springboot整合mybatis实现数据的持久化

之前我们分别使用了spring-data-jpa和jdbcTemplate实现对数据的增删改查,这一篇我们使用更加常用的方法实现数据的持久化,整合mybatis。

我们依然通过做一个实例来学习,始终相信先看着做出来,再加强理论,搞清原理的学习方法比较快。

下图是项目整体结构:

springboot整合mybatis实现数据的持久化

新建一个MySQL数据库,这里数据库名为springboot,建立user_t数据表,作为我们示例操作的表对象。

user_t信息如下:

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SET FOREIGN_KEY_CHECKS=0;
 
-- ----------------------------
-- Table structure for user_t
-- ----------------------------
DROP TABLE IF EXISTS `user_t`;
CREATE TABLE `user_t` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(255) NOT NULL,
  `password` varchar(255) NOT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for user_t
-- ----------------------------
DROP TABLE IF EXISTS `user_t`;
CREATE TABLE `user_t` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_name` varchar(255) NOT NULL,
`password` varchar(255) NOT NULL,
`age` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

数据库及表创建成功后,回到我们的工程中

第零步,我们这里集成druid,使用连接池,引入mybatis及druid的依赖包:

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<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
 
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
 
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.0</version>
        </dependency>
    </dependencies>

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

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>

<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.0</version>
</dependency>
</dependencies>

第一步,在yml配置文件中配置数据源、Mybatis的实体和配置文件路径:

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mybatis:
  typeAliasesPackage: com.javazhiyin.entity
  mapperLocations: classpath:mapper/*.xml
 
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 1011

spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 1011

第二步,创建一个实体类,对应数据表实体映射:

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package com.javazhiyin.entity;
 
/**
* Created by 57783 on 2018/7/6.
*/
public class User {
    private Integer id;
 
    private String userName;
 
    private String password;
 
    private Integer age;
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getUserName() {
        return userName;
    }
 
    public void setUserName(String userName) {
        this.userName = userName == null ? null : userName.trim();
    }
 
    public String getPassword() {
        return password;
    }
 
    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
}

/**
* Created by 57783 on 2018/7/6.
*/
public class User {
private Integer id;

private String userName;

private String password;

private Integer age;

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getUserName() {
return userName;
}

public void setUserName(String userName) {
this.userName = userName == null ? null : userName.trim();
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password == null ? null : password.trim();
}

public Integer getAge() {
return age;
}

public void setAge(Integer age) {
this.age = age;
}
}

第三步,写DAO接口(增删改查):

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package com.javazhiyin.dao;
 
import com.javazhiyin.entity.User;
 
import java.util.List;
 
/**
* Created by 57783 on 2018/7/6.
*/
public interface UserDao {
 
    List<User> findAll();
 
    void addUser(User user);
 
    void updUser(User user);
 
    int delUser(Integer id);
 
}

import com.javazhiyin.entity.User;

import java.util.List;

/**
* Created by 57783 on 2018/7/6.
*/
public interface UserDao {

List<User> findAll();

void addUser(User user);

void updUser(User user);

int delUser(Integer id);

}

第四步,编写xml映射文件:

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.javazhiyin.dao.UserDao" >
 
    <resultMap id="BaseResultMap" type="com.javazhiyin.entity.User" >
        <id column="id" property="id" jdbcType="INTEGER" />
        <result column="user_name" property="userName" jdbcType="VARCHAR" />
        <result column="password" property="password" jdbcType="VARCHAR" />
        <result column="age" property="age" jdbcType="INTEGER" />
    </resultMap>
 
    <sql id="Base_Column_List" >
        id, user_name, password, age
    </sql>
 
    <select id="findAll" resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List" />
        from user_t
    </select>
 
    <insert id="addUser" parameterType="com.javazhiyin.entity.User">
        insert into user_t (user_name, password, age)
        values (#{userName,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
        #{age,jdbcType=INTEGER})
    </insert>
 
    <update id="updUser" parameterType="com.javazhiyin.entity.User" >
        update user_t
        set user_name = #{userName,jdbcType=VARCHAR},
        password = #{password,jdbcType=VARCHAR},
        age = #{age,jdbcType=INTEGER}
        where id = #{id,jdbcType=INTEGER}
    </update>
 
