文章目录
- 1.中文乱码处理
- 1.引出问题
- 1.恢复原来取消掉的属性绑定
- 2.启动服务器,引出问题
- 2.自定义中文乱码过滤器
- 1.MyCharacterFilter.java
- 2.web.xml配置过滤器(这个解决乱码的过滤器放到最前面)
- 3.结果展示
- 3.使用Spring过滤器处理(方便)
- web.xml
- 2.处理json和HttpMessageConverter
- 导入jar包
- 1.处理json—@ReponseBody
- 1.需求分析
- 2.具体实现
- 1.JsonHandler.java后端接口
- 2.Dog.java
- 3.json.jsp发送ajax请求
- 4.结果展示
- 2.处理json—@ResquestBody
- 1.需求分析
- 2.具体实现
- 1.User.java
- 2.JsonHandler.java(这里故意没有使用@resquestBody注解)
- 3.json2.jsp前端界面
- 4.结果展示
- 5.添加注解解决数据为空
- 6.postman测试
- 3.处理json注意事项和细节
- 1.处理json对象数组
- 1.JsonHandler.java
- 2.postman测试
- 2.将@ReponseBody直接放在类中,可以使所有的方法都生效
- 3.@ReponseBody和@Controller可以合并成一个@RestController
- 4.当使用这个@ReponseBody注解的时候会将结果转换成json字符串直接返回到发送请求的位置
- 4.HttpMessageConverter<T>
- 1.流程图
- 2.底层实现
- 3.文件下载
- 1.需求分析
- 2.具体实现
- 1.后端接口
- 2.结果展示
- 4.文件上传
- 1.基本介绍
- 2.导入jar包
- 3.具体实现
- 1.配置文件上传解析器
- 2.编写fileUpload.jsp
- 3.FileUploadHandler.java
- 4.postman测试
1.中文乱码处理
1.引出问题
1.恢复原来取消掉的属性绑定
2.启动服务器,引出问题
2.自定义中文乱码过滤器
1.MyCharacterFilter.java
package com.sun.web.filter;import javax.servlet.*;
import java.io.IOException;/*** @author 孙显圣* @version 1.0*/
public class MyCharacterFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {//在这里解决中文乱码问题servletRequest.setCharacterEncoding("utf-8");//放行filterChain.doFilter(servletRequest, servletResponse);}@Overridepublic void destroy() {}
}
2.web.xml配置过滤器(这个解决乱码的过滤器放到最前面)
<!--配置过滤器——放到最前面,因为这个应该是最先处理的--><filter><filter-name>MyCharacterFilter</filter-name><filter-class>com.sun.web.filter.MyCharacterFilter</filter-class></filter><!--过滤所有请求--><filter-mapping><filter-name>MyCharacterFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>
3.结果展示
3.使用Spring过滤器处理(方便)
web.xml
<!--配置Spring自带的过滤器,解决乱码问题--><filter><filter-name>CharacterEncodingFilter</filter-name><filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class><!--这里指定字符编码--><init-param><param-name>encoding</param-name><param-value>utf-8</param-value></init-param></filter><filter-mapping><filter-name>CharacterEncodingFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>
2.处理json和HttpMessageConverter
导入jar包
1.处理json—@ReponseBody
1.需求分析
- 后端发送一个javabean对象给前端,可以使用注解自动将其转换成json字符串
2.具体实现
1.JsonHandler.java后端接口
package com.sun.web.json;import com.sun.web.json.entity.Dog;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;/*** @author 孙显圣* @version 1.0*/
//作为Controller注入容器
@Controller
public class JsonHandler {@RequestMapping("/json/dog")@ResponseBody //将结果转换成json类型返回public Dog getJson() {Dog dog = new Dog("小狗", "北京四合院");return dog;}
}
2.Dog.java
package com.sun.web.json.entity;/*** @author 孙显圣* @version 1.0*/
public class Dog {private String name;private String address;public Dog() {}public Dog(String name, String address) {this.name = name;this.address = address;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}@Overridepublic String toString() {return "Dog{" +"name='" + name + '\'' +", address='" + address + '\'' +'}';}
}
3.json.jsp发送ajax请求
<%--Date: 2024/2/29Time: 13:23User: 孙显圣Version:1.0
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Title</title><script src="script/jquery-3.6.0.min.js"></script><script>$(function () {//绑定点击事件$("#getJson").click(function (){let url = this.href;let args = {"time": new Date}; //发送一个时间,防止页面缓存//发送ajax请求$.post(url,args,function (data) {console.log("dog.name=", data.name);console.log("dog.address=", data.address);},"json")//阻止超链接提交return false;})})</script>
</head>
<body>
<a href="json/dog" id="getJson">点击获取json数据</a>
</body>
</html>
4.结果展示
2.处理json—@ResquestBody
1.需求分析
- 前端向目标方法发送一个json字符串,后端使用注解将其自动转换为javabean对象,然后再以json字符串的形式发送回去
2.具体实现
1.User.java
package com.sun.web.json.entity;/*** @author 孙显圣* @version 1.0*/
public class User {private String userName;private String age;public User() {}public User(String userName, String age) {this.userName = userName;this.age = age;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getAge() {return age;}public void setAge(String age) {this.age = age;}@Overridepublic String toString() {return "User{" +"userName='" + userName + '\'' +", age='" + age + '\'' +'}';}
