从java.sql.ResultSet中检索列名称
用java.sql.ResultSet有没有办法通过使用列的索引来获取列的名称作为String ？ 我浏览了API文档，但找不到任何东西。
您可以从ResultSet元数据中获取此信息。 请参阅ResultSetMetaData
例如
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2"); ResultSetMetaData rsmd = rs.getMetaData(); String name = rsmd.getColumnName(1);
你可以从那里得到列名。 如果你这样做
select x as y from table
那么rsmd.getColumnLabel()也会得到你检索的标签名称。
除了上面的答案之外，如果您正在使用dynamic查询并且想要列名但不知道有多less列，则可以使用ResultSetMetaData对象先获取列数，然后循环访问它们。
修改Brian的代码：
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2"); ResultSetMetaData rsmd = rs.getMetaData(); int columnCount = rsmd.getColumnCount(); // The column count starts from 1 for (int i = 1; i <= columnCount; i++ ) { String name = rsmd.getColumnName(i); // Do stuff with name }
您可以使用ResultSetMetaData（ http://java.sun.com/javase/6/docs/api/java/sql/ResultSetMetaData.html ）对象，如下所示：
ResultSet rs = stmt.executeQuery("SELECT * FROM table"); ResultSetMetaData rsmd = rs.getMetaData(); String firstColumnName = rsmd.getColumnName(1);
这个问题是古老的，以前的答案也是正确的。 但是当我发现这个话题的时候，我正在寻找的就是这个解决scheme。 希望它可以帮助别人。
// Loading required libraries import java.util.*; import java.sql.*; public class MySQLExample { public void run(String sql) { // JDBC driver name and database URL String JDBC_DRIVER = "com.mysql.jdbc.Driver"; String DB_URL = "jdbc:mysql://localhost/demo"; // Database credentials String USER = "someuser"; // Fake of course. String PASS = "somepass"; // This too! Statement stmt = null; ResultSet rs = null; Connection conn = null; Vector<String> columnNames = new Vector<String>(); try { // Register JDBC driver Class.forName(JDBC_DRIVER); // Open a connection conn = DriverManager.getConnection(DB_URL, USER, PASS); // Execute SQL query stmt = conn.createStatement(); rs = stmt.executeQuery(sql); if (rs != null) { ResultSetMetaData columns = rs.getMetaData(); int i = 0; while (i < columns.getColumnCount()) { i++; System.out.print(columns.getColumnName(i) + "\t"); columnNames.add(columns.getColumnName(i)); } System.out.print("\n"); while (rs.next()) { for (i = 0; i < columnNames.size(); i++) { System.out.print(rs.getString(columnNames.get(i)) + "\t"); } System.out.print("\n"); } } } catch (Exception e) { System.out.println("Exception: " + e.toString()); } finally { try { if (rs != null) { rs.close(); } if (stmt != null) { stmt.close(); } if (conn != null) { conn.close(); } } catch (Exception mysqlEx) { System.out.println(mysqlEx.toString()); } } } }
从数据库查询读取数据的SQL语句返回结果集中的数据。 SELECT语句是从数据库中select行并在结果集中查看它们的标准方法。 **java.sql.ResultSet**接口表示数据库查询的结果集。
- 获取方法：用于查看光标指向的当前行的列中的数据。
使用MetaData of a result set to fetch the exact column count
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2"); ResultSetMetaData rsmd = rs.getMetaData(); int numberOfColumns = rsmd.getColumnCount(); boolean b = rsmd.isSearchable(1);
http://docs.oracle.com/javase/7/docs/api/java/sql/ResultSetMetaData.html
并进一步将其绑定到数据模型表
public static void main(String[] args) { Connection conn = null; Statement stmt = null; try{ //STEP 2: Register JDBC driver Class.forName("com.mysql.jdbc.Driver"); //STEP 3: Open a connection System.out.println("Connecting to a selected database..."); conn = DriverManager.getConnection(DB_URL, USER, PASS); System.out.println("Connected database successfully..."); //STEP 4: Execute a query System.out.println("Creating statement..."); stmt = conn.createStatement(); String sql = "SELECT id, first, last, age FROM Registration"; ResultSet rs = stmt.executeQuery(sql); //STEP 5: Extract data from result set while(rs.next()){ //Retrieve by column name int id = rs.getInt("id"); int age = rs.getInt("age"); String first = rs.getString("first"); String last = rs.getString("last"); //Display values System.out.print("ID: " + id); System.out.print(", Age: " + age); System.out.print(", First: " + first); System.out.println(", Last: " + last); } rs.close(); }catch(SQLException se){ //Handle errors for JDBC se.printStackTrace(); }catch(Exception e){ //Handle errors for Class.forName e.printStackTrace(); }finally{ //finally block used to close resources try{ if(stmt!=null) conn.close(); }catch(SQLException se){ }// do nothing try{ if(conn!=null) conn.close(); }catch(SQLException se){ se.printStackTrace(); }//end finally try }//end try System.out.println("Goodbye!"); }//end main }//end JDBCExample
