mybatis-4 mybatis與spring結(jié)合使用及原理解析

<dependencies>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-context</artifactId>
 <version>5.0.8.RELEASE</version>
 </dependency>
 <dependency>
 <groupId>org.mybatis</groupId>
 <artifactId>mybatis-spring</artifactId>
 <version>2.0.0</version>
 </dependency>
 <dependency>
 <groupId>org.mybatis</groupId>
 <artifactId>mybatis</artifactId>
 <version>3.4.6</version>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <version>5.1.34</version>
 </dependency>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-jdbc</artifactId>
 <version>5.0.8.RELEASE</version>
 </dependency>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-core</artifactId>
 <version>5.0.8.RELEASE</version>
 </dependency>
</dependencies>

package com.config;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import javax.sql.DataSource;
@Configuration
@MapperScan("com.dao")//注解 與XML<mybatis:scan base-package="org.mybatis.spring.sample.mapper" />
//注冊(cè)包中遞歸搜索映射器
@ComponentScan("com")//注冊(cè)Bean
public class AppConfig {
 @Bean
 @Autowired
 public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource ){
 SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
 sqlSessionFactoryBean.setDataSource(dataSource);
 return sqlSessionFactoryBean;
 }
 @Bean
 public DataSource getDataSource(){
 DriverManagerDataSource dataSource = new DriverManagerDataSource();
 dataSource.setDriverClassName("com.mysql.jdbc.Driver");
 dataSource.setUsername("root");
 dataSource.setPassword("110226wjwj");
 dataSource.setUrl("jdbc:mysql://localhost:3306/mybatis_wjw?useUnicode=true&characterEncoding=UTF-8&useSSL=false");
 return dataSource;
 }
}

package com.dao;
import org.apache.ibatis.annotations.Select;
import java.util.List;
import java.util.Map;
public interface UserDao {
 @Select ("select * from t_user where tid =3")
 public List<Map> query();
}

package com.service;
import com.dao.UserDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
//spring注解中service與component意思差不多，區(qū)別在于component是中立注解，而service是業(yè)務(wù)邏輯層的注解
//@Component
@Service
public class UserService {
 @Autowired
 UserDao userDao;
 public void query(){
 System.out.println(userDao.query());
 }
}

package com.test;
import com.config.AppConfig;
import com.service.UserService;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class MainTest {
 public static void main(String args[]){
 AnnotationConfigApplicationContext acc = new AnnotationConfigApplicationContext(AppConfig.class);
 UserService us = acc.getBean(UserService.class);
 us.query();
 }
}

public <T> T selectOne(String statement, Object parameter) {
 List<T> list = this.selectList(statement, parameter);
 if (list.size() == 1) {
  return list.get(0);
 } else if (list.size() > 1) {
  throw new TooManyResultsException("Expected one result (or null) to be returned by selectOne(), but found: " + list.size());
 } else {
  return null;
 }
 }

public <E> List<E> selectList(String statement, Object parameter, RowBounds rowBounds) {
 List var5;
 try {
  MappedStatement ms = this.configuration.getMappedStatement(statement);
  var5 = this.executor.query(ms, this.wrapCollection(parameter), rowBounds, Executor.NO_RESULT_HANDLER);
 } catch (Exception var9) {
  throw ExceptionFactory.wrapException("Error querying database. Cause: " + var9, var9);
 } finally {
  ErrorContext.instance().reset();
 }
 return var5;
 }

protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
 Assert.notEmpty(basePackages, "At least one base package must be specified");
 Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet();
 String[] var3 = basePackages;
 int var4 = basePackages.length;
 for(int var5 = 0; var5 < var4; ++var5) {
  String basePackage = var3[var5];
  Set<BeanDefinition> candidates = this.findCandidateComponents(basePackage);
  Iterator var8 = candidates.iterator();
  while(var8.hasNext()) {
  BeanDefinition candidate = (BeanDefinition)var8.next();
  ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(candidate);
  candidate.setScope(scopeMetadata.getScopeName());
  String beanName = this.beanNameGenerator.generateBeanName(candidate, this.registry);
  if (candidate instanceof AbstractBeanDefinition) {
   this.postProcessBeanDefinition((AbstractBeanDefinition)candidate, beanName);
  }
  if (candidate instanceof AnnotatedBeanDefinition) {
   AnnotationConfigUtils.processCommonDefinitionAnnotations((AnnotatedBeanDefinition)candidate);
  }
  if (this.checkCandidate(beanName, candidate)) {
   BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(candidate, beanName);
   definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
   beanDefinitions.add(definitionHolder);
   this.registerBeanDefinition(definitionHolder, this.registry);
  }
  }
 }
 return beanDefinitions;
 }

public interface Executor {
 ResultHandler NO_RESULT_HANDLER = null;
 int update(MappedStatement var1, Object var2) throws SQLException;
 <E> List<E> query(MappedStatement var1, Object var2, RowBounds var3, ResultHandler var4, CacheKey var5, BoundSql var6) throws SQLException;
 <E> List<E> query(MappedStatement var1, Object var2, RowBounds var3, ResultHandler var4) throws SQLException;
 <E> Cursor<E> queryCursor(MappedStatement var1, Object var2, RowBounds var3) throws SQLException;
 List<BatchResult> flushStatements() throws SQLException;
 void commit(boolean var1) throws SQLException;
 void rollback(boolean var1) throws SQLException;
 CacheKey createCacheKey(MappedStatement var1, Object var2, RowBounds var3, BoundSql var4);
 boolean isCached(MappedStatement var1, CacheKey var2);
 void clearLocalCache();
 void deferLoad(MappedStatement var1, MetaObject var2, String var3, CacheKey var4, Class<?> var5);
 Transaction getTransaction();
 void close(boolean var1);
 boolean isClosed();
 void setExecutorWrapper(Executor var1);
}