Day21-SSM项目整合

SSM整合项目

新建数据库

CREATE DATABASE ssmbuild;

USE `ssmbuild`

DROP TABLE IF EXISTS `books`;

CREATE TABLE `books`(
`bookID` INT (10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR (100) NOT NULL COMMENT '书名',
`bookCounts` INT (11) NOT NULL COMMENT '数量',
`detail` VARCHAR (200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
)ENGINE=INNODB DEFAULT CHARSET=utf8

INSERT INTO `books`(`bookID`, `bookName`, `bookCounts`,`detail`) VALUES
(1,'Java',1,'从入门到放弃'),
(2, 'MySQL',10,'MySQL从删库到跑路'),
(3,'Linux',5,'从进门到进牢');

新建maven项目

导包(junit、数据库驱动、连接池【c3p0】、servlet、jsp、mybatis、mybatis-spring、spring、json)

 <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2.1-b03</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.13</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.15.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.20</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.15.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>2.0.32</version>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

连接数据库

把各层包和xml文件建好

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
    
    <typeAliases>
        <package name="com.lsq.pojo"/>
    </typeAliases>

    <mappers>
        <mapper class="com.lsq.dao.BookMapper"/>
    </mappers>
</configuration>

创建数据库配置文件(注意：数据库是8.0以后的版本，配置url时需要加一个时区配置)

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/ssmbulid?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8&useSSL=false
username=root
password=12345678

创建spring-dao.xml，整合dao层

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <!--1.关连数据库配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>
    <!--2.连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}"/>
        <property name="jdbcUrl" value="${jdbc.url}"/>
        <property name="user" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>

        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <property name="autoCommitOnClose" value="false"/>
        <property name="checkoutTimeout" value="10000"/>
        <property name="acquireRetryAttempts" value="2"/>
     </bean>
    <!--3.sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <!--4.配置dao接口扫描包，动态的实现了Dao接口可以注入到Spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="basePackage" value="com.lsq.dao"/>
    </bean>
</beans>

创建spring-service.xml,整合service层

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd 
        http://www.springframework.org/schema/aop 
        https://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/cache/spring-tx.xsd">

    <!--1.扫描service下的包-->
    <context:component-scan base-package="com.lsq.service"/>

    <!--2.将我们的所有业务类，注入到Spring，可以通过配置，或者注解实现-->
    <bean id="bookServiceImpl" class="com.lsq.service.BookServiceImpl">
        <property name="bookMapper" ref="bookMapper"/>
    </bean>
    <!--3.声明式事务配置-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="add" propagation="REQUIRED"/>
            <tx:method name="delete" propagation="REQUIRED"/>
            <tx:method name="update" propagation="REQUIRED"/>
            <tx:method name="select" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>
    
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* com.lsq.dao.*(..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut"/>
    </aop:config>
</beans>

配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!--DispatchServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    
    <!--乱码过滤-->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>
</web-app>

创建spring-mvc.xml,整合controller层

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <!--1.注解驱动-->
    <mvc:annotation-driven/>
    <!--2.静态资源过滤-->
    <mvc:default-servlet-handler/>
    <!--3.扫描包：controller-->
    <context:component-scan base-package="com.lsq.controller"/>
    <!--4.视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

配置applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <import resource="spring-dao.xml"/>
    <import resource="spring-serivce.xml"/>
    <import resource="spring-mvc.xml"/>

</beans>

dao-service-controller层开发

AJax

编写一个cotroller

package com.lsq.controller;

import com.lsq.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.jws.WebParam;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/login")
    public String loginController(String name, String pwd) {
        String msg = "";
        if (name != null) {
            if ("admin".equals(name)) {
                msg = "ok";
            } else {
                msg = "用户名错误";
            }
        }

        if (pwd != null) {
            if ("12345678".equals(pwd)) {
                msg = "ok";
            } else {
                msg = "密码错误";
            }
        }
        return msg;
    }
}

