RestTemplate使用

Posted 2021-08-18 ITdfq

tags:

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什么是RestTemplate ？

RestTemplate是Spring用于同步client端的核心类，简化了与http服务的通信，并满足RestFul原则，程序代码可以给它提供URL，并提取结果。默认情况下，RestTemplate默认依赖jdk的HTTP连接工具。

如何使用

编写配置类，注入到Spring容器

```
package com.itdfq.resttemplate.config;

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

/**
 * @Author GocChin
 * @Date 2021/7/20 10:51
 * @Blog: itdfq.com
 * @QQ: 909256107
 * @Description:
 */
@Configuration
public class ResttemplateConfig {
    @Bean
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}

```

RestTemplate常用请求方法

用于GET请求

getForObject

源码：

   @Nullable
    <T> T getForObject(String var1, Class<T> var2, Object... var3) throws RestClientException;

    @Nullable
    <T> T getForObject(String var1, Class<T> var2, Map<String, ?> var3) throws RestClientException;

    @Nullable
    <T> T getForObject(URI var1, Class<T> var2) throws RestClientException;

getForEntity

源码：

    <T> ResponseEntity<T> getForEntity(String var1, Class<T> var2, Object... var3) throws RestClientException;

    <T> ResponseEntity<T> getForEntity(String var1, Class<T> var2, Map<String, ?> var3) throws RestClientException;

    <T> ResponseEntity<T> getForEntity(URI var1, Class<T> var2) throws RestClientException;

用于POST请求

postForObject

源码：

    @Nullable
    <T> T postForObject(String var1, @Nullable Object var2, Class<T> var3, Object... var4) throws RestClientException;

    @Nullable
    <T> T postForObject(String var1, @Nullable Object var2, Class<T> var3, Map<String, ?> var4) throws RestClientException;

    @Nullable
    <T> T postForObject(URI var1, @Nullable Object var2, Class<T> var3) throws RestClientException;

postForEntity

源码：


    <T> ResponseEntity<T> postForEntity(String var1, @Nullable Object var2, Class<T> var3, Object... var4) throws RestClientException;

    <T> ResponseEntity<T> postForEntity(String var1, @Nullable Object var2, Class<T> var3, Map<String, ?> var4) throws RestClientException;

    <T> ResponseEntity<T> postForEntity(URI var1, @Nullable Object var2, Class<T> var3) throws RestClientException;

兼容多种请求方式的exchange

支持的请求类型有:

    GET,
    HEAD,
    POST,
    PUT,
    PATCH,
    DELETE,
    OPTIONS,
    TRACE;

例子

创建实体类

package com.itdfq.resttemplate.entity;

import lombok.AllArgsConstructor;
import lombok.Data;

import java.io.Serializable;

/**
 * @Author GocChin
 * @Date 2021/7/20 10:54
 * @Blog: itdfq.com
 * @QQ: 909256107
 * @Description:
 */
public class HouseInfo implements Serializable {

    private static final long serialVersionUID = 7499502427245128735L;

    private Long l;
    private String city;
    private String street;
    private String address;

    public HouseInfo() {

    }


    public HouseInfo(Long l, String city, String street, String address) {
        this.l = l;
        this.city = city;
        this.street = street;
        this.address = address;
    }

    public static long getSerialVersionUID() {
        return serialVersionUID;
    }

    public Long getL() {
        return l;
    }

    public void setL(Long l) {
        this.l = l;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "HouseInfo{" +
                "l=" + l +
                ", city='" + city + '\\'' +
                ", street='" + street + '\\'' +
                ", address='" + address + '\\'' +
                '}';
    }
}

编写请求接口

package com.itdfq.resttemplate.controller;

import com.itdfq.resttemplate.entity.HouseInfo;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
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;

/**
 * @Author GocChin
 * @Date 2021/7/20 10:52
 * @Blog: itdfq.com
 * @QQ: 909256107
 * @Description: 测试Controller
 */
@RestController
@Slf4j
public class HouseController {
    @GetMapping("/house/data")
    public HouseInfo getData(@RequestParam("name") String name) {
        return new HouseInfo(1L, "上海", "虹口", "东体小区");
    }

