tableinfotest.java

JAVA编程百例书中各章节的所有例子的源代码,包括套接字编程

package ch03.section09;

//Properties对象定义在util包中
//导入JDBCAPI
import java.sql.*;
import java.util.*;

public class TableInfoTest {
  public static void main(String args[]) {
    //指定数据源
    String url = "jdbc:odbc:sample";

    //声明连接对象
    Connection con;

    //声明结果集元数据对象
    ResultSetMetaData dmd;

    Statement sm;
    //声明结果集对象存储数据库信息
    ResultSet rs;

    try {
      //指定驱动程序名称
      String driverName = "sun.jdbc.odbc.JdbcOdbcDriver";
      //装载驱动程序
      Driver driver = (Driver) Class.forName(driverName).newInstance();

      //检测驱动程序是否正确装入
      if (driver == null) {
        System.out.println("驱动程序装入不成功");
      }
      else {
        System.out.println("驱动程序装入成功");
      }

    }
    catch (Exception e) {
      System.err.println(e.getMessage());
    }

    try {
      //添加用户名和密码
      Properties conn_prp = new Properties();
      conn_prp.put("user", "sa");
      conn_prp.put("password", "sa");

      //获取与指定数据源连接的连接对象
      con = DriverManager.getConnection(url, conn_prp);
      if (con == null) {
        System.out.println("数据库连接不成功！");
      }
      else {
        System.out.println("数据库连接成功！");
      }
      sm = con.createStatement();
      rs = sm.executeQuery("select * from tickets");
      dmd = rs.getMetaData();
      //Gets the designated column's table's catalog name
      String CatalogName = dmd.getCatalogName(2);
      if (CatalogName != null || CatalogName.equals("")) {
        System.out.println(" 2 column's table's catalog name: " + CatalogName);
      }
      else {
        System.out.println("CatalogName is null");
      }
      //Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.
      //getObject is called to retrieve a value from the column.
      String ColumnClassName = dmd.getColumnClassName(2);
      if (ColumnClassName != null) {
        System.out.println("the fully-qualified name of the Java class:" +
                           ColumnClassName);
      }
      else {
        System.out.println("ColumnClassName is null");
      }

      //Returns the number of columns in this ResultSet object.
      int ColumnCount = dmd.getColumnCount();
      System.out.println("the number of columns in this ResultSet object:" +
                         ColumnCount);
      //Indicates the designated column's normal maximum width in characters.
      int ColumnDisplaySize = dmd.getColumnDisplaySize(2);
      System.out.println(
          "the designated column's normal maximum width in characters: " +
          ColumnDisplaySize);
      //Gets the designated column's suggested title for use in printouts and displays.
      String ColumnLabel = dmd.getColumnName(2);
      if (ColumnLabel != null) {
        System.out.println("the designated column's suggested title:" +
                           ColumnLabel);
      }
      else {
        System.out.println("ColumnLabel is null");
      }
      //Get the designated column's name.
      String ColumnName = dmd.getColumnName(2);
      if (ColumnName != null) {
        System.out.println("the designated column's name:" + ColumnName);
      }
      else {
        System.out.println("ColumnName is null");
      }

      //Retrieves the designated column's database-specific type name.
      String ColumnTypeName = dmd.getColumnTypeName(2);
      if (ColumnTypeName != null) {
        System.out.println(
            "the designated column's database-specific type name:" +
            ColumnTypeName);
      }
      else {
        System.out.println("ColumnTypeName is null");
      }
      //Retrieves the designated column's SQL type.
      int ColumnType = dmd.getColumnType(2);
      System.out.println("the designated column's SQL type: " +
                         dmd.getColumnType(2));
      //Gets the designated column's number of digits to right of the decimal point.
      int Scale = dmd.getScale(2);
      System.out.println(
          "the designated column's number of digits to right of the decimal point:  " +
          Scale);
      //Gets the designated column's table name.
      String TableName = dmd.getTableName(2);
      if (TableName != null) {
        System.out.println("the designated column's table name:  " + TableName);
      }
      else {
        System.out.println("TableName is null");
      }

      //Indicates whether a write on the designated column will definitely succeed.
      boolean DefinitelyWritable = dmd.isDefinitelyWritable(2);
      if (DefinitelyWritable) {
        System.out.println(
            "A write on the designated column will definitely succeed");
      }
      else {
        System.out.println(
            "A write on the designated column will definitely unsucceed");
      }
      //Indicates whether the designated column is definitely not writable.
      boolean ReadOnly = dmd.isReadOnly(2);
      if (ReadOnly) {
        System.out.println("the designated column is definitely not writable");
      }
      else {
        System.out.println("the designated column is  writable");
      }
      //Indicates whether the designated column can be used in a where clause.
      boolean Searchable = dmd.isSearchable(2);
      if (Searchable) {
        System.out.println(
            "the designated column can be used in a where clause");
      }
      else {
        System.out.println(
            "the designated column can  not be used in a where clause");
      }
      //Indicates whether it is possible for a write on the designated column to succeed.
      boolean Writable = dmd.isWritable(2);
      if (Writable) {
        System.out.println(
            "it is possible for a write on the designated column to succeed");
      }
      else {
        System.out.println(
            "it isn't possible for a write on the designated column to succeed");
      }
      //Indicates whether values in the designated column are signed numbers.
      boolean Signed = dmd.isSigned(2);
      if (Signed) {
        System.out.println("values in the designated column are signed numbers");
      }
      else {
        System.out.println(
            "values in the designated column aren't signed numbers");
      }
      //closed all
      rs.close();
      sm.close();
      con.close();
    }
    catch (SQLException ex) {
      System.err.println(ex.toString());
    }
  }
}