编写前端页面

<%--
  Created by IntelliJ IDEA.
  User: liushaoqin
  Date: 2023/8/6
  Time: 19:06
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
    <script src="${pageContext.request.contextPath}/statics/js/jquery-3.5.1.js"></script>
    <script>
        function a1(){
            $.post({
                url:"${pageContext.request.contextPath}/user/login",
                data:{'name':$("#username").val()},
                success:function (data){
                    if (data.toString()=='ok'){
                        $("#userInfo").css("color","green");
                    }else {
                        $("#userInfo").css("color","red");
                    }
                    $("#userInfo").html(data);
                }
            });
        }
        function a2(){
          $.post({
            url:"${pageContext.request.contextPath}/user/login",
            data:{'pwd':$("#password").val()},
            success:function (data){
              if (data.toString()=='ok'){
                $("#pwdInfo").css("color","green");
              }else {
                $("#pwdInfo").css("color","red");
              }
              $("#pwdInfo").html(data);
            }
          });
        }
    </script>
  </head>
  <body>
  <p>
    用户名：<input type="text" id="username" onblur="a1()"/>
    <span id="userInfo"></span>
  </p>
  <p>
    密码：<input type="password" id="password" onblur="a2()"/>
    <span id="pwdInfo"></span>
  </p>
  </body>
</html>

编写ajax函数

 function a1(){
            $.post({
                url:"${pageContext.request.contextPath}/user/login",
                data:{'name':$("#username").val()},
                success:function (data){
                    if (data.toString()=='ok'){
                        $("#userInfo").css("color","green");
                    }else {
                        $("#userInfo").css("color","red");
                    }
                    $("#userInfo").html(data);
                }
            });
        }
        function a2(){
          $.post({
            url:"${pageContext.request.contextPath}/user/login",
            data:{'pwd':$("#password").val()},
            success:function (data){
              if (data.toString()=='ok'){
                $("#pwdInfo").css("color","green");
              }else {
                $("#pwdInfo").css("color","red");
              }
              $("#pwdInfo").html(data);
            }
          });
        }

导入jquery ，可以使用在线的CDN ，也可以下载导入

<script src="${pageContext.request.contextPath}/statics/js/jquery-3.5.1.js"></script>

拦截器

SpringMVC的处理器拦截器类似于Servlet开发中的过滤器Filter,用于对处理器进行预处理和后处理。开发者可以自己定义一些拦截器来实现特定的功能。

拦截器是AOP思想的具体应用

拦截器配置

<!--拦截器配置-->
    <!--关于拦截器的配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--/** 包括路径及其子路径-->
            <!--/admin/* 拦截的是/admin/add等等这种 , /admin/add/user不会被拦截-->
            <!--/admin/** 拦截的是/admin/下的所有-->
            <mvc:mapping path="/**"/>
            <!--bean配置的就是拦截器-->
            <bean class="com.lsq.config.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

继承拦截器，编写MyInterceptor类

package com.lsq.config;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor{
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("============执行前==========");
        return HandlerInterceptor.super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("============执行后==========");
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("============清理==========");
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

编写controller类

package com.lsq.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class InterceptorController {
    @RequestMapping("/t1")
    public String test(){
        System.out.println("InterceptorController-->执行了");
        return "OK";
    }
}

执行结果

用户判断验证

拦截器

package com.lsq.config;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        if (request.getRequestURI().contains("Login")){
            return true;
        }
        if (request.getRequestURI().contains("login")){
            return true;
        }
        if (session.getAttribute("userInfo")!=null){
            return true;
        }
        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
        return HandlerInterceptor.super.preHandle(request, response, handler);
    }
}

cotroller

package com.lsq.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;

@Controller
public class InterceptorController {

    @RequestMapping("/main")
    public String main(){
        return "main";
    }

    @RequestMapping("/goLogin")
    public String goLogin(){
        return "login";
    }

    @RequestMapping("/login")
    public String login(HttpSession session,String username, String password,Model model){
        session.setAttribute("userInfo",username);
        model.addAttribute("username",username);
        return "main";
    }

    @RequestMapping("/loginOut")
    public String loginOut(HttpSession session){
        session.removeAttribute("userInfo");
        return "redirect:index.jsp";
    }
}

首页

<%--
  Created by IntelliJ IDEA.
  User: liushaoqin
  Date: 2023/8/7
  Time: 00:20
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>未登陆用户拦截</title>
</head>
<body>
<h1>
  <a href="${pageContext.request.contextPath}/main">首页</a>
</h1>
<h1>
  <a href="${pageContext.request.contextPath}/goLogin">登陆</a>
</h1>
</body>
</html>

登陆页

<%--
  Created by IntelliJ IDEA.
  User: liushaoqin
  Date: 2023/8/6
  Time: 21:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登陆页面</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/login" method="post">
    用户名：<input type="text" name="username"/>
    密码：<input type="password" name="password"/>
    <input type="submit" value="提交">
</form>
</body>
</html>

