这段代码我试过了可以获取模式下所有表的主键列名

			/*
			 * 获取主键字段名
			 * */
			DatabaseMetaData meta=con.getMetaData();
			ResultSet tables = meta.getTables(null, null, "%", new String[] { "TABLE" });					
			while (tables.next()) {
			 String catalog = tables.getString("TABLE_CAT");
			 String schema = tables.getString("TABLE_SCHEM");
			 String tableName = tables.getString("TABLE_NAME");
			 System.out.println("Table: " + tableName);
			 try (ResultSet primaryKeys = meta.getPrimaryKeys(catalog, schema, tableName)) {
			  while (primaryKeys.next()) {
			                System.out.println("Primary key: " + primaryKeys.getString("COLUMN_NAME"));
			            }
			        }
			        // similar for exportedKeys
			    }