RestTemplate的超全讲解（全）转

https://blog.csdn.net/weixin_47872288/article/details/121842374

(81条消息) RestTemplate的超全讲解（全）_码农研究僧的博客-CSDN博客_resttemplate

视频地址：

https://www.bilibili.com/video/BV1tJ41147uj?t=624.5&p=4

post与get的区别在于post的方法传参map必须是MultiValueMap

基本类型传参和实体类型传参

@RestController
public class UserController{
    //实体传参
    @RequestMapping(value="/addUser1")
public UserDTO addUser(userDTO userdto)
{
    return userdto;
}

@ResquestMapping(value="/addUser2")
public UserDTO addUser2(Long userId,String userName)
{
UserDTO u=new UserDTO();
u.setUserId(userId);
u.setUserName(userName);
return u;
}

}

Post 请求方式调用服务接口

//http://localhost:8080/postFor0bject1
@GetMapping("/postForObject1")
public UserDT0 postForObject1 ( ) {
    //远程访问的Url UserDTO
    String url = "http://localhost:8080/addUser1";
    // Post方法必须使用MultiValueMap传参。//使用UserDTO传参也可以
    
    MultiValueMap<String，0bject> paramMap = new LinkedMultiValueMap<>();
    paramMap.add ("userId", 1008L);
    paramMap.add ("userName "，"巧克力");
    UserDT0 userDTO = restTemplate.postForObject(url,paramMap，UserDT0.class);
    return userDTO;
}

如果服务接口使用到@RequestBody,用httpentity ，此时不能使用MultiValueMap 传参！！

@RequestMapping( value = "/addUser3" )
public UserDT0 addUser3(@RequestBody UserDT0 userDTO) {
    userDTo.setUserName(userDTo.getUserName() + " from RequestBody" );
    return userDTO;
}

//http://localhost:8888/postForObject2
@GetMapping("/postForObject2")
public UserDT0 postForObject2( ) {
    //申明一个请求头
    HttpHeaders headers = new HttpHeaders();
    //application/json
    headers.setContentType( MediaType .APPLICATION_JSON);//远程访问的Url UserDTO
    string url = "http://localhost:8080/addUser3";
    /**
        此处使用MultiValueMap会报错
        MultiValueMap<String，0bject> paramMap = new LinkedMultiValueMap<>( );
        paramMap.add("userId",100OL) ;
        paramMap.add("userName","fencaibc");*/
    //此处可以使用HashMap代替，但是会有警告
    
    UserDT0 userDTO = new UserDTO( );
    userDTO.setUserId( 1088L);
    userDT0.setUserName("课程");
    HttpEntity<UserDTO> entityParam new HttpEntity<UserDTO>(userDTO，headers) ;
    UserDT0 result = restTemplate.postFor0bject(url, entityParam，UserDTO.class);
    return result ;
}

PostForEntity 方法返回内容比 postForObject 更丰富，但是要注意，基本类型的参数采用 MultiValueMap封装参数，@ReqeustBody 修饰的参数要以httpEntity 封装对象实例作为参数

同时，返回结果要是 ResponseEntity类型

//http://localhost:8088/ postForEntity1@GetMapping( " / postForEntity1")
public UserDT0 postForEntity1( ) {
    string url = "http://localhost:8080/addUser1" ;
    
    MultiValueMap<String，object> paramMap = new LinkedMultiValueMap<>( );
    
    paramMap.add("userId", 100);
    paramMap.add("userName" ，"课程");
    
    ResponseEntity<UserDT0> userDTOResponseEntity =restTemplate.postForEntity(url,paramMap，UserDTO.class) ;
    
    HttpStatus statusCode = userDTOResponseEntity.getStatusCode( );
    
    int statusCodeValue = userDTOResponseEntity.getStatusCodeValue( );
    
    HttpHeaders headers = userDTOResponseEntity. getHeaders( );
    
    return userDTOResponseEntity. getBody( );
}