使用RESTful风格编写用户增删改查模拟操作

三种参数接收方式的区别：
@RequestParam 用于接收url地址传参或表单传参
@RequestBody 用于接收json数据
@PathVariable 用于接收路径参数，使用{参数名称}描述路径参数

package com.wu.controller;

import com.wu.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;


@Controller
public class UserController {

    @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':'user update'}";
    }

    @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'}";
    }
}

以图书信息管理为例进行代码优化

@RestController注解
类型：类注解
位置：基于SpringMvc的RESTful开发控制器类定义上方
作用：设置当前控制器类为RESTful风格，等同于@Controller与@ResponseBody两个注解组合功能

RESTful快速开发
名称：@GetMapping(GET) @PostMapping(POST) @PutMapping(PUT) @DeleteMapping(DELETE)
类型：方法注解
位置：基于SpringMVC的RESful开发控制器方法定义上方
作用：设置当前控制器方法请求访问路径与请求动作，每种对应一个请求动作

package com.wu.controller;
import com.wu.domain.Book;
import org.springframework.web.bind.annotation.*;

//@Controller
//@ResponseBody
@RestController // 将上方两个注解合二为一
@RequestMapping("/books")
public class BookController {

//    @RequestMapping(method = RequestMethod.POST)
    @PostMapping
    public String save(@RequestBody Book book) {
        System.out.println("book save ==> " + book);
        return "{'module':'book save'}";
    }

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

//    @RequestMapping(method = RequestMethod.PUT)
    @PutMapping
    public String update(@RequestBody Book book) {
        System.out.println("book update ==> " + book);
        return "{'module':'book update'}";
    }

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

//    @RequestMapping(method = RequestMethod.GET)
    @GetMapping
    public String getAll() {
        System.out.println("book getAll");
        return "{'module':'book getAll'}";
    }
}