我是通过spring和mybatis结合做的这个事情，通过spring去管理SqlHelper工具类
1：建立一个SqlHelper工具类，
2：类里面必须有一个属性SqlSessionFactory。
3：在你业务类里面，直接注入SqlHelper类，这样你就可以直接在你的业务类里面调用工具类，（工具类里面有好几个接口，自己可以根据实际情况适用）
4：在代码的最后我会贴一部分实例代码来给出结果
5：不多说了，下面贴SqlHelper工具类代码
package com.heygam.common.util;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ParameterMode;
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 org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeHandlerRegistry;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class SqlHelper {
@Autowired
private SqlSessionFactory sqlSessionFactory;
private final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory();
private 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 MetaObject forObject(Object object) {
return MetaObject.forObject(object, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY);
}
/**
* 通过接口获取sql
*
* @param mapper
* @param methodName
* @param args
* @return
*/
public String getMapperSql(Object mapper, String methodName, Object... args) {
MetaObject metaObject = forObject(mapper);
SqlSession session = (SqlSession) metaObject.getValue("h.sqlSession");
Class mapperInterface = (Class) metaObject.getValue("h.mapperInterface");
String fullMethodName = mapperInterface.getCanonicalName() + "." + methodName;
if (args == null || args.length == 0) {
return getNamespaceSql(fullMethodName, null);
} else {
return getMapperSql(mapperInterface, methodName, args);
}
}
/**
* 通过Mapper方法名获取sql
*
* @param session
* @param fullMapperMethodName
* @param args
* @return
*/
public String getMapperSql(String fullMapperMethodName, Object... args) {
if (args == null || args.length == 0) {
return getNamespaceSql(fullMapperMethodName, null);
}
String methodName = fullMapperMethodName.substring(fullMapperMethodName.lastIndexOf(‘.‘) + 1);
Class mapperInterface = null;
try {
mapperInterface = Class.forName(fullMapperMethodName.substring(0, fullMapperMethodName.lastIndexOf(‘.‘)));
return getMapperSql(mapperInterface, methodName, args);
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException("参数" + fullMapperMethodName + "无效！");
}
}
/**
* 通过Mapper接口和方法名
*
* @param session
* @param mapperInterface
* @param methodName
* @param args
* @return
*/
public String getMapperSql(Class mapperInterface, String methodName, Object... args) {
String fullMapperMethodName = mapperInterface.getCanonicalName() + "." + methodName;
if (args == null || args.length == 0) {
return getNamespaceSql(fullMapperMethodName, null);
}
Method method = getDeclaredMethods(mapperInterface, methodName);
Map params = new HashMap();
final Class<?>[] argTypes = method.getParameterTypes();
for (int i = 0; i < argTypes.length; i++) {
if (!RowBounds.class.isAssignableFrom(argTypes[i]) && !ResultHandler.class.isAssignableFrom(argTypes[i])) {
String paramName = "param" + String.valueOf(params.size() + 1);
paramName = getParamNameFromAnnotation(method, i, paramName);
params.put(paramName, i >= args.length ? null : args[i]);
}
}
if (args != null && args.length == 1) {
Object _params = wrapCollection(args[0]);
if (_params instanceof Map) {
params.putAll((Map) _params);
}
}
return getNamespaceSql(fullMapperMethodName, params);
}
/**
* 通过命名空间方式获取sql
*
* @param session
* @param namespace
* @return
*/
public String getNamespaceSql(SqlSession session, String namespace) {
return getNamespaceSql(namespace, null);
}
/**
* 通过命名空间方式获取sql
*
* @param session
* @param namespace
* @param params
* @return
*/
public String getNamespaceSql(String namespace, Object params) {
params = wrapCollection(params);
Configuration configuration = sqlSessionFactory.openSession().getConfiguration();
MappedStatement mappedStatement = configuration.getMappedStatement(namespace);
