Mybatis如何实现自动加载类、配置和映射XML文件的功能？

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自动加载类，自动加载MyBatis配置，自动扫描mapper.xml文件及包

javapackage com.amiu.mybatisTest.autoMybatis;

import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.net.URL;import java.util.ArrayList;import java.util.List;

public class AutoLoadMyBatisConfig { public static void main(String[] args) { // 获取当前项目路径 URL url=AutoLoadMyBatisConfig.class.getClassLoader().getResource(); if (url !=null) { String filePath=url.getPath(); // 扫描mapper.xml文件 List mapperFiles=scanMapperXml(filePath); // 加载MyBatis配置 loadMyBatisConfig(mapperFiles); } }

// 扫描mapper.xml文件 private static List scanMapperXml(String baseDir) { List files=new ArrayList(); File file=new File(baseDir); File[] fileList=file.listFiles(); if (fileList !=null) { for (File f : fileList) { if (f.isDirectory()) { files.addAll(scanMapperXml(f.getPath())); } else if (f.getName().endsWith(.xml)) { files.add(f); } } } return files; }

// 加载MyBatis配置 private static void loadMyBatisConfig(List mapperFiles) { try { for (File mapperFile : mapperFiles) { // 加载配置 FileInputStream inputStream=new FileInputStream(mapperFile); // 此处可以添加加载配置的代码 inputStream.close(); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }}

自动加载类，自动加载mybatis配置，自动扫描mapper.xml文件

package com.amiu.mybatisTest.autoMybatis; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.lang.annotation.Annotation; import java.net.URL; import java.util.ArrayList; import java.util.List; import java.util.Properties; import javax.sql.DataSource; import org.apache.ibatis.datasource.pooled.PooledDataSource; import org.apache.ibatis.mapping.Environment; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import org.apache.ibatis.transaction.TransactionFactory; import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory; import com.amiu.PackageUtil; import com.amiu.mybatisTest.mapper.DBTable; import com.amiu.mybatisTest.mapper.DaoInterface; import com.amiu.mybatisTest.mapper.Mapper; public class MybatisInitialization { /** * propertiesReader应变为1个类，专门处理properties * sqlSession应变为一个类，处理事务，和close() * */ //默认扫描整个项目，用junit@Test会出错，不会扫描整个项目 //详见packagePath2FilePath()中的url.path() private String baseScanPackage = ""; private SqlSessionFactory sqlSessionFactory; //注解，标记我们的mapper类的注解 private Class scanAnnotation; //public MybatisInitialization(){} public MybatisInitialization(Class annotationClazz){ this.scanAnnotation = annotationClazz; } public void setBaseScanPackage(String baseScanPackage) { this.baseScanPackage = baseScanPackage; } public SqlSessionFactory getSqlSessionFactory() { if(sqlSessionFactory == null){ try { sqlSessionFactory = load(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } return sqlSessionFactory; } public void setAnnotationClazz(Class annotationClazz) { this.scanAnnotation = annotationClazz; } SqlSessionFactory load() throws Exception{ Properties props = propertiesReader("com.amiu.mybatisTest","dbConfig.properties"); String