带有Java 1.5代码抛出的iBatis（2.0版）：找不到类型处理程序来将属性“codec”映射到列“codec”

我正在使用Java 1.5、PostgreSQL 8.4.20和iBatis版本<2.3.4.726开发一个遗留应用程序，因为我必须为iBatis使用两个jar，即iBatis-common-2.jar和iBatis-sqlmap-2.jar。我必须使用codec作为Java枚举，db中对应的列是varchar。尝试从后端数据库获取数据并在屏幕上显示时，我遇到以下错误：

[root@cent610-server iBatis-jdk18-work]# javac15 -cp .:jars-old-postgre/ibatis-sqlmap-2.jar:jars-old-postgre/ibatis-common-2.jar:jars-old-postgre/postgresql.jdbc3.jar:jars-old-postgre/commons-logging-1.1.1.jar com/dummy/iBatis/*.java
[root@cent610-server iBatis-jdk18-work]#
[root@cent610-server iBatis-jdk18-work]# java15 -cp .:jars-old-postgre/ibatis-sqlmap-2.jar:jars-old-postgre/ibatis-common-2.jar:jars-old-postgre/postgresql.jdbc3.jar:jars-old-postgre/commons-logging-1.1.1.jar com/dummy/iBatis/EnumMain5
Going to read record.....
Exception in thread "main" com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred in SqlMapPostgre.xml.  
--- The error occurred while applying a result map.  
--- Check the codec-dscp-result.  
--- Check the result mapping for the 'codec' property.  
--- Cause: com.ibatis.sqlmap.client.SqlMapException: No type handler could be found to map the property 'codec' to the column 'codec'.  One or both of the types, or the combination of types is not supported.
Caused by: com.ibatis.sqlmap.client.SqlMapException: No type handler could be found to map the property 'codec' to the column 'codec'.  One or both of the types, or the combination of types is not supported.
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback(GeneralStatement.java:183)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryForObject(GeneralStatement.java:99)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(SqlMapExecutorDelegate.java:561)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(SqlMapExecutorDelegate.java:536)
    at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForObject(SqlMapSessionImpl.java:97)
    at com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForObject(SqlMapClientImpl.java:69)
    at com.dummy.iBatis.EnumMain5.main(EnumMain5.java:28)
Caused by: com.ibatis.sqlmap.client.SqlMapException: No type handler could be found to map the property 'codec' to the column 'codec'.  One or both of the types, or the combination of types is not supported.
    at com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getPrimitiveResultMappingValue(BasicResultMap.java:521)
    at com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getResults(BasicResultMap.java:274)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.handleResults(SqlExecutor.java:354)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.executeQuery(SqlExecutor.java:179)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.sqlExecuteQuery(GeneralStatement.java:200)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback(GeneralStatement.java:168)
    ... 6 more

Caused by: 
com.ibatis.sqlmap.client.SqlMapException: No type handler could be found to map the property 'codec' to the column 'codec'.  One or both of the types, or the combination of types is not supported.
    at com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getPrimitiveResultMappingValue(BasicResultMap.java:521)
    at com.ibatis.sqlmap.engine.mapping.result.BasicResultMap.getResults(BasicResultMap.java:274)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.handleResults(SqlExecutor.java:354)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.executeQuery(SqlExecutor.java:179)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.sqlExecuteQuery(GeneralStatement.java:200)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback(GeneralStatement.java:168)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryForObject(GeneralStatement.java:99)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(SqlMapExecutorDelegate.java:561)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(SqlMapExecutorDelegate.java:536)
    at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForObject(SqlMapSessionImpl.java:97)
    at com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForObject(SqlMapClientImpl.java:69)
    at com.dummy.iBatis.EnumMain5.main(EnumMain5.java:28)
[root@cent610-server iBatis-jdk18-work]# 

请注意，在JDK1.5代码库中使用单个iBatis 2.3.4.726 jar，而不使用任何自定义的typehandler，可以顺利工作，但在我的遗留应用程序中，我必须使用旧的iBatis版本

以下是db模式：

          Table "public.enumtest"
 Column |         Type          | Modifiers 
--------+-----------------------+-----------
 id     | integer               | not null
 codec  | character varying(10) | not null
 dscp   | integer               | not null
Indexes:
    "enumtest_pkey" PRIMARY KEY, btree (id)

这是main:EnumMain5.java的类，用于从后端数据库中提取数据并显示：

package com.dummy.iBatis;


import java.io.Reader;
import java.util.List;

import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;

/**
 * @author geek
 *
 */
public class EnumMain5 {

        /**
         * @param args
         */
        public static void main(String[] args) throws Exception {
                // TODO Auto-generated method stub
                String resource = "SqlMapConfigPostgre.xml";
                Reader reader = Resources.getResourceAsReader(resource);
                SqlMapClient smc = SqlMapClientBuilder.buildSqlMapClient(reader);

                int id = 4;
              System.out.println("Going to read record.....");
              EnumiBatisTest e = (EnumiBatisTest)smc.queryForObject ("getCodecDscpPairValues", id);

              System.out.println("dscp:  " + e.getDscp());
              System.out.println("codec:  " + e.getCodec());
              System.out.println("Record read Successfully ");
        }
}

