JavaWeb笔记_10

SpringBoot 项目练习

1. 创建SpringBoot项目

2. 编辑 application.properties 配置文件

#驱动类名称
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#数据库连接的url
spring.datasource.url=jdbc:mysql://localhost:3306/tliasdb
#连接数据库的用户名
spring.datasource.username=root
#连接数据库的密码
spring.datasource.password=root

#配置mybatis的日志, 指定输出到控制台
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
#开启mybatis的驼峰命名自动映射开关 a_column ------> aCloumn
mybatis.configuration.map-underscore-to-camel-case=true

3. 创建实体类

• 编辑统一结果实体

package com.practice.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Result {
    private Integer code;//响应码，1 代表成功; 0 代表失败
    private String msg;  //响应信息 描述字符串
    private Object data; //返回的数据
    //增删改 成功响应
    public static Result success(){
        return new Result(1,"success",null);
    }
    //查询 成功响应
    public static Result success(Object data){
        return new Result(1,"success",data);
    }
    //失败响应
    public static Result error(String msg){
        return new Result(0,msg,null);
    }
}

4. 创建web三层架构

5. 为各层添加接口

• 控制层(Controller)
  • 添加 @RestController 注解，该注解包含了@Controller和@ResponseBody
• 服务层(Service)
  • 添加@Service注解
• 持久层(Dao)
  • 添加@Mapper注解

6. 代码实现

• 控制层

package com.practice.controller;
import com.practice.pojo.Account;
import com.practice.pojo.Result;
import com.practice.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class AccountController {
    @Autowired
    AccountService as;
    @RequestMapping("/hello")
    Result findAll() {
        List<Account> list = as.findAll();
        list.forEach(System.out::println);
        return Result.success(list);
    }
}

• 服务层
  
  
  接口

package com.practice.service;
import com.practice.pojo.Account;
import org.springframework.stereotype.Service;
import java.util.List;
public interface AccountService {
    List<Account> findAll();
}

**实现类**

package com.practice.service.impl;
import com.practice.mapper.AccountMapper;
import com.practice.pojo.Account;
import com.practice.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    AccountMapper am;
    @Override
    public List<Account> findAll() {
        return am.findAll();
    }
}

• 持久层

package com.practice.mapper;
import com.practice.pojo.Account;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import java.util.List;
@Mapper
public interface AccountMapper {
    @Select("select * from account")
    List<Account> findAll();
}

• 数据库内容
  
• 浏览器访问结果