package com.mogujie.trade.tsharding.route.orm;
import com.mogujie.trade.tsharding.client.ShardingCaculator;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.bytecode.ClassFile;
import javassist.bytecode.ConstPool;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ResultMap;
import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
import org.apache.ibatis.reflection.factory.ObjectFactory;
import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;
import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
import org.apache.ibatis.session.Configuration;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* 通用Mapper增强基类，扩展Mapper sql时需要继承该类
*
* @author qigong on 5/1/15
*/
public abstract class MapperEnhancer {
private static ClassPool pool = ClassPool.getDefault();
private Map<String, Method> methodMap = new HashMap<String, Method>();
private Class<?> mapperClass;
public MapperEnhancer(Class<?> mapperClass) {
this.mapperClass = mapperClass;
}
/**
* 代码增加方法标记
*
* @param record
*/
public String enhancedShardingSQL(Object record) {
return "enhancedShardingSQL";
}
public MapperEnhancer() {
super();
}
/**
* 对mapper进行增强，生成新的mapper，并主动加载新mapper类到classloader
*
* @param mapperClassName
*/
public static void enhanceMapperClass(String mapperClassName) throws Exception {
Class originClass = Class.forName(mapperClassName);
Method[] originMethods = originClass.getDeclaredMethods();
CtClass cc = pool.get(mapperClassName);
for (CtMethod ctMethod : cc.getDeclaredMethods()) {
CtClass enhanceClass = pool.makeInterface(mapperClassName + "Sharding" + ctMethod.getName());
for (long i = 0L; i < 512; i++) {
CtMethod newMethod = new CtMethod(ctMethod.getReturnType(), ctMethod.getName() + ShardingCaculator.getNumberWithZeroSuffix(i), ctMethod.getParameterTypes(), enhanceClass);
Method method = getOriginMethod(newMethod, originMethods);
if(method.getParameterAnnotations()[0].length > 0) {
ClassFile ccFile = enhanceClass.getClassFile();
ConstPool constPool = ccFile.getConstPool();
//拷贝注解信息和注解内容，以支持mybatis mapper类的动态绑定
newMethod.getMethodInfo().addAttribute(MapperAnnotationEnhancer.duplicateParameterAnnotationsAttribute(constPool, method));
}
enhanceClass.addMethod(newMethod);
}
Class<?> loadThisClass = enhanceClass.toClass();
//2015.09.22后不再输出类到本地
// enhanceClass.writeFile(".");
}
}
private static Method getOriginMethod(CtMethod ctMethod, Method[] originMethods) {
for (Method method : originMethods) {
int len = ctMethod.getName().length();
if (ctMethod.getName().substring(0, len-4).equals(method.getName())) {
return method;
}
}
throw new RuntimeException("enhanceMapperClass find method error!");
}
/**
* 添加映射方法
*
* @param methodName
* @param method
*/
public void addMethodMap(String methodName, Method method) {
methodMap.put(methodName, method);
}
private static final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory();
private static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();
/**
* 反射对象，增加对低版本Mybatis的支持
*
* @param object 反射对象
* @return
*/
public static MetaObject forObject(Object object) {
return MetaObject.forObject(object, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY);
}
/**
* 是否支持该通用方法
*
* @param msId
* @return
*/
public boolean supportMethod(String msId) {
Class<?> mapperClass = getMapperClass(msId);
if (this.mapperClass.isAssignableFrom(mapperClass)) {
String methodName = getMethodName(msId);
return methodMap.get(methodName) != null;
}
return false;
}
/**
* 重新设置SqlSource
*
* @param ms
* @param sqlSource
*/
protected void setSqlSource(MappedStatement ms, SqlSource sqlSource) {
MetaObject msObject = forObject(ms);
msObject.setValue("sqlSource", sqlSource);
}
/**
* 重新设置SqlSource
*
* @param ms
* @throws java.lang.reflect.InvocationTargetException
* @throws IllegalAccessException
*/
public void setSqlSource(MappedStatement ms, Configuration configuration) throws Exception {
Method method = methodMap.get(getMethodName(ms));
try {
if (method.getReturnType() == Void.TYPE) {
method.invoke(this, ms);
} else if (SqlSource.class.isAssignableFrom(method.getReturnType())) {
//代码增强 扩充为512个方法。
for (long i = 0; i < 512; i++) {
//新的带sharding的sql
SqlSource sqlSource = (SqlSource) method.invoke(this, ms, configuration, i);
String newMsId = ms.getId() + ShardingCaculator.getNumberWithZeroSuffix(i);
newMsId = newMsId.replace("Mapper.", "MapperSharding" + getMethodName(ms) + ".");
//添加到ms库中
MappedStatement newMs = copyFromMappedStatement(ms, sqlSource, newMsId);
configuration.addMappedStatement(newMs);
setSqlSource(newMs, sqlSource);
}
} else {
throw new RuntimeException("自定义Mapper方法返回类型错误,可选的返回类型为void和SqlNode!");
}
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e.getTargetException() != null ? e.getTargetException() : e);
}
}
protected MappedStatement copyFromMappedStatement(MappedStatement ms,
SqlSource newSqlSource, String newMsId) {
MappedStatement.Builder builder = new MappedStatement.Builder(ms.getConfiguration(), newMsId, newSqlSource, ms.getSqlCommandType());
builder.resource(ms.getResource());
builder.fetchSize(ms.getFetchSize());
builder.statementType(ms.getStatementType());
builder.keyGenerator(ms.getKeyGenerator());
// setStatementTimeout()
builder.timeout(ms.getTimeout());
// setParameterMap()
builder.parameterMap(ms.getParameterMap());
// setStatementResultMap()
List<ResultMap> resultMaps = ms.getResultMaps();
builder.resultMaps(resultMaps);
builder.resultSetType(ms.getResultSetType());
// setStatementCache()
builder.cache(ms.getCache());
builder.flushCacheRequired(ms.isFlushCacheRequired());
builder.useCache(ms.isUseCache());
return builder.build();
}
/**
* 根据msId获取接口类
*
* @param msId
* @return
* @throws ClassNotFoundException
*/
public static Class<?> getMapperClass(String msId) {
String mapperClassStr = msId.substring(0, msId.lastIndexOf("."));
try {
return Class.forName(mapperClassStr);
} catch (ClassNotFoundException e) {
throw new RuntimeException("无法获取Mapper接口信息:" + msId);
}
}
/**
* 获取执行的方法名
*
* @param ms
* @return
*/
public static String getMethodName(MappedStatement ms) {
return getMethodName(ms.getId());
}
/**
* 获取执行的方法名
*
* @param msId
* @return
*/
public static String getMethodName(String msId) {
return msId.substring(msId.lastIndexOf(".") + 1);
}
}