# RestTemplate

**Repository Path**: godchin/RestTemplate

## Basic Information

- **Project Name**: RestTemplate
- **Description**: RestTemplate基本使用
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-07-20
- **Last Updated**: 2021-12-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

## 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
 ![参数](https://img-blog.csdnimg.cn/20210720134927540.png)
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
 ![getForEntity](https://img-blog.csdnimg.cn/20210720135121972.png)
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
![postForObject](https://img-blog.csdnimg.cn/20210720135847645.png)
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
 ![postForEntity](https://img-blog.csdnimg.cn/20210720140030700.png)
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;
	```
	![exchange](https://img-blog.csdnimg.cn/20210720140848451.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)
## 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](https://img-blog.csdnimg.cn/20210720141410223.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)
控制台：
![控制台](https://img-blog.csdnimg.cn/20210720141447980.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)
`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
	![结果](https://img-blog.csdnimg.cn/20210720142149882.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)

	 - 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](https://img-blog.csdnimg.cn/20210720144934686.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)

 - 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：
![结果](https://img-blog.csdnimg.cn/20210720145123508.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDE3Mjc2,size_16,color_FFFFFF,t_70)