mysql中blob类型乱码的解决。

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"; 

    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 = (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!"); 

        } 

    } 

    public String getNullableResult(CallableStatement cs, int columnIndex) 

            throws SQLException { 

        Blob 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!"); 

        } 

    }

    @Override

    public String getNullableResult(ResultSet rs, int columnIndex)

            throws SQLException {

        // TODO Auto-generated method stub

        return null;

    }

}

<result column="settlementContent" property="settlementContent" typeHandler="cn.xxx.utils.MyBlobTypeHandler"/>