driver = props.getProperty("driver"); String url = props.getProperty("url"); String username = props.getProperty("username"); String password = props.getProperty("password"); // 获取DataSource，DataSource接口有多个实现类，我们用的是mybatis给我们提供的PooledDataSource PooledDataSource pooledDataSource = new PooledDataSource(driver, url, username, password); // 若需要配置pooledDatasource，则可以用他的set方法，如 pooledDataSource.setLoginTimeout(6000); DataSource dataSource = pooledDataSource; // 配置事务管理，这里我们使用JDBC的事务 TransactionFactory trcFactory = new JdbcTransactionFactory(); // 配置Environment对象，"development"是我们给起的名字 Environment env = new Environment("development", trcFactory, dataSource); // 创建Configuration对象 Configuration config = new Configuration(env); // 中的内容在此处配置 //config.setLazyLoadingEnabled(true); //扫描baseScanPackage，添加mapper List > mapperClazzList = scanDaoMapper(baseScanPackage); for (Class mapperClazz : mapperClazzList) { //添加映射接口，若有xml文件，则xml的文件应和接口文件同名 config.addMapper(mapperClazz); } SqlSessionFactory ssFactory = new SqlSessionFactoryBuilder() .build(config); return ssFactory; } private Properties propertiesReader(String packagePath,String fileName) throws IOException, FileNotFoundException { String filePath = packagePath2FilePath(packagePath); Properties props = new Properties(); props.load(new FileInputStream(filePath+ File.separator +fileName)); return props; } //包路径转换为文件绝对路径 public String packagePath2FilePath(String packagePath) { ClassLoader loader = Thread.currentThread().getContextClassLoader(); String filePath = packagePath.replace(".", "/"); //包路径 URL url = loader.getResource(filePath); return url.getPath(); } /** * 扫描mybatis Mapper.class * @param basePackage * @return * @throws Exception */ List > scanDaoMapper(String basePackage) throws Exception{ List > anntationClazz = new ArrayList >(); List classOfString = PackageUtil.getClassName(basePackage, true); for (String className : classOfString) { //不处理内部类，内部类className型如ClassA&ClassB if(!className.contains("&")){ Class clazz = Class.forName(className); //只处理接口，我们使用mybatis时，Dao全是接口 if(clazz.isInterface() && isMarkClass(clazz)){ anntationClazz.add(clazz); } } } return anntationClazz; } /** * 这个类是否是我们标记注解scanAnnotation的类 * @param clazz * @return * @throws Exception */ private boolean isMarkClass(Class clazz)throws Exception{ for (Annotation annotation : clazz.getAnnotations()) { if(scanAnnotation == null)throw new Exception("请添加需扫描的注解"); if(annotation.annotationType() == scanAnnotation){ return true; } } return false; } public static void main(String[] args) { MybatisInitialization init = new MybatisInitialization(Mapper.class); //可以不设置基础扫描包，默认扫描整个项目 init.setBaseScanPackage("com.amiu"); SqlSessionFactory sqlSessionFactory = init.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); DaoInterface dao = sqlSession.getMapper(DaoInterface.class); System.out.println(dao.findById(1).getName()); } } PackageUtil扫描包的工具类

