JavaWeb_Web后端_请求响应
- 概述
- 请求
- 简单参数
- 原始方式
- SpringBoot方式
- RequestParam注解
- 实体参数
- 数组集合参数
- 日期参数
- JSON参数
- 路径参数
- 响应
- ResponseBody注解
- 统一响应结果
- Result.java
- ResponseController
- 案例
- 来源
概述
前端控制器DispatcherServlet:
- HttpServletRequest: 获取请求数据
- HttpServletResponse: 设置响应数据
BS架构: Browser/Server, 浏览器/服务器架构模式. 客户端只需要浏览器, 应用程序的逻辑和数据都存储在服务端.(维护方便, 体验一般)
CS架构: Client/Server, 客户端/服务器架构模式.(开发和维护麻烦, 体验不错)
请求
简单参数
原始方式
// 原始方式@RequestMapping("/simpleParam")public String simpleParam(HttpServletRequest request){ // 获取请求参数 String name = request.getParameter("name"); String ageStr = request.getParameter("age"); int age = Integer.parseInt(ageStr); System.out.println(name + ":" + age); return "OK";} SpringBoot方式
- 参数名与形参变量名相同, 定义形参即可接收参数
// SpringBoot方式@RequestMapping("/simpleParam")public String simpleParam(String name, Integer age){ System.out.println(name + ":" + age); return "OK";} - 参数名与形参变量名不相同
// SpringBoot方式-参数名与形参变量名不相同// 没有对应的参数为null@RequestMapping("/simpleParam")public String simpleParam(String username, Integer age){ System.out.println(username + ":" + age); return "OK";} RequestParam注解
- 方法形参名称与请求参数名称不匹配, 可以通过该注解完成映射
- 该注解的required属性默认为true, 表示请求参数必须传递
// RequestParam注解@RequestMapping("/simpleParam")public String simpleParam(@RequestParam(value = "name") String username, Integer age){ System.out.println(username + ":" + age); return "OK";} 实体参数
- 简单实体对象: 请求参数名与形参对象属性名相同, 定义POJO接收即可.
public class User { private String name; private Integer age;}@RequestMapping("/simplePojo")public String simplePojo(User user){ System.out.println(user); return "ok";} - 复杂实体对象: 请求参数名与形参对象属性名相同，按照对象层次结构关系即可接收嵌套POJO属性参数
public class Address { private String province; private String city;}public class User{ private String name; private Integer age; private Address address;}@RequestMapping("/complexPojo")public String complexPojo(User user){ // localhost:8080/complexPojo?name=Tom&age=10&address.province=beijing&address.city=beijing System.out.println(user); return "ok";} 数组集合参数
- 数组参数: 请求参数名与形参数组名称相同且请求参数为多个, 定义数组类型形参即可接收参数.
@RequestMapping("/arrayParam")public String complexPojo(String[] hobby){ // localhost:8080/arrayParam?hobby=sing&hobby=jump&hobby=rap System.out.println(Arrays.toString(hobby)); return "ok";} - 集合参数: 请求参数名与形参集合名称相同且请求参数为多个, @RequestParam绑定参数关系
@RequestMapping("/listParam")public String listParam(@RequestParam List hobby){ // localhost:8080/listParam?hobby=sing&hobby=jump&hobby=rap System.out.println(hobby); return "ok";} 日期参数
@RequestMapping("/dateParam")public String dateParam(@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") LocalDateTime updateTime){ // localhost:8080/dateParam?updateTime=2022-12-12 10:00:05 System.out.println(updateTime); return "ok";} JSON参数
JSON参数: JSON数据键名与形参对象属性名相同，定义POJO类型形参即可接收参数，需要使用@RequestBody标识.
@RequestMapping("/jsonParam")public String dateParam(@RequestBody User user){ System.out.println(user); return "ok";} 路径参数
路径参数: 通过请求URL直接传递参数，使用{…}来标识该路径参数，需要使用 @PathVariable 获取路径参数.
