描述

java.sql.ResultSet接口表示SQL查询语句执行完成后的结果集，可以通过Statement的executeQuery方法或者getResultSet方法获取。该接口核心作用是：

• 存储数据库查询返回的所有行数据。
• 提供遍历、读取、操作行或列数据的方法。
• 支持对结果集的灵活定位（如移动到指定行、双向遍历）。
• 部分场景下支持更新结果集并同步到数据库。

详细接口说明请参考JDBC官方网站 (opens new window)。

方法

YashanDB JDBC驱动对ResultSet接口有如下方法：

方法	返回类型
next()	boolean
close()	void
wasNull()	boolean
getString(int columnIndex)	String
getString(String columnLabel)	String
getNString(int columnIndex)	String
getNString(String columnLabel)	String
getBoolean(int columnIndex)	boolean
getBoolean(String columnLabel)	boolean
getByte(int columnIndex)	byte
getByte(String columnLabel)	byte
getShort(int columnIndex)	short
getShort(String columnLabel)	short
getInt(int columnIndex)	int
getInt(String columnLabel)	int
getLong(int columnIndex)	long
getLong(String columnLabel)	long
getNClob(int columnIndex)	NClob
getNClob(String columnLabel)	NClob
getSQLXML(int columnIndex)	SQLXML
getSQLXML(String columnLabel)	SQLXML
getFloat(int columnIndex)	float
getFloat(String columnLabel)	float
getDouble(int columnIndex)	double
getDouble(String columnLabel)	double
getBigDecimal(int columnIndex)	BigDecimal
getBigDecimal(String columnLabel)	BigDecimal
getBigDecimal(int columnIndex, int scale)	BigDecimal
getBigDecimal(String columnLabel, int scale)	BigDecimal
getBytes(int columnIndex)	byte[]
getBytes(String columnLabel)	byte[]
getDate(int columnIndex)	java.sql.Date
getDate(String columnLabel)	java.sql.Date
getDate(int columnIndex, Calendar cal)	java.sql.Date
getDate(String columnLabel, Calendar cal)	java.sql.Date
getTimestamp(int columnIndex)	java.sql.Timestamp
getTimestamp(String columnLabel)	java.sql.Timestamp
getTimestamp(int columnIndex, Calendar cal)	java.sql.Timestamp
getTimestamp(String columnLabel, Calendar cal)	java.sql.Timestamp
getAsciiStream(int columnIndex)	java.io.InputStream
getAsciiStream(String columnLabel)	java.io.InputStream
getBinaryStream(int columnIndex)	java.io.InputStream
getBinaryStream(String columnLabel)	java.io.InputStream
getCharacterStream(int columnIndex)	java.io.Reader
getCharacterStream(String columnLabel)	java.io.Reader
getMetaData()	ResultSetMetaData
getObject(int columnIndex)	Object
getObject(String columnLabel)	Object
findColumn(String columnLabel)	int
isFirst()	boolean
getRow()	int
getType()	int
getConcurrency()	int
getFetchDirection()	int
getFetchSize()	int
getWarnings()	int
getStatement()	Statement
getRowId(int columnIndex)	RowId
getRowId(String columnLabel)	RowId
isClosed()	boolean
getNCharacterStream(int columnIndex)	java.io.Reader
getNCharacterStream(String columnLabel)	java.io.Reader
getTime(int columnIndex)	java.sql.Time
getTime(String columnLabel)	java.sql.Time
getTime(int columnIndex, Calendar cal)	java.sql.Time
getTime(String columnLabel, Calendar cal)	java.sql.Time
getBlob(int columnIndex)	Blob
getBlob(String columnLabel)	Blob
getClob(int columnIndex)	Clob
getClob(String columnLabel)	Clob
getObject(int columnIndex, Class<T> type)	<T> T
getObject(String columnLabel, Class<T> type)	<T> T
getObject(int columnIndex, java.util.Map<String,Class<?>> map)	Object
getObject(String columnLabel, java.util.Map<String,Class<?>> map)	Object
getArray(int columnIndex)	Array
getArray(String columnLabel)	Array
isBeforeFirst()	boolean
isAfterLast()	boolean
isLast()	boolean
beforeFirst()	void
afterLast()	void
first()	boolean
last()	boolean
absolute( int row )	boolean
relative( int rows )	boolean
previous()	boolean
rowUpdated()	boolean
rowInserted()	boolean
rowDeleted()	boolean
clearWarnings()	void
setFetchSize(int rows)	void
updateNull(int columnIndex)	void
updateNull(String columnLabel)	void
updateByte(int columnIndex, byte x)	void
updateByte(String columnLabel, byte x)	void
updateShort(int columnIndex, short x)	void
updateShort(String columnLabel, short x)	void
updateInt(int columnIndex, int x)	void
updateInt(String columnLabel, int x)	void
updateLong(int columnIndex, long x)	void
updateLong(String columnLabel, long x)	void
updateFloat(int columnIndex, float x)	void
updateFloat(String columnLabel, float x)	void
updateDouble(int columnIndex, double x)	void
updateDouble(String columnLabel, double x)	void
updateBigDecimal(int columnIndex, BigDecimal x)	void
updateBigDecimal(String columnLabel, BigDecimal x)	void
updateString(int columnIndex, String x)	void
updateString(String columnLabel, String x)	void
updateSQLXML(int columnIndex, SQLXML xmlObject)	void
updateSQLXML(String columnLabel, SQLXML xmlObject)	void
updateDate(int columnIndex, java.sql.Date x)	void
updateDate(String columnLabel, java.sql.Date x)	void
updateTime(int columnIndex, java.sql.Time x)	void
updateTime(String columnLabel, java.sql.Time x)	void
updateTimestamp(int columnIndex, java.sql.Timestamp x)	void
updateTimestamp(String columnLabel, java.sql.Timestamp x)	void
updateBoolean(String columnLabel, boolean x)	void
updateObject(int columnIndex, Object x, int scaleOrLength)	void
updateObject(int columnIndex, Object x)	void
updateObject(String columnLabel, Object x, int scaleOrLength)	void
updateObject(String columnLabel, Object x)	void
updateObject(int columnIndex, Object x, SQLType targetSqlType, int scaleOrLength)	void
updateObject(String columnLabel, Object x, SQLType targetSqlType, int scaleOrLength)	void
updateObject(int columnIndex, Object x, SQLType targetSqlType)	void
updateObject(String columnLabel, Object x, SQLType targetSqlType)	void
insertRow()	void
updateRow()	void
deleteRow()	void
updateBytes(int columnIndex, byte x[])	void
updateBytes(String columnLabel, byte x[])	void
updateRowId(int columnIndex, RowId x)	void
updateRowId(String columnLabel, RowId x)	void
moveToInsertRow()	void
moveToCurrentRow()	void
refreshRow()	void
setFetchDirection(int direction)	void

