Spring Boot整合Mybatis

在pom.xml中添加依赖


    mysql
    mysql-connector-java
    5.1.38



    com.alibaba
    druid-spring-boot-starter
    1.1.2

配置数据源在application.yml添加如下配置并修改url连接的数据库用户名和密码

spring:
    # 数据源配置
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driverClassName: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8
        username: root
        password: 1234
        # Druid配置
        druid:
            initial-size: 10  #初始化时建立物理连接的个数。初始化发生在显示调用init方法，或者第一次getConnection时
            max-active: 100   #最大连接池数量
            min-idle: 10      #最小连接池数量
            max-wait: 60000   #获取连接时最大等待时间，单位毫秒。
            pool-prepared-statements: true    #是否缓存preparedStatement，也就是PSCache
            max-open-prepared-statements: 100 #要启用PSCache，必须配置大于0，当大于0时，poolPreparedStatements自动触发修改为true。
            max-pool-prepared-statement-per-connection-size: 20
            time-between-eviction-runs-millis: 60000
            min-evictable-idle-time-millis: 300000
            validation-query: SELECT 1 FROM DUAL  #验证连接有效性
            test-while-idle: true   #建议配置为true，不影响性能，并且保证安全性。
            test-on-borrow: false   #申请连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。
            test-on-return: false   #归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
            stat-view-servlet:      #内置监控
                enabled: true
                url-pattern: /druid/*
                #login-username: admin
                #login-password: admin
            filter:
                stat:
                    log-slow-sql: true
                    slow-sql-millis: 1000
                    merge-sql: true
                wall:
                    config:
                        multi-statement-allow: true #是否允许一次执行多条语句，缺省关闭

在pom.xml中添加依赖


    org.mybatis.spring.boot
    mybatis-spring-boot-starter
    1.3.0

在application.yml添加如下配置

# Mybatis配置
mybatis:
    mapperLocations: classpath:mapper/**/*.xml
    typeAliasesPackage: com.xiaohan.bootdemo.entity
    #config-location: classpath:mybatis.xml

mapperLocations 扫描mapper.xml文件
typeAliasesPackage 为实体类型起别名

接下来别名包下新建一个Entity类

package com.xiaohan.bootdemo.entity;
import java.util.Date;

public class UserEntity {
    private Integer id;
    private String name;
    private Date createTime;

    //省略get set
}

Entity类与数据库中的t_user表对应

image.png

接下来新建一个接口在该接口中编写对表进行增删查改的方法
要注意接口上的@Mapper注解

package com.xiaohan.bootdemo.dao;
import com.xiaohan.bootdemo.entity.UserEntity;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

@Mapper
public interface UserDao {

    @Insert({"insert into t_user (name,create_time) values (#{name},#{createTime})"})
    int insert(UserEntity userEntity);
}

在测试之前先配置好日志查看sql语句
在resources文件夹下新建 logback-spring.xml

编写测试类进行测试

package com.xiaohan.bootdemo;

import com.xiaohan.bootdemo.dao.UserDao;
import com.xiaohan.bootdemo.entity.UserEntity;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class BootdemoApplicationTests {

    @Autowired
    private UserDao userDao;

    @Test
    public void insertTest() {
        UserEntity userEntity = new UserEntity();
        userEntity.setName("张三");
        int insert = userDao.insert(userEntity);
        Integer id = userEntity.getId();
        System.err.println("影响行数==>" + insert);
        System.err.println("id==>" + id);
    }
}

输出如下

影响行数==>1
id==>null

可以看到id的值为null 要得到id的值还需要以下两步

数据库的id设为自增长
在方法上添加注解 @Options

@Insert({"insert into t_user (name,create_time) values (#{name},#{createTime})"})
@Options(useGeneratedKeys = true, keyProperty = "id")
int insert(UserEntity userEntity);

重新运行测试类

影响行数==>1
id==>2

后面我就不一一写了直接把UserDao跟测试类贴出来了

UserDao 在update那里使用了jdk1.8的新特性可以在接口里面写被default修饰的方法

package com.xiaohan.bootdemo.dao;

import com.xiaohan.bootdemo.entity.UserEntity;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.ibatis.annotations.*;
import org.apache.ibatis.jdbc.SQL;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
@Mapper
public interface UserDao {

    @Insert({"insert into t_user (name,create_time) values (#{name},#{createTime})"})
    @Options(useGeneratedKeys = true, keyProperty = "id")
    int insert(UserEntity userEntity);

    @Select({"select * from t_user"})
    List selectAll();

    @Select({"select * from t_user where id=#{id}"})
    UserEntity selectById(Integer id);

    @Delete({"delete from t_user where id=#{id}"})
    int deleteById(Integer id);

    @Update({"${value}"})
    int update(String sql);
    default int updateById(UserEntity userEntity) {
        return update(new SQL() {{
            UPDATE("t_user");
            if (userEntity.getName() != null) {
                SET("name=" + StringUtils.wrap(userEntity.getName(), "\'"));
            }
            if (userEntity.getCreateTime() != null) {
                String format = DateFormatUtils.format(userEntity.getCreateTime(), "yyyy-MM-dd HH:mm:ss");
                SET("create_time=" + StringUtils.wrap(format, "\'"));
            }
            WHERE("id=" + userEntity.getId());
        }}.toString());
    }
}

测试类

package com.xiaohan.bootdemo;

import com.xiaohan.bootdemo.dao.UserDao;
import com.xiaohan.bootdemo.entity.UserEntity;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.Date;
import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest
public class BootdemoApplicationTests {

    @Autowired
    private UserDao userDao;

    @Test
    public void insertTest() {
        UserEntity userEntity = new UserEntity();
        userEntity.setName("李四");
        int i = userDao.insert(userEntity);
        Integer id = userEntity.getId();
        System.err.println("影响行数==>" + i);
        System.err.println("id==>" + id);
    }

    @Test
    public void selectAllTest() {
        List list = userDao.selectAll();
        for (UserEntity userEntity:
             list) {
            System.err.println(userEntity);
        }
    }

    @Test
    public void selectByIdTest() {
        UserEntity userEntity = userDao.selectById(1);
        System.err.println(userEntity);
    }

    @Test
    public void deleteTest() {
        int i = userDao.deleteById(1);
        System.err.println("影响行数==>" + i);
        selectAllTest();
    }

    @Test
    public void updateByIdTest() {
        UserEntity userEntity = new UserEntity();
        userEntity.setId(2);
        userEntity.setName("王五");
        userEntity.setCreateTime(new Date());
        int i = userDao.updateById(userEntity);
        System.err.println("影响行数==>" + i);
        selectAllTest();
    }
}

影响行数==>1
2017-08-09 20:33:45.569 DEBUG 11588 --- [           main] c.x.bootdemo.dao.UserDao.selectAll       : ==> Parameters: 
UserEntity{id=2, name='王五', createTime=null}
UserEntity{id=3, name='李四', createTime=null}

当直接updateByIdTest方法后可以看到怎么王五的createTime是null呢
是因为数据库中是create_time跟createTime不匹配造成的
需要增加 map-underscore-to-camel-case: true

# Mybatis配置
mybatis:
    mapperLocations: classpath:mapper/**/*.xml
    typeAliasesPackage: com.xiaohan.bootdemo.entity
    #config-location: classpath:mybatis.xml
    configuration:
      map-underscore-to-camel-case: true  #使用驼峰法映射属性

之后就能看到时间了

UserEntity{id=2, name='王五', createTime=Wed Aug 09 20:42:44 CST 2017}
UserEntity{id=3, name='李四', createTime=null}

Spring Boot整合Mybatis

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