Coding style: SSM environment in MVC mode, code hierarchical management

Want to make APP Same thing as WeChat , Can run small programs smoothly ？ | Experience will send you to Xinjiang 、 Huawei 、 Cherry keyboard ！>>>

​MVC Pattern and code layering strategy ,MVC The full name is ModelViewController The model － View － controller , As a software design paradigm , Using a business logic 、 data 、 The interface displays the separated method organization code , Gather business logic into a component , While improving and personalizing the interface and user interaction , No need to rewrite business logic , It's a development model , But it's not the layered pattern of code in actual development

In this paper, the source code ：GitHub· Click here || GitEE· Click here

One 、 Layering strategy

MVC Pattern and code layering strategy ,MVC The full name is ModelViewController The model － View － controller , As a software design paradigm , Using a business logic 、 data 、 The interface displays the separated method organization code , Gather business logic into a component , While improving and personalizing the interface and user interaction , No need to rewrite business logic , It's a development model , But it's not the layered pattern of code in actual development , Usually SSM The framework's back-end code layers are as follows ：

• controller Control layer ： Define the server interface , In and out , And some input parameters ;
• service Business services layer ： Assemble business logic , Business verification , The parameter model needed to build the control layer ;
• dao Data interaction layer ： Provide the data query method needed by the service layer , Dealing with logic related to data interaction conditions ;
• mapper Persistence layer ： be based on mybatis The framework needs native support , The most commonly used persistence layer component at present ;

Two 、 Control layer

1、Rest The interface style

Based on the logic of resource access and processing , Use different styles of annotations . For example, new resources , to update , Inquire about , Delete .

/** *  newly added  */@PostMapping("/insert")public Integer insert (@RequestBody BaseInfo baseInfo){ return baseInfoService.insert(baseInfo);}/** *  to update  */@PutMapping("/update/{id}")public String update(@PathVariable(value = "id") Integer id,      @RequestBody BaseInfo baseInfo) { if (id<1){  return "error"; } baseInfo.setId(id); return "update="+baseInfoService.update(baseInfo);}/** *  Primary key query  */@GetMapping("/detail/{id}")public InfoModel detail(@PathVariable(value = "id") Integer id) { return baseInfoService.detail(id) ;}/** *  Delete primary key  */@DeleteMapping("/delete/{id}")public String delete(@PathVariable(value = "id") Integer id) { baseInfoService.delete(id) ; return "SUS" ;}

2、 Interface reuse

High reuse of interfaces is not recommended , For example, add, delete, modify and check all the interfaces , The basic principle of , Different client side operations , For independent interfaces .

/** *  List loading  */@GetMapping("/list")public List<BaseInfo> list() { return baseInfoService.list(new BaseInfoExample()) ;}/** *  List search  */@PostMapping("/search")public List<BaseInfo> search (@RequestParam("userName") String userName,        @RequestParam("phone") String phone) { return baseInfoService.search(userName,phone) ;}

For example, common list Interface ,list Usually, there will be conditional loading search Mechanism , And the search criteria are complex , It is suggested that there are two interfaces , From a practical point of view , Most of the scenarios are only used list Interface , Rarely used search Search for .

3、 In and out

Verification client must be conditional , For example, a certain condition is required , If there are questions , Quickly block the request link , The program entrance control layer intercepts and returns .

@PutMapping("/update/{id}")public String update(@PathVariable(value = "id") Integer id,      @RequestBody BaseInfo baseInfo) { if (id<1){  return "error"; } baseInfo.setId(id); return "update="+baseInfoService.update(baseInfo);}

The parameters are less than three , It can be displayed directly into the reference , If there are three or more parameters, entity classes can be used to encapsulate them .

@PostMapping("/search")public List<BaseInfo> search (@RequestParam("userName") String userName,        @RequestParam("phone") String phone) { return baseInfoService.search(userName,phone) ;}

4、 Processing parameters

The basic principle of the processing degree of the output parameter format , Servers as public resources , Avoid unnecessary operations , For example, the client can judge whether the return value is empty ,null etc. , Or some common format processing , Use the client to share the server pressure properly .

3、 ... and 、 Business services layer

1、 Business verification

For example, pass in the order number , Through the database layer query , No order data , This is called a business nature exception , There's no problem with the code itself , But business logic doesn't work properly .

public InfoModel detail(Integer id){ BaseInfo baseInfo = baseInfoDao.selectByPrimaryKey(id) ; if .........