1. httpservletrequest与httpservletresponse
浏览器输入：http://localhost:8080/community/alpha/http?code=10
@RequestMapping("/http")
public void http(HttpServletRequest request, HttpServletResponse response) {
// 获取请求数据
System.out.println(request.getMethod());
System.out.println(request.getServletPath());
Enumeration<String> enumeration = request.getHeaderNames();
while (enumeration.hasMoreElements()) {
String name = enumeration.nextElement();
String value = request.getHeader(name);
System.out.println(name + ": " + value);
}
System.out.println(request.getParameter("code"));
// 返回响应数据
response.setContentType("text/html;charset=utf-8");
try {
PrintWriter writer = response.getWriter();
writer.write("<h2>nowcoder</h2>");
} catch (IOException e) {
e.printStackTrace();
}
}前端页面显示：nowcoder
同时，IDEA控制台输出：
GET
/alpha/http
host: localhost:8080
connection: keep-alive
sec-ch-ua: " Not;A Brand";v="99", "Google Chrome";v="97", "Chromium";v="97"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
upgrade-insecure-requests: 1
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36
accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
sec-fetch-site: none
sec-fetch-mode: navigate
sec-fetch-user: ?1
sec-fetch-dest: document
accept-encoding: gzip, deflate, br
accept-language: zh-CN,zh;q=0.9
cookie: Idea-10659edd=72fa12c3-9b68-4da6-8b68-38a81c822aa0
10
2. GET类型的请求
在AlphaController中增加方法，处理GET类型的请求。
2.1 /students?current=1&limit=20
浏览器输入：http://localhost:8080/community/alpha/students?current=1&limit=100
@GetMapping("/students")
@ResponseBody
public String getStudents(
@RequestParam(name = "current" ,required = false, defaultValue = "1") int current,
@RequestParam(name = "limit" ,required = false, defaultValue = "10") int limit) {
System.out.println(current);
System.out.println(limit);
return "some students";
}前端页面显示：some students
同时，IDEA控制台输出：
1
100
2.2 /student/123
浏览器输入：http://localhost:8080/community/alpha/student/123
@GetMapping("/student/{id}")
@ResponseBody
public String getStudent(@PathVariable("id") int id) {
System.out.println(id);
return "one student";
}前端页面显示：one students
同时，IDEA控制台输出：
123
3. POST类型的请求
在AlphaController中增加方法，处理POST类型的请求。
浏览器输入：http://localhost:8080/community/html/student.html
@PostMapping("/student")
@ResponseBody
public String saveStudent(String name, int age) {
System.out.println(name);
System.out.println(age);
return "success";
}resources/static/html/student.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>增加学生</title>
</head>
<body>
<form method="post" action="/community/alpha/student">
<p>
姓名：<input type="text" name="name">
</p>
<p>
年龄：<input type="text" name="age">
</p>
<p>
<input type="submit" value="保存">
</p>
</form>
</body>
</html>前端页面显示一个表单，包含两行：姓名、年龄，还有一个 “保存” 按钮。
输入 “Lebron”、38 后，点击 “保存” 后，显示 “success”。
4. 响应HTML格式的数据
在AlphaController中增加方法，向浏览器响应HTML格式的数据。
4.1 使用ModelAndView
浏览器输入：http://localhost:8080/community/alpha/teacher
@GetMapping("/teacher")
public ModelAndView getTeacher() {
ModelAndView mav = new ModelAndView();
mav.addObject("name", "Lebron");
mav.addObject("age", 38);
mav.setViewName("/demo/view");
return mav;
}前端页面显示：
Lebron
38
4.2 使用Model
浏览器输入：http://localhost:8080/community/alpha/school
@GetMapping("/school")
public String getSchool(Model model) {
model.addAttribute("name", "xx大学");
model.addAttribute("age", 100);
return "/demo/view";
}resources/templates/demo/view.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Teacher</title>
</head>
<body>
<p th:text="${name}"></p>
<p th:text="${age}"></p>
</body>
</html>前端页面显示：
xx大学
100
5. 响应JSON格式的数据
在AlphaController中增加方法，向浏览器响应JSON格式的数据。
5.1 单组数据
浏览器输入：http://localhost:8080/community/alpha/emp
@GetMapping("/emp")
@ResponseBody
public Map<String, Object> getEmp() {
Map<String, Object> emp = new HashMap<>();
emp.put("name", "Kitty");
emp.put("age", 20);
emp.put("salary", 12000.00);
return emp;
}前端页面显示：
{"name":"Kitty","salary":12000.0,"age":20}
5.2 多组数据
浏览器输入：http://localhost:8080/community/alpha/emps
@GetMapping("/emps")
@ResponseBody
public List<Map<String, Object>> getEmps() {
List<Map<String, Object>> list = new ArrayList<>();
Map<String, Object> emp = new HashMap<>();
emp.put("name", "Tom");
emp.put("age", 20);
emp.put("salary", 12000.00);
list.add(emp);
emp = new HashMap<>();
emp.put("name", "Jerry");
emp.put("age", 18);
emp.put("salary", 15000.00);
list.add(emp);
emp = new HashMap<>();
emp.put("name", "Leo");
emp.put("age", 25);
emp.put("salary", 8000.00);
list.add(emp);
return list;
}前端页面显示：
[{"name":"Tom","salary":12000.0,"age":20},{"name":"Jerry","salary":15000.0,"age":18},{"name":"Leo","salary":8000.0,"age":25}]
