Spring REST Template 快速入门

本篇将使用Spring Boot发布REST Service，使用Spring REST Template来调用服务

本篇代码均已上传到GITHUB，<https://github.com/IloveZiHan/restfultemplate.git>

介绍

我们之前都使用过HttpClient来发送HTTP请求，但我们很多时间都需要将HttpClient请求或者响应的数据转换为Java对象，HttpClient需要我们自己手动来解析。我们今天要介绍的Spring REST Template比HttpClient用起来更加方便简洁。

背景

案例分为两个部分：

CRM_MANAGEMENT——后台主要提供RESTFUL Service服务，因为尽量使案例简单，所以数据部分是直接使用内存中的列表来模拟
PORTAL——门户，也就是前端系统，用来处理浏览器提交的请求，接收到用户请求会使用Spring REST Template来提交RESTFUL Service请求

环境说明

本案例基于Maven构建，使用Spring Boot 2.x开发
可以选择IDEA或者Eclipse导入案例运行

项目开发

CRM_DOMAIN实体

POM依赖

pom.xml

<?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>resttemplate_common</artifactId>
        <groupId>com.itheima</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>crm_domain</artifactId>
    <packaging>jar</packaging>
</project>

User实体类

package com.itheima.crm.domain;

public class User {

    private Integer id;     // id
    private String username; // 用户名
    private String password; // 密码

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public boolean matchUsernameAndPassword(String username, String password) {
        if(this.username.equals(username) && this.password.equals(password)) {
            return true;
        }
        else {
            return false;
        }
    }
}

ResResult——封装响应结果

package com.itheima.crm.domain;

/**
 * 响应结果
 */
public class ResResult {

    private Boolean success; // 是否操作成功
    private String message; // 消息

    public ResResult() {
    }

    public ResResult(Boolean success, String message) {
        this.success = success;
        this.message = message;
    }

    public Boolean getSuccess() {
        return success;
    }

    public void setSuccess(Boolean success) {
        this.success = success;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
}

CRM_MANAGEMENT后台

POM依赖

pom.xml

<?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>

    <artifactId>crm_management</artifactId>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.itheima</groupId>
            <artifactId>crm_domain</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

RESTFUL Service接口开发

package com.itheima.crm.webservice;

import com.itheima.crm.domain.ResResult;
import com.itheima.crm.domain.User ;
import com.itheima.crm.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserRestService {

    @Autowired
    private UserService userService;

    /**
     * 注册服务
     * @param user 用户
     * @return
     */
    @RequestMapping(method = RequestMethod.POST)
    public ResResult regist(@RequestBody User user) {
        try {
            userService.regist(user);
            return new ResResult(true, "添加成功");
        } catch (Exception e) {
            e.printStackTrace();
            return new ResResult(false, "添加失败");
        }
    }

    /**
     * 登录服务
     * @param username 用户名
     * @param password 密码
     * @return
     */
    @RequestMapping(value = "/{username}/{password}", method = RequestMethod.GET)
    public User login(@PathVariable("username") String username, @PathVariable("password") String password) {
        try {
            return userService.login(username, password);
        } catch (Exception e) {
            return null;
        }
    }

    @RequestMapping(method = RequestMethod.GET)
    public List<User> findAll() {
        return userService.findAll();
    }
}

Service层开发

UserService接口

package com.itheima.crm.service;

import com.itheima.crm.domain.User ;

import java.util.List;

public interface UserService {
    void regist(User user);

    User login(String username, String password);

    List<User> findAll();
}

UserServiceImpl实现类

package com.itheima.crm.service;

import com.itheima.crm.dao.UserDao;
import com.itheima.crm.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserDao userDao;

    @Override
    public void regist(User user) {
        userDao.save(user);
    }

    @Override
    public User login(String username, String password) {
        return userDao.findOne(username, password);
    }

    @Override
    public List<User> findAll() {
        return userDao.findAll();
    }
}

DAO层开发

UserDao接口

package com.itheima.crm.dao;

import com.itheima.crm.domain.User ;

import java.util.List;

public interface UserDao {
    /**
     * 保存用户
     * @param user 用户
     */
    void save(User user);

    User findOne(String username, String password);

    List<User> findAll();
}

UserDaoImpl实现类

package com.itheima.crm.dao;

import com.itheima.crm.domain.User;
import org.springframework.stereotype.Repository;

import java.util.ArrayList;
import java.util.List;

@Repository
public class UserDaoImpl implements UserDao{

    private List<User> users = new ArrayList<>();

    @Override
    public void save(User user) {
        users.add(user);
    }

    @Override
    public User findOne(String username, String password) {
        User userTmp = new User();
        userTmp.setUsername(username);
        userTmp.setPassword(password);

        for(User user : users) {
            if(user.matchUsernameAndPassword(username, password)) {
                return user;
            }
        }

        return null;
    }

    @Override
    public List<User> findAll() {
        return users;
    }

    public UserDaoImpl() {
        // 添加一些测试的用户
        User user1 = new User();
        user1.setId(1);
        user1.setUsername("zhangsan");
        user1.setPassword("0");

        User user2 = new User();
        user2.setId(2);
        user2.setUsername("lisi");
        user2.setPassword("0");

        User user3 = new User();
        user3.setId(3);
        user3.setUsername("wangwu");
        user3.setPassword("0");

        User user4 = new User();
        user4.setId(4);
        user4.setUsername("zhaoliu");
        user4.setPassword("0");

        users.add(user1);
        users.add(user2);
        users.add(user3);
        users.add(user4);
    }
}