    <delete id="delUser" parameterType="java.lang.Integer" >
            delete from user_t
            where id = #{id,jdbcType=INTEGER}
        </delete>
 
</mapper>

<resultMap id="BaseResultMap" type="com.javazhiyin.entity.User" >
<id column="id" property="id" jdbcType="INTEGER" />
<result column="user_name" property="userName" jdbcType="VARCHAR" />
<result column="password" property="password" jdbcType="VARCHAR" />
<result column="age" property="age" jdbcType="INTEGER" />
</resultMap>

<sql id="Base_Column_List" >
id, user_name, password, age
</sql>

<select id="findAll" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from user_t
</select>

<insert id="addUser" parameterType="com.javazhiyin.entity.User">
insert into user_t (user_name, password, age)
values (#{userName,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
#{age,jdbcType=INTEGER})
</insert>

<update id="updUser" parameterType="com.javazhiyin.entity.User" >
update user_t
set user_name = #{userName,jdbcType=VARCHAR},
password = #{password,jdbcType=VARCHAR},
age = #{age,jdbcType=INTEGER}
where id = #{id,jdbcType=INTEGER}
</update>

<delete id="delUser" parameterType="java.lang.Integer" >
delete from user_t
where id = #{id,jdbcType=INTEGER}
</delete>

</mapper>

第五步,编写Service接口

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package com.javazhiyin.service;
 
import com.javazhiyin.entity.User;
 
import java.util.List;
 
/**
* Created by 57783 on 2018/7/6.
*/
public interface UserService {
    List<User> getUser();
 
    void addUser(User user);
 
    void updUser(User user);
 
    int delUser(Integer id);
 
}

import com.javazhiyin.entity.User;

import java.util.List;

/**
* Created by 57783 on 2018/7/6.
*/
public interface UserService {
List<User> getUser();

void addUser(User user);

void updUser(User user);

int delUser(Integer id);

}

第六步,Service接口的实现类:

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package com.javazhiyin.service.impl;
 
import com.javazhiyin.dao.UserDao;
import com.javazhiyin.entity.User;
import com.javazhiyin.service.UserService;
import org.springframework.stereotype.Service;
 
import javax.annotation.Resource;
import java.util.List;
 
/**
* Created by 57783 on 2018/7/6.
*/
@Service("userService")
public class UserServiceImpl implements UserService {
 
    @Resource
    private UserDao userDao;
 
 
    public List<User> getUser() {
        return userDao.findAll();
    }
 
    public void addUser(User user){
        userDao.addUser(user);
    }
 
    public void updUser(User user){
        userDao.updUser(user);
    }
 
    public int delUser(Integer id){
        return userDao.delUser(id);
    }
 
}

import com.javazhiyin.dao.UserDao;
import com.javazhiyin.entity.User;
import com.javazhiyin.service.UserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
* Created by 57783 on 2018/7/6.
*/
@Service("userService")
public class UserServiceImpl implements UserService {

@Resource
private UserDao userDao;

public List<User> getUser() {
return userDao.findAll();
}

public void addUser(User user){
userDao.addUser(user);
}

public void updUser(User user){
userDao.updUser(user);
}

public int delUser(Integer id){
return userDao.delUser(id);
}

}

第七步,新建一个Controller类,实现增删改查操作接口:

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package com.javazhiyin.controller;
 
import com.javazhiyin.entity.User;
import com.javazhiyin.service.UserService;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.List;
 
/**
* Created by 57783 on 2018/7/6.
*/
@RestController
public class UserController {
    @Resource
    private UserService userService;
 
    @GetMapping("/showUser")
    public List<User> getUser(){
        List<User> user = this.userService.getUser();
        return user;
    }
 
    @PostMapping(value = "/addUser")
    public void addUser(@RequestParam("username") String username,
                            @RequestParam("password") String password,
                        @RequestParam("age") Integer age){
        User user = new User();
        user.setUserName(username);
        user.setPassword(password);
        user.setAge(age);
        userService.addUser(user);
    }
 
    @PutMapping(value = "updUser/{id}")
    public void updUser(@PathVariable("id") Integer id,
                            @RequestParam("username") String username,
                            @RequestParam("password") String password,
                           @RequestParam("age") Integer age){
        User user = new User();
        user.setId(id);
        user.setUserName(username);
        user.setPassword(password);
        user.setAge(age);
        userService.updUser(user);
 
