Spring Boot一步步整合Mybatis框架

在這篇文章（http://www.lxweimin.com/p/483841e4b7d5）中創建的spring boot項目基礎上，進行mybatis整合。

1、引入相關依賴包：

 <!-- 連接MySQL數據庫 -->
 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<!-- mybatis相關包 -->
 <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>1.3.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.3</version>
</dependency>

<!-- Spring對JDBC數據訪問進行封裝的所有類 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
</dependency>

<!-- 數據庫連接池相關 -->
<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.1</version>
</dependency>

<!-- 支持 @ConfigurationProperties 注解 -->  
<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-configuration-processor</artifactId>  
    <optional>true</optional>  
</dependency>

2、在application.yml中spring節點下添加數據庫配置：

spring: 
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    username: root
    password: beibei
    url: jdbc:mysql://123.207.188.73:3306/beibeiDoc?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8&useSSL=false
    initialSize: 5
    minIdle: 5
    maxActive: 30
    maxWait: 60000
    showsql: true

注意：如果是版本號比較高的數據庫，url后面一定要加上 useSSL=false

3、創建DBProperties.java類，用來讀取數據庫配置：

package com.beibei.doc.config.properties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * 數據庫配置
 * @author beibei
 *
 */
@Component // 必須要有這個注解,否則無法在其他地方自動注入
@ConfigurationProperties(prefix="spring.datasource")//此處表示只讀取application.yml中spring下面的datasource下面的屬性
public class DBProperties {

//各個屬性名稱和application.yml中spring.datasource下面的各個屬性key一一對應
private String driverClassName;
private String url;
private String username;
private String password;
private String initialSize;
private String minIdle;
private String maxActive;
private String maxWait;
private String showsql;
//為了節省篇幅，此處略去getter、setter方法
}

4、創建DataBaseConfig.java類，以配置數據庫連接池、事務管理、
加載mapper.xml文件等，要注意各種注解的使用，類名隨意。

package com.beibei.doc.config;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executor;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.scheduling.annotation.AsyncConfigurerSupport;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import com.alibaba.druid.filter.Filter;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.wall.WallConfig;
import com.alibaba.druid.wall.WallFilter;
import com.beibei.doc.config.properties.DBProperties;


/**
 * 
 * @author beibei
 *
 */
@Configuration
@ComponentScan({
"com.beibei.doc.*.controller",
"com.beibei.doc.*.service"
})
@MapperScan({"com.beibei.doc.dao.*","com.beibei.doc.dao.*.ext"}) //dao層類所在包
@EnableTransactionManagement
@EnableScheduling
@EnableAsync
public class DataBaseConfig {

/**自動注入數據庫配置類*/
@Autowired 
private DBProperties db;

/**
 * 構建數據源
 * @return
 */
@Bean
public DataSource dataSource() {
    DruidDataSource dataSource = new DruidDataSource();
    dataSource.setDriverClassName(db.getDriverClassName());
    dataSource.setUrl(db.getUrl());
    dataSource.setUsername(db.getUsername());
    dataSource.setPassword(db.getPassword());
    // 配置初始化大小、最小、最大
    dataSource.setInitialSize(Integer.valueOf(db.getInitialSize()));
    dataSource.setMinIdle(Integer.valueOf(db.getMinIdle()));
    dataSource.setMaxActive(Integer.valueOf(db.getMaxActive()));
    // 配置獲取連接等待超時的時間
    dataSource.setMaxWait(Long.valueOf(db.getMaxWait()));
    //配置間隔多久才進行一次檢測，檢測需要關閉的空閑連接，單位是毫秒
    dataSource.setTimeBetweenEvictionRunsMillis(60000);
    //配置一個連接在池中最小生存的時間，單位是毫秒
    dataSource.setMinEvictableIdleTimeMillis(300000);

    //打開PSCache，并且指定每個連接上PSCache的大小
    //dataSource.setPoolPreparedStatements(true);
    //dataSource.setMaxPoolPreparedStatementPerConnectionSize(20);
    //禁用對于長時間不使用的連接強制關閉的功能
    dataSource.setRemoveAbandoned(false);
    
    try {
        WallConfig wc=new WallConfig();
        wc.setMultiStatementAllow(true);
        WallFilter wf=new WallFilter();
        wf.setConfig(wc);
        List<Filter> filters = new ArrayList<>();
        filters.add(wf);
        dataSource.setFilters("stat,wall");
        dataSource.setProxyFilters(filters);
    } catch (Exception e) {
        e.printStackTrace();
    }

    return dataSource;
}

@Bean
public PlatformTransactionManager transactionManager() {
    return new DataSourceTransactionManager(dataSource());
}

