package cn.lemon.mybatis.plugin;

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;


/**
 * 自定义typehandler,解决mybatis存储blob字段后,出现乱码的问题 
 * 配置mapper.xml: 
 * <result typeHandler="cn.lemon.mybatis.plugin.BlobTypeHandler"/> 
 * 
 * @author lonyee
 */
public class BlobTypeHandler 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!");    
        }    
    }  
  
    @Override  
    public String getNullableResult(ResultSet arg0, int arg1)  
            throws SQLException {  
        // TODO Auto-generated method stub  
        return null;  
    }    
}