主页

<%--
  Created by IntelliJ IDEA.
  User: liushaoqin
  Date: 2023/8/6
  Time: 21:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>首页</title>
</head>
<body>
<p>
    <h1>首页</h1>
    <span>${sessionScope.userInfo}</span>
</p>
<p>
    <a href="${pageContext.request.contextPath}/loginOut" >注销</a>
</p>
</body>
</html>

文件上传和下载

文件上传

前端表单要求：为了能上传文件，必须将表单的method设置为POST，并将enctype设置为multipart/form-data。只有在这样的情况下，浏览器才会把用户选择的文件以二进制数据发送给服务器；
```
<form action="" enctype="multipart/form-data" method="post">
    <input type="file" name="file"/>
    <input type="submit">
</form>
```

导入依赖包

<!--文件上传-->
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.3</version>
</dependency>
<!--servlet-api导入高版本的-->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
</dependency>

配置bean：multipartResolver,bena的id必须为：multipartResolver ，否则上传文件会报400的错误

<!--文件上传配置-->
<bean id="multipartResolver"  class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
    <property name="defaultEncoding" value="utf-8"/>
    <!-- 上传文件大小上限，单位为字节（10485760=10M） -->
    <property name="maxUploadSize" value="10485760"/>
    <property name="maxInMemorySize" value="40960"/>
</bean>

前端页面

<form action="/upload" enctype="multipart/form-data" method="post">
  <input type="file" name="file"/>
  <input type="submit" value="upload">
</form>

编写cotroller文件

package com.lsq.controller;
 
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
 
import javax.servlet.http.HttpServletRequest;
import java.io.*;
 
@Controller
public class FileController {
    //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象
    //批量上传CommonsMultipartFile则为数组即可
    @RequestMapping("/upload")
    public String fileUpload(@RequestParam("file") CommonsMultipartFile file , HttpServletRequest request) throws IOException {
 
        //获取文件名 : file.getOriginalFilename();
        String uploadFileName = file.getOriginalFilename();
 
        //如果文件名为空，直接回到首页！
        if ("".equals(uploadFileName)){
            return "redirect:/index.jsp";
        }
        System.out.println("上传文件名 : "+uploadFileName);
 
        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        //如果路径不存在，创建一个
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        System.out.println("上传文件保存地址："+realPath);
 
        InputStream is = file.getInputStream(); //文件输入流
        OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流
 
        //读取写出
        int len=0;
        byte[] buffer = new byte[1024];
        while ((len=is.read(buffer))!=-1){
            os.write(buffer,0,len);
            os.flush();
        }
        os.close();
        is.close();
        return "redirect:/index.jsp";
    }
}

采用file.Transto 来保存上传的文件

/*
 * 采用file.Transto 来保存上传的文件
 */
@RequestMapping("/upload2")
public String  fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
 
    //上传路径保存设置
    String path = request.getServletContext().getRealPath("/upload");
    File realPath = new File(path);
    if (!realPath.exists()){
        realPath.mkdir();
    }
    //上传文件地址
    System.out.println("上传文件保存地址："+realPath);
 
    //通过CommonsMultipartFile的方法直接写文件（注意这个时候）
    file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
 
    return "redirect:/index.jsp";
}

文件下载

设置 response 响应头
读取文件 -- InputStream
写出文件 -- OutputStream
执行操作
关闭流（先开后关）

@RequestMapping(value="/download")
public String downloads(HttpServletResponse response ,HttpServletRequest request) throws Exception{
    //要下载的图片地址
    String  path = request.getServletContext().getRealPath("/upload");
    String  fileName = "基础语法.jpg";
 
    //1、设置response 响应头
    response.reset(); //设置页面不缓存,清空buffer
    response.setCharacterEncoding("UTF-8"); //字符编码
    response.setContentType("multipart/form-data"); //二进制传输数据
    //设置响应头
    response.setHeader("Content-Disposition",
            "attachment;fileName="+URLEncoder.encode(fileName, "UTF-8"));
 
    File file = new File(path,fileName);
    //2、 读取文件--输入流
    InputStream input=new FileInputStream(file);
    //3、 写出文件--输出流
    OutputStream out = response.getOutputStream();
 
    byte[] buff =new byte[1024];
    int index=0;
    //4、执行 写出操作
    while((index= input.read(buff))!= -1){
        out.write(buff, 0, index);
        out.flush();
    }
    out.close();
    input.close();
    return null;
}

前端jsp页面

<a href="/download">点击下载</a>

posted @ 2023-08-07 01:33 仓鼠的气垫床阅读(12) 评论(0) 编辑收藏举报

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