【SpringBoot】Service和Dao的编写

浅浅的花香味﹌ 2022-12-22 11:26 104阅读 0赞

# 效果图 #

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# 配置环境 #

## 创建数据库 ##

数据库中文编码  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQ2OTY4MA_size_16_color_FFFFFF_t_70_pic_center 1]  
建表

create table `student` (
    	`id` int(11) Not NULL AUTO_INCREMENT COMMENT '主键自增id',
    	`name` varchar(250) NOT NULL DEFAULT ' ' COMMENT '姓名',
    	PRIMARY KEY(`id`)
    )ENGINE=INNODB DEFAULT CHARSET=utf8;

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQ2OTY4MA_size_16_color_FFFFFF_t_70_pic_center 2]

## pom依赖和配置 ##

mybatis 和 mysql

<dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.1</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>

application.properties

# mysql
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/rxguo_test?serverTimezone=UTC&characterEncoding=utf8&useSSL=false
    spring.datasource.username=root
    spring.datasource.password=

# java #

## bean ##

package com.bennyrhys.com.shop.bean;
    
    public class Student { 
        Integer id;
        String name;
    
        public Integer getId() { 
            return id;
        }
    
        public void setId(Integer id) { 
            this.id = id;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        @Override
        public String toString() { 
            return "Student{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    '}';
        }
    }

## Controller ##

package com.bennyrhys.com.shop;
    
    import com.bennyrhys.com.shop.bean.Student;
    import com.bennyrhys.com.shop.service.StudentService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class StudentController { 
        @Autowired
        StudentService studentService;
    
        @GetMapping("/student")
        public String getStudentById(@RequestParam Integer id) { 
            Student student = studentService.getStudentById(id);
            return student.toString();
        }
    }

## Service ##

package com.bennyrhys.com.shop.service;
    
    import com.bennyrhys.com.shop.bean.Student;
    import com.bennyrhys.com.shop.mapper.StudentMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    @Service
    public class StudentService { 
    
        @Autowired
        StudentMapper studentMapper;
    
        public Student getStudentById(Integer id) { 
            return studentMapper.getStudentById(id);
        }
    }

## Mapper接口 ##

package com.bennyrhys.com.shop.mapper;
    
    import com.bennyrhys.com.shop.bean.Student;
    import org.apache.ibatis.annotations.Mapper;
    import org.apache.ibatis.annotations.Select;
    import org.springframework.stereotype.Repository;
    
    
    @Mapper
    @Repository
    public interface StudentMapper { 
        @Select("select * from student where id = #{id}")
        Student getStudentById(Integer id);
    }

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