response打印字节和字符串的方法区别
response中的内容只要mvc返回了就自动会返回页面，在相应的结构可以看到，+return null;或者return;
用response.getWriter().print("未找到图片");/////////////打印普通字符或者response.getOutputStream().write(bytes,0,length);///打印流
这是自动当着页面返回请求页（下载之类）
@RequestMapping(value = "/account/tbCusFirmChg/showImage")
public void showReportImage(@RequestParam(value = "path") String path,
HttpServletRequest request,HttpServletResponse response) throws IOException, NumberFormatException, EsteelException {
// response.setContentType("image/jpeg");
response.setCharacterEncoding("UTF-8");
// String filePath= WebConfig.get("filePath");
String pathBase = StaticVariables.Base_Path;
File file=null;
if(path!=null&&!"".equals(path)){
file=new File(pathBase+path);
}
if( file==null||!file.exists()){
response.getWriter().print("未找到图片");/////////////打印普通字符
}else {
response.setContentType("image/jpeg");
FileInputStream fos = new FileInputStream(file);
byte[] bytes = new byte[1024*1024];
int length = 0;
while((length=fos.read(bytes))!=-1){
response.getOutputStream().write(bytes,0,length);///打印流
}
}
}