如何快速的为现有数据库建立数据字典？

大部分项目在验收时都需要向客户提供一份详细的数据字典，而编写数据字典是一件既耗时又耗力的事情。为了解决这个问题，提高工作效率，本人写了一个工具类。该工具类能够根据现有的数据库快速的生成对应的数据字典，它可以为我们完成80%的工作量，我们只需要做剩下的20%的工作就可以了。该工具类目前支持Oracle、SqlServer数据库，操作简单，快捷。

1、以下是部分关键代码：

public class MetadataUtil {
	private Connection cn = null;
	private String catalog = null;//SqlServer use
	private String schemaPattern = "AGENTSKY";//Oracle use
	
	public MetadataUtil()throws Exception{
		String driver = "oracle.jdbc.driver.OracleDriver";
   		String url = "jdbc:oracle:thin:@localhost:1521:CRM";
   		String uid = "agentsky";
   		String pwd = "agentsky";

   		Class.forName(driver);
	   	this.cn = DriverManager.getConnection(url,uid,pwd);
	}
	
	private String getTablePrimaryKeys(String tableName){
		try{
			DatabaseMetaData dbmd = cn.getMetaData();
			ResultSet rs = dbmd.getPrimaryKeys(catalog, schemaPattern, tableName);
			StringBuffer sb = new StringBuffer(",");
			while(rs.next()){
				sb.append(rs.getString("COLUMN_NAME") + ",");
			}
			rs.close();
			return sb.toString();
		}catch(Exception ex){
			return "";
		}
	}
	
	private boolean containFieldType(String fieldType){
		List types = new ArrayList();
		types.add("CHAR");
		types.add("NCHAR");
		types.add("NVARCHAR");
		types.add("VARCHAR");
		types.add("VARCHAR2");
		return types.contains(fieldType.toUpperCase());
	}
	
	/**
	 * 取得表的备注信息
	 */
	private Map getTableComments()throws Exception{
		Map colMap = new HashMap();
		
		StringBuffer sb = new StringBuffer();
		sb.append("select TABLE_NAME,TABLE_TYPE,COMMENTS from user_tab_comments");
		
		PreparedStatement pstm = cn.prepareStatement(sb.toString());
		ResultSet rs = pstm.executeQuery();
		while(rs.next()){
			colMap.put(rs.getString("TABLE_NAME").toUpperCase(), rs.getString("COMMENTS"));
		}
	    rs.close();
	    pstm.close();
		
		return colMap;
	}
	
	/**
	 * 取得表字段的备注信息
	 */
	private Map getColumnComments(String tableName)throws Exception{
		Map colMap = new HashMap();
		
		StringBuffer sb = new StringBuffer();
		sb.append(" select TABLE_NAME,COLUMN_NAME,COMMENTS from user_col_comments ");
		sb.append(" where upper(TABLE_NAME)=upper('" + tableName + "') ");
		
		PreparedStatement pstm = cn.prepareStatement(sb.toString());
		ResultSet rs = pstm.executeQuery();
		while(rs.next()){
			colMap.put(rs.getString("COLUMN_NAME").toUpperCase(), rs.getString("COMMENTS"));
		}
	    rs.close();
	    pstm.close();
		
		return colMap;
	}
	
	public void createTableMetadata(String fileName){
		try{
			if(fileName == null || fileName.trim().length() == 0){
				throw new IllegalArgumentException("argument fileName can not be null");
			}
			File file = new File(fileName);
			
			//delete old file
			if(file.exists() && file.isFile()) file.delete();
			
			//create sheet
			FileOutputStream out = new FileOutputStream(file);
			WritableWorkbook book = Workbook.createWorkbook(out);
			WritableSheet sheet = book.createSheet("数据字典",0);
			
			//表备注
			Map tableMap = getTableComments();
			
			DatabaseMetaData dbmd = cn.getMetaData();
			String[] types = {"TABLE"};
			ResultSet rs = dbmd.getTables(catalog ,schemaPattern, null, types);
			int rowIndex = 0;
			int tableCount = 0;
			while(rs.next()){
				try{
					String tableName = rs.getString("TABLE_NAME");
					if(tableName.indexOf("=")!=-1) continue;
					
					tableCount++;
					System.out.println(tableCount + "、" + tableName + " doing...");
					
					//表字段备注信息
					Map colMap = getColumnComments(tableName);
					
					//表备注
					String tableComment = tableMap.get(tableName);
					if(CommonUtil.isNotEmpty(tableComment)){
						tableComment = "：" + tableComment;
					}else{
						tableComment = CommonUtil.trim(tableComment);
					}
					
					//表名
					sheet.mergeCells(0,rowIndex,6,rowIndex);  //合并单元格，6数字要与表头的cell个数一致
					sheet.addCell(new Label(0,rowIndex,tableName + tableComment));
					rowIndex++;
					
					//表头
					sheet.addCell(new Label(0,rowIndex,"序号"));
					sheet.addCell(new Label(1,rowIndex,"字段名"));
					sheet.addCell(new Label(2,rowIndex,"字段描述"));
					sheet.addCell(new Label(3,rowIndex,"字段类型"));
					sheet.addCell(new Label(4,rowIndex,"主键"));
					sheet.addCell(new Label(5,rowIndex,"可空"));
					sheet.addCell(new Label(6,rowIndex,"备注"));
					rowIndex++;
					
					//主键
					String strPrimaryKeys = getTablePrimaryKeys(tableName);
					
					Statement stm = cn.createStatement();
					stm.setMaxRows(1);
					ResultSet rsColumn = stm.executeQuery("select * from " + tableName);
					ResultSetMetaData rsmd = rsColumn.getMetaData();
					int recordIndex = 1;
					for(int i=1;i<=rsmd.getColumnCount();i++){
						sheet.addCell(new Label(0,rowIndex,String.valueOf(recordIndex))); //序号
						sheet.addCell(new Label(1,rowIndex,rsmd.getColumnName(i))); //字段名
						sheet.addCell(new Label(2,rowIndex,colMap.get(rsmd.getColumnName(i).toUpperCase()))); //描述
						
						//字段类型
						String fieldType = rsmd.getColumnTypeName(i);
						if(containFieldType(fieldType)){
							fieldType += "(" + String.valueOf(rsmd.getColumnDisplaySize(i)) + ")";
						}
						sheet.addCell(new Label(3,rowIndex,fieldType));
						
						//是否主键
						if(strPrimaryKeys.indexOf("," + rsmd.getColumnName(i) + ",") != -1){
							sheet.addCell(new Label(4,rowIndex,"Y"));
						}else{
							sheet.addCell(new Label(4,rowIndex,""));
						}
						
						//是否可空
						sheet.addCell(new Label(5,rowIndex,(rsmd.isNullable(i)==1)?"":"N"));
						
						//备注
						sheet.addCell(new Label(6,rowIndex,""));
						
						
						rowIndex++;
						recordIndex++;
					}
					rowIndex += 2;
					
					rsColumn.close();
					stm.close();
				}catch(Exception e){
					e.printStackTrace();
				}
			}
			rs.close();
			
			book.write();
			book.close();
		}catch(Exception ex){
			ex.printStackTrace();
		}finally{
			try{
				if(cn != null)cn.close();
			}catch(Exception e){
				e.printStackTrace();
			}
		}
	}
	
	public static void main(String[] args) {
		try{
			System.out.println("start...");
			MetadataUtil md = new MetadataUtil();
			md.createTableMetadata("c:\\agentsky_audit.xls");
			System.out.println("end");
			
		}catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
}