当前位置：首页 > news >正文

学设计的网站推荐项目网站

news 2025/8/15 9:17:50

学设计的网站推荐,项目网站,青岛响应式网站建设,网络营销的成功案例看本文之前，请确保你已经在SpringBoot中集成MyBatis，并能正常使用。如果没有，那么请先移步 http://blog.csdn.net/catoop/article/details/50553714 做了解后，再按本文步骤操作。使用MyBatis在我们通过xml集中配置SQL&#xf…

看本文之前，请确保你已经在SpringBoot中集成MyBatis，并能正常使用。
如果没有，那么请先移步 http://blog.csdn.net/catoop/article/details/50553714 做了解后，再按本文步骤操作。

使用MyBatis在我们通过xml集中配置SQL，并通过创建接口Mapper文件来完成持久化DAO层（mybatis内部使用的是动态代理，所以我们不需要自己编写实现类）。

然而在实际开发中，单表操作非常多，如果你也想像JPA、JDBC那样做一个所谓的BaseDao。那么可以实现一个通用Mapper来达到目的。现在有现成的通用Mapper插件，我们无需重新创造轮子（代码是开源的，你也可以自己在其基础上修改）。

通用Mapper插件网址：https://github.com/abel533/Mapper

下面是使用方法（本文直接将分页插件PageHelper也集成了）：
一、添加或修改pom依赖

        <!-- MyBatis -->
<!--        <dependency> -->
<!--            <groupId>org.mybatis.spring.boot</groupId> -->
<!--            <artifactId>mybatis-spring-boot-starter</artifactId> -->
<!--            <version>1.0.1-SNAPSHOT</version> -->
<!--        </dependency> --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.3.0</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.2.3</version></dependency><!-- 分页插件 --><dependency><groupId>com.github.pagehelper</groupId><artifactId>pagehelper</artifactId><version>4.1.1</version></dependency><!--通用Mapper插件--><dependency><groupId>tk.mybatis</groupId><artifactId>mapper</artifactId><version>3.3.4</version></dependency>

这里说一下，文章开始指定的那篇文章中直接依赖的mybatis的starter。因为本文在集成通用Mapper的时候直接使用出现了错误，所以将mybatis的starter中的Java类（它本身只有2个Java类，非常简单）拷贝到工程中，注释掉了头部的//@ConditionalOnBean(DataSource.class)，你不用去找那2个类的源码了，下面会粘贴出来。

二、将下面4个Java类加入到工程中

将文件
MybatisAutoConfiguration.java
MyBatisMapperScannerConfig.java
MybatisProperties.java
MyMapper.java
添加到 org.springboot.sample.config.mybatis 中（包名根据自己工程修改）

最有一个MyMapper.java要特别注意，不要把MyMapper放到同其他Mapper一起，该类不能被当做普通Mapper一样被扫描，否则会出错。

package org.springboot.sample.config.mybatis;import java.util.Properties;import javax.annotation.PostConstruct;
import javax.sql.DataSource;import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;import com.github.pagehelper.PageHelper;/*** {@link EnableAutoConfiguration Auto-Configuration} for Mybatis. Contributes a* {@link SqlSessionFactory} and a {@link SqlSessionTemplate}.** If {@link org.mybatis.spring.annotation.MapperScan} is used, or a configuration file is* specified as a property, those will be considered, otherwise this auto-configuration* will attempt to register mappers based on the interface definitions in or under the* root auto-configuration package.** @author Eddú Meléndez* @author Josh Long*/
@Configuration
@ConditionalOnClass({ SqlSessionFactory.class, SqlSessionFactoryBean.class })
//@ConditionalOnBean(DataSource.class)
@EnableConfigurationProperties(MybatisProperties.class)
@AutoConfigureAfter(DataSourceAutoConfiguration.class)
public class MybatisAutoConfiguration {private static Log log = LogFactory.getLog(MybatisAutoConfiguration.class);@Autowiredprivate MybatisProperties properties;@Autowired(required = false)private Interceptor[] interceptors;@Autowiredprivate ResourceLoader resourceLoader = new DefaultResourceLoader();@PostConstructpublic void checkConfigFileExists() {if (this.properties.isCheckConfigLocation()) {Resource resource = this.resourceLoader.getResource(this.properties.getConfig());Assert.state(resource.exists(),"Cannot find config location: " + resource+ " (please add config file or check your Mybatis "+ "configuration)");}}@Bean(name = "sqlSessionFactory")@ConditionalOnMissingBeanpublic SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {SqlSessionFactoryBean factory = new SqlSessionFactoryBean();factory.setDataSource(dataSource);if (StringUtils.hasText(this.properties.getConfig())) {factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfig()));} else {if (this.interceptors != null && this.interceptors.length > 0) {factory.setPlugins(this.interceptors);}factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());factory.setMapperLocations(this.properties.getMapperLocations());}return factory.getObject();}@Bean@ConditionalOnMissingBeanpublic SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {return new SqlSessionTemplate(sqlSessionFactory,this.properties.getExecutorType());}/*** 分页插件** @param dataSource* @return* @author SHANHY* @create  2016年2月18日*/@Beanpublic PageHelper pageHelper(DataSource dataSource) {log.info("注册MyBatis分页插件PageHelper");PageHelper pageHelper = new PageHelper();Properties p = new Properties();p.setProperty("offsetAsPageNum", "true");p.setProperty("rowBoundsWithCount", "true");p.setProperty("reasonable", "true");pageHelper.setProperties(p);return pageHelper;}}