@RequestMapping("/path/{id}/{name}")public String pathParam(@PathVariable Integer id, @PathVariable String name){ // localhost:8080/path/10/Tom System.out.println(id+":"+name); return "OK";} 响应
ResponseBody注解
- 类型: 方法注解, 类注解
- 位置: Controller方法上/类上
- 作用: 将方法返回值直接响应, 如果返回值类型是实体对象/集合, 将会转换成JSON格式响应
- 说明: @RestController = @Controller + @ResponseBody
@RestControllerpublic class ResponseController { @RequestMapping("/hello") public String hello() { System.out.println("Hello World!"); return "Hello World!"; } @RequestMapping("/getAddr") public Address getAddr() { Address addr = new Address(); addr.setProvince("广东"); addr.setCity("深圳"); return addr; } @RequestMapping("/listAddr") public List listAddr() { List list = new ArrayList<>(); Address addr = new Address(); addr.setProvince("广东"); addr.setCity("深圳"); Address addr2 = new Address(); addr2.setProvince("广东"); addr2.setCity("广州"); list.add(addr); list.add(addr2); return list; }} 统一响应结果
Result.java
public class Result { private Integer code ;//1 成功 , 0 失败 private String msg; //提示信息 private Object data; //数据 data public Result() { } public Result(Integer code, String msg, Object data) { this.code = code; this.msg = msg; this.data = data; } public Integer getCode() { return code; } public void setCode(Integer code) { this.code = code; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } public Object getData() { return data; } public void setData(Object data) { this.data = data; } public static Result success(Object data){ return new Result(1, "success", data); } public static Result success(){ return new Result(1, "success", null); } public static Result error(String msg){ return new Result(0, msg, null); } @Override public String toString() { return "Result{" + "code=" + code + ", msg='" + msg + ''' + ", data=" + data + '}'; }} ResponseController
@RestControllerpublic class ResponseController { @RequestMapping("/hello") public Result hello() { System.out.println("Hello World!"); //return new Result(1, "success", "Hello World!"); return Result.success("Hello World!"); } @RequestMapping("/getAddr") public Result getAddr() { Address addr = new Address(); addr.setProvince("广东"); addr.setCity("深圳"); return Result.success(addr); } @RequestMapping("/listAddr") public Result listAddr() { List list = new ArrayList<>(); Address addr = new Address(); addr.setProvince("广东"); addr.setCity("深圳"); Address addr2 = new Address(); addr2.setProvince("广东"); addr2.setCity("广州"); list.add(addr); list.add(addr2); return Result.success(list); }} 案例
- 在pom.xml文件中引入dom4j的依赖, 用于解析xml文件
org.dom4j dom4j 2.1.3
- 引入资料中提供的解析XML的工具类XMLParserUtils, 对应的实体类Emp, XML文件emp.xml.
XMLParserUtils.java:
public class XmlParserUtils { public static List parse(String file , Class targetClass) { ArrayList list = new ArrayList(); //封装解析出来的数据 try { //1.获取一个解析器对象 SAXReader saxReader = new SAXReader(); //2.利用解析器把xml文件加载到内存中,并返回一个文档对象 Document document = saxReader.read(new File(file)); //3.获取到根标签 Element rootElement = document.getRootElement(); //4.通过根标签来获取 user 标签 List elements = rootElement.elements("emp"); //5.遍历集合,得到每一个 user 标签 for (Element element : elements) { //获取 name 属性 String name = element.element("name").getText(); //获取 age 属性 String age = element.element("age").getText(); //获取 image 属性 String image = element.element("image").getText(); //获取 gender 属性 String gender = element.element("gender").getText(); //获取 job 属性 String job = element.element("job").getText(); //组装数据 Constructor constructor = targetClass.getDeclaredConstructor(String.class, Integer.class, String.class, String.class, String.class); constructor.setAccessible(true); T object = constructor.newInstance(name, Integer.parseInt(age), image, gender, job); list.add(object); } } catch (Exception e) { e.printStackTrace(); } return list; }} Emp.java:
public class Emp { private String name; private Integer age; private String image; private String gender; private String job; public Emp() { } public Emp(String name, Integer age, String image, String gender, String job) { this.name = name; this.age = age; this.image = image; this.gender = gender; this.job = job; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getImage() { return image; } public void setImage(String image) { this.image = image; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public String getJob() { return job; } public void setJob(String job) { this.job = job; } @Override public String toString() { return "Emp{" + "name='" + name + ''' + ", age=" + age + ", image='" + image + ''' + ", gender='" + gender + ''' + ", job='" + job + ''' + '}'; }} emp.xml:
金毛狮王 55 http://www.quxuehao.com/file/tupian/20230516/1.jpg 1 1 白眉鹰王 65 http://www.quxuehao.com/file/tupian/20230516/2.jpg 1 1 青翼蝠王 45 http://www.quxuehao.com/file/tupian/20230516/3.jpg 1 2 紫衫龙王 38 http://www.quxuehao.com/file/tupian/20230516/4.jpg 2 3
- 引入资料中提供的静态页面文件, 放在resources下的static目录下
员工信息 员工信息列表展示
- 编写Controller程序, 处理请求, 响应数据.
@RestControllerpublic class EmpController { @RequestMapping("/listEmp") public Result list() { // 1. 加载emp.xml并解析emp.xml中的数据 String file = this.getClass().getClassLoader().getResource("emp.xml").getFile(); List emplist = XmlParserUtils.parse(file, Emp.class); // 2. 对员工信息中的gender, job字段进行处理 emplist.stream().forEach(emp -> { String gender = emp.getGender(); if("1".equals(gender)){ emp.setGender("男"); }else if("2".equals(gender)){ emp.setGender("女"); } String job = emp.getJob(); if("1".equals(job)){ emp.setJob("讲师"); }else if("2".equals(job)){ emp.setJob("班主任"); }else if("3".equals(job)){ emp.setJob("就业指导"); } }); // 3.组作数据并返回 return Result.success(emplist); }} 来源
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