1. application.properties增加spring配置資料庫連結地址

spring.datasource.url=jdbc:mysql://localhost:3306/***?useUnicode=true&characterEncoding=utf8&useSSL=false
spring.datasource.username=***
spring.datasource.password=***
mybatis.config-location=classpath:mybatis-config.xml

在resource下面新建一個mybatis-config.xml，如圖

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        <!-- Globally enables or disables any caches configured in any mapper under this configuration -->
        <setting name="cacheEnabled" value="true"/>
        <!-- Sets the number of seconds the driver will wait for a response from the database -->
        <setting name="defaultStatementTimeout" value="3000"/>
        <!-- Enables automatic mapping from classic database column names A_COLUMN to camel case classic Java property names aColumn -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <!-- Allows JDBC support for generated keys. A compatible driver is required.
        This setting forces generated keys to be used if set to true,
         as some drivers deny compatibility but still work -->
        <setting name="useGeneratedKeys" value="true"/>
    </settings>

    <!-- Continue going here -->

</configuration>
 

2. pom.xml引入mybatis-spring-boot-starter和mysql-connector-java

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.1.1</version>
		</dependency>
 

3. http://www.mybatis.org/mybatis3/zh/index.html3. （MyBatis官方網站，推薦學習）
4. 演示如何利用MyBatis操作資料庫
   新建和資料苦欄位相同的實體類

package com.nowcoder.model;
public class User {
    private int id;
    private String name;
    private String password;
    private String salt;
    private String headUrl;
    public User() {
    }
    public User(String name) {
        this.name = name;
        this.password = "";
        this.salt = "";
        this.headUrl = "";
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

    public String getSalt() {
        return salt;
    }
    public void setSalt(String salt) {
        this.salt = salt;
    }
    public String getHeadUrl() {
        return headUrl;
    }
    public void setHeadUrl(String headUrl) {
        this.headUrl = headUrl;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
}

在Dao層，新建UserDao介面

package com.nowcoder.dao;

import com.nowcoder.model.User;
import org.apache.ibatis.annotations.*;

@Mapper
public interface UserDAO {
    // 注意空格
    String TABLE_NAME = " user ";
    String INSERT_FIELDS = " name, password, salt, head_url ";
    String SELECT_FIELDS = " id, " + INSERT_FIELDS;

    @Insert({"insert into ", TABLE_NAME, "(", INSERT_FIELDS,
            ") values (#{name},#{password},#{salt},#{headUrl})"})
    int addUser(User user);

    @Select({"select ", SELECT_FIELDS, " from ", TABLE_NAME, " where id=#{id}"})
    User selectById(int id);

    @Update({"update ", TABLE_NAME, " set password=#{password} where id=#{id}"})
    void updatePassword(User user);

    @Delete({"delete from ", TABLE_NAME, " where id=#{id}"})
    void deleteById(int id);
}

這裡採用註解方式寫入SQL語句，當sql語句比較麻煩的時候，我們選用xml來寫sql語句
接下來，就可以定義一個測試用例，呼叫userDao操作資料庫。

package com.nowcoder;

import com.nowcoder.dao.QuestionDAO;
import com.nowcoder.dao.UserDAO;
import com.nowcoder.model.Question;
import com.nowcoder.model.User;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.jdbc.Sql;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;

import java.util.Date;
import java.util.Random;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = WendaApplication.class)
@Sql("/init-schema.sql")
public class InitDatabaseTests {
    @Autowired
    UserDAO userDAO;

    @Autowired
    QuestionDAO questionDAO;

    @Test
    public void contextLoads() {
        Random random = new Random();
        for (int i = 0; i < 11; ++i) {
            User user = new User();
            user.setHeadUrl(String.format("http://images.nowcoder.com/head/%dt.png", random.nextInt(1000)));
            user.setName(String.format("USER%d", i));
            user.setPassword("");
            user.setSalt("");
            userDAO.addUser(user);

            user.setPassword("newpassword");
            userDAO.updatePassword(user);

            Question question = new Question();
            question.setCommentCount(i);
            Date date = new Date();
            date.setTime(date.getTime() + 1000 * 3600 * 5 * i);
            question.setCreatedDate(date);
            question.setUserId(i + 1);
            question.setTitle(String.format("TITLE{%d}", i));
            question.setContent(String.format("Balaababalalalal Content %d", i));
            questionDAO.addQuestion(question);
        }

        Assert.assertEquals("newpassword", userDAO.selectById(1).getPassword());
        userDAO.deleteById(1);
        Assert.assertNull(userDAO.selectById(1));
    }
}

這樣就可以完成對資料庫的操作了。