package com.amiu; import java.io.File; import java.io.IOException; import java.net.URL; import java.net.URLClassLoader; import java.util.ArrayList; import java.util.Enumeration; import java.util.List; import java.util.jar.JarEntry; import java.util.jar.JarFile; import com.amiu.mybatisTest.autoMybatis.MybatisInitialization; import com.amiu.mybatisTest.autoMybatis.SqlSessionHelper; import com.amiu.mybatisTest.mapper.DBTable; import com.amiu.mybatisTest.mapper.DaoInterface; public class PackageUtil { /** * 获取某包下（包括该包的所有子包）所有类 * * @param packageName * 包名 * @return 类的完整名称 */ public static List getClassName(String packageName) { return getClassName(packageName, true); } /** * 获取某包下所有类 * * @param packageName * 包名 * @param childPackage * 是否遍历子包 * @return 类的完整名称 */ public static List getClassName(String packageName, boolean childPackage) { List fileNames = null; ClassLoader loader = Thread.currentThread().getContextClassLoader(); String packagePath = packageName.replace(".", "/"); URL url = loader.getResource(packagePath); if (url != null) { String type = url.getProtocol(); if (type.equals("file")) { fileNames = getClassNameByFile(url.getPath(), null, childPackage); } else if (type.equals("jar")) { fileNames = getClassNameByJar(url.getPath(), childPackage); } } else { fileNames = getClassNameByJars(((URLClassLoader) loader).getURLs(), packagePath, childPackage); } return fileNames; } /** * 从项目文件获取某包下所有类 * * @param filePath * 文件路径 * @param className * 类名集合 * @param childPackage * 是否遍历子包 * @return 类的完整名称 */ private static List getClassNameByFile(String filePath, List className, boolean childPackage) { List myClassName = new ArrayList (); File file = new File(filePath); File[] childFiles = file.listFiles(); for (File childFile : childFiles) { if (childFile.isDirectory()) { if (childPackage) { myClassName.addAll(getClassNameByFile(childFile.getPath(), myClassName, childPackage)); } } else { String childFilePath = childFile.getPath(); if (childFilePath.endsWith(".class")) { childFilePath = childFilePath.substring( childFilePath.indexOf("\\classes") + 9, childFilePath.lastIndexOf(".")); childFilePath = childFilePath.replace("\\", "."); myClassName.add(childFilePath); } } } return myClassName; } /** * 从jar获取某包下所有类 * * @param jarPath * jar文件路径 * @param childPackage * 是否遍历子包 * @return 类的完整名称 */ private static List getClassNameByJar(String jarPath, boolean childPackage) { List myClassName = new ArrayList (); String[] jarInfo = jarPath.split("!"); String jarFilePath = jarInfo[0].substring(jarInfo[0].indexOf("/")); String packagePath = jarInfo[1].substring(1); try { JarFile jarFile = new JarFile(jarFilePath); Enumeration entrys = jarFile.entries(); while (entrys.hasMoreElements()) { JarEntry jarEntry = entrys.nextElement(); String entryName = jarEntry.getName(); if (entryName.endsWith(".class")) { if (childPackage) { if (entryName.startsWith(packagePath)) { entryName = entryName.replace("/", ".").substring( 0, entryName.lastIndexOf(".")); myClassName.add(entryName); } } else { int index = entryName.lastIndexOf("/"); String myPackagePath; if (index != -1) { myPackagePath = entryName.substring(0, index); } else { myPackagePath = entryName; } if (myPackagePath.equals(packagePath)) { entryName = entryName.replace("/", ".").substring( 0, entryName.lastIndexOf(".")); myClassName.add(entryName); } } } } } catch (Exception e) { e.printStackTrace(); } return myClassName; } /** * 从所有jar中搜索该包，并获取该包下所有类 * * @param urls * URL集合 * @param packagePath * 包路径 * @param childPackage * 是否遍历子包 * @return 类的完整名称 */ private static List getClassNameByJars(URL[] urls, String packagePath, boolean childPackage) { List myClassName = new ArrayList (); if (urls != null) { for (int i = 0; i < urls.length; i++) { URL url = urls[i]; String urlPath = url.getPath(); // 不必搜索classes文件夹 if (urlPath.endsWith("classes/")) { continue; } String jarPath = urlPath + "!/" + packagePath; myClassName.addAll(getClassNameByJar(jarPath, childPackage)); } } return myClassName; } } @注解Mapper，用来标记我们Mybatis Xml文件映射的接口

package com.amiu.mybatisTest.mapper; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * 标记我们的mapper * @author amiu */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) public @interface Mapper { } 我们的@Mapper就添加在Dao的接口上，这个和DaoInterface.xml做映射

package com.amiu.mybatisTest.mapper; import java.util.List; import java.util.Map; import org.apache.ibatis.annotations.MapKey; import com.amiu.TestBean; @Mapper public interface DaoInterface { public TestBean findById(long id); public List findByPhone(long phone); public int insert(TestBean bean); public void deleteById(long id); public void updateById(TestBean bean); } DaoInterface.xml

select * from test where id = #{id} select * from test where phone = #{phone} select last_insert_id() insert into test(id,name,password,phone) values(#{id},#{name},#{password},#{phone}) delete from test where id=#{id} update test set name=#{name},password=#{password},phone=#{phone} where id=#{id}