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SpringBoot 如何使用RestTemplate发送Post请求

作者：占位符号　　发布时间：2022-03-03 09:35:47　

标签：SpringBoot,RestTemplate,Post请求

Spring中有个RestTemplate类用来发送HTTP请求很方便，本文分享一个SpringBoot发送POST请求并接收返回数据的例子。

背景：

用户信息放在8081端口的应用上，8082端口应用通过调用api，传递参数，从8081端口应用的数据库中获取用户的信息。

1、待访问的API

我要访问的api是 localhost:8081/authority/authorize，这个api需要传递三个参数，分别是domain(域名)，account（用户账号），key（用户秘钥）。先用postman测试一下，返回结果如下：

分别展示了验证成功和验证失败的例子。

2、返回对象

ResultVO类是我构造的类，将会格式化api返回的数据，实现如下：

ResultVO.java

package com.seven.site.VO;
/**
* @author: Seven.wk
* @description: 数据返回类
* @create: 2018/07/04
*/
public class ResultVO<T> {
private Integer code;
private String message;
private T data;
public ResultVO() {
}
public ResultVO(Integer code, String message) {
this.code = code;
this.message = message;
}
public ResultVO(Integer code, String message, T data) {
this.code = code;
this.message = message;
this.data = data;
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
}

3、将发送Post请求的部分封装如下

Utils.java

package com.seven.site.utils;
import com.seven.site.VO.ResultVO;
import org.springframework.http.*;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;
/**
* @author: Seven.wk
* @description: 辅助工具类
* @create: 2018/07/04
*/
public class Utils {
/**
* 向目的URL发送post请求
* @param url 目的url
* @param params 发送的参数
* @return ResultVO
*/
public static ResultVO sendPostRequest(String url, MultiValueMap<String, String> params){
RestTemplate client = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
HttpMethod method = HttpMethod.POST;
// 以表单的方式提交
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
//将请求头部和参数合成一个请求
HttpEntity<MultiValueMap<String, String>> requestEntity = new HttpEntity<>(params, headers);
//执行HTTP请求，将返回的结构使用ResultVO类格式化
ResponseEntity<ResultVO> response = client.exchange(url, method, requestEntity, ResultVO.class);
return response.getBody();
}
}

4、UserInfo对象

UserInfo.java

package com.seven.site.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import java.util.Date;
/**
* @author: Seven.wk
* @description: 用户信息实体
* @create: 2018/07/04
*/
@Entity
public class UserInfo {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer userId; //用户标识id
private String userName; //用户姓名
private String userAccount; //用户账号
private String userPassword; //用户密码
private Date createTime = new Date(System.currentTimeMillis()); //创建时间
public UserInfo() {
}
public UserInfo(Object userAccount, Object userName) {
}
public UserInfo(String userAccount, String userName) {
this.userName = userName;
this.userAccount = userAccount;
}
public UserInfo(String userAccount, String userName, String userPassword) {
this.userName = userName;
this.userAccount = userAccount;
this.userPassword = userPassword;
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserAccount() {
return userAccount;
}
public void setUserAccount(String userAccount) {
this.userAccount = userAccount;
}
public String getUserPassword() {
return userPassword;
}
public void setUserPassword(String userPassword) {
this.userPassword = userPassword;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Override
public String toString() {
return "UserInfo{" +
"userId=" + userId +
", userName='" + userName + '\'' +
", userAccount='" + userAccount + '\'' +
", userPassword='" + userPassword + '\'' +
", createTime=" + createTime +
'}';
}
}

5、在Service层封装将要发送的参数

并调用该方法，将返回的结果格式化成UserInfo对象，其中的异常处理部分就不详述了。

注:其中的URL地址一定要加上协议前缀（http，https等）

UserInfoServiceImpl.java

public UserInfo getUserInfoFromAuthority(String domain, String account, String key) {
String authorizeUrl = "http://localhost:8081/authority/authorize";
MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
params.add("domain", domain);
params.add("account", account);
params.add("key", key);
//发送Post数据并返回数据
ResultVO resultVo = Utils.sendPostRequest(authorizeUrl, params);
if(resultVo.getCode() != 20){ //进行异常处理
switch (resultVo.getCode()){
case 17: throw new SiteException(ResultEnum.AUTHORIZE_DOMAIN_NOT_EXIST);
case 18: throw new SiteException(ResultEnum.AUTHORIZE_USER_NOT_EXIST);
case 19: throw new SiteException(ResultEnum.AUTHORIZE_USER_INFO_INCORRECT);
default: throw new SiteException(ResultEnum.SYSTEM_ERROR);
}
}
LinkedHashMap infoMap = (LinkedHashMap) resultVo.getData();
return new UserInfo((String) infoMap.get("userAccount"), (String) infoMap.get("userName"), key);
}

6、在控制器中调用service中的方法，并返回数据

IndexController.java

/**
* 获取用户信息
* @param domain 域名
* @param account 用户输入的账号
* @param password 用户输入的密码
* @return ResultVO
*/
@PostMapping("/getInfo")
@ResponseBody
public ResultVO getInfo(@RequestParam("domain") String domain,
@RequestParam("account") String account,
@RequestParam("password") String password) {
UserInfo userInfo;
try{
userInfo = userInfoService.getUserInfoFromAuthority(domain, account, password);
}catch(SiteException e){
return new ResultVO(e.getCode(), e.getMessage());
}
return new ResultVO<>(20, "登录成功", userInfo);
}