Java问题，泛型问题，通过实例对象获取T的类型如:public class Base<T>{}

在父类的构造方法中，获取泛型的具体类型

import javalangreflectParameterizedType;

import javalangreflectType;

import comopensymphonyxwork2ModelDriven;

/

工具类直接返回ModelDriven的对象

/

public class ModelBaseAction<T> extends BaseAction implements ModelDriven<T> {

protected T model;

/

通过反射，获取泛型的具体类型并实例化这个类型

/

public ModelBaseAction() {

// 获取反射的类型

javalangreflectType cls = supergetClass()getGenericSuperclass();

if (cls instanceof ParameterizedType) {

ParameterizedType pt = (ParameterizedType) cls;

// 获取所有放到泛型里面的类型

Type[] tps = ptgetActualTypeArguments();

Systemerrprintln(tps[0]getTypeName());

try {

// 实例化这个泛型所代表的类对象

model = (T) ClassforName(tps[0]getTypeName())newInstance();

} catch (Exception e) {

throw new RuntimeException("没有默认构造方法", e);

}

}

}

@Override

public final T getModel() {

return model;

}

}

泛型的类型是无法在运行时通过反射取得的，泛型类型在编译成字节码的时候已经被虚拟机给去掉了，只是起到提示编译器进行类型检查的作用

用这种方法你试一试:父类:import javalangreflectParameterizedType;

public class Parent<T {

public Parent() {

ParameterizedType type = (ParameterizedType)thisgetClass()getGenericSuperclass();

Systemoutprintln("type==" + type);

Systemoutprintln("entityClass==" + typegetActualTypeArguments()[0]);

Systemoutprintln("getOwnerType==" + typegetOwnerType());

Systemoutprintln("getRawType==" + typegetRawType());}}子类:public class Child<T extends Parent<String {

我可以给你demo，你可以参考

package comshoppingb2bdaoimpl;

import javaioSerializable;

import javalangreflectField;

import javautilCollection;

import javautilList;

import javautilMap;

import javaxannotationResource;

import javaxpersistenceTable;

import orgapachelog4jLogger;

import orghibernateHibernate;

import orghibernateQuery;

import orghibernateSQLQuery;

import orghibernateSession;

import orghibernateSessionFactory;

import orghibernatetransformTransformers;

import orgspringframeworkbeansfactoryannotationAutowired;

import orgspringframeworkstereotypeRepository;

import comshoppingb2bdaoISuperDao;

@Repository("superDao")

public class SuperDaoImpl implements ISuperDao{

@Resource

private SessionFactory hibernateSessionFactory;

public SessionFactory getHibernateSessionFactory() {

return hibernateSessionFactory;

}

public void setHibernateSessionFactory(SessionFactory hibernateSessionFactory) {

thishibernateSessionFactory = hibernateSessionFactory;

}

private Logger logger = LoggergetLogger(thisgetClass());

private Session getCurrentSession() {

return thishibernateSessionFactorygetCurrentSession();

}

@Override

public <T> T get(Class<T> clazz, Serializable id) {

return (T)thisgetCurrentSession()get(clazz, id);

}

@Override

public <T> T getSql(String sql, Map<String, Object> params, Class<T> po) {

SQLQuery q = thisgetCurrentSession()createSQLQuery(sql);

/

say:

从数据库查出来的数据类型给po，如果要自定义，那么需要扩展addScalar

默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好

可扩展

/

if(po != null){

qsetResultTransformer(TransformersaliasToBean(po));

}else{

qsetResultTransformer(TransformersALIAS_TO_ENTITY_MAP);

}

if(params != null && !paramsisEmpty()){

for (String k : paramskeySet()) {

Object v = paramsget(k);

if(v != null){

if(v instanceof Object[]){

qsetParameterList(k, (Object[])v);

}else if(v instanceof Collection<>){

qsetParameterList(k, (Collection<>)v);

}else{

qsetParameter(k, v);

};

}

}

}

List<T>  list = qlist();

return list == null || listisEmpty() null:listget(0);

}

@Override

public Serializable save(Object entity) {

return thisgetCurrentSession()save(entity);

}

@Override

public boolean update(Object entity) {

boolean result = false;

try {

thisgetCurrentSession()update(entity);

result = true;

} catch (Exception e) {

result = false;

}

return result;

}

@Override

public boolean updateSql(String sql,Map<String, Object> params) {

SQLQuery q = thisgetCurrentSession()createSQLQuery(sql);

if(params != null && !paramsisEmpty()){

for (String k : paramskeySet()) {

Object v = paramsget(k);

if(v != null){

if(v instanceof Object[]){

qsetParameterList(k, (Object[])v);

}else if(v instanceof Collection<>){

qsetParameterList(k, (Collection<>)v);

