restful风格入门

概述

简介：REST(Representational State Transfer),表现形式状态转换。

传统风格
http://localhost/users/getById?id=1
http://localhost/users/saveUser
REST风格
http://localhost/users/1
http://localhost/users

对比：
对比可以发现，虽然传统风格的更详细，知道调用哪个函数，但是了太长了写起来不方便，REST风格的话就很简介，而且还可以隐藏函数调用的函数的名字，无法通过地址得知对资源进行何种操作，更加安全。

如何区分资源访问形式
在后面的代码演示的时候就会知道，REST风格定义了很多种类的Mapping注解，通过这些注解进行识别。

http://localhost/users 查询全部用户信息 GET（查询）
http://localhost/users/1 查询指定用户信息 GET（查询）
http://localhost/users 添加用户信息 POST（添加/保存）
http://localhost/users 修改用户信息 PUT（修改/更新）
http://localhost/users 删除用户信息 DELETE（删除）

规范
REST风格更多的是一种规范，对于描述模块名称通常使用复数，比如users。

快速入门

文件结构

在这里插入图片描述
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SpringBootRestful</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SpringBootRestful</name>
    <description>SpringBootRestful</description>
    <properties>
        <java.version>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-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

</project>

User

package com.example.springbootrestful.bean;

public class User {
    private Integer id;
}

Controller

传统代码

package com.example.springbootrestful.controller;

import com.example.springbootrestful.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {
    // save与update需要的是post方法才可以访问
    @RequestMapping("/save")
    @ResponseBody
    public String save(@RequestBody User user){
        System.out.println("user save..." + user);
        return "{'module':'user save'}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delete(Integer id){
        System.out.println("user delete..." + id);
        return "{'module':'user delete'}";
    }

    @RequestMapping("/update")
    @ResponseBody
    public String update(@RequestBody User user){
        System.out.println("user update..." + user);
        return "{'module':'update save'}";
    }

    @RequestMapping("/getById")
    @ResponseBody
    public String getById(Integer id){
        System.out.println("user getById..." + id);
        return "{'module':'user getById'}";
    }

    @RequestMapping("/getAll")
    @ResponseBody
    public String getAll(){
        System.out.println("user getAll...");
        return "{'module':'user getAll'}";
    }
}

运行演示：
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RESTful风格代码

package com.example.springbootrestful.controller;

import com.example.springbootrestful.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

@Controller
public class UserController {
    // save与update需要的是post方法才可以访问
    @RequestMapping(value = "/users",method = RequestMethod.POST)
    @ResponseBody
    public String save(@RequestBody User user){
        System.out.println("user save..." + user);
        return "{'module':'user save'}";
    }

    @RequestMapping(value = "/users/{id}",method = RequestMethod.DELETE)
    @ResponseBody
    public String delete(@PathVariable Integer id){
        System.out.println("user delete..." + id);
        return "{'module':'user delete'}";
    }

    @RequestMapping(value = "/users",method = RequestMethod.PUT)
    @ResponseBody
    public String update(@RequestBody User user){
        System.out.println("user update..." + user);
        return "{'module':'update save'}";
    }

    @RequestMapping(value = "/users/{id}",method = RequestMethod.GET)
    @ResponseBody
    public String getById(@PathVariable Integer id){
        System.out.println("user getById..." + id);
        return "{'module':'user getById'}";
    }

    @RequestMapping(value = "/users",method = RequestMethod.GET)
    @ResponseBody
    public String getAll(){
        System.out.println("user getAll...");
        return "{'module':'user getAll'}";
    }
}

完善

package com.example.springbootrestful.controller;

import com.example.springbootrestful.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/Users")
public class UserController {
    // save与update需要的是post方法才可以访问
    @PostMapping
    public String save(@RequestBody User user){
        System.out.println("user save..." + user);
        return "{'module':'user save'}";
    }

    @DeleteMapping
    public String delete(@PathVariable Integer id){
        System.out.println("user delete..." + id);
        return "{'module':'user delete'}";
    }

    @PutMapping
    public String update(@RequestBody User user){
        System.out.println("user update..." + user);
        return "{'module':'update save'}";
    }

    @GetMapping("/{id}")
    public String getById(@PathVariable Integer id){
        System.out.println("user getById..." + id);
        return "{'module':'user getById'}";
    }

    @GetMapping
    public String getAll(){
        System.out.println("user getAll...");
        return "{'module':'user getAll'}";
    }
}