概述

前言

2个团队，分别开发了“商品管理系统”和“用户管理系统”

问题：“商品管理系统”需要使用“用户管理系统”某个功能，怎么办？

根据用户的会员等级，显示不同的打折

什么是远程调用

客户端程序通过接口调用服务端程序，并获得该服务返回的数据的过程，称为远程调用。
“商品管理系统”调用“用户管理系统”的过程，就是“远程调用”。此时“商品管理系统”相当于模拟“浏览器”。

调用方式

常见的远程调用方式有2种：

RPC：Remote Produce Call远程过程调用，==自定义数据==格式的远程调用方式。基于原生TCP通信，速度快，效率高。
Http：采用http协议远程调用方式，==规定==了数据传输的格式，缺点是消息封装臃肿。现在热门的Rest风格，就可以通过http协议来实现。

常见框架：

RPC常见框架： dubbo、WebService
Http常见框架：HttpClient、RestTemplate

区别	HTTP	RPC
速度	较慢	快
难度	简单	复杂
灵活性	灵活，跨平台、跨语言

如何选择

那么我们该怎么选择呢？

==微服务==，基于Spring Cloud的微服务，更加强调的是独立、自治、灵活，一般都会采用基于Http的Rest风格服务。

搭建环境

父项目

项目名：nacos-parent-2.1
添加坐标：

 <parent>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-build</artifactId>
        <version>2.3.5.RELEASE</version>
    </parent>
    <properties>
        <spring.cloud.version>Hoxton.SR12</spring.cloud.version>
        <spring.cloud.alibaba.version>2.2.7-SNAPSHOT</spring.cloud.alibaba.version>
        <mybatis.plus.starter.version>3.4.0</mybatis.plus.starter.version>
        <durid.starter.version>1.1.10</durid.starter.version>
        <swagger.version>2.7.0</swagger.version>
        <jwt.jjwt.version>0.9.0</jwt.jjwt.version>
        <jwt.joda.version>2.9.7</jwt.joda.version>
    </properties>
    <dependencyManagement>
        <dependencies>
            <!-- Spring Dependencies -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring.cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring.cloud.alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- mybatis-plus -->
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>${mybatis.plus.starter.version}</version>
            </dependency>
            <!-- Druid连接池 -->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>${durid.starter.version}</version>
            </dependency>
            <!--swagger2-->
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger2</artifactId>
                <version>${swagger.version}</version>
            </dependency>
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger-ui</artifactId>
                <version>${swagger.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

测试数据项目

环境

项目：nacos-data
添加依赖

  <dependencies>
        <!--web起步依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--swagger2-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
        </dependency>
        <!--支持lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

yml配置

server:
  port: 7778

拷贝BaseResult 和 Swagger2ConfigurationV3
编写启动类

1.package com.czxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
 * Created by liangtong.
 */
@SpringBootApplication
public class DataApplication {
    public static void main(String[] args) {
        SpringApplication.run(DataApplication.class, args);
    }
}

基本功能

创建JavaBean

package com.czxy.domain;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
 * Created by liangtong.
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    private Integer uid;
    private String username;
    private String password;
    private Integer age;
}

编写基本功能（模拟数据）

package com.czxy.controller;
import com.czxy.domain.User;
import com.czxy.vo.BaseResult;
import org.springframework.web.bind.annotation.*;
import java.util.ArrayList;
import java.util.List;
/**
 * Created by liangtong.
 */
@RestController
@RequestMapping("/user")
public class UserController {
    @GetMapping
    public BaseResult findAll(){
        List<User> list = new ArrayList<>();
        list.add(new User(1,"jack","1234",18));
        list.add(new User(2,"rose","5678",21));
        list.add(new User(3,"tom","6666",25));
        return BaseResult.ok("查询所有",list);
    }
    @GetMapping("/{uid}")
    public BaseResult findById(@PathVariable("uid")Integer uid){
        User user = new User(1,"jack","1234",18);
        return BaseResult.ok("查询成功",user);
    }
    @GetMapping("/search")
    public BaseResult search(User user){
        System.out.println(user);
        return BaseResult.ok("查询成功",user);
    }
    @PostMapping
    public BaseResult save(@RequestBody User user){
        System.out.println(user);
//        return ResponseEntity.status(302).body(BaseResult.ok("添加成功"));
        return BaseResult.ok("添加成功");
    }
    @PutMapping
    public BaseResult update(@RequestBody User user){
        System.out.println(user);
        return BaseResult.ok("更新成功");
    }
    @DeleteMapping("/{uid}")
    public BaseResult deleteById(@PathVariable("uid")Integer uid){
        System.out.println(uid);
        return BaseResult.ok("删除成功");
    }
}

