新手接触springboot

新手使用springboot或者说，刚接触java行业，有些不明白的就是项目的架构是怎么样的，我今天在这儿稍微整理了一下

有些新手可能在想，springboot是怎么解决最原始的增-删-改-查，

快速搭建是多么舒服的一件事，哈哈

今天，火浴带大家哎熟悉一下流程

1、首先创建一个springboot的工程

2、点击继续

3、这里可以什么都不选，要是你会的话，可以选

4、改好你的项目名称和路劲后点击完成

5、这是我的maven依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency>

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

6、这是yml的配置

server:
  port: 9000

# mysql
spring:
  datasource:
    #MySQL\u914D\u7F6E
    driverClassName:  com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/easyproject?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC
    username: root
    password: root
#mybatis\u914D\u7F6E
mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.example.demo.model

7、我们先介绍查询所有的方法，这是dao层，

添加

public List<User> getAllUser(@Param("username") String username,@Param("pageStart") int pageStart, @Param("pageSize") int pageSize);

8、编写原生xml，里面是mysql的 查询语句

    <select id="getAllUser" resultType="com.springboot_sport.entity.User">
        SELECT * FROM easyUser
        <if test="username !=null ">
            WHERE username like #{username}
        </if>
        LIMIT #{pageStart},#{pageSize}
    </select>

9、定义entity类，里面的内容是你查询的数据库的字段

生成get、set方法，可能小伙伴不会，2020版的快捷键是shift+alt+s，，或者你鼠标右键Generate。。。这个也可以看到

10、定义Contronller接口，我用的前端框架是vue的

package com.springboot_sport.controller;

import com.alibaba.fastjson.JSON;
import com.springboot_sport.entity.QueryInfo;
import com.springboot_sport.dao.UserDao;
import com.springboot_sport.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.List;

/**
 * @author huoyu Email:23198997662@qq.com
 * @version v1.0
 * @Description
 * @create 2020--09--1621:17
 */
@RestController
public class UserController {
@Autowired
    private UserDao uDao;
@RequestMapping("/alluser")
    public String getUserList(QueryInfo queryInfo){
        //获取最大列表数和当前编号
        int numbers = uDao.getUserCounts("%" + queryInfo.getQuery() + "%");
        int pageStart = (queryInfo.getPageNum() - 1) * queryInfo.getPageSize();
        List<User> users = uDao.getAllUser("%" + queryInfo.getQuery() + "%", pageStart, queryInfo.getPageSize());
        HashMap<String, Object> res = new HashMap<>();
        res.put("unmbers",numbers);
        res.put("data",users);
        String res_string = JSON.toJSONString(res);
        return res_string;
    }
}

这样一个查询接口就相当于做完了，我在给大家说一个就是关于springboot+vue的跨域问题怎么解决的

![](https://img2020.cnblogs.com/blog/1566889/202009/1566889-20200921115941604-1252214819.png)

下面是代码

package com.springboot_sport.util;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.config.annotation.CorsRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**

• @author huoyu Email:23198997662@qq.com

• @version v1.0

• @Description

• @create 2020--09--0223:05
  
  */
  
  //全局配置类--配置跨域请求
  
  @Configuration
  
  public class WebConfig extends WebMvcConfigurerAdapter {

  @Override
  
  public void addCorsMappings(CorsRegistry registry) {
  
  registry.addMapping("/**")
  
  .allowedMethods("")
  
  .allowedOrigins("")
  
  .allowedHeaders("*");
  
  super.addCorsMappings(registry);
  
  }
  
  }

好了，完成