关于springboot:02第四阶段内容

整合mtbatis plus这个是pom依赖<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>2.3.4.RELEASE</version>        <relativePath/> <!-- lookup parent from repository -->    </parent>    <groupId>com.com.jt.jt</groupId>    <artifactId>springboot_demo2_mybatis</artifactId>    <version>0.0.1-SNAPSHOT</version>    <name>springboot_demo2_mybatis</name>    <description>Demo project for Spring Boot</description>    <properties>        <java.version>1.8</java.version>    </properties>    <dependencies>        <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>            <exclusions>                <exclusion>                    <groupId>org.junit.vintage</groupId>                    <artifactId>junit-vintage-engine</artifactId>                </exclusion>            </exclusions>        </dependency>        <!--引入插件lombok 主动的set/get/构造方法插件  -->        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>        </dependency>        <!--引入数据库驱动 -->        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <scope>runtime</scope>        </dependency>        <!--springBoot数据库连贯  -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-jdbc</artifactId>        </dependency>        <!--spring整合mybatis-plus -->        <dependency>            <groupId>com.baomidou</groupId>            <artifactId>mybatis-plus-boot-starter</artifactId>            <version>3.2.0</version>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build></project>

dao层接口 须要继承BaseMapper<User> 能力应用MP工具/@Mapper //将接口交给Spring治理public interface UserDao extends BaseMapper<User> {    //查问user表的所有的记录    @Select("select * from user")    List<User> findAll();}

pojo层 设置办法@Data@Accessors(chain = true)@TableName  //("user")      //1.将对象与表 进行一对一关联public class User implements Serializable {    @TableId(type = IdType.AUTO)    //主键的信息  设定自增    private Integer Id;    //@TableField("name")     //如果字段名称与属性的名称统一(蕴含驼峰规定),能够省略不写    private String name;    private Integer age;    private String sex;}

加这个注解能够间接 不必在dao层加mappr单注解了@SpringBootApplication@MapperScan("com.com.jt.jt.dao") //次要通知mapper的包门路,会主动的实现包扫描public class SpringbootDemo2MybatisApplication {    public static void main(String[] args) {        SpringApplication.run(SpringbootDemo2MybatisApplication.class, args);    }}

xml总配置server:  port: 8090    #定义端口  servlet:    context-path: /   #定义我的项目的公布门路spring:  datasource:    #driver-class-name: com.mysql.cj.jdbc.Driver   springboot程序采纳默认的配置    url: jdbc:mysql://127.0.0.1:3306/jtdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true    username: root    password: rootmybatis-plus:  #定义别名包  type-aliases-package: com.com.jt.jt.pojo  #加载user标签的mapper文件  mapper-locations: classpath:/mybatis/mappers/*.xml  #开启驼峰映射  configuration:    map-underscore-to-camel-case: true#引入日志信息.logging:  level:    com.jt.dao: debug

根本数据MP工具@SpringBootTestclass SpringbootDemo2MybatisApplicationTests {    @Autowired    private UserDao userDao;    @Test    public void testFind(){        List<User> userList = userDao.findAll();        System.out.println(userList);    }    @Test    public void testSelect01(){        List<User> userList = userDao.selectList(null);        System.out.println(userList);    }    /** * 业务: 查问id=11的用户信息   主键... */    @Test    public void testSelect02(){        User user = userDao.selectById(11);        System.out.println(user);    }    /** * 业务: 查问name属性为"小乔"的数据 * sql:  select * from user where name="小乔"; * 对象的形式  >  sql形式 */    @Test    public void testSelect03(){        //条件结构器        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.eq("name", "小乔");        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 业务: 查问name属性为"小乔"的数据 并且 age >=18岁 * sql:  select * from user where name="小乔" and age>=18; * * 大于   >  gt| 小于 <  lt   | * 大于等于  >= ge  |  小于等于 le */    @Test    public void testSelect04(){        //条件结构器        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.eq("name", "小乔")                    .ge("age", 18);        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 业务: 查问name中蕴含 "精"的用户,并且sex为女 * 业务: 查问name中蕴含 以精结尾的数据,并且sex为女 * sql:  select * from user where name like "%精%" and sex="女"; */    @Test    public void testSelect05(){        //条件结构器        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.likeLeft("name", "精")                    .eq("sex", "女");        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 需要: 查问user表中的数据 要求依照年龄降序排列,如果年龄雷同依照id降序排列 */    @Test    public void testSelect06(){        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.orderByDesc("age","id");        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 需要: 查问name属性为null的数据. * where name is null */    @Test    public void testSelect07(){        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.isNull("name");        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 查问name="小乔" age=17 性别=女的用户 * 如果传递的是对象.会依据对象中不为null的属性充当where条件. */    @Test    public void testSelect08(){        User user = new User();        user.setName("小乔").setAge(17).setSex("女");        QueryWrapper<User> queryWrapper = new QueryWrapper<>(user);        List<User> userList = userDao.selectList(queryWrapper);        System.out.println(userList);    }    /** * 查问id=1,3,5,10数据. * sql: select * from user where id in (1,3,5,10) */    @Test    public void testSelect09(){        //转化时,留神应用对象的类型        Integer[] ids = {1,3,5,10};        List<Integer> idList = Arrays.asList(ids);        List<User> userList = userDao.selectBatchIds(idList);        System.out.println(userList);    }    @Test    public void testInsert(){        User user = new User();        user.setName("特朗普").setAge(70).setSex("男");        userDao.insert(user);    }    /** * 删除name=null的数据,或者name="特朗普" */    @Test    public void testDelete(){        QueryWrapper<User> queryWrapper = new QueryWrapper<>();        queryWrapper.isNull("name")                    .or()                    .eq("name", "特朗普");        userDao.delete(queryWrapper);    }    /** * 案例1: 将id=1的数据的年龄改为8000岁. * sql1:  update user set age=8000 where id=1; * 案例2: 要求将name="黑熊精" age=5500. * sql2:  update user set age=5500 where name="黑熊精"; */    @Test    public void testUpdate(){        User user = new User();        user.setId(1);    //主键充当where条件        user.setAge(8000);        userDao.updateById(user);        //参数阐明  1.实体对象  封装set条件的值        //           2.更新条件结构器        User temp = new User();        temp.setAge(5500);        UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();        updateWrapper.eq("name", "黑熊精");        userDao.update(temp,updateWrapper);    }