    }
 
    @DeleteMapping(value = "delUser/{id}")
    public void delUser(@PathVariable("id") Integer id){
        userService.delUser(id);
    }
 
}

import com.javazhiyin.entity.User;
import com.javazhiyin.service.UserService;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import java.util.List;

/**
* Created by 57783 on 2018/7/6.
*/
@RestController
public class UserController {
@Resource
private UserService userService;

@GetMapping("/showUser")
public List<User> getUser(){
List<User> user = this.userService.getUser();
return user;
}

@PostMapping(value = "/addUser")
public void addUser(@RequestParam("username") String username,
@RequestParam("password") String password,
@RequestParam("age") Integer age){
User user = new User();
user.setUserName(username);
user.setPassword(password);
user.setAge(age);
userService.addUser(user);
}

@PutMapping(value = "updUser/{id}")
public void updUser(@PathVariable("id") Integer id,
@RequestParam("username") String username,
@RequestParam("password") String password,
@RequestParam("age") Integer age){
User user = new User();
user.setId(id);
user.setUserName(username);
user.setPassword(password);
user.setAge(age);
userService.updUser(user);

}

@DeleteMapping(value = "delUser/{id}")
public void delUser(@PathVariable("id") Integer id){
userService.delUser(id);
}

}

最后,我们修改Bootdemo03Application启动类,添加@MapperScan注解,使其可以扫描DAO层接口:

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package com.javazhiyin;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
 
@SpringBootApplication
@MapperScan("com.javazhiyin.dao")
public class Bootdemo03Application extends SpringBootServletInitializer {
 
    public static void main(String[] args) {
        SpringApplication.run(Bootdemo03Application.class, args);
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
@MapperScan("com.javazhiyin.dao")
public class Bootdemo03Application extends SpringBootServletInitializer {

public static void main(String[] args) {
SpringApplication.run(Bootdemo03Application.class, args);
}
}

这样,我们就实现了springboot整合mybatis完成对数据简单的增删改查的demo,我们测试一下所写的程序是否可以正常工作:

查询测试:

springboot整合mybatis实现数据的持久化

新增测试:

springboot整合mybatis实现数据的持久化

修改测试:

springboot整合mybatis实现数据的持久化

删除测试:

springboot整合mybatis实现数据的持久化

我们可以看到可以全部测试通过。

几个问题:

1、@Resource注解的理解?
@Resource的作用相当于@Autowired,只不过@Autowired按byType自动注入,而@Resource默认按 byName自动注入罢了。@Resource有两个属性是比较重要的,分是name和type,Spring将@Resource注解的name属性解析为bean的名字,而type属性则解析为bean的类型。所以如果使用name属性,则使用byName的自动注入策略,而使用type属性时则使用byType自动注入策略。如果既不指定name也不指定type属性,这时将通过反射机制使用byName自动注入策略。
@Resource装配顺序
1. 如果同时指定了name和type,则从Spring上下文中找到唯一匹配的bean进行装配,找不到则抛出异常
2. 如果指定了name,则从上下文中查找名称(id)匹配的bean进行装配,找不到则抛出异常
3. 如果指定了type,则从上下文中找到类型匹配的唯一bean进行装配,找不到或者找到多个,都会抛出异常
4. 如果既没有指定name,又没有指定type,则自动按照byName方式进行装配;如果没有匹配,则回退为一个原始类型进行匹配,如果匹配则自动装配;

2、@Autowired 与@Resource的区别:
1、 @Autowired与@Resource都可以用来装配bean. 都可以写在字段上,或写在setter方法上。
2、 @Autowired默认按类型装配,默认情况下必须要求依赖对象必须存在,如果要允许null值,可以设置它的required属性为false,如:@Autowired(required=false) 。
3、@Resource,默认安装名称进行装配,名称可以通过name属性进行指定,如果没有指定name属性,当注解写在字段上时,默认取字段名进行安装名称查找,如果注解写在setter方法上默认取属性名进行装配。当找不到与名称匹配的bean时才按照类型进行装配。但是需要注意的是,如果name属性一旦指定,就只会按照名称进行装配。

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