Java复习重点!!.doc

1、写结果class StringTest1public static void main(String args) String s1=hello;String s2=new String(hello);if(s1.equals(s2)System.out.println(相等);elseSystem.out.println(不相等);或者public class IfTest public static void main(String args) int x=3; int y=1; if(x=y) System.out.println(Not equal); else System.out.println(Equal); 2、写结果public class TestArray public static void main(String args ) int i , j ;int a = 5,9,6,8,7; for ( i = 0 ; i a.length-1; i + ) int k = i; for ( j = i ; j a.length ; j+ ) if ( ajak ) k = j; int temp =ai; ai = ak; ak = temp; for ( i =0 ; ia.length; i+ ) System.out.print(ai+ ); System.out.println( ); 3、写出以下程序的功能。import java.io.*;public class TestFile public static void main(String args) throws Exception BufferedReader br=new BufferedReader(new InputStreamReader(System.in); BufferedWriter bw = new BufferedWriter(new FileWriter(“input.txt); String s; while (true) System.out.print(请输入一个字符串： ); System.out.flush(); s=br.readLine(); if (s.length()=0) break; bw.write(s); bw.newLine(); bw.close(); 4、写出结果class Animal Animal() System.out.print (Animal ); public class Dog extends Animal Dog() System.out.print (Dog ); public static void main(String args) Dog snoppy= new Dog(); 5、下面程序是实现采用JDBC-ODBC的数据库连接，连接数据数据源table1，并实现查询功能，请在适当的位置填写语句。class Conn String sDBDriver = _; String sConnStr = jdbc:odbc:table1; Connection connect = null; ResultSet rs = null; public Conn() try _(sDBDriver); catch(java.lang.ClassNotFoundException e) System.err.println( e.getMessage(); public ResultSet executeQuery(String sql) try connect = DriverManager.getConnection(sConnStr); Statement stmt = connect.createStatement(); rs = stmt.executeQuery(sql); catch(SQLException ex) System.err.println(ex.getMessage(); return rs; 1. 阅读下面的程序, 分析程序输出的结果.class Leaf int i=0;Leaf(int i)this.i=i;Leaf increament()i+;return this;void print()System.out.println(i=+i);public static void main(String args) Leaf leaf=new Leaf(100);leaf.increament().increament().print();i=1022. class StaticTest static int x=1;int y;StaticTest()y+; public static void main(String args ) StaticTest st=new StaticTest(); System.out.println(x= + x); System.out.println(st.y= + st.y); st=new StaticTest(); System.out.println(st.y= + st.y); static x+;x=2st.y=1st.y=13、interface Apublic void mA( );interface Bpublic void mB( );abstract class Cabstract public void mC ( );class D extends C implements A,Bpublic void mA( )System.out.println(“A”);public void mB( )System.out.println(“B”);public void mC( )System.out.println(“C”);class Testpublic static void main(String args)Test t =new Test ( );D d=new D( );t.method1(d);t.method2(d);t.method3(d);public void method1(A a)a.mA( ); public void method2(B b)b.mB( ); public void method3(C c)c.mC( ); ABC4、阅读以下程序，写出输出结果。 class Cruncher void crunch( int i ) System.out.print(“int”); void crunch(String s) System.out.print(“String”); public static void ma