1. Basic usage
- effect: Extract query parameters or form data from the request.
- grammar：
@RequestParam("Parameter name") Data Type Parameter name- Example：
@GetMapping("/greet")
public String greet(@RequestParam("name") String name) {
return "Hello, " + name + "!";
}- ask:
/greet?name=John - response:
Hello, John!
2. Default value
- effect: When the parameter does not exist, use the default value.
- grammar：
@RequestParam(value = "Parameter name", defaultValue = "default value") Data Type Parameter name
- Example：
@GetMapping("/greet")
public String greet(@RequestParam(value = "name", defaultValue = "Guest") String name) {
return "Hello, " + name + "!";
}- ask:
/greet - response:
Hello, Guest!
3. Optional parameters
- effect: The allowed parameters do not exist.
- grammar：
@RequestParam(value = "Parameter name", required = false) Data Type Parameter name
- Example：
@GetMapping("/greet")
public String greet(@RequestParam(value = "name", required = false) String name) {
return "Hello, " + (name != null ? name : "Guest") + "!";
}- ask:
/greet - response:
Hello, Guest!
4. Bind to an object
- effect: Bind multiple parameters into one object.
- Example：
public class User {
private int id;
private String name;
// Getter and Setter methods}
@GetMapping("/user")
public String getUser(User user) {
return "User ID: " + () + ", Name: " + ();
}- ask:
/user?id=1&name=John - response:
User ID: 1, Name: John
5. Bind to a collection or array
- effect: Bind multiple parameters of the same name into a collection or array.
- Example：
@GetMapping("/hobbies")
public String getHobbies(@RequestParam("hobby") List<String> hobbies) {
return "Hobbies: " + (", ", hobbies);
}- ask:
/hobbies?hobby=Reading&hobby=Traveling - response:
Hobbies: Reading, Traveling
6. Bind to Map
-
effect: Bind dynamic parameters to
Mapmiddle. - Example：
@GetMapping("/params")
public String getParams(@RequestParam Map<String, String> params) {
return "Params: " + ();
}- ask:
/params?name=John&age=25 - response:
Params: {name=John, age=25}
7. Handle complex types
- effect: Supports conversion of complex types such as dates and enumerations.
- Example：
@GetMapping("/date")
public String getDate(@RequestParam("date") @DateTimeFormat(pattern = "yyyy-MM-dd") LocalDate date) {
return "Date: " + ();
}- ask:
/date?date=2023-10-01 - response:
Date: 2023-10-01
Summary
The above is personal experience. I hope you can give you a reference and I hope you can support me more.