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数据交互
在项⽬中，经常会遇到这样的场景，前端⻚⾯中发送ajax请求给Controller中的处理⽅法，处理⽅法返回 json格式的字符串给这个ajax请求。
当然，前⾯⻚⾯发送的请求中携带的参数，也可以是正常的k=v的形式
接收参数
1、参数是基本数据类型/包装类型/String
@RequestMapping("test") public String test(int age){...}
public String test(long id){...}
public String test(boolean flag){...}
public String test(Long id){...}
public String test(String name){...}
注意，参数名字要和客户端传的参数名⼀致,否则需要使⽤
@RequestParam 来指定参数名
2.参数是数组类型
@RequestMapping("test") public String test(int[] age){...}
public String test(long[] id){...}
public String test(boolean[] flag){...}
public String test(Long[] id){...}
public String test(String[] name){...}
注意，客户端传值类似于这样：name=tom&name=lisi
3、参数是数组类型（json格式）
@RequestMapping("/index")
@ResponseBody
public String index(@RequestBody String[] arr){...}
4、参数是类类型
例如，实体类Uesr、Student等
@RequestMapping("test")
public String test(User user){...}
注意，客户端传值类似于这样：
id=1&name=tom&dob=1999-11-11
5、参数是类类型的数组（json格式）
@RequestMapping("/test")
public String test(@RequestBody User[] users){...}
6、参数是List/Set集合（json格式）
@RequestMapping("/index")
@ResponseBody
public String index(@RequestBody List<String> list){...}
例如：
@RequestMapping("/index")
@ResponseBody
public String index(@RequestBody List<User> list){....}
7、参数是Map集合（json格式）
@RequestMapping("/index")
@ResponseBody
public String index(@RequestBody Map<Long,User> map){...}
8 采⽤restful⻛格进⾏请求：
@RestController
public class UserController {
@GetMapping("/hello/{userid}")
public String hello(@PathVariable("userid") String userid) {
System.out.println(userid);
return userid;
}
}
返回数据
1、给ajax请求返回单值
@ResponseBody
@RequestMapping(value="test1",consumes="application/json",produces="applic
ation/js
on" ,method=RequestMethod.POST)
public String test1(@RequestBody User user){
System.out.println("user = "+user);
return "hello world";
}
2、给ajax请求返回数组（json格式）
@ResponseBody
@RequestMapping(value="test2",consumes="application/json",produces="applicat
ion/js on" ,method=RequestMethod.POST)
public String[] test2(@RequestBody User user){
System.out.println("user = "+user);
return new String[]{"hello","world","tom"};
}
3、给ajax请求返回⾃定义类型的数组（json格式）
@ResponseBody
@RequestMapping(value="test3",consumes="application/json",produces="applicat
ion/js on" ,method=RequestMethod.POST)
public User[] test3(@RequestBody User user){
System.out.println("user = "+user);
return new User[]{new User(1L,"tom1"),new User(2L,"tom2"),new
User(3L,"tom3")};
}
4、给ajax请求返回List集合（json格式）
@ResponseBody
@RequestMapping(value="test4",consumes="application/json",produces="applicat
ion/js on" ,method=RequestMethod.POST)
public List<User> test4(@RequestBody User user){
System.out.println("user = "+user);
return Arrays.asList(new User(1L,"tom1"),new User(2L,"tom2"),new
User(3L,"tom3"));
}
5、给ajax请求返回Set集合（json格式）
@ResponseBody
@RequestMapping(value="test5",consumes="application/json",produces="applicat
ion/j son" ,method=RequestMethod.POST)
public Set<User> test5(@RequestBody User user){
System.out.println("user = "+user);
Set<User> set = new HashSet<>();
set.add(new User(1L,"tom1"));
set.add(new User(2L,"tom2"));
set.add(new User(3L,"tom3")); return set;
}
6、给ajax请求返回Map集合（json格式）
@ResponseBody
@RequestMapping(value="test6",consumes="application/json",produces="applicat
ion/j son" ,method=RequestMethod.POST)
public Map<String,User> test6(@RequestBody User user){
System.out.println("user = "+user);
Map<String,User> map = new HashMap<>();
map.put("tom1", new User(1L,"tom1"));
map.put("tom2", new User(2L,"tom2"));
map.put("tom3", new User(3L,"tom3"));
return map;
}
