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📜  Java ResultSet

📅  最后修改于: 2020-10-13 01:23:35             🧑  作者: Mango

ResultSet界面

ResultSet对象维护一个光标，该光标指向表的一行。最初，光标指向第一行之前。

默认情况下，ResultSet对象只能向前移动，并且不可更新。

但是我们可以通过在createStatement(int，int)方法中传递TYPE_SCROLL_INSENSITIVE或TYPE_SCROLL_SENSITIVE来使该对象向前和向后移动，还可以通过以下方式使该对象可更新：

Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
     ResultSet.CONCUR_UPDATABLE);

ResultSet接口的常用方法

1) public boolean next(): is used to move the cursor to the one row next from the current position.
2) public boolean previous(): is used to move the cursor to the one row previous from the current position.
3) public boolean first(): is used to move the cursor to the first row in result set object.
4) public boolean last(): is used to move the cursor to the last row in result set object.
5) public boolean absolute(int row): is used to move the cursor to the specified row number in the ResultSet object.
6) public boolean relative(int row): is used to move the cursor to the relative row number in the ResultSet object, it may be positive or negative.
7) public int getInt(int columnIndex): is used to return the data of specified column index of the current row as int.
8) public int getInt(String columnName): is used to return the data of specified column name of the current row as int.
9) public String getString(int columnIndex): is used to return the data of specified column index of the current row as String.
10) public String getString(String columnName): is used to return the data of specified column name of the current row as String.

可滚动ResultSet的示例

让我们看一下用于检索第三行数据的ResultSet接口的简单示例。

import java.sql.*;
class FetchRecord{
public static void main(String args[])throws Exception{

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","system","oracle");
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
ResultSet rs=stmt.executeQuery("select * from emp765");

//getting the record of 3rd row
rs.absolute(3);
System.out.println(rs.getString(1)+" "+rs.getString(2)+" "+rs.getString(3));

con.close();
}}