文件下载 Response（狂神JavaWeb笔记）

文件下载 Response（狂神JavaWeb笔记）"/>

文件下载 Response（狂神JavaWeb笔记）

文件下载 Response（狂神JavaWeb笔记）

学习笔记源码下载地址

下载文件思路

1、获取下载文件的路径
2、下载的文件名
3、设置想办法让浏览器能够支持下载我们需要的东西
4、获取下载文件的输入流
5、创建缓冲区
6、获取OutputStream对象
7、将FileOutStream流写入到buffer缓冲区
8、使用OutputStream将缓冲区中的数据输出到客户端

实现过程

1、在idea中使用maven创建新的JavaWeb项目
2、代码实现
配置 pom.xml

<?xml version="1.0" encoding="UTF-8"?><project xmlns=".0.0" xmlns:xsi=""xsi:schemaLocation=".0.0 .0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>Servlet03</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><name>Servlet03 Maven Webapp</name><!-- FIXME change it to the project's website --><url>;/url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.7</maven.compiler.source><maven.compiler.target>1.7</maven.compiler.target></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>4.0.1</version><scope>compile</scope></dependency></dependencies><build><finalName>Servlet03</finalName><pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --><plugins><plugin><artifactId>maven-clean-plugin</artifactId><version>3.1.0</version></plugin><!-- see .html#Plugin_bindings_for_war_packaging --><plugin><artifactId>maven-resources-plugin</artifactId><version>3.0.2</version></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version></plugin><plugin><artifactId>maven-surefire-plugin</artifactId><version>2.22.1</version></plugin><plugin><artifactId>maven-war-plugin</artifactId><version>3.2.2</version></plugin><plugin><artifactId>maven-install-plugin</artifactId><version>2.5.2</version></plugin><plugin><artifactId>maven-deploy-plugin</artifactId><version>2.8.2</version></plugin></plugins></pluginManagement></build>
</project>

servlet

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
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.net.URLEncoder;public class FileServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.获取下载文件的路径String realPath = ("C:\\Code\\JavaWeb\\Servlet_03\\src\\main\\resources\\db");System.out.println("下载的文件路径为：" + realPath);
//        2.下载的文件名String Filename = realPath.substring(realPath.lastIndexOf("\\") + 1);
//        3.设置浏览器能够支持下载我们需要的东西resp.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(Filename, "utf-8"));
//        4.获取下载文件输入流FileInputStream fileInputStream = new FileInputStream(realPath);
//        5.创建缓冲区int length = 0;byte[] buffer = new byte[1024];
//        6.获取OutputStream流ServletOutputStream outputStream = resp.getOutputStream();
//        7.将获取的FileOutputStream流写入到缓冲区while ((length = fileInputStream.read(buffer)) > 0) {outputStream.write(buffer, 0, length);}fileInputStream.close();outputStream.close();
//        8.使用缓冲区的数据写到本地客户端}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}
}

配置xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns=""xmlns:xsi=""xsi:schemaLocation="://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"version="4.0"metadata-complete="true"><!--配置servlet --><servlet><servlet-name>file</servlet-name><servlet-class>com.dmsd.servlet.FileServlet</servlet-class></servlet><servlet-mapping><servlet-name>file</servlet-name><url-pattern>/down</url-pattern></servlet-mapping>
</web-app>

测试

发布启动tomcat后地址栏中走down请求即可下载。