SpringBoot RestTemplate GET POST请求的实例讲解

一）RestTemplate简介

RestTemplate是HTTP客户端库提供了一个更高水平的API。主要用于Rest服务调用。

RestTemplate方法：

二）RestTemplate案例

第一步：创建一个maven项目，在pom.xml引入一个springboot的版本

pom.xml内容：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.oysept</groupId>
  <artifactId>spring_resttemplate</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.4.RELEASE</version>
    <relativePath/>
  </parent>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <mainClass>com.oysept.RestTemplateApplication</mainClass>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
</project>

application.yml配置：该配置就一个默认端口

server:

port: 8080

创建一个springboot启动类RestTemplateApplication

package com.oysept;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;

@SpringBootApplication
public class RestTemplateApplication {

  public static void main(String[] args) {
    new SpringApplicationBuilder(RestTemplateApplication.class).run(args);
  }
}

到此步骤时，可以先运行RestTemplateApplication中的main方法，检验springboot启动是否正常。

第二步：创建一个RestTemplate配置类并注入，因为在使用时，不提前注入ResttTemplate，在通过@Autowired使用会报RestTemplate找不到

package com.oysept.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

/**
 * 注册一个RestTemplate Bean, 否则直接通过@Autowired使用会报RestTemplate找不到
 * @author ouyangjun
 */
@Configuration
public class RestTemplateConfig {

  /**
   * 方式一: 默认是使用JDK原生java.net.HttpURLConnection请求
   * @return
   */
  @Bean(name = "restTemplate")
  public RestTemplate restTemplate() {
    return new RestTemplate();
  }

  /**
   * 方式二: 使用apache http内置请求, 需要在pom.xml中引入相应的apache jar
   * 可以使用HttpClient，设置一些http连接池等信息
   * @return
   *
  @Bean(name = "restTemplate")
  public RestTemplate restTemplate() {
    return new RestTemplate(new HttpComponentsClientHttpRequestFactory());
  }
   */

  /**
   * 方式三: 使用OkHttp内置请求, 需要在pom.xml中引入相应的OkHttp3 jar
   * 可以使用OkHttpClient，设置一些http连接池信息
   * @return
   *
  @Bean(name = "restTemplate")
  public RestTemplate restTemplate() {
    return new RestTemplate(new OkHttp3ClientHttpRequestFactory());
  }
  */
}

第三步：创建一个VO类，用于测试入参和出参

package com.oysept.vo;
public class MsgVO {
  private String msgKey;
  private String msgValue;

  public String getMsgKey() {return msgKey;}
  public void setMsgKey(String msgKey) {this.msgKey = msgKey;}

  public String getMsgValue() {return msgValue;}
  public void setMsgValue(String msgValue) {this.msgValue = msgValue;}

  public String toString() {
    return "MsgVO [msgKey: "+this.msgKey+", msgValue: "+this.msgValue+"]";
  }
}

第四步：创建一个服务端接口，用于测试

package com.oysept.controller;

import java.util.ArrayList;
import java.util.List;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.oysept.vo.MsgVO;

/**
 * 服务端, 提供接口被调用
 * @author ouyangjun
 */
@RestController
public class ServerController {

  // 无参GET请求: http://localhost:8080/server/get
  @RequestMapping(value = "/server/get", method = RequestMethod.GET)
  public String get() {
    return "/server/get";
  }

  // 带参GET请求: http://localhost:8080/server/get/param?param=111222333444
  @RequestMapping(value = "/server/get/param", method = RequestMethod.GET)
  public String getParam(@RequestParam(value = "param") String param) {
    return "/server/get/param," + param;
  }

  // 路径中带参GET请求: http://localhost:8080/server/get/url/AAAA/BBBB
  @RequestMapping(value = "/server/get/url/{one}/{two}", method = RequestMethod.GET)
  public String getUrl(@PathVariable("one") String one, @PathVariable("two") String two) {
    return "/get/url/{one}/{two}," + one + "," + two;
  }

  // 无参GET请求, 返回List: http://localhost:8080/server/get/list
  @RequestMapping(value = "/server/get/list", method = RequestMethod.GET)
  public List<Object> getList() {
    List<Object> list = new ArrayList<Object>();
    list.add(11);
    list.add("AA");
    return list;
  }

  // 无参GET请求, 返回对象: http://localhost:8080/server/get/MsgVO
  @RequestMapping(value = "/server/get/MsgVO", method = RequestMethod.GET)
  public MsgVO getMsgVO() {
    MsgVO vo = new MsgVO();
    vo.setMsgKey("keyAAA");
    vo.setMsgValue("valueBBB");
    return vo;
  }

  // POST请求, 表单参数, application/x-www-form-urlencoded
  @RequestMapping(value = "/server/post/form", method = RequestMethod.POST,
    consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
  public MsgVO postForm(MsgVO msgVO) {
    System.out.println("msgKey: " + msgVO.getMsgKey() + ", msgValue: " + msgVO.getMsgValue());
    return msgVO;
  }

  // POST请求, JSON参数, application/json
  @RequestMapping(value = "/server/post/json", method = RequestMethod.POST,
      consumes = MediaType.APPLICATION_JSON_UTF8_VALUE,
      produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
  public MsgVO postJson(@RequestBody MsgVO msgVO) {
    System.out.println("msgKey: " + msgVO.getMsgKey() + ", msgValue: " + msgVO.getMsgValue());
    return msgVO;
  }
}

