解决方法：

1，写一个 typehandler

package com.aes.util;import java.io.ByteArrayInputStream;
import java.io.UnsupportedEncodingException;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;public class MyBlobTypeHandler extends BaseTypeHandler<String>
{//指定字符集  private static final String DEFAULT_CHARSET = "utf-8";  @Override  public void setNonNullParameter(PreparedStatement ps, int i,  String parameter, JdbcType jdbcType) throws SQLException {  ByteArrayInputStream bis;  try {  //把String转化成byte流  bis = new ByteArrayInputStream(parameter.getBytes(DEFAULT_CHARSET));  } catch (UnsupportedEncodingException e) {  throw new RuntimeException("Blob Encoding Error!");  }     ps.setBinaryStream(i, bis, parameter.length());  }  @Override  public String getNullableResult(ResultSet rs, String columnName)  throws SQLException {  Blob blob = rs.getBlob(columnName);  byte[] returnValue = null;  if (null != blob) {  returnValue = blob.getBytes(1, (int) blob.length());  }  try {  //把byte转化成string  return new String(returnValue, DEFAULT_CHARSET);  } catch (UnsupportedEncodingException e) {  throw new RuntimeException("Blob Encoding Error!");  }  }  @Override  public String getNullableResult(CallableStatement cs, int columnIndex)  throws SQLException {  Blob blob = cs.getBlob(columnIndex);  byte[] returnValue = null;  if (null != blob) {  returnValue = blob.getBytes(1, (int) blob.length());  }  try {  return new String(returnValue, DEFAULT_CHARSET);  } catch (UnsupportedEncodingException e) {  throw new RuntimeException("Blob Encoding Error!");  }  }@Overridepublic String getNullableResult(ResultSet rs, int index) throws SQLException{Blob blob = rs.getBlob(index);  byte[] returnValue = null;  if (null != blob) {  returnValue = blob.getBytes(1, (int) blob.length());  }  try {  //把byte转化成string  return new String(returnValue, DEFAULT_CHARSET);  } catch (UnsupportedEncodingException e) {  throw new RuntimeException("Blob Encoding Error!");  }  }
}

2，修改mybatis配置文件

<resultMap type="com.aes.wfm.model.ActHiComInfo" id="actHiComInfo">  <id column="id" property="id"/><result column="userId" property="userId"/><result column="startTime" property="startTime"/><result column="endTime" property="endTime"/><result column="taskName" property="taskName"/><result column="message" property="message"/><result column="fullMsg" property="fullMsg" typeHandler="com.aes.util.MyBlobTypeHandler"/>
</resultMap>