Java面向对象程序设计案例教程 习题答案 (王贺 ) 第8-11章

1、第8章习题答案一、选择题. C 2.A 3.B 4.BC 5.D二。、简答题.JDBC操作步骤(1)导入驱动程序(2)创立连接(3)创立 Statement(4)书写SQL语句(5)执行SQL语句获得结果(6)处理结果(7)关闭连接.列表对于数据类型Java数据类型SQL数据类型bytetiny intSshortsmall intintintlongbig intfloatnumberDoublenumberDatedata/time/datatimeStringvarchar.next方法工作流程，首先跳转进入结果集对象的下一行记录，如果记录不为空，返回值为 true,否那么返回值为fal

2、se。三、编程题.固定SQL语句方式：public int adminReg(String uname, String pswd) int result = -1;String driverclass = com.microsoft.sqlserver.jdbc.SQLServerDriver;String dbUrl = jdbc:sqlserver:/localhost:1433;databaseName=TestDB;Connection connection = null;Statement stmt = null;try(Class.forName(driverClass);conn

3、ection = DriverManager.getConnection(dbUrl, sa, sasa);stmt = connection.createStatement();String sql = insert into tb_admin(admin_name/admin_pswd) values ( + uname + 7 + pswd +result = stmt.executeUpdate(sql); catch (ClassNotFoundException e) e.printStackTrace(); catch (SQLException e) e.printStackT

4、race();)finally if (stmt != null) trystmt.closeO; catch (Exception e) )if (connection != null)try(connection.closef); catch (Exception e) )return result;)预编译SQL语句方式：public int adminRegfString uname, String pswd) int result = -1;String driverClass = com.microsoft.sqlserver.jdbc.SQLServerDriver;String

5、 dbUrl = jdbc:sqlserver:/localhost:1433;databaseName=TestDB;Connection connection = null;PreparedStatement pstmt = null;try (Class.forName(driverClass);connection = DriverManager.getConnection(dbUrlz sa, sasa);String sql = insert into tb_admin(admin_name,admin_pswd) values (?,?);pstmt = connection.p

6、repareStatement(sql);pstmt.setString(l, uname);pstmt.setString(2, pswd);result = pstmt.executellpdate(); catch (ClassNotFoundException e) e.printStackTrace(); catch (SQLException e) e.printStackTrace();)finally if (pstmt != null)try(pstmt.closef); catch (Exception e) )if (connection != null)try(conn

7、ection.close); catch (Exception e) )return result;).通用性很强的JDBC类import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sqLStatement;public class DBConn private final String className = com.microsoft.sqlserver.jdbc.SQLServerDriver;pr

8、ivatefinalStringconnectionllrljdbc:sqlserver:/localhost:1433;databaseName=TestDB;private final String username = sa;private final String password = sasa;private Connection connection;private Statement stmt;public DBConn() try(Class.forName(className);connection = DriverManager.getConnection(connecti

9、onUrl, username, password);System.out.println(connection);stmt = connection.createStatement(); catch (Exception e) e.printStackTrace();)public int update(String sql) int r = -1;if (stmt != null) try(r = stmt.executellpdate(sql); catch (SQLException e) /TODO Auto-generated catch blocke.printStackTrac

10、e();return r;public ResultSet queryfString sql) ResultSet rs = null;if (stmt != null) try(rs = stmt.executeQuery(sql); catch (SQLException e) / TODO Auto-generated catch block e.printStackTrace();) return rs;)public void close() if (connection != null) try(connection.close(); catch (SQLException e)

11、/ TODO Auto-generated catch block e.printStackTrace();)第9章习题答案一、选择题1. C 2.A 3.AB 4.AD 5,A 6.A7.B二、简答题.字节流是以直接的方式传送数据，字符流是以字符的方式传送数据。.读取操作步骤：(1)翻开文件，(2)声明缓存空间，(3)读取/写入，(4)关闭.构造方法：File (String pathname)：通过给定路径创立一个新的File类对象。File(String parent, String chi Id)：通过给定的文件夹目录和文件名创立一个新 的File类对象。File(File paren

12、t, String child)：通过给定的文件对象和文件名创立一个新的 File类对象。常用方法public String getName0 ：返回文件对象的 XXXXXXX。public String getPathO ：返回文件对象所在路径名。public String getAbsolutePath ()：返回文件对象的绝对路径名。public String getParentO：返回文件对象所在父目录路径。如果文件对象没有父目录， 那么返回nullopublic boolean exists()：判断文件对象所表示的文件或文件夹是否存在，存在返回 true,不存在返回falseopu

13、blic boolean isDirectory ()：判断文件对象所表示的是否为目录(文件夹),如果是 返回true,否那么返回false。publ ic boolean isFi le()：判断文件对象所表示的是否为一个标准文件,如果是,返回 true,否那么返回falseo三、编程题package p9_7;import java.io.FileWriter;import java.io.lOException;import java.util.Scanner;public class C97_l SuppressWarnings(resource)public static void

14、main(String args) (请输入字符串：);Scanner scanner=new Scanner(System.in);String s=scanner.nextLine();String ss=s.tollpperCase();try (FileWriter writer=new FileWriterfa.txt)； writer.write(ss);writer.close(); catch (lOException e) / TODO Auto-generated catch block e.printStackTrace();)package p9_7;import ja

15、va.io.File;import java.io.FileWriter;import java.io.lOException;import java.util.Random;public class C97_2 public static void main(String args) File f=new File(test.txt)； if(!f.exists() (try(f.createNewFile(); catch (lOException e) / TODO Auto-generated catch block e.printStackTrace();)Random r=new Random();StringBuffer sbf=new StringBuffer(); for(i