Response响应字节数据

Response响应字节数据

响应字节数据首先需要获取到自己输出流

ServletOutputStream outputStream = resp.getOutputStream();

然后通过字节输出流写数据

outputStream.write(字节数据);

现在我们通过自己输出流来将一张图片传到浏览器
准备的一张图片

package com.itheima.web.response;


import org.apache.commons.io.IOUtils;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * 响应字节数据：设置字节数据的响应体
 */
@WebServlet("/resp4")
public class ResponseDemo4 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1. 读取文件
        FileInputStream fis = new FileInputStream("E:\\java_project__\\request-demo\\src\\main\\java\\com\\itheima\\web\\response\\be.png");

        //2. 获取response字节输出流
        ServletOutputStream os = response.getOutputStream();

        //3. 完成流的copy
       /* byte[] buff = new byte[1024];
        int len = 0;
        while ((len = fis.read(buff))!= -1){
            os.write(buff,0,len);
        }*/

        IOUtils.copy(fis,os);

        fis.close();

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

==IOUtils.copy(fis,os);==该方法需要我们加入相关的依赖

        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>