hibernate createnativequery返回clob的代理对象

tsm1rwdh  于 2021-06-30  发布在  Java
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我被迫使用hibernate createnativequery返回对象数组列表。
查询返回值的(许多)列中有一列是clob。
返回的对象是com.sun.proxy对象。
我看到一个问题在哪里

getClass().getInterfaces()

用于标识它是正在返回的wrappedclob。
但是,考虑到我现在在java代码中有了这个代理对象,如何将它转换成有用的东西。。。像一根绳子?

insrf1ej

insrf1ej1#

以下代码有助于解除clob的固定
链接帮助我,只是添加了一点化妆的代码:d

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Clob;
import java.sql.SQLException;
    /**
         * Unproxy clob.
         *
         * @param proxy the proxy
         * @return the string
         * @throws InvocationTargetException the invocation target exception
         * @throws IntrospectionException the introspection exception
         * @throws IllegalAccessException the illegal access exception
         * @throws SQLException the SQL exception
         * @throws IOException Signals that an I/O exception has occurred.
         */
        public static String unproxyClob(Object proxy)
            throws InvocationTargetException, IntrospectionException, IllegalAccessException, SQLException, IOException {
            try {
                BeanInfo beanInfo = Introspector.getBeanInfo(proxy.getClass());
                for (PropertyDescriptor property : beanInfo.getPropertyDescriptors()) {
                    Method readMethod = property.getReadMethod();
                    if (readMethod.getName().contains(GET_WRAPPED_CLOB)) {
                        Object result = readMethod.invoke(proxy);
                        return clobToString((Clob) result);
                    }
                }
            } catch (InvocationTargetException | IntrospectionException | IllegalAccessException | SQLException | IOException exception) {
                LOGGER.fatal(exception);
                throw exception;
            }
            return null;
        }

        /**
         * Clob to string.
         *
         * @param data the data
         * @return the string
         * @throws SQLException the SQL exception
         * @throws IOException Signals that an I/O exception has occurred.
         */
        public static String clobToString(Clob data) throws SQLException, IOException {
            StringBuilder sb = new StringBuilder();
            Reader reader = data.getCharacterStream();
            BufferedReader br = new BufferedReader(reader);
            String line;
            while (null != (line = br.readLine())) {
                sb.append(line);
            }
            br.close();

            return sb.toString();
        }
uoifb46i

uoifb46i2#

你可以试试这个代码。它可能并不完美,但对我来说很有用:)我正在使用它将常规clob转换为字符串,因此如果使用getwrappedclob()展开clob对象,它也应该可以工作

Clob clob = wrappedClob.getWrappedClob();
String result = null;
Long length = clob.length();
char[] char_array = new char[length.intValue()];
Reader characterStream = clob.getCharacterStream();
try {
    int read = characterStream.read(char_array, 0, length.intValue());
    result = new String(char_array);
} catch (IOException e) {
    log.error("Exception during read from CLOB: " + e);
}

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