@Bean
public SqlSessionFactory sqlSessionFactory(){
    SqlSessionFactory factory = null;
    try {
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource());
        
        //讀取mybatis各個類的 *mapper.xml文件,這個地方的locationPattern一定要寫對，不然會找不到輸出到target\classes\mybatis\*目錄下的mapper.xml文件
        String locationPattern = "classpath*:/mybatis/*/*.xml";
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        Resource[] resources = resolver.getResources(locationPattern);
        List<Resource> filterResourceList = new ArrayList<Resource>();
        List<String> fileNameList = new ArrayList<String>();
        for (int i=0; i<resources.length; i++){
            Resource resource = resources[i];
            if(!fileNameList.contains(resource.getFilename())){
                filterResourceList.add(resource);
                fileNameList.add(resource.getFilename());
            }
        }

        Resource[] result = new Resource[filterResourceList.size()];
        sessionFactoryBean.setMapperLocations(filterResourceList.toArray(result));

        factory = (SqlSessionFactory) sessionFactoryBean.getObject();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return  factory;
}

@Bean
public AsyncConfigurerSupport configurerSupport(){
    return new AsyncConfigurerSupport(){
        @Override
        public Executor getAsyncExecutor() {
            ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
            executor.setCorePoolSize(10);
            executor.setMaxPoolSize(20);
            executor.setQueueCapacity(50000);
            executor.setThreadNamePrefix("DocThreadPool");
            executor.initialize();
            return executor;

        }

        @Override
        public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
            return super.getAsyncUncaughtExceptionHandler();
        }
    };
}
}

5、創建一張數據庫表

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `username` varchar(20) DEFAULT NULL COMMENT '用戶名',
  `password` varchar(100) DEFAULT NULL COMMENT '密碼',
  `age` int(3) DEFAULT NULL COMMENT '年齡',
  `sex` varchar(1) DEFAULT NULL COMMENT '性別',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

插入一條數據

Paste_Image.png

6、用相關工具生成該表對應的User.java類，UserExample.java類以及UserMapper.xml文件。這些文件放置目錄如下圖：

其中UserMapper.xml生成后記得要把其命名空間改成UserMapper.java的類全名稱，
其中引用到User.java、UserExample.java也要使用全名稱：

Paste_Image.png

7、創建BaseMapper.java類，該類中各個方法名稱和mapper.xml中各個select的id相同：

package com.beibei.doc.dao.base;

import java.util.List;
import org.apache.ibatis.annotations.Param;

/**
 * dao層基類
 * @author beibei
 *
 * @param <M> 實體類
 * @param <E> 實體類對應的mapper
 */
public interface BaseMapper<M, E> {

public int countByExample(E example);

public int deleteByExample(E example);

public int deleteByPrimaryKey(Integer id);

public int insert(M record);

public int insertSelective(M record);

public List<M> selectByExample(E example);

public M selectByPrimaryKey(Integer id);

public int updateByExampleSelective(@Param("record") M record, @Param("example") E example);

public int updateByExample(@Param("record") M record, @Param("example") E example);

public int updateByPrimaryKeySelective(M record);

public int updateByPrimaryKey(M record);
}

創建UserMapper.java繼承BaseMapper.java。（因為兩個類都是接口）

package com.beibei.doc.dao.user;

import com.beibei.doc.dao.base.BaseMapper;
import com.beibei.doc.model.user.User;
import com.beibei.doc.model.user.UserExample;

public interface UserMapper extends BaseMapper<User, UserExample> {

}

8、構建service層基類：

創建BaseService.java接口文件

package com.beibei.doc.service.base;
import java.util.List;

/**
 * service基類實現類
 * @author beibei 
 *
 * @param <M>  實體類
 * @param <E>  對應的mapper類
 */
public interface BaseService<M, E> {

/**
 * 通過id獲取數據
 * @param id
 * @return
 * @throws RuntimeException
 */
public M selectByPrimaryKey(Integer id) throws RuntimeException;

/**
 * 根據Example類進行查詢
 * @param example
 * @return
 * @throws RuntimeException
 */
public List<M> selectByExample(E example) throws RuntimeException;

/**
 * 根據主鍵刪除
 * @param id
 * @throws RuntimeException
 */
public int deleteByPrimaryKey(Integer id) throws RuntimeException;

/**
 * 根據Example類進行刪除
 * @param example
 * @throws RuntimeException
 */
public int deleteByExample(E example) throws RuntimeException;