测试

http://localhost:7778/swagger-ui.html

HttpClient入门

概述

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

搭建环境

创建项目：nacos-http
pom配置

 <dependencies>
        <!--web起步依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--httpclient-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.6</version>
        </dependency>
        <!--支持lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <!--fastjson-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.49</version>
        </dependency>
        <!-- 测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
    </dependencies>

创建启动类

package com.czxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class HttpApplication {
    public static void main(String[] args) {
        SpringApplication.run(HttpApplication.class, args);
    }
}

编写测试类

package com.czxy;
public class TestHttp {
}

基本功能

GET请求--无参：查询所有

以get请求的方式，获得所有结果

1.创建客户端（相当于打开浏览器）。CloseableHttpClient

2.创建GET请求实例（确定访问路径） HTTPGet

3.发送请求（回车访问）execute

4.判断响应的状态码200

5.通过工具处理响应内容

6.关闭资源

代码

@Test
    public void testFindAll() {
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpGet httpGet = new HttpGet("http://localhost:7778/user");
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if(response.getStatusLine().getStatusCode() == 200) {
                String str = EntityUtils.toString(response.getEntity());
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

如果响应的数据乱码，需要手动设定

练习：GET请求：查询详情

 @Test
    public void testFindId() {
        String id = "1";
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpGet httpGet = new HttpGet("http://localhost:7778/user/" + id);
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if(response.getStatusLine().getStatusCode() == 200) {
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

GET请求--有参：拼凑URL

基本使用

    @Test
    public void testDemo03(){
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            StringBuilder params = new StringBuilder();
            params.append("username=张三");
            params.append("&");
            params.append("password=1234");
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpGet httpGet = new HttpGet("http://localhost:7778/user/search" + "?" + params.toString());
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if(response.getStatusLine().getStatusCode() == 200){
                // 3.1 获得响应数据的类型
                System.out.println(response.getEntity().getContentType());
                // 3.2 获得响应体内容
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

拼凑特殊数据：URL中的特殊符号，需要使用URLEncoder处理

@Test
    public void testDemo04(){
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            StringBuilder params = new StringBuilder();
            params.append("username=" + URLEncoder.encode("&","UTF-8"));
            params.append("&");
            params.append("password=1234");
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpGet httpGet = new HttpGet("http://localhost:7778/user/search" + "?" + params.toString());
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if(response.getStatusLine().getStatusCode() == 200){
                // 3.1 获得响应数据的类型
                System.out.println(response.getEntity().getContentType());
                // 3.2 获得响应体内容
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

POST请求：手动拼凑JSON

@Test
    public void testInsert() {
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpPost httpPost = new HttpPost ("http://localhost:7778/user/");
            // 2.1 准备json数据
            String jsonStr = "{\n" +
                    "      \"uid\": \"1\",\n" +
                    "      \"username\": \"jack\",\n" +
                    "      \"password\": \"1234\",\n" +
                    "      \"age\": \"18\"\n" +
                    "    }";
            // 2.2 设置请求体
            httpPost.setEntity(new StringEntity(jsonStr,"UTF-8"));
            // 2.3 设置请求数据类型为json
            httpPost.setHeader("content-type","application/json;charset=UTF-8");
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpPost);
            if(response.getStatusLine().getStatusCode() == 200) {
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

POST请求：fastjson

fastjson 是阿里巴巴提供最快的json转换工具
如果要使用fastjson，修改pom.xml文件，添加坐标（如果已有，忽略此步）

<!--fastjson-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.49</version>
</dependency>

拷贝JavaBean：User
代码

 @Test
    public void testInsert2() {
        try {
            //1 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2 确定请求方式和请求路径，相当于在浏览器输入地址
            HttpPost httpPost = new HttpPost ("http://localhost:7778/user/");
            // 2.1 准备json数据
            User user = new User(1,"jack","1234",18);
            String jsonStr = JSON.toJSONString(user);
            // 2.2 设置请求体
            httpPost.setEntity(new StringEntity(jsonStr,"UTF-8"));
            // 2.3 设置请求数据类型为json
            httpPost.setHeader("content-type","application/json;charset=UTF-8");
            //3 执行请求并获取响应，相当于敲完地址后按下回车。
            CloseableHttpResponse response = httpClient.execute(httpPost);
            if(response.getStatusLine().getStatusCode() == 200) {
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
            response.close();
            httpClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

【微服务~远程调用】HttpClient入门

概述

前言

什么是远程调用

调用方式

搭建环境

父项目

测试数据项目

环境

基本功能

HttpClient入门

概述

搭建环境

基本功能

GET请求--无参：查询所有

练习：GET请求：查询详情

GET请求--有参：拼凑URL

POST请求：手动拼凑JSON

POST请求：fastjson

微服务

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