jdbc获取mysql、oracle数据库的表、字段、主键、唯一索引

根据数据库的四大参数获取指定库中的所有表

//根据数据库的参数获取指定库中的所有表
 public static List> getDbTables(String driver, String url, String user, String pwd) {
        Connection conn = null;
        ResultSet rs = null;
        List> tables = new ArrayList<>();
        try {
            conn = getConnections(driver, url, user, pwd);
            DatabaseMetaData dbMetaData = conn.getMetaData();
            rs = dbMetaData.getTables(null, getSchema(conn), null, new String[]{"TABLE"});
            while (rs.next()) {
                Map map = new HashMap<>(1 << 3);
                //获取数据库的表名
                map.put("tableNam", rs.getString("TABLE_NAME"));
                //获取数据库的表类型
                map.put("tableType", rs.getString("TABLE_TYPE"));
                // 所属数据库
                map.put("tableCat", rs.getString("TABLE_CAT"));
                // 所属用户
                map.put("tableSchem", rs.getString("TABLE_SCHEM"));
                map.put("tableRemarks", rs.getString("REMARKS"));

                tables.add(map);
            }
        } catch (Exception e) {
            LoggerUtil.error(String.valueOf(RetCode.DB_CONN_ERROR), Utils.getStackTrace(e));
            throw new ServiceException(RetCode.DB_CONN_ERROR, "failed to get db tables", null);
        } finally {
            safeClose(rs, conn);
        }
        return tables;
    }

根据数据库的表名获取数据库的字段、主键、唯一索引

注意：oracle区分大小写，所以在获取唯一索引时和oracle有区别。

public static Map>> getColumnsByTableList(String driver, String url,
                                                                               String user, String pwd, List tableList, int dbType) {
        LoggerUtil.debug("tableList: {}", tableList);
        if (CollectionUtils.isEmpty(tableList)) {
            return null;
        }

        Map>> tableColumns = new HashMap<>(tableList.size());

        Connection conn = null;
        ResultSet rs = null;
        try {
            conn = getConnections(driver, url, user, pwd);
            DatabaseMetaData dbMetaData = conn.getMetaData();
            String userName = conn.getMetaData().getUserName();
            if ((userName == null) || (userName.length() == 0)) {
                throw new Exception("ORACLE数据库模式不允许为空");
            }


            List> columns = null;
            for (String tableName : tableList) {
                columns = new ArrayList<>();

                // 获取主键字段
                ResultSet primaryKeys = dbMetaData.getPrimaryKeys(null, userName, tableName);
                Set keySet = new HashSet<>(8);

                //根据结果集元数据打印内容
                ResultSetMetaData pkmd = primaryKeys.getMetaData();
                while (primaryKeys.next()) {
                    for (int i = 1; i <= pkmd.getColumnCount(); i++) {
                        //获取主键的名称
                        if ("COLUMN_NAME".equalsIgnoreCase(pkmd.getColumnName(i))) {
                            keySet.add(primaryKeys.getString(i));
                        }
                    }
                }

                Set uniqueKeyMap = new HashSet<>(16);
                //获取唯一索引
                if (Constants.DB_TYPE_ORACLE11 == dbType || Constants.DB_TYPE_ORACLE12 == dbType) {
                	// 由于oracle区分大小写，在写oracle的sql语句时，表名或字段是小写的话，需要添加双引号
                    String tableName1 = "\'" + tableName + "\'";
                    String sql = "select t.*,i.index_type from user_ind_columns t,user_indexes i where t.index_name = i.index_name and i.uniqueness='UNIQUE' and t.table_name = " + tableName1;
                    PreparedStatement pstmt = conn.prepareStatement(sql);
                    ResultSet rsKey = pstmt.executeQuery();

                    while (rsKey.next()) {
                        String indexName = rsKey.getString("COLUMN_NAME");
                        uniqueKeyMap.add(indexName);
                    }
                } else {
                    //mysql数据库
                    ResultSet indexInfo = dbMetaData.getIndexInfo(null, null, tableName, false, false);
                    while (indexInfo.next()) {
                        String indexName = indexInfo.getString("INDEX_NAME");
                        //如果为真则说明索引值不唯一，为假则说明索引值必须唯一。
                        boolean nonUnique = indexInfo.getBoolean("NON_UNIQUE");
                        if (!nonUnique) {
                            uniqueKeyMap.add(indexName);
                        }
                    }
                }
                rs = dbMetaData.getColumns(null, "%", tableName, "%");
                while (rs.next()) {
                    Map map = new HashMap<>(1 << 4);
                    map.put("columnName", rs.getString("COLUMN_NAME"));
                    map.put("columnType", rs.getString("TYPE_NAME"));
                    map.put("datasize", rs.getInt("COLUMN_SIZE"));
                    map.put("remarks", rs.getString("REMARKS"));
                    // 默认值
                    map.put("columnDefault", rs.getString("COLUMN_DEF"));
                    // 是否允许为null, NO:不允许空，YES:可以为空，空: 不确定
                    map.put("isNullable", rs.getString("IS_NULLABLE"));
                    // 是否主键
                    map.put("key", keySet.contains(map.get("columnName")) ? Constants.IS_KEY : Constants.NOT_KEY);
                    map.put("uniqueKey", uniqueKeyMap.contains(rs.getString("COLUMN_NAME")) ? Constants.IS_UNIQUE_KEY : Constants.NOT_UNIQUE_KEY);
                    columns.add(map);
                }

                if (!columns.isEmpty()) {
                    tableColumns.put(tableName, columns);
                }
            }
        } catch (Exception e) {
            LoggerUtil.warn("get columns by table list happened exception, detail:{}", Utils.getStackTrace(e));
            throw new ServiceException(RetCode.DB_CONN_ERROR, "failed to get columns by table list");
        } finally {
            safeClose(rs, conn);
        }
        return tableColumns;
    }