/**
 * 插入數據（全值）
 * @param model
 * @throws RuntimeException
 */
public int insert(M model) throws RuntimeException;

/**
 * 插入數據（非空值）
 * @param model
 * @throws Exception
 */
public int insertSelective(M model) throws Exception;

/**
 * 根據Example類查詢數量
 * @param k
 * @return
 * @throws RuntimeException
 */
public Integer countByExample(E example) throws RuntimeException;

/**
 */
public int updateByExampleSelective(M model, E example) throws RuntimeException;

/**
 * 根據Example類更新對象
 * @param model 更新模版
 * @param example Example類
 * @throws RuntimeException
 */
public int updateByExample(M model, E example) throws RuntimeException;

/**
 * 根據主鍵更新對象（非空）
 * @param model
 * @throws RuntimeException
 */
public int updateByPrimaryKeySelective(M model) throws RuntimeException;

/**
 * 根據主鍵更新對象
 * @param model
 * @throws RuntimeException
 */
public int updateByPrimaryKey(M model) throws RuntimeException;
}

創建實現類BaseServiceImpl.java

package com.beibei.doc.service.base.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;

import com.beibei.doc.dao.base.BaseMapper;
import com.beibei.doc.service.base.BaseService;

/**
 * service層基類
 * @author beibei
 *
 * @param <M>
 * @param <E>
 */
public class BaseServiceImpl<M, E> implements BaseService<M, E> {

@Autowired
protected BaseMapper<M, E> baseMapper;

@Transactional(readOnly = true)
public M selectByPrimaryKey(Integer id) throws RuntimeException {
    return baseMapper.selectByPrimaryKey(id);
}

@Transactional(readOnly = true)
public List<M> selectByExample(E example) throws RuntimeException {
    return baseMapper.selectByExample(example);
}

public int deleteByPrimaryKey(Integer id) throws RuntimeException {
    return baseMapper.deleteByPrimaryKey(id);
}

public int deleteByExample(E example) throws RuntimeException {
    return baseMapper.deleteByExample(example);
}

public int insert(M model) throws RuntimeException {
    return baseMapper.insert(model);
}

public int insertSelective(M model) throws RuntimeException {
    return baseMapper.insertSelective(model);
}

public Integer countByExample(E example) throws RuntimeException {
    return baseMapper.countByExample(example);
}

public int updateByExampleSelective(M model, E example) throws RuntimeException {
    return baseMapper.updateByExampleSelective(model, example);
}

public int updateByExample(M model, E example) throws RuntimeException {
    return baseMapper.updateByExample(model, example);
}

public int updateByPrimaryKeySelective(M model) throws RuntimeException {
    return baseMapper.updateByPrimaryKeySelective(model);
}

public int updateByPrimaryKey(M model) throws RuntimeException {
    return  baseMapper.updateByPrimaryKey(model);
}
}

這兩個類是提取了公共方法的基類，和BaseMapper.java中各個方法一致。

9、創建Service層各個實體類對應的Service類，下面是分別創建UserService.java接口和其實現類UserServiceImpl.java。

UserService.java

package com.beibei.doc.service.user;

import com.beibei.doc.model.user.User;
import com.beibei.doc.model.user.UserExample;
import com.beibei.doc.service.base.BaseService;

public interface UserService extends BaseService<User, UserExample> {

}

UserServiceImpl.java

package com.beibei.doc.service.user.impl;

import org.springframework.stereotype.Service;

import com.beibei.doc.model.user.User;
import com.beibei.doc.model.user.UserExample;
import com.beibei.doc.service.base.impl.BaseServiceImpl;
import com.beibei.doc.service.user.UserService;

@Service
public class UserServiceImpl extends BaseServiceImpl<User, UserExample> implements UserService {

}

這樣子UserService就有了基礎的增刪改查方法了，如果需要添加其他業務操作方法，就直接在UserService.java中添加接口，并且在UserServiceImpl.java中實現就可以了。

10、在HelloController.java中編輯接口代碼，調用service層業務方法：

package com.beibei.doc.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;

import com.beibei.doc.model.user.User;
import com.beibei.doc.service.user.UserService;

@RestController
@RequestMapping("/hello")
public class HelloConrtoller {

@Autowired
private UserService userService;

@RequestMapping(value="/say")
public String say(){
    User user = userService.selectByPrimaryKey(1);
    if(user == null){
        return null;
    }
    return user.getUsername() + ", 年齡=" + user.getAge();
}
}

11、在瀏覽器中輸入路徑訪問，結果如下：

Paste_Image.png
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