How to use Java SSM to implement joint debugging of front-end and back-end protocols

Environment preparation

The project structure is the same as before:

We add new static resources:

Because static resources are added, SpringMVC will intercept them. All static resources need to be released in the SpringConfig configuration class:

We create a new SpringMvcSupport

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
        registry.addResourceHandler("/css/**").addResourceLocations("/css/");
        registry.addResourceHandler("/js/**").addResourceLocations("/js/");
        registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins/");
    }
}

After the configuration is completed, we need to Scan SpringMvcSupport in SpringMvcConfig:

@Configuration
@ComponentScan({"com.nefu.controller","com.nefu.config"})
@EnableWebMvc
public class SpringMvcConfig {
}

Next we need to implement all list query, addition, modification, deletion and other functions one by one.

List function

Requirements: After the page is loaded, send an asynchronous request to the background to obtain the list data for display.

• Find the hook function of the page, created()

• created() method Called the this.getAll() method

• Use axios in the getAll() method to send an asynchronous request to obtain data from the background

• The access path is http://localhost/books

• Return data

Return data res. The content of data is as follows:

{
"data": [
" "id": 1,
"type": "Computer Theory",
"name": "Spring Practical Fifth Edition",
"Description": "Classic tutorial for getting started with Spring, in-depth understanding of Spring principles and technology"
},
"id": 2 ,
        "type": "Computer Theory",
        "name": "Spring 5 Core Principles and 30 Kinds of Handwriting Practice",
        "description": "Ten Years of Precipitation,  The Essence of Handwriting Spring Thoughts"
},...
],
"code": 20041,
"msg": ""
}

Sending method:

getAll() {
    //发送ajax请求
    axios.get("/books").then((res)=>{
        this.dataList = res.data.data;
    });
}

Add function

Requirement: Complete the new function module of the picture

Find the new button on the page, which is bound to
1. @click="handleCreate()"

   Method

Find
2. handleCreate in method

   Method, open the new panel in the method

Find the OK button in the new panel, the button is bound
3. @click="handleAdd()"

   Method

Find in method
4. handleAdd

   Method

Send the request and data in the method. After the response is successful, the new Close the new panel and query the data again
##handleCreate

Open the new panel

handleCreate() {
    this.dialogFormVisible = true;
},

handleAdd

The method sends an asynchronous request and carries Data

handleAdd () {
    //发送ajax请求
    //this.formData是表单中的数据，最后是一个json数据
    axios.post("/books",this.formData).then((res)=>{
        this.dialogFormVisible = false;
        this.getAll();
    });
}

Add function status processing

The basic new functions have been completed, but there are still some problems that need to be solved:

Requirements: The panel is closed if the new addition is successful. Query the data again, what should you do if the new addition fails?

1. In the handlerAdd method, perform different processing according to the data returned by the background

2. If the background returns success, It will prompt a success message and close the panel

3. If the background returns failure, it will prompt an error message

(1) Modify the front-end page

handleAdd () {
    //发送ajax请求
    axios.post("/books",this.formData).then((res)=>{
        //如果操作成功，关闭弹层，显示数据
        if(res.data.code == 20011){
            this.dialogFormVisible = false;
            this.$message.success("添加成功");
        }else if(res.data.code == 20010){
            this.$message.error("添加失败");
        }else{
            this.$message.error(res.data.msg);
        }
    }).finally(()=>{
        this.getAll();
    });
}

(2)Backend Return the operation result and change the return value of the Dao layer's addition, deletion and modification methods from

void

to

int

public interface BookDao {
//    @Insert("insert into tbl_book values(null,#{type},#{name},#{description})")
    @Insert("insert into tbl_book (type,name,description) values(#{type},#{name},#{description})")
    public int save(Book book);
    @Update("update tbl_book set type = #{type}, name = #{name}, description = #{description} where id = #{id}")
    public int update(Book book);
    @Delete("delete from tbl_book where id = #{id}")
    public int delete(Integer id);
    @Select("select * from tbl_book where id = #{id}")
    public Book getById(Integer id);
    @Select("select * from tbl_book")
    public List<Book> getAll();
}

(3) In BookServiceImpl, the addition, deletion and modification methods are based on DAO's The return value determines whether to return true/false

@Service
public class BookServiceImpl implements BookService {
    @Autowired
    private BookDao bookDao;
    public boolean save(Book book) {
        return bookDao.save(book) > 0;
    }
    public boolean update(Book book) {
        return bookDao.update(book) > 0;
    }
    public boolean delete(Integer id) {
        return bookDao.delete(id) > 0;
    }
    public Book getById(Integer id) {
        if(id == 1){
            throw new BusinessException(Code.BUSINESS_ERR,"请不要使用你的技术挑战我的耐性!");
        }
//        //将可能出现的异常进行包装，转换成自定义异常
//        try{
//            int i = 1/0;
//        }catch (Exception e){
//            throw new SystemException(Code.SYSTEM_TIMEOUT_ERR,"服务器访问超时，请重试!",e);
//        }
        return bookDao.getById(id);
    }
    public List<Book> getAll() {
        return bookDao.getAll();
    }
}

(4) To test the error situation, set the book category length out of the range

After processing the new addition Afterwards, you will find that there is still a problem with the new addition.

After the new addition is successful, if you click the Add button again, you will find that the previous data still exists. At this time, you need to clear the form content when adding.

resetForm(){
	this.formData = {};
}
handleCreate() {
    this.dialogFormVisible = true;
    this.resetForm();
}

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