public interface ResultSetMetaData可用于获取关于 ResultSet 对象中列的类型和属性信息的对象。相当于反射Class:
代码示例如下:
package com.ambow.day21.jdbc.NewFecture;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import com.ambow.day19.jdbc.util.MySqlDBConnection;
public class ResultMetadateTest {
public static void main(String args[]) {
Connection con = null;
PreparedStatement pstm = null;
ResultSet rs=null;
ResultSetMetaData rsm = null;
try {
con = MySqlDBConnection.DBConnection();
String sql = "select * from student order by id";
pstm= con.prepareStatement(sql);
rs=pstm.executeQuery();
rsm=pstm.getMetaData();
System.out.println("*****开始获取元数据*****");
System.out.print("此 ResultSet 对象中一共有列数为————");
System.out.println(rsm.getColumnCount());
for(int i=1;i<=rsm.getColumnCount();i++){
System.out.println("第"+i+"字段的列名为:"+rsm.getColumnName(i)+" 数据类型为:"+rsm.getColumnTypeName(i));
}
System.out.println("数据库名称为:"+rsm.getCatalogName(1));
System.out.println("数据库表名称为:"+rsm.getTableName(1));
System.out.println("是否自动为指定列进行编号 :"+rsm.isAutoIncrement(1));
System.out.println("指定的列是否明确不可写入:"+rsm.isReadOnly(1));
System.out.println("是否可以在 where 子句中使用指定的列:"+rsm.isSearchable(2));
System.out.println("在指定的列上进行写操作是否可以获得成功:"+rsm.isWritable(1));
} catch (SQLException e) {
e.printStackTrace();
}finally{
MySqlDBConnection.closeResultSet(rs);
MySqlDBConnection.closePreparedStatement(pstm);
MySqlDBConnection.closeConnection(con);
}
}
}
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