package org.springboot.sample.config.mybatis;import java.util.Properties;import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import tk.mybatis.spring.mapper.MapperScannerConfigurer;/*** MyBatis扫描接口，使用的tk.mybatis.spring.mapper.MapperScannerConfigurer <br/>* 如果你不使用通用Mapper，可以改为org.xxx...**/
@Configuration
//TODO 注意，由于MapperScannerConfigurer执行的比较早，所以必须有下面的注解
@AutoConfigureAfter(MybatisAutoConfiguration.class)
public class MyBatisMapperScannerConfig {@Beanpublic MapperScannerConfigurer mapperScannerConfigurer() {MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");mapperScannerConfigurer.setBasePackage("org.springboot.sample.mapper");Properties properties = new Properties();// 这里要特别注意，不要把MyMapper放到 basePackage 中，也就是不能同其他Mapper一样被扫描到。 properties.setProperty("mappers", MyMapper.class.getName());properties.setProperty("notEmpty", "false");properties.setProperty("IDENTITY", "MYSQL");mapperScannerConfigurer.setProperties(properties);return mapperScannerConfigurer;}}

package org.springboot.sample.config.mybatis;import org.apache.ibatis.session.ExecutorType;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.core.io.Resource;/*** Configuration properties for Mybatis.** @author Eddú Meléndez*/
@ConfigurationProperties(prefix = MybatisProperties.MYBATIS_PREFIX)
public class MybatisProperties {public static final String MYBATIS_PREFIX = "mybatis";/*** Config file path.*/private String config;/*** Location of mybatis mapper files.*/private Resource[] mapperLocations;/*** Package to scan domain objects.*/private String typeAliasesPackage;/*** Package to scan handlers.*/private String typeHandlersPackage;/*** Check the config file exists.*/private boolean checkConfigLocation = false;/*** Execution mode.*/private ExecutorType executorType = ExecutorType.SIMPLE;public String getConfig() {return this.config;}public void setConfig(String config) {this.config = config;}public Resource[] getMapperLocations() {return this.mapperLocations;}public void setMapperLocations(Resource[] mapperLocations) {this.mapperLocations = mapperLocations;}public String getTypeHandlersPackage() {return this.typeHandlersPackage;}public void setTypeHandlersPackage(String typeHandlersPackage) {this.typeHandlersPackage = typeHandlersPackage;}public String getTypeAliasesPackage() {return this.typeAliasesPackage;}public void setTypeAliasesPackage(String typeAliasesPackage) {this.typeAliasesPackage = typeAliasesPackage;}public boolean isCheckConfigLocation() {return this.checkConfigLocation;}public void setCheckConfigLocation(boolean checkConfigLocation) {this.checkConfigLocation = checkConfigLocation;}public ExecutorType getExecutorType() {return this.executorType;}public void setExecutorType(ExecutorType executorType) {this.executorType = executorType;}
}

package org.springboot.sample.config.mybatis;import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;/*** 被继承的Mapper，一般业务Mapper继承它**/
public interface MyMapper<T> extends Mapper<T>, MySqlMapper<T> {//TODO//FIXME 特别注意，该接口不能被扫描到，否则会出错
}

三、属性配置文件
属性配置文件中和文章开头指定的文章一样配置，没有什么修改，下面粘贴出来：

mybatis.mapper-locations=classpath*:org/springboot/sample/mapper/sql/mysql/*Mapper.xml
mybatis.type-aliases-package=org.springboot.sample.entity

四、在业务Mapper中继承基础MyMapper接口

public interface StudentMapper extends MyMapper<Student> {List<Student> likeName(String name);Student getById(int id);int add(Student stu);String getNameById(int id);}

然后在Service中使用即可，后面就没什么说的了。

@Service
public class StudentService {@Autowiredprivate JdbcTemplate jdbcTemplate;@Autowiredprivate StudentMapper studentMapper;@TargetDataSource(name="ds2")public List<Student> likeName(String name){return studentMapper.likeName(name);}public int testSave(){Student stu = new Student();stu.setAge(33);stu.setName("测试新增");stu.setSumScore("66");stu.setAvgScore("22");return studentMapper.insert(stu);//这里调用的是基础Mapper中的insert方法}}

最后还有一点要说明，使用公共Mapper“可能”需要对实体类进行修改。如果你的实体字段和数据库字段不一致（或者实体名称和数据库表名不一致），这样才需要修改，例如：

/*** 学生实体** @author   单红宇(365384722)* @myblog  http://blog.csdn.net/catoop/* @create    2016年1月12日*/
public class Student implements Serializable{@Idprivate int id;private String name;@Column(name="SCORE_SUM")private String sumScore;@Column(name="SCORE_AVG")private String avgScore;private int age;// getter setter }