    @GetMapping("/house/data/{name}")
    public String getData2(@PathVariable("name") String name) {
        return name;
    }

    @RequestMapping(value = "/house/save", method = RequestMethod.POST)
    public HouseInfo getData3(@RequestBody HouseInfo houseInfo) {
        log.info("执行了post请求方法");
        return houseInfo;
    }

    @RequestMapping(value = "/house/save", method = RequestMethod.POST, headers = {"token=123456"})
    public HouseInfo getData4(@RequestBody HouseInfo houseInfo) {
        log.info("执行了post 带heads的方法");
        houseInfo.setCity("海南");
        return houseInfo;
    }
}

测试

Get请求测试

/**
     * 发送Get请求，传递参数
     * @param name
     * @return
     */
    @GetMapping("/test1/data")
    public String test1(@RequestParam("name") String name) {
        //使用getForObject
        String forObject = restTemplate.getForObject("http://localhost:8081/house/data?name="+name, String.class);
        System.out.println(forObject);
        //getForEntity
        ResponseEntity<HouseInfo> forEntity = restTemplate.getForEntity("http://localhost:8081/house/data?name=123", HouseInfo.class);
        System.out.println(forEntity);
        System.out.println(forEntity.getStatusCodeValue());
        return forObject;
    }

结果
浏览器
控制台：

注意：
当请求返回值用实体类接受的话，实体类中需要加上toString方法，否则请求的数据无法转入json
get请求无法加入请求头，可以自定义拦截器加入请求头，或者使用exchange方法，加入请求头

Post请求

不带请求头

	/**
     * 发送post请求 不带请求头的方法
     *
     */
    @GetMapping("/test3/save")
    public void test3(){

        HouseInfo houseInfo2 = new HouseInfo(2l, "杭州", "余杭", "桃花港");
        HouseInfo houseInfo1 = restTemplate.postForObject("http://localhost:8081/house/save",houseInfo2 , HouseInfo.class);
        System.out.println(houseInfo1);
    }

结果

带请求头的post请求


    /**
     * 带请求头的 post方法
     * restTemplate.postForEntity():返回的信息比较全面 包含请求body headers 状态等等
     */
    @GetMapping("/test4/save")
    public void test4(){

        HouseInfo houseInfo2 = new HouseInfo(2l, "杭州", "余杭", "桃花港");
        //设置header信息
        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.setContentType(MediaType.APPLICATION_JSON);
        requestHeaders.add("token","123456");
        //封装信息
        HttpEntity requestEntity =new HttpEntity(houseInfo2,requestHeaders);
        HouseInfo houseInfo1 = restTemplate.postForObject("http://localhost:8081/house/save",requestEntity , HouseInfo.class);
        System.out.println(houseInfo1);
    }

结果：
执行结果

exchange请求

/**
 * exchange 可以请求
 *     GET,
 *     HEAD,
 *     POST,
 *     PUT,
 *     PATCH,
 *     DELETE,
 *     OPTIONS,
 *     TRACE;
 *     使用exchange 需要制定请求的方式，以及请求参数
 */
@GetMapping("/test5/save")
public void test5(){
    HouseInfo houseInfo2 = new HouseInfo(2l, "杭州", "余杭", "桃花港");
    //设置header信息
    HttpHeaders requestHeaders = new HttpHeaders();
    requestHeaders.setContentType(MediaType.APPLICATION_JSON);
    requestHeaders.add("token","123456");
    //封装信息
    HttpEntity requestEntity =new HttpEntity(houseInfo2,requestHeaders);
    ResponseEntity<HouseInfo> exchange = restTemplate.exchange("http://localhost:8081/house/save", HttpMethod.POST, requestEntity, HouseInfo.class);
    System.out.println(exchange.getBody());
}

结果：

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