RestTemplate的调用方式、服务消费者

二：RestTemplate

通过RestTemplate可以实现不同微服务之间的调用

RestTemplate是spring框架提供的一种基于RESTful的服务组件，底层对HTTP请求及其相应进行了封装，提供了很多的远程访问REST服务的方式，可以简化代码的开发

如何使用RestTemplate

1.创建maven工程

<?xml version="1.0" encoding="UTF-8"?>

<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>org.example</groupId>

    <artifactId>springCloud02</artifactId>

    <version>1.0-SNAPSHOT</version>

    <parent>

        <artifactId>spring-boot-starter-parent</artifactId>

        <groupId>org.springframework.boot</groupId>

        <version>2.0.7.RELEASE</version>

    </parent>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

<!--        lombok-->

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

        </dependency>

    </dependencies>

</project>

2.创建实体类：

package com.southwind.entity;

import lombok.AllArgsConstructor;

import lombok.Data;

@Data

@AllArgsConstructor

public class User {

    private Integer id;

    private String name;

}

3.持久层

接口：

package com.southwind.repository;

import com.southwind.entity.User;

import java.util.Collection;

public interface UserRepository {

    public Collection<User> findAll();

    public User findById(Integer id);

    public void saveOrUpdate(User user);

    public void deleteById(Integer id);

}

实体类：

package com.southwind.repository.impl;

import com.southwind.entity.User;

import com.southwind.repository.UserRepository;

import java.util.Collection;

import java.util.HashMap;

import java.util.Map;

public class UserRepositoryImpl implements UserRepository {

    private static Map<Integer,User> map;

    static {

        map=new HashMap<>();

        map.put(1,new User(1,"张三"));

        map.put(2,new User(2,"李四"));

        map.put(3,new User(3,"王五"));

    }

    @Override

    public Collection<User> findAll() {

        return map.values();

    }

    @Override

    public User findById(Integer id) {

        return map.get(id);

    }

    @Override

    public void saveOrUpdate(User user) {

        map.put(user.getId(),user);

    }

    @Override

    public void deleteById(Integer id) {

        map.remove(id);

    }

}

测试接口可以使用

RestTemplate访问服务REST服务

1.将RestTemplate的实例化对象通过@Bean注解注入到IoC容器

package com.southwind.config;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.client.RestTemplate;

@Configuration

public class MyConfig {

    @Bean

    public RestTemplate restTemplate(){

        return new RestTemplate();

    }

}

方法名为id名

2.创建RestHandler

package com.southwind.Handler;

import com.southwind.entity.User;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.client.RestTemplate;

import java.util.Collection;

@RestController

@RequestMapping("/rest")

public class RestHandler {

    @Autowired

    private RestTemplate restTemplate;

    @GetMapping("/findall")

    public Collection<User> findAll(){

        return restTemplate.getForObject("http://localhost:8080/user/findall",Collection.class);

    }

    @GetMapping("/findbyid/{id}")

    public User findById(@PathVariable("id") Integer id){

        return restTemplate.getForObject("http://localhost:8080/user/findbyid/{id}",User.class,id);

    }

    @PostMapping("/save")

    public void save(@RequestBody User user){

         restTemplate.postForObject("http://localhost:8080/user/save",user,Collection.class);

    }

    @PutMapping("/update")

    public void update(User user){

        restTemplate.put("http://localhost:8080/user/save",user);

    }

    @DeleteMapping("/delete{id}")

    public void delete(@PathVariable("id") Integer id){

        restTemplate.delete("http://localhost:8080/user/delete{id}",id);

    }

}

底层RestTemplate是对http请求和相应的封装，提供了很多访问远程REST服务的方法，基于它的这个特性，我们可以实现不同微服务之间的调用。

服务消费者

1.创建Module，配置环境

<?xml version="1.0" encoding="UTF-8"?>

<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">

    <parent>

        <artifactId>springCloud01</artifactId>

        <groupId>org.example</groupId>

        <version>1.0-SNAPSHOT</version>

    </parent>

    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer</artifactId>

    <dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

        </dependency>

    </dependencies>

</project>

2.application.yml

server:

  port: 8020

spring:

  application:

    name: consumer

eureka:

  client:

    service-url:

      defaultZone: http://localhost:8761/eureka/

  instance:

    prefer-ip-address: true

3.启动类：

package com.southwind;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class ConsumerApplication {

    public static void main(String[] args) {

        SpringApplication.run(ConsumerApplication.class,args);

    }

}

4.Handler

package com.southwind.controller;

import com.southwind.entity.Student;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.client.RestTemplate;

import java.util.Collection;

@RestController

@RequestMapping("/consumer")

public class StudentHandler {

    @Autowired

    private RestTemplate restTemplate;

    @GetMapping("/findall")

    public Collection<Student> findall(){

        return restTemplate.getForObject("http://localhost:8010/provider/findall",Collection.class);

    }

    @GetMapping("/findbyid/{id}")

    public Student findById(@PathVariable("id") Integer id){

        return restTemplate.getForObject("http://localhost:8010/provider/findbyid/{id}",Student.class,id);

    }

    @PostMapping("/save")

    public void save(@RequestBody Student student){

        restTemplate.postForObject("http://localhost:8010/provider/save",student,Collection.class);

    }

    @DeleteMapping("/delete")

    public void deletebyid(Integer id){

        restTemplate.delete("http://localhost:8010/provider/delete/{id}",id);

    }

}

5.配置类：

package com.southwind.config;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.client.RestTemplate;

@Configuration

public class MyConfig {

    @Bean

    public RestTemplate restTemplate(){

        return new RestTemplate();

    }

}

巴特西

RestTemplate的调用方式、服务消费者

二：RestTemplate

如何使用RestTemplate

RestTemplate访问服务REST服务

服务消费者

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