RESTful style, exception handling, Spring Framework

1.RESTful style

What is RESTful style?
- REpressentational State Transfer REST is an acronym, the Chinese translation for the Representational State Transfer, REST is an architecture, and HTTP is a REST framework agreement contains the property, in order to facilitate understanding, we have split it into different initials of several parts:
  - Representational (REpressentational): REST resources can actually be expressed in a variety of forms, including XML, JSON, or even HTML-- most suitable for any form of resource users;
  - State (State): When was using REST, we are more concerned about the state of the resource rather than the behavior of resources taken;
  - Escape (Transfer): REST resource data related to escape, it is transferred in some form of expression from one application to another
Simply put, REST is the state of the resource to suit the client or server in the form of transfer from the server to the client (or vice versa). In REST, to identify and locate resources by URL, and then REST is defined by behavior (ie HTTP methods) to complete what function.

Example shows

In the usual Web development, forms method attribute values are commonly used in the POST and GET, but in fact, HTTP methods other values PATCH, DELETE, PUT, etc. These methods generally matching CRUD actions of:

CRUD action	HTTP method
Create (increase)	POST
Select (check)	GET
Update（改）	PUT or PATCH
Delete (删)	DELETE

Before using RESTful style, we have added a product data is this:
/addProduct?name=xxx
it will become after using a RESTful style:

/product

This became to use the same URL, to implement different business agreement through different HTTP methods, this is the style of doing things RESTful

User User entity class

package com.alibaba.wlq.bean;

public class User {
    @Override
    public String toString() {
        return "User [account=" + account + ", password=" + password + ", phone=" + phone + "]";
    }

    private String account;
    private String password;
    private String phone;

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public User(String account, String password, String phone) {
        super();
        this.account = account;
        this.password = password;
        this.phone = phone;
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account;
    }

    public String getPassword() {
        return password;
    }

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

    public User(String account, String password) {
        super();
        this.account = account;
        this.password = password;
    }

    public User() {
        super();
    }
    
}

Controller control class

package com.alibaba.wlq.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.alibaba.wlq.bean.User;
@Controller
@RequestMapping("user")
public class UserController {
    //RESTful--->user/1
    //method：表示该方法处理get请求
    //1赋值给了{uid}了    
    @RequestMapping(value="{uid}",method=RequestMethod.GET)//查询操作
    public String selectById(@PathVariable("uid")int id) {//@PathVariable：把uid的值赋值给形参id
        System.out.println("id====="+id);
        return "index";
    }
    @RequestMapping(value="{uid}",method=RequestMethod.POST)//添加操作
    public String addUser(@PathVariable("uid")int id,User user) {
        System.out.println(user);
        System.out.println("id====="+id);
        return "index";
    }
    //SpringMVC提供了一个过滤器，该过滤器可以把post请求转化为put和delete请求
    @RequestMapping(method=RequestMethod.PUT)//修改操作
    @ResponseBody
    public String updateUser(User user) {
        System.out.println(user+"======update");
        return "index";
    }
    @RequestMapping(value="{id}",method=RequestMethod.DELETE)//删除操作
    @ResponseBody
    public String deleteById(@PathVariable int id) {
        System.out.println(id+"=====delete");
        return "index";
    }
}

Arranged filter configuration file web.xml

<!-- 把post请求转化为put和delete请求
    使用_method表示真正的提交方式 -->
<filter>
    <filter-name>hiddenHttpMethodFilter</filter-name>
    <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>hiddenHttpMethodFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

index interface

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="/9.5springmvcdemo/js/jquery-3.2.1.min.js"></script>
<script type="text/javascript">
    $.ajax({
        url:"../user",
        type:"POST",
        data:{
            _method:"PUT",
            "account":"zhangsan",
            "password":"123456",
            "phone":"18360917652"
        },
        success:function(result){
            alert(result);
        }
    });
    
</script>
</head>
<body>
index界面
</body>
</html>

2. Exception Handling

Global exception handler

package com.alibaba.wlq.controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;
@ControllerAdvice
public class ExceptionController {
 @ExceptionHandler
 public ModelAndView error(Exception exception) {
     ModelAndView mv = new  ModelAndView();
     mv.addObject("error",exception.getMessage());
     mv.setViewName("error");
     return mv;
 }
}

3.Spring framework

Spring is an open source framework

Join jar package
Join Profiles