Question

Struts1框架 用Java代码实现文件下载 不弹出下载框 代码：

response.setContentType("application/octet-stream; charset=UTF-8");
response.setHeader("Content-Disposition", "attachment;filename=" + m+"");
response.setHeader("Content-Length", String.valueOf(file.length()));

Answer 1

下载代码：
这里我使用的是SpringMVC，不过它在这里的唯一用途就是用来获取ServletContext对象，这个对象的用途，下面实例中有说明
下载，需要用到两个jar包：commons-fileupload.jar和commons-io.jar

Java代码
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.context.ServletContextAware;

import javax.servlet.ServletContext;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

@Controller
public class FileController implements ServletContextAware{
//Spring这里是通过实现ServletContextAware接口来注入ServletContext对象
private ServletContext servletContext;

@RequestMapping("file/download")
public void fileDownload(HttpServletResponse response){
//获取网站部署路径(通过ServletContext对象)，用于确定下载文件位置，从而实现下载
String path = servletContext.getRealPath("/");

//1.设置文件ContentType类型，这样设置，会自动判断下载文件类型
response.setContentType("multipart/form-data");
//2.设置文件头：最后一个参数是设置下载文件名(假如我们叫a.pdf)
response.setHeader("Content-Disposition", "attachment;fileName="+"a.pdf");
ServletOutputStream out;
//通过文件路径获得File对象(假如此路径中有一个download.pdf文件)
File file = new File(path + "download/" + "download.pdf");

try {
FileInputStream inputStream = new FileInputStream(file);

//3.通过response获取ServletOutputStream对象(out)
out = response.getOutputStream();

int b = 0;
byte[] buffer = new byte[512];
while (b != -1){
b = inputStream.read(buffer);
//4.写到输出流(out)中
out.write(buffer,0,b);
}
inputStream.close();
out.close();
out.flush();

} catch (IOException e) {
e.printStackTrace();
}
}

@Override
public void setServletContext(ServletContext servletContext) {
this.servletContext = servletContext;
}
}