第五步：创建一个测试服务端接口的API

import的类和注入的RestTemplate：

package com.oysept.controller;
import java.net.URI;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

import com.oysept.vo.MsgVO;

/**
 * 客户端, 调用服务端提供的接口
 * @author ouyangjun
 */
@RestController
public class ClientController {

  // 使用默认请求方式
  @Autowired
  @Qualifier(value = "restTemplate")
  private RestTemplate restTemplate;

  // 在此处添加客户端测试代码
}

1、GET请求

// 直接在浏览中输入访问地址: http://localhost:8080/client/get
@RequestMapping(value = "/client/get", method = RequestMethod.GET)
public String get() {
  // 无参GET请求
  String get = restTemplate.getForObject("http://localhost:8080/server/get", String.class);
  System.out.println("==>/server/get return: " + get);

  // 带参GET请求
  String getParam = restTemplate.getForObject("http://localhost:8080/server/get/param?param=111222333444", String.class);
  System.out.println("==>/server/get/param return: " + getParam);

  // 带参GET url请求
  String getUrlParam = restTemplate.getForObject("http://localhost:8080/server/get/url/{one}/{two}", String.class, "AAAA", "BBBB");
  System.out.println("==>/server/get/url/{one}/{two} return: " + getUrlParam);

  // 带参GET url请求
  Map<String, String> vars = new HashMap<String, String>();
  vars.put("one", "HHHH");
  vars.put("two", "EEEE");
  String getUrlVars = restTemplate.getForObject("http://localhost:8080/server/get/url/{one}/{two}", String.class, vars);
  System.out.println("==>/server/get/url/{one}/{two} return: " + getUrlVars);

  // 无参GET请求, 返回List
  @SuppressWarnings("unchecked")
  List<String> getList = restTemplate.getForObject("http://localhost:8080/server/get/list", List.class);
  System.out.println("==>/server/get/list return: " + getList);

  // GET请求, 返回对象
  ResponseEntity<MsgVO> entity = restTemplate.getForEntity("http://localhost:8080/server/get/MsgVO", MsgVO.class);
  System.out.println("==>/server/get/list return: " + entity.getBody());
  return "GET SUCCESS";
}

2、GET url中传参请求

// 直接在浏览中输入访问地址: http://localhost:8080/client/get/request
// GET请求, url参数, 在表头中添加参数
@RequestMapping(value = "/client/get/request", method = RequestMethod.GET)
public String getRequest() {
  // url中参数
  Map<String, String> vars = new HashMap<String, String>();
  vars.put("one", "HHHH");
  vars.put("two", "EEEE");

  // 请求地址
  String uriTemplate = "http://localhost:8080/server/get/url/{one}/{two}";
  // 给URL地址encode转码
  URI uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand(vars).toUri();
  // GET请求参数
  RequestEntity<Void> requestEntity =
        RequestEntity.get(uri)
        .header("MyHeader", "aaabbbcccddd")
        .build();
  // 响应
  ResponseEntity<String> response = restTemplate.exchange(requestEntity, String.class);
  // 结果
  System.out.println("==>/get/request header: " + response.getHeaders().getFirst("MyHeader"));
  System.out.println("==>/get/request body: " + response.getBody());
  return "POST SUCCESS";
}

3、POST application/x-www-form-urlencoded表单传参请求

// 直接在浏览中输入访问地址: http://localhost:8080/client/postForm
// POST请求, form表单入参
@RequestMapping(value = "/client/postForm", method = RequestMethod.GET)
public String postForm() {
  // uri
  String uriTemplate = "http://localhost:8080/server/post/form";

  // 设置请求头为form形式: application/x-www-form-urlencoded
  HttpHeaders headers = new HttpHeaders();
  headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

  // 设置参数, 和MsgVO中变量名对应
  MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
  map.add("msgKey", "1234");
  map.add("msgValue", "TestTest");

  // 封装请求参数
  HttpEntity<MultiValueMap<String, String>> requestb = new HttpEntity<MultiValueMap<String, String>>(map,
  headers);
  ResponseEntity<String> response = restTemplate.postForEntity(uriTemplate, requestb, String.class);
  System.out.println("==>/server/post/form return: " + response.getBody());
  return "POST SUCCESS";
}

4、POST application/json JSON传参请求

// 直接在浏览中输入访问地址: http://localhost:8080/client/postJson
// POST请求, JSON入参
@RequestMapping(value = "/client/postJson", method = RequestMethod.GET)
public String postJson() {
  // json入参
  MsgVO vo = new MsgVO();
  vo.setMsgKey("TTT");
  vo.setMsgValue("KKK");

  String uriTemplate = "http://localhost:8080/server/post/json";
  URI uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand().toUri();

  RequestEntity<MsgVO> requestEntity =
      RequestEntity.post(uri)
      .header("Content-Type", "application/json; charset=UTF-8")
      .body(vo);

  ResponseEntity<MsgVO> response = restTemplate.exchange(requestEntity, MsgVO.class);
  System.out.println("==>/server/post/json return: " + response.getBody());
  return "POST SUCCESS";
}

项目结构图：

以上这篇SpringBoot RestTemplate GET POST请求的实例讲解就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持我们。