java 使用mysql 的 blob 存储 protobuf 数据 的读写操作核心代码

场景：使用mysql 的  blob 存储  protobuf 数据

1：写入数据库

		Message.Builder builder=null;
		PreparedStatement pre = null;
		try {
			String sql = "insert into " + tableName + "  values (?,?)";
			pre = connection.prepareStatement(sql);
			// 写入数据库，要把它改写为流的形式
			ByteArrayInputStream stream = new ByteArrayInputStream(builder
					.build().toByteArray());
			pre.setLong(1, uid);
			pre.setBlob(2, stream, stream.available());
			pre.execute();
		} catch (SQLException e) {
			e.printStackTrace();
		}

2:读取数据库数据

	if (resultSet != null) {  
            try {  
                if (resultSet.next()) {  
                    String label = "data";  
                    if (resultSet.getBoolean(label)) {  
                        java.sql.Blob blob = resultSet.getBlob(label);  
  
                        try {  
                            byte[] b = blob.getBytes(1, (int) blob.length());  
  
                            buildUserMessage userBlobBuilder = null;  
                            //解析相关的数据  
                            userBlobBuilder = buildUserMessage.parseFrom(b);  
  
                        } catch (IOException e) {  
                            // TODO Auto-generated catch block  
                            e.printStackTrace();  
                        }  
  
                    }  
                }  
            } catch (SQLException e) {  
                e.printStackTrace();  
            }  
        }