is, out);
     is.close();
     out.close();
   }

来源：https://blog.csdn.net/qq_33770498/article/details/80525182