​

1.SpringBoot导入依赖

spring-boot-starter-parent org.springframework.boot 2.0.1.RELEASE

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
</dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId>
</dependency><!--Mybatis-Plus 注意版本-->
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.1</version>
</dependency>
<!--mysql驱动-->
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.46</version>
</dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope>
</dependency>

2.配置application.yml文件

2.1 注意url的配置需要加上后面的东西 数据库后面

?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai

2.2Mybatis-plus有自己的日志处理配置

#控制台打印sql
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl·
server:port: 1000spring:application:name: SMdatasource:url: jdbc:mysql://127.0.0.1:3306/twoclass?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghaidriver-class-name: com.mysql.jdbc.Driverusername: rootpassword: roothouzhicong
#控制台打印sql
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
#逻辑删除配置global-config:db-config:logic-delete-field: flaglogic-delete-value: 1 #逻辑已删除默认为1logic-not-delete-value: 0 #逻辑没有删除字段0

3.dao层的创建使用 注意启动文件Application.java加上@MapperScan(“com.hou.dao”)

package com.hou.dao;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.hou.pojo.User;
import org.apache.ibatis.annotations.Mapper;@Mapper
public interface UserDao extends BaseMapper<User> {
}

4.pojo实体类的创建 （注意一下createTime和updateTime的填充机制）

package com.hou.pojo;import com.baomidou.mybatisplus.annotation.*;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import java.util.Date;@Data
@AllArgsConstructor
@NoArgsConstructor@TableName
public class User {@TableId(type = IdType.AUTO)private Integer id;private String username;private String password;private String email;private Integer age;@TableField(fill = FieldFill.INSERT)private Date createTime;@TableField(fill = FieldFill.INSERT_UPDATE)private Date updateTime;@TableLogicprivate Integer deleted;@Versionprivate Integer version;public User( String username, String password, String email, Integer age) {this.username = username;this.password = password;this.email = email;this.age = age;}public User(Integer id, String username, String password, String email, Integer age) {this.id = id;this.username = username;this.password = password;this.email = email;this.age = age;}
}

5.使用controller层进行相关的测试工作

package com.hou.controller;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hou.dao.UserDao;
import com.hou.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;@RestController
@RequestMapping("user")
public class UserController {@Autowiredprivate UserDao userDao;@RequestMapping("/list")public List<User> queryAllUser(){List<User> users = userDao.selectList(null);System.out.println(users);return users;}
/*@RequestMapping("/queryByPage")public List<User> queryByPe(){Page<User> userPage=new Page<>();}*///    批量查询
@RequestMapping("/queryBatch")
public List<User> queryManyUser(){List<User> users = userDao.selectBatchIds(Arrays.asList(3, 10, 11));return users;}
//条件查询根据多个条件进行相关的查询
@RequestMapping("/queryByMap")
public List<User> queryByMap() {Map<String, Object> map = new HashMap<>();map.put("age", 22);map.put("password", "sdfds");List<User> users = userDao.selectByMap(map);return users;}/*条件构造器Wrapper
1.查询name不为null的用户，并且邮箱不为null的永不，年龄大于等于22的用户*/@RequestMapping("/queryByWarpper")public List<User> queryByWarpper() {QueryWrapper<User> queryWrapper=new QueryWrapper<>();queryWrapper.isNotNull("username");queryWrapper.isNotNull("email");queryWrapper.ge("age",22);List<User> users = userDao.selectList(queryWrapper);return users;}/** 条件查询的构造器* 2.查询年龄在20-30之间的用户信息,和用户个数** */@RequestMapping("/queryByWarpper1")public List<User> queryByWarpper1() {QueryWrapper<User> queryWrapper=new QueryWrapper<>();queryWrapper.between("age",20,30);List<User> users = userDao.selectList(queryWrapper);Integer count = userDao.selectCount(queryWrapper);System.out.println(count);return users;}/** 模糊查询* */@RequestMapping("/queryByWarpper2")public void queryByWarpper2() {QueryWrapper<User> queryWrapper=new QueryWrapper<>();queryWrapper.notLike("name","z"); //相当于 NOT LIKE '%Z%'queryWrapper.likeLeft("email","@qq.com"); //相当于 like '%@qq.com'List<Map<String, Object>> maps = userDao.selectMaps(queryWrapper);for (Map<String, Object> map : maps) {System.out.println(map);}}/** 测试子查询** */@RequestMapping("/queryByWarpper3")public void queryByWarpper3() {QueryWrapper<User> queryWrapper=new QueryWrapper<>();//子查询queryWrapper.inSql("id","select id from user where id<5");List<Object> objects = userDao.selectObjs(queryWrapper);for (Object object : objects) {System.out.println(object);}
//        降序进行查询
//        queryWrapper.orderByAsc("age");}@RequestMapping(value = "/add",method = RequestMethod.POST)public int addUser(){User user=new User(9,"houzhicong","66666","233@qq.com",18);int i = userDao.insert(user);return i;}@RequestMapping(value = "/delBatch",method = RequestMethod.DELETE)public int deletUser(){
//批量删除功能实现int i = userDao.deleteBatchIds(Arrays.asList(2, 6, 9));return i;}@RequestMapping(value = "/delbyid",method = RequestMethod.DELETE)public int deletUserByid(){
//批量删除功能实现int i = userDao.deleteById(20);return i;}@RequestMapping(value = "/up",method = RequestMethod.PUT)public int upUserByid(){User user=new User(3,"houzhicong","666666","233@qq.com",18);int i = userDao.updateById(user);return i;}}​

6.时间的填充机制需要创建一个配置文件类，创建一个config包，下面加上配置类：

package com.hou.config;import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;import java.util.Date;@Slf4j
@Component //不要忘记吧处理器加到IOC容器中
public class MyMetaObjectHandler implements MetaObjectHandler {//插入时候的填充策略@Overridepublic void insertFill(MetaObject metaObject) {log.info("start insert fill ....");  //日志//设置字段的值（String fieldName字段名,Object fieldVal要传递的值,MetaObject metaObject)this.setFieldValByName("createTime",new Date(),metaObject);this.setFieldValByName("updateTime",new Date(),metaObject);}//更新时间的填充策略@Overridepublic void updateFill(MetaObject metaObject) {log.info("start update fill ....");this.setFieldValByName("updateTime",new Date(),metaObject);}
}

7.分页插件的配置文件

package com.hou.config;import com.baomidou.mybatisplus.extension.plugins.OptimisticLockerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.plugins.pagination.optimize.JsqlParserCountOptimize;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;@EnableTransactionManagement
@Configuration
@MapperScan("com.hou.dao")
public class MybatisPlusConfig {@Beanpublic PaginationInterceptor paginationInterceptor() {PaginationInterceptor paginationInterceptor = new PaginationInterceptor();// 设置请求的页面大于最大页后操作， true调回到首页，false 继续请求  默认false// paginationInterceptor.setOverflow(false);// 设置最大单页限制数量，默认 500 条，-1 不受限制// paginationInterceptor.setLimit(500);// 开启 count 的 join 优化,只针对部分 left joinpaginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));return paginationInterceptor;}}

8.Mybatis-Plus也可以进行mapper.xml文件的使用这个没有改变mybatis的使用

9.也可以使用逆向工程生成相关的controller,dao,pojo,service层。

10.注意一下springBoot2.0已经有自己的默认的连接池了 HikariCp(号称性能最好的连接池)