8.03 Day34---BaseMapper query statement usage

目录

BaseMapperquery statement usage：

Wrapper：

 WrapperClause constructor parent class：

用@Dataand add dependencies instead of the ones in the entity classtoString Getter和Setter方法

 验证 List selectList(@Param("ew") Wrapper queryWrapper);语句：

 Page类：

Add the following method in the startup class,即可告诉MyBatis,我们使用的是MySql数据库：

框架整合：

 创建工程：

 创建web目录：

 安装依赖 MySQL版本降级：

配置web/resource目录 JSP的前缀和后缀 Tomcat端口号： 

开启MyBatis的SQLStatement log print： 

创建文件：

---

BaseMapperquery statement usage：

Wrapper：

双击Shift找Wrapper的源代码：

 

 WrapperClause constructor parent class：

1.QueryWrapper<T> 作为whereConstructor for conditional clauses

2.UpdateWrapper<T> 修改setConstructor for clauses

用@Dataand add dependencies instead of the ones in the entity classtoString Getter和Setter方法

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

@Data注解：用于注解实体类 

 

 

 

 验证 List<T> selectList(@Param("ew") Wrapper<T> queryWrapper);语句：

 Page类：

Add the following method in the startup class,即可告诉MyBatis,我们使用的是MySql数据库：

验证<E extends IPage<T>> E selectPage(E page, @Param("ew") Wrapper<T> queryWrapper);方法：

@Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor(DbType.MYSQL);
        mybatisPlusInterceptor.addInnerInterceptor(paginationInnerInterceptor);
        return mybatisPlusInterceptor;
    }

框架整合：

 创建工程：

 

 创建web目录：

 安装依赖 MySQL版本降级：

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-jasper</artifactId>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>jstl</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>taglibs</groupId>
    <artifactId>standard</artifactId>
    <version>1.1.2</version>
    <scope>provided</scope>
</dependency>

配置web/resource目录 JSP的前缀和后缀 Tomcat端口号： 

spring.application.name=springboot-mybatisplus-01
server.port=8084
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.name=defaultDataSource
spring.datasource.url=jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
spring.mvc.view.prefix=/jsp/
spring.mvc.view.suffix=.jsp

<resources>
    <resource>
        <directory>src/main/web</directory>
        <targetPath>META-INF/resources</targetPath>
        <includes>
            <include>**/*.*</include>
        </includes>
    </resource>
    <resource>
        <directory>src/main/resources</directory>
        <includes>
            <include>**/*.xml</include>
            <include>**/*.properties</include>
        </includes>
    </resource>
</resources>

开启MyBatis的SQLStatement log print： 

@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor(){
  MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
  PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor(DbType.MYSQL);
  mybatisPlusInterceptor.addInnerInterceptor(paginationInnerInterceptor);
  return mybatisPlusInterceptor;
}

创建文件：