非常好的教程在这里： http : //www.tutorialspoint.com/jdbc/
ResultSetMetaData meta = resultset.getMetaData(); // for a valid resultset object after executing query Integer columncount = meta.getColumnCount(); int count = 1 ; // start counting from 1 always String[] columnNames = null; while(columncount <=count){ columnNames [i] = meta.getColumnName(i); } System.out.println (columnNames.size() ); //see the list and bind it to TableModel object. the to your jtbale.setModel(your_table_model);
import java.sql.*; public class JdbcGetColumnNames { public static void main(String args[]) { Connection con = null; Statement st = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection( "jdbc:mysql://localhost:3306/komal", "root", "root"); st = con.createStatement(); String sql = "select * from person"; rs = st.executeQuery(sql); ResultSetMetaData metaData = rs.getMetaData(); int rowCount = metaData.getColumnCount(); System.out.println("Table Name : " + metaData.getTableName(2)); System.out.println("Field \tDataType"); for (int i = 0; i < rowCount; i++) { System.out.print(metaData.getColumnName(i + 1) + " \t"); System.out.println(metaData.getColumnTypeName(i + 1)); } } catch (Exception e) { System.out.println(e); } } }
表名称：person字段DataType id VARCHAR cname VARCHAR dob DATE
SQLite 3
使用getMetaData（）;
DatabaseMetaData md = conn.getMetaData(); ResultSet rset = md.getColumns(null, null, "your_table_name", null); System.out.println("your_table_name"); while (rset.next()) { System.out.println("\t" + rset.getString(4)); }
编辑：这也适用于PostgreSQL
@Cyntech是对的。
如果你的表是空的，你仍然需要得到表列名称，你可以得到你的列为Vectortypes，请参阅以下内容：
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2"); ResultSetMetaData rsmd = rs.getMetaData(); int columnCount = rsmd.getColumnCount(); Vector<Vector<String>>tableVector = new Vector<Vector<String>>(); boolean isTableEmpty = true; int col = 0; while(rs.next()) { isTableEmpty = false; //set to false since rs.next has data: this means the table is not empty if(col != columnCount) { for(int x = 1;x <= columnCount;x++){ Vector<String> tFields = new Vector<String>(); tFields.add(rsmd.getColumnName(x).toString()); tableVector.add(tFields); } col = columnCount; } } //if table is empty then get column names only if(isTableEmpty){ for(int x=1;x<=colCount;x++){ Vector<String> tFields = new Vector<String>(); tFields.add(rsmd.getColumnName(x).toString()); tableVector.add(tFields); } } rs.close(); stmt.close(); return tableVector;
ResultSet rsTst = hiSession.connection().prepareStatement(queryStr).executeQuery(); ResultSetMetaData meta = rsTst.getMetaData(); int columnCount = meta.getColumnCount(); // The column count starts from 1 String nameValuePair = ""; while (rsTst.next()) { for (int i = 1; i < columnCount + 1; i++ ) { String name = meta.getColumnName(i); // Do stuff with name String value = rsTst.getString(i); //.getObject(1); nameValuePair = nameValuePair + name + "=" +value + ","; //nameValuePair = nameValuePair + ", "; } nameValuePair = nameValuePair+"||" + "\t"; }
当你需要列名时，但不想抓取条目：
PreparedStatement stmt = connection.prepareStatement("SHOW COLUMNS FROM `yourTable`"); ResultSet set = stmt.executeQuery(); //store all of the columns names List<String> names = new ArrayList<>(); while (set.next()) { names.add(set.getString("Field")); }
注：只适用于MySQL