}else{

qsetParameter(k, v);

};

}

}

}

return qexecuteUpdate() == 0 false :true;

}

@Override

public boolean delete(Object entity) {

boolean result = false;

try {

thisgetCurrentSession()delete(entity);

result = true;

} catch (Exception e) {

result = false;

}

return result;

}

@Override

public <T> boolean deleteSql(Class<T> clazz,Serializable id) {

boolean result = false;

try {

Table table = (Table)clazzgetAnnotation(Tableclass);

if(table != null){

String tableName = tablename();

thisgetCurrentSession()

createSQLQuery("delete from :tableName where id = :id")

setParameter("tableName", tableName)

setParameter("id", id)

executeUpdate();

}

result = true;

} catch (Exception e) {

result = false;

}

return result;

}

@Override

public <T> List<T> queryList(String sql, Map<String, Object> params, Class<T> po) {

SQLQuery q = thisgetCurrentSession()createSQLQuery(sql);

/

say:

从数据库查出来的数据类型给po，如果要自定义，那么需要扩展addScalar

默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好

可扩展

/

if(po != null){

qsetResultTransformer(TransformersaliasToBean(po));

}else{

qsetResultTransformer(TransformersALIAS_TO_ENTITY_MAP);

}

if(params != null && !paramsisEmpty()){

for (String k : paramskeySet()) {

Object v = paramsget(k);

if(v != null){

if(v instanceof Object[]){

qsetParameterList(k, (Object[])v);

}else if(v instanceof Collection<>){

qsetParameterList(k, (Collection<>)v);

}else{

qsetParameter(k, v);

}

}

}

}

List<T>  list = qlist();

return list == null || listisEmpty() null:list;

}

@Override

public <T> List<T> queryList(String sql, Map<String, Object> params, int firstResult, int maxResults, Class<T> po) {

SQLQuery query = thisgetCurrentSession()createSQLQuery(sql);

/

say:

从数据库查出来的数据类型给po，如果要自定义数据类型，那么需要扩展addScalar

默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好

可扩展

/

if(po != null){

querysetResultTransformer(TransformersaliasToBean(po))setFirstResult(firstResult)setMaxResults(maxResults);

}else{

querysetResultTransformer(TransformersALIAS_TO_ENTITY_MAP)setFirstResult(firstResult)setMaxResults(maxResults);

}

//thisaddScalarsToString(query, po)setFirstResult(firstResult)setMaxResults(maxResults);//test

if(params != null && !paramsisEmpty()){

for (String k : paramskeySet()) {

Object v = paramsget(k);

if(v != null){

if(v instanceof Object[]){

querysetParameterList(k, (Object[])v);

}else if(v instanceof Collection<>){

querysetParameterList(k, (Collection<>)v);

}else{

querysetParameter(k, v);

}

}

}

}

List<T>  list = querylist();

return list == null || listisEmpty() null:list;

}

@Override

public <T> Serializable queryCount(String sql, Map<String, Object> params) {

Query query = thisgetCurrentSession()createSQLQuery(sql);

if(params != null && !paramsisEmpty()){

for (String k : paramskeySet()) {

Object v = paramsget(k);

if(v != null){

if(v instanceof Object[]){

querysetParameterList(k, (Object[])v);

}else if(v instanceof Collection<>){

querysetParameterList(k, (Collection<>)v);

}else{

querysetParameter(k, v);

}

}

}

}

return IntegerparseInt(queryuniqueResult()toString());

}

/

扩展

默认将class的属性类型转换为hibernate所对应的的类型<br/>

如果严格的话请使用TransformersaliasToBean(Tclass)<br/>

对应表如下：

未实现

@param query

@param cls

@return

/

private  <T> Query addScalarsToCustom(SQLQuery query,Class<T> cls){

Field[] fields = clsgetDeclaredFields();

for(Field item:fields){

////Systemoutprintln(itemgetName() + ":" + itemgetGenericType());

//该接口需要判断，返回的属性类型，然后转换为hibernate语法

//Systemoutprintln(itemgetName() + ":" + itemgetGenericType());

//该接口需要判断，返回的属性类型，然后转换为hibernate语法

if("class javamathBigInteger"equals(itemgetGenericType()toString())){

//Systemoutprintln(clsgetName() +":"+itemgetName()  + "    ||==int");

}else if("class javalangString"equals(itemgetGenericType()toString())){

//Systemoutprintln(clsgetName() +":"+itemgetName()  +  "    ||==String");

}else if("class javamathBigDecimal"equals(itemgetGenericType()toString())){

//Systemoutprintln(clsgetName() +":"+itemgetName()  +  "    ||==String");

}else{

//Systemoutprintln(clsgetName() +":"+itemgetName()  +  "    ||==未匹配类型");

}

}

return null;

}

}

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