示例

package quickstart;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

public class ResultSetExample {
    private static final String TABLE = "jdbc_resultset_users";

    public static Connection getConnection()
            throws SQLException, ClassNotFoundException {
        String url = "jdbc:yasdb://192.168.1.2:1688/yasdb";
        Properties info = new Properties();
        info.setProperty("user", "username");
        info.setProperty("password", "passwd");
        Class.forName("com.yashandb.jdbc.Driver");
        return DriverManager.getConnection(url, info);
    }

    public static void main(String[] args) throws Exception {
        ResultSetExample example = new ResultSetExample();
        try (Connection conn = getConnection();
             Statement stmt = conn.createStatement()) {
            stmt.execute("DROP TABLE IF EXISTS " + TABLE);
            stmt.execute("CREATE TABLE " + TABLE
                    + " (id INTEGER PRIMARY KEY, name VARCHAR(30), "
                    + "email VARCHAR(60), age INTEGER)");
            stmt.execute("INSERT INTO " + TABLE
                    + " VALUES (1, 'User1', 'user1@example.com', 20)");
            stmt.execute("INSERT INTO " + TABLE
                    + " VALUES (2, 'User2', 'user2@example.com', 25)");
            stmt.execute("INSERT INTO " + TABLE
                    + " VALUES (3, 'User3', 'user3@example.com', 30)");

            System.out.println(example.getUserById(conn, 1));
            System.out.println(example.getAllUsers(conn));
            example.updateUserAge(conn);
        }
    }

    // 读取单行
    public String getUserById(Connection conn, int id) throws SQLException {
        String sql = "SELECT id, name, email FROM " + TABLE + " WHERE id = ?";
        try (PreparedStatement ps = conn.prepareStatement(sql)) {
            ps.setInt(1, id);
            try (ResultSet rs = ps.executeQuery()) {
                if (rs.next()) {
                    return rs.getInt("id") + ", " + rs.getString("name") + ", " + rs.getString("email");
                }
            }
        }
        return null;
    }

    // 读取多行
    public List<String> getAllUsers(Connection conn) throws SQLException {
        List<String> users = new ArrayList<>();
        String sql = "SELECT id, name FROM " + TABLE + " ORDER BY id";

        try (Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery(sql)) {
            while (rs.next()) {
                users.add(rs.getInt("id") + ", " + rs.getString("name"));
            }
        }
        return users;
    }

    // 可更新 ResultSet
    public void updateUserAge(Connection conn) throws SQLException {
        String sql = "SELECT id, name, age FROM " + TABLE + " FOR UPDATE";
        try (Statement stmt = conn.createStatement(
                ResultSet.TYPE_SCROLL_SENSITIVE,
                ResultSet.CONCUR_UPDATABLE);
             ResultSet rs = stmt.executeQuery(sql)) {

            while (rs.next()) {
                int age = rs.getInt("age");
                rs.updateInt("age", age + 1);
                rs.updateRow();
            }
        }
    }

    // 批量读取
    public void processLargeResultSet(ResultSet rs) throws SQLException {
        int batchSize = 100;
        int count = 0;

        while (rs.next()) {
            processRow(rs);
            count++;

            if (count % batchSize == 0) {
                System.out.println("Processed " + count + " rows");
            }
        }
    }

    private void processRow(ResultSet rs) throws SQLException {
        // 处理每一行数据
    }
}

正常情况下，程序输出如下：

1, User1, user1@example.com
[1, User1, 2, User2, 3, User3]