中山建网站哪家好wordpress数据库合并

目录

一、引子

二、注解解析

@RequestParam

一、要求形参名=请求参数名，或者是请求实体类时（已有实体类），可以不需要加该注解

二、请求参数名!=参数名时，需要写该注解@RequestParam，其中

三、一名多值的情况使用list时，需要用到该注解@RequestParam，将集合add加入对应数据类型

@PathVariable

@RequestBody

@RequestHeader

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一、引子

最近在写项目时，时不时会忘记或者漏写对应的参数注解，所以决定简单整理一下相关注解。

二、注解解析

@RequestParam

一、要求形参名=请求参数名，或者是请求实体类时（已有实体类），可以不需要加该注解

package com.atguigu.param;import com.atguigu.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;import java.util.List;@Controller
@RequestMapping("param")
public class ParamController {@RequestMapping("data")@ResponseBody//直接接收//要求请求参数名=形参名public String data(String name,int age){System.out.println("name = " + name + ", age = " + age);return "name = " + name + ", age = " + age;}@GetMapping("data3")@ResponseBody//使用实体对象接值public String data3(User user){System.out.println("user = " + user);return "user = " + user;}}

二、请求参数名!=参数名时，需要写该注解@RequestParam，其中

value=“指定请求参数名”

required=false，前端是否必须传递此参数，默认是必须，不传报错400

default=“1”，当非必须传递false，可以设默认值

package com.atguigu.param;import com.atguigu.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;import java.util.List;@Controller
@RequestMapping("param")
public class ParamController {@GetMapping("data1")@ResponseBody//注解指定public String data1(@RequestParam(value = "account") String username,@RequestParam(required = false,defaultValue = "1") int page){System.out.println("username = " + username + ", page = " + page);return "username = " + username + ", page = " + page;}}

三、一名多值的情况使用list时，需要用到该注解@RequestParam，将集合add加入对应数据类型

如果不加该注解，将会让hbs对应的一个字符串直接赋值给集合。

package com.atguigu.param;import com.atguigu.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;import java.util.List;@Controller
@RequestMapping("param")
public class ParamController {@GetMapping("data2")@ResponseBody//特殊值一名多值public String data2(@RequestParam List<String> hbs){System.out.println("hbs = " + hbs);return "hbs = " + hbs;}}

@PathVariable

路径传参时，必须用到@PathVariable

package com.atguigu.path;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;@Controller
@RequestMapping("path")
@ResponseBody
public class PathController {@GetMapping("{account}/{password}")public String login(@PathVariable String account,@PathVariable String password){System.out.println("account = " + account + ", password = " + password);return "account = " + account + ", password = " + password;}}

@RequestBody

前端传入json数据时需要用到@RequestBody，如@PostMapping，@DeleteMapping，@PutMapping中有时会用到

package com.atguigu.json;import com.atguigu.pojo.Person;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;@Controller
@RequestMapping("json")
@ResponseBody
public class JsonController {@PostMapping("data")public String data(@RequestBody Person person){System.out.println("person = " + person);return "person = " + person;}}

@RequestHeader

用于接收请求头

package com.atguigu.header;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;@Controller
@RequestMapping("header")
@ResponseBody
public class HeaderController {@RequestMapping ("data")public String data(@RequestHeader String host){System.out.println("host = " + host);return "host = " + host;}}