Spring Boot入口

配置文件(application.properties)

server.port=9001
server.servlet.context-path=/

入口

package com.itheima.crm;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

RESTFUL Service接口调用URL

添加用户

Requsest URL: <http://localhost:9001/user/> Request Method: POST
根据用户名密码查询用户
Requsest URL: <http://localhost:9001/user/用户名/密码> Request Method: GET
查询所有用户
Requeset URL: <http://localhost:9001/user/> Request Method: GET

PORTAL门户

POM依赖

<?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>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <modelVersion>4.0.0</modelVersion>
    <artifactId>portal</artifactId>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency><dependency>
            <groupId>com.itheima</groupId>
            <artifactId>crm_domain</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

Controller开发

package com.itheima.portal.controller;

import com.itheima.crm.domain.ResResult;
import com.itheima.crm.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private RestTemplate restTemplate;

    private String USERSERVICE_URL = "http://localhost:9001/user";

    @RequestMapping("/login")
    public Map login(String username, String password) {
        // 构建要传递的参数
        Map<String, String> params = new HashMap<>();
        params.put("username", username);
        params.put("password", password);
        // 发送GET请求
        User user = restTemplate.getForObject(USERSERVICE_URL + "/{username}/{password}", User.class, params);
        Map<String, Object> result = new HashMap<>();
        if(user != null) {
             result.put("success", true);
        }
        else {
            result.put("success", false);
            result.put("message", "登录失败");
        }

        return result;
    }

    @RequestMapping("/regist")
    public ResResult login(@RequestBody  User user) throws IOException {
        // 使用REST Template发送POST请求
        return restTemplate.postForObject(USERSERVICE_URL + "/", user, ResResult.class);
    }
}

Spring Boot入口

配置文件(application.properties)

server.port=9002
server.servlet.context-path=/

入口

package com.itheima.portal;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    /**
     * 创建RestTemplate Bean
     */
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

前端页面

导入jquery.js
login.html登录页面

<!doctype html>
<html lang="`">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>登录</title>
    <script src="jquery-1.11.3.js"></script>
</head>
<body>
    <table class="table">
        <tr>
            <td>用户名</td>
            <td><input type="text" id="username"></td>
        </tr>
        <tr>
            <td>密码</td>
            <td><input type="text" id="password"></td>
        </tr>
        <tr>
            <td></td>
            <td>
                <button id="btn">登录</button>
                <button id="btn1">注册</button>
            </td>
        </tr>
    </table>

    <script type="text/javascript">
        $(function() {
           $(‘#btn‘).click(function() {
               $.get(‘user/login?username=‘ + $(‘#username‘).val() + ‘&password=‘ + $(‘#password‘).val(), function(data) {
                  if(!data.success) {
                      alert(data.message);
                  }
                  else {
                      window.location.href = "success.html";
                  }
               });
           });

            $(‘#btn1‘).click(function() {
                var user = {
                        username: $(‘#username‘).val(),
                        password: $(‘#password‘).val()
                };
                $.ajax({
                    type:‘POST‘,
                    url:‘user/regist‘,
                    dataType:"json",
                    contentType:"application/json",
                    data:JSON.stringify(user),
                    success:function(data){
                        if(!data.success) {
                            alert(data.message);
                        }
                        else {
                            alert("注册成功！");
                        }
                    }
                });
            });
        });
    </script>
</body>
</html>

success.html登录成功页面

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录成功</title>
</head>
<body>
    <h1>登录成功</h1>
</body>
</html>

总结

Spring REST Template比HttpClient更加快捷方便的调用RS服务，它自动封装和解析Java对象。而且可以很方便的与Spring整合，快速注入Spring的bean对象。

注意

注意Jquery $.get、$.post、$.ajax的区别

$.get(url, json对象)表示发送一个get请求，使用queryString的方式提交。url?username=tom...

$.post(url, json对象)表示发送一个post请求，数据部分类似于提交表单。

$.ajax可以选择数据传递的格式、类型等。我们要将一个json串发送到spring mvc @RequestBody来接收需要使用$.ajax。下面是示例代码

$.ajax({
  type:‘POST‘,
  url:‘user/regist‘,
  dataType:"json",
  contentType:"application/json",
  data:JSON.stringify(user),
  success:function(data){
    if(!data.success) {
      alert(data.message);
    }
    else {
      alert("注册成功！");
    }
  }
});

原文地址：https://blog.51cto.com/14473726/2429176

时间： 2024-10-08 19:33:00

Spring REST Template 快速入门

介绍

背景

环境说明

项目开发

CRM_DOMAIN实体

POM依赖

CRM_MANAGEMENT后台

POM依赖

RESTFUL Service接口开发

Service层开发

DAO层开发

Spring Boot入口

RESTFUL Service接口调用URL

PORTAL门户

POM依赖

Controller开发

Spring Boot入口

总结

Spring REST Template 快速入门的相关文章

笔记：Spring Cloud Zuul 快速入门

Spring MVC 教程,快速入门,深入分析

Spring Boot框架——快速入门

(Spring Boot框架)快速入门

Spring Boot【快速入门】

[转]Spring MVC 教程,快速入门,深入分析

Spring Data Redis —— 快速入门

Spring Boot （十四）：响应式编程以及 Spring Boot Webflux 快速入门

Spring Cloud Zuul 快速入门