其他Java类文件如下所示 枚举测试：

package com.dummy.iBatis;


/**
 * @author geek
 *
 */
public class EnumiBatisTest {

        /* codec value for a pair */
        private Codec codec;

        /* dscp value for a pair */
        private Integer dscp;

        /**
         * @return the codec
         */
        public Codec getCodec() {
                return codec;
        }

        /**
         * @param codec the codec to set
         */
        public void setCodec(Codec codec) {
                this.codec = codec;
        }
       /**
         * @return the dscp
         */
        public Integer getDscp() {
                return dscp;
        }

        /**
         * @param dscp the dscp to set
         */
        public void setDscp(Integer dscp) {
                this.dscp = dscp;
        }

}

SqlMapConfigPostgre.xml：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMapConfig
    PUBLIC "-//iBATIS.com//DTD SQL Map Config 2.0//EN"
    "http://www.ibatis.com/dtd/sql-map-config-2.dtd">

<sqlMapConfig>

  <settings
    lazyLoadingEnabled="false"
    cacheModelsEnabled="true"
    enhancementEnabled="true"
    errorTracingEnabled="false"
    maxRequests="512"
    maxSessions="128"
    maxTransactions="32"
    />

<typeHandler callback="com.dummy.iBatis.CodecTypeHandlerCallback" javaType="com.dummy.iBatis.Codec" jdbcType="VARCHAR"/>

<transactionManager type="JDBC">
    <dataSource type="SIMPLE">
        <property name="JDBC.Driver" value="org.postgresql.Driver"/>
        <property name="JDBC.ConnectionURL" value="jdbc:postgresql://localhost:7654/mydb"/>
        <property name="JDBC.Username" value="dbuser"/>
        <property name="JDBC.Password" value="nano123"/>
    </dataSource>
  </transactionManager>

  <sqlMap resource="SqlMapPostgre.xml" />

</sqlMapConfig>

自定义typehandler回调类CodeTypeHandlerCallback是：

package com.dummy.iBatis;
/**
 * 
 */

import java.sql.SQLException;

import com.ibatis.sqlmap.client.extensions.ParameterSetter;
import com.ibatis.sqlmap.client.extensions.ResultGetter;
import com.ibatis.sqlmap.client.extensions.TypeHandlerCallback;

/**
 * @author geek
 *
 */
public class CodecTypeHandlerCallback implements TypeHandlerCallback {

    private static final String G711 = "G711";
    private static final String G729 = "G729";
    private static final String UNDEFINED = null;

    public void setParameter(
                  ParameterSetter setter, Object parameter
                ) throws SQLException {
                    setter.setString(enumToString((Enum) parameter));
                }

    private String enumToString(Enum b) {
          if (b == null) {
                  return UNDEFINED;
          } else if (b==Codec.G711) {
            return G711;
          } else if (b==Codec.G729) {
            return G729;
          } else
                  return UNDEFINED;
    }
private Enum stringToEnum(String str) {
        if (str == null) return Codec.UNDEFINED;
        if (str.toUpperCase().indexOf("G711") >= 0) return Codec.G711;
        if (str.toUpperCase().indexOf("G729") >= 0) return Codec.G729;
        return Codec.UNDEFINED;
        }


    public Object getResult(ResultGetter getter)
            throws SQLException {
          return stringToEnum(getter.getString());
        }

    public Object valueOf(String s) {
        return stringToEnum(s);
    }

}

SqlMapPostgre.xml如下：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
      "http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap>
    <resultMap id="codec-dscp-result" 
               class="com.dummy.iBatis.EnumiBatisTest">
            <result property="dscp" column="dscp"/>
            <result property="codec" column="codec"/>
    </resultMap>
    
    <select id="getCodecDscpPairValues"  
            resultMap="codec-dscp-result"
            parameterClass="int">
            SELECT codec, dscp
              FROM enumtest
                where id=#id#
    </select>
</sqlMap>

这里少了什么？如何正确使用这里提到的自定义typehandler？我还检查了自定义类型处理程序exampleYesNo-one from iBatis docs:并创建了我的自定义类型处理程序。 iBatis配置xml文件有什么问题吗？

---

感谢您的时间。

在尝试了很多东西并搜索了web教程之后，找到了一个快速的解决方案。还有很多其他方法，这只是一种方法：在sqlmapconfigupostgre.xml文件中，从typehandler语句中删除这部分jdbcType=VARCHAR

简而言之，请更新此行： 为此：

编译并运行代码，它应该可以正常工作。

---

希望这对处理类似问题的人有所帮助。

与你的问题无关，但是：现在，Postgres 8.4已经有五年了。您应该计划尽快升级到受支持和维护的版本，例如12。

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
      "http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap>
    <resultMap id="codec-dscp-result" 
               class="com.dummy.iBatis.EnumiBatisTest">
            <result property="dscp" column="dscp"/>
            <result property="codec" column="codec"/>
    </resultMap>
    
    <select id="getCodecDscpPairValues"  
            resultMap="codec-dscp-result"
            parameterClass="int">
            SELECT codec, dscp
              FROM enumtest
                where id=#id#
    </select>
</sqlMap>