TypeHandlerRegistry typeHandlerRegistry = mappedStatement.getConfiguration().getTypeHandlerRegistry();
BoundSql boundSql = mappedStatement.getBoundSql(params);
List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
String sql = boundSql.getSql();
if (parameterMappings != null) {
for (int i = 0; i < parameterMappings.size(); i++) {
ParameterMapping parameterMapping = parameterMappings.get(i);
if (parameterMapping.getMode() != ParameterMode.OUT) {
Object value;
String propertyName = parameterMapping.getProperty();
if (boundSql.hasAdditionalParameter(propertyName)) {
value = boundSql.getAdditionalParameter(propertyName);
} else if (params == null) {
value = null;
} else if (typeHandlerRegistry.hasTypeHandler(params.getClass())) {
value = params;
} else {
MetaObject metaObject = configuration.newMetaObject(params);
value = metaObject.getValue(propertyName);
}
JdbcType jdbcType = parameterMapping.getJdbcType();
if (value == null && jdbcType == null)
jdbcType = configuration.getJdbcTypeForNull();
sql = replaceParameter(sql, value, jdbcType, parameterMapping.getJavaType());
}
}
}
return sql;
}
/**
* 根据类型替换参数
* 仅作为数字和字符串两种类型进行处理，需要特殊处理的可以继续完善这里
*
* @param sql
* @param value
* @param jdbcType
* @param javaType
* @return
*/
private String replaceParameter(String sql, Object value, JdbcType jdbcType, Class javaType) {
String strValue = String.valueOf(value);
if (jdbcType != null) {
switch (jdbcType) {
// 数字
case BIT:
case TINYINT:
case SMALLINT:
case INTEGER:
case BIGINT:
case FLOAT:
case REAL:
case DOUBLE:
case NUMERIC:
case DECIMAL:
break;
// 日期
case DATE:
case TIME:
case TIMESTAMP:
// 其他，包含字符串和其他特殊类型
default:
strValue = "‘" + strValue + "‘";
}
} else if (Number.class.isAssignableFrom(javaType)) {
// 不加单引号
} else {
strValue = "‘" + strValue + "‘";
}
return sql.replaceFirst("\\?", strValue);
}
/**
* 获取指定的方法
*
* @param clazz
* @param methodName
* @return
*/
private Method getDeclaredMethods(Class clazz, String methodName) {
Method[] methods = clazz.getDeclaredMethods();
for (Method method : methods) {
if (method.getName().equals(methodName)) {
return method;
}
}
throw new IllegalArgumentException("方法" + methodName + "不存在！");
}
/**
* 获取参数注解名
*
* @param method
* @param i
* @param paramName
* @return
*/
private String getParamNameFromAnnotation(Method method, int i, String paramName) {
final Object[] paramAnnos = method.getParameterAnnotations()[i];
for (Object paramAnno : paramAnnos) {
if (paramAnno instanceof Param) {
paramName = ((Param) paramAnno).value();
}
}
return paramName;
}
/**
* 简单包装参数
*
* @param object
* @return
*/
private Object wrapCollection(final Object object) {
if (object instanceof List) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("list", object);
return map;
} else if (object != null && object.getClass().isArray()) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("array", object);
return map;
}
return object;
}
public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
this.sqlSessionFactory = sqlSessionFactory;
}
}
注：下面的是示例代码 （必须在类中注入了SqlHelper才能使用）
String sql = sqlHelper.getNamespaceSql("com.heygam.business.dao.UserMapper.selectUserByUserName", userName);
log.debug("================通过sql辅助工具拿到的sql=====================");
log.debug(sql);
log.debug("================通过sql辅助工具拿到的sql=====================");
打印的结果：
================通过sql辅助工具拿到的sql=====================
2014-12-26 16:05:42.183 [queue-disruptor-0-1] DEBUG com.heygam.business.service.UserService-select * from p_user where userName=‘15647‘ and isBan != 1
2014-12-26 16:05:42.183 [queue-disruptor-0-1] DEBUG com.heygam.business.service.UserService-
================通过sql辅助工具拿到的sql=====================