}
2.JsonHandler.java(这里故意没有使用@resquestBody注解)
@RequestMapping("/json/user")@ResponseBody //将结果转换成json类型返回public User getJson2(User user) {System.out.println(user);return user;}
3.json2.jsp前端界面
<%--Date: 2024/2/29Time: 14:13User: 孙显圣Version:1.0
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Title</title><script src="script/jquery-3.6.0.min.js"></script><script>$(function () {//绑定添加用户按钮$("button[name='butt1']").click(function () {//得到用户输入信息var userName = $("#userName").val();var age = $("#age").val();//封装成json对象var jsonObject = {"userName": userName, "age": age};//转换成json字符串var jsonString = JSON.stringify(jsonObject);//编写urlvar url = "/springmvc/json/user";//编写contentType,来告诉后端发送数据类型是jsonvar contentType = "application/json;charset=utf-8";//发送ajax请求$.ajax({url: url,data: jsonString,type: "post",success: function (data) {console.log("返回的数据是=", data);},contentType: contentType,dataType: "json"})})})</script>
</head>
<body>
u:<input type="text" id="userName"><br>
a:<input type="text" id="age"><br>
<button name="butt1">添加用户</button>
</body>
</html>
4.结果展示
数据为空
5.添加注解解决数据为空
6.postman测试
3.处理json注意事项和细节
1.处理json对象数组
1.JsonHandler.java
//编写方法,以json格式返回多个dog@RequestMapping("/json/dogs")@ResponseBody //将结果转换成json类型返回public List<Dog> getJson3(@RequestBody List<Dog> dogs) { //接受请求的json对象数组字符串,并自动封装到dogs中for (Dog dog : dogs) {System.out.println(dog);}return dogs;}
2.postman测试
2.将@ReponseBody直接放在类中,可以使所有的方法都生效
3.@ReponseBody和@Controller可以合并成一个@RestController
4.当使用这个@ReponseBody注解的时候会将结果转换成json字符串直接返回到发送请求的位置
4.HttpMessageConverter
1.流程图
2.底层实现
3.文件下载
1.需求分析
2.具体实现
1.后端接口
//编写方法,响应用户下载文件的需求@RequestMapping("/downFile")public ResponseEntity<byte[]> downFile(HttpSession session) throws Exception {//构建这个对象并返回//public ResponseEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers, HttpStatus status)//@Nullable T body//1.获取要下载的本地文件的流InputStream resourceAsStream = session.getServletContext().getResourceAsStream("/img/7.png");//2.创建一个byte数组来接收byte[] bytes = new byte[resourceAsStream.available()];//3.使用输入流读取信息到数组中resourceAsStream.read(bytes);//HttpStatus status//4.获取一个状态码HttpStatus ok = HttpStatus.OK;//@Nullable MultiValueMap<String, String> headers//5.构建一个响应头HttpHeaders httpHeaders = new HttpHeaders();//attachment表示以附件的形式,filename是指下载后的httpHeaders.add("Content-Disposition", "attachment;filename=2.jpg");//构建这个ResponseEntity<byte[]>ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, httpHeaders, ok);return responseEntity;}
2.结果展示
4.文件上传
1.基本介绍
2.导入jar包
3.具体实现
1.配置文件上传解析器
<!--配置文件上传解析器,注意这里的id必须是接口首字母小写--><bean class="org.springframework.web.multipart.commons.CommonsMultipartResolver" id="multipartResolver"></bean>
2.编写fileUpload.jsp
<%--Date: 2024/2/29Time: 16:59User: 孙显圣Version:1.0
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Title</title>
</head>
<body>
<form action="upload" method="post" enctype="multipart/form-data">文件介绍:<input type="text" name="introduce"><br>选择文件:<input type="file" name="file"><br><input type="submit" value="上传文件">
</form></body>
</html>
3.FileUploadHandler.java
package com.sun.web.fileupload;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;/*** @author 孙显圣* @version 1.0*/
@Controller
public class FileUploadHandler {@RequestMapping("/upload")public String fileUpload(MultipartFile file, HttpServletRequest request, String introduce) throws IOException {System.out.println("文件的描述为:" + introduce);//接受要提交的文件名String originalFilename = file.getOriginalFilename();System.out.println("文件名:" + originalFilename);//找到要上传的文件路径String realPath = request.getServletContext().getRealPath("/img/");String toSavePath = realPath + originalFilename;File file1 = new File(toSavePath);//将文件转存//创建一个文件对象file.transferTo(file1);return "success";}
}