??xml version="1.0" encoding="utf-8" standalone="yes"?>
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class TestZip {
static final int BUFFER = 40960;
public static void main(String argv[]) {
try {
BufferedInputStream origin = null;
FileOutputStream dest = new FileOutputStream("E:/test/myfiles.zip");//压羃后保存\径和文g?br />
ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(dest));
byte data[] = new byte[BUFFER];
File f = new File("e:/test/a/");//压羃文g夹名
File files[] = f.listFiles();
for (int i = 0; i < files.length; i++) {
FileInputStream fi = new FileInputStream(files[i]);
origin = new BufferedInputStream(fi, BUFFER);
ZipEntry entry = new ZipEntry(files[i].getName());
out.putNextEntry(entry);
int count;
while ((count = origin.read(data, 0, BUFFER)) != -1) {
out.write(data, 0, count);
}
origin.close();
}
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}}
1.public class MyClass
2.{
3. static String s1 = "I am unique!";
4. public static void main(String args[])
5. {
6. String s2 = "I am unique!";
7. String s3 = new String(s1);
8. System.out.println(s1 == s2);
9. System.out.println(s1.equals(s2));
10. System.out.println(s3 == s1);
11. System.out.println(s3.equals(s1));
12. System.out.println(TestClass.s4 == s1);
13. }
14.}
---------------------------------------------------------------
q段E序是非常简单的。但是ؓ(f)什么new出来的对象用Q=判断为falseQ而基本类型的直接赋值用Q=判断是true呢?
q是因ؓ(f)在JAVA的对象存储机刉Qnew出来的一定是对象Q而对象在内存中的存贮位置在HeapQ堆Q中Q而基本类型在E序中出现的比较频繁Q注QJAVA中的基本cd?中,分别是:(x)booleanQcharQbyteQshortQintQlongQfloatQdoubleQ,所以通过new产生q些对象而将其放入在heap中效率反而不高,所以JAVA直接采取C/C++的方式,也就是不以new来分配其I间Q而是产生一U所谓的“automatic”变量Q不在是reference的Ş式)Q来解决效率的问题,此类变量直接放数据|q且|于stackQ栈Q中Q因为stack在空间的分配和释放上Q效率要好的多。而恰恰是q种在内存中位置的不同,在stack中ؓ(f)基本cd变量分配I间Ӟ如果stack中有一L(fng)数据Ӟ不在创建新的数据,所以导致这个时候比较的两个基本cd值时Q即使用Q=也是true?/p>
因ؓ(f)JAVA保存了基本类型,而基本类型(入int、char{)q不具备面向对象的特点,比如拥有cȝ对象和方法。所以在JAVA中引入了new出来的基本类型,比如character c Q?new character( )的Ş式。基于此Q严格的ԌJAVAq不是像Z所宣称的是d的纯_的面向对象语言?br />
单点是
==Q?/font>
1、比较的是操作符两端的操作数是否是同一个对?br />
2、两边的操作数必L同一cd的(可以是父子类之间Q才能编译通过?br />
3、比较的是地址Q如果是具体的阿拉伯数字的比较,值相{则为TRUEQ如Q?br />
int a=10 ?long b=10L ?double c=10.0都是相同的(为trueQ,因ؓ(f)他们都指向地址?0的堆
equalsQ?/font>
1、比较的是两个对象的内容是否一?
SAP DB
Class.forName ("com.sap.dbtech.jdbc.DriverSapDB");
java.sql.Connection connection = java.sql.DriverManager.getConnection ( "jdbc:sapdb://" + host + "/" + database_name,user_name, password)
InterBase
String url = "jdbc:interbase://localhost/e:/testbed/database/employee.gdb";
Class.forName("interbase.interclient.Driver");
//Driver d = new interbase.interclient.Driver (); /* this will also work if you do not want the line above */
Connection conn = DriverManager.getConnection( url, "sysdba", "masterkey" );
Microsoft SQL Server series (6.5, 7.x and 2000) and Sybase 10
JDBC Name: jTDS
URL: http://jtds.sourceforge.net/
Version: 0.5.1
Download URL: http://sourceforge.net/project/showfiles.php?group_id=33291
语法:
Class.forName("net.sourceforge.jtds.jdbc.Driver ");
Connection con = DriverManager.getConnection("jdbc:jtds:sqlserver://host:port/database","user","password");
or
Connection con = DriverManager.getConnection("jdbc:jtds:sybase://host:port/database","user","password");
Postgresql
JDBC Name: PostgreSQL JDBC
URL: http://jdbc.postgresql.org/
Version: 7.3.3 build 110
Download URL: http://jdbc.postgresql.org/download.html
语法:
Class.forName("org.postgresql.Driver");
Connection con=DriverManager.getConnection("jdbc:postgresql://host:port/database","user","password");
IBM AS400L在用的JDBC语法
有装V4R4以上版本的Client Access Express
可以在C:Program FilesIBMClient Accessjt400lib
扑ֈ driver 档案 jt400.zipQƈ更改扩展名成?jt400.jar
语法
java.sql.DriverManager.registerDriver (new com.ibm.as400.access.AS400JDBCDriver ());
Class.forName("com.ibm.as400.access.AS400JDBCConnection");
con = DriverManager.getConnection("jdbc:as400://IP","user","password");
informix数据?/p>
Class.forName("com.informix.jdbc.IfxDriver").newInstance();
String url =
"jdbc:informix-sqli://123.45.67.89:1533/testDB:INFORMIXSERVER=myserver;
user=testuser;password=testpassword";
Sybase数据?/p>
LibQjdbcdrv.zip Class.forName( "com.sybase.jdbc.SybDriver" ) url="jdbc:sybase:Tds:127.0.0.1:2638/asademo"; SybConnection connection= (SybConnection)DriverManager.getConnection(url,"dba","sql"); |