1 基本介绍
可以?/span>CSV格式的文件经常碰刎ͼ何ؓ(f)CSV格式Q?/span>CVS全称comma-separated valuesQ就是典型的用逗号隔开的文Ӟ比如下面q种文g格式
Name,company
zhangsan,ibm
lisi,oracle
q种是典型?/span>CSV格式文g。不q也可以扩展到其它符号隔开的字W，比如
Name#company
Zhangsan#ibm
Lisi#oracle
q种也算CSV格式
Java开源框?/span>CVSReader提供?jin)一个轻量、简单方便的l一操作接口可用Q下面具体讲解如何操?/span>CVS格式
2 安装和?/span>
下蝲
目前CSV reader的最新发布版本是1.8。我们可以从
http://opencsv.sourceforge.net/
上面下蝲到最新的csvreader包?/span>
安装
直接?/span>jar包分别存攑ֈ开发工E的c\径下面即可用?/span>
3 dCSV格式文g
基本?/span>
首先Q读?/span>CSV格式的文仉要创Z?/span>CSVReaderQ如?/span>
CsvReader reader = new CsvReader(Reader r, char c);
其中W一个参Cؓ(f)d文gQ第二个参数为分割符Q比?#8220;,”Q或?#8220;#”
另外Q也有其它几个参敎ͼ可以查阅APIQ比?/span>
CsvReader reader = new CsvReader(InputStream r, char c, Charset charset);{等
其次Q一般需要读取头信息Q如下：(x)
reader.readHeaders();
String[] headers = reader.getHeaders();
d?jin)后Q指针就?x)移动到下一行，也就是可以开始读取文件内?/span>
假如Q有多行的话Q可以用一个@环套入，例如下面Q?/span>
while (reader.readRecord()) {
for (int i = 0; i < headers.length; i++) {
String value = reader.get(headers[i]);
System.out.print(value+" ");
}
System.out.println("");
}
l合例子
?/span>C盘(sh)创徏一个测试文?/span>test.cvsQ内容如下：(x)
a#b#c
1#2#3
4#5#6
下面是解析代码：(x)
public static void main(String[] args) throws Exception {
CsvReader reader = new CsvReader(new FileReader("c://csv.txt"), '#');
reader.readHeaders();
String[] headers = reader.getHeaders();
while (reader.readRecord()) {
for (int i = 0; i < headers.length; i++) {
String value = reader.get(headers[i]);
System.out.print(value+" ");
}
System.out.println("");
}
}
q行以上E序Q可以看到输?/span>
1 2 3
4 5 6
4 ?/span>CSV格式文g
?/span>CSV格式文g也比较简单，写每一列只要直接调?/span>
csvWriter.write()另外Q写完每行结束后Q都要调?/span> csvWriter.endRecord();
表示l束一?/span>
文g写完毕后Q要记得h一下ƈx(chng)Q如下：(x)
csvWriter.flush();
csvWriter.close();
代码如下Q?/span>
publicstaticvoid main(String[] args) throws Exception {
CsvWriter csvWriter = new CsvWriter(new FileWriter("c://test.text"), '#');
csvWriter.write("name");
csvWriter.write("company");
csvWriter.endRecord();
csvWriter.write("11");
csvWriter.write("12");
csvWriter.endRecord();
csvWriter.write("21");
csvWriter.write("22");
csvWriter.flush();
csvWriter.close();
}
}
C内容如下Q?/span>
name#company
11#12
21#22
]]>
(tng) (tng) (tng) (tng)
(tng) (tng) (tng) (tng)Sun HotSpot 1.4.1使用分代攉器，它把堆分Z个主要的域：(x)新域、旧域以?qing)永久域。Jvm生成的所有新对象攑֜新域中。一旦对象经历了(jin)一定数量的垃圾攉循环后，便获得用期q进入旧域。在怹域中jvm则存储class和method对象。就配置而言Q永久域是一个独立域q且不认为是堆的一部分?br />
(tng) (tng) (tng) (tng)下面介绍如何控制q些域的大小。可使用-Xms?Xmx 控制整个堆的原始大小或最大倹{?br /> (tng) (tng) (tng) (tng)下面的命令是把初始大设|ؓ(f)128MQ?br /> (tng) (tng) (tng) (tng)java –Xms128m
(tng) (tng) (tng) (tng) –Xmx256m为控制新域的大小Q可使用-XX:NewRatio讄新域在堆中所占的比例?br />
(tng) (tng) 下面的命令把整个堆设|成128mQ新域比率设|成3Q即新域与旧域比例ؓ(f)1Q?Q新域ؓ(f)堆的1/4?2MQ?br /> (tng) (tng) java –Xms128m –Xmx128m
(tng) (tng) (tng) (tng)–XX:NewRatio =3可?XX:NewSize?XX:MaxNewsize讄新域的初始值和最大倹{?br />
(tng) (tng) 下面的命令把新域的初始值和最大D|成64m:
(tng) (tng) (tng) (tng) java –Xms256m –Xmx256m –Xmn64m
(tng) (tng) 怹域默认大ؓ(f)4m。运行程序时Qjvm?x)调整永久域的大以满需要。每ơ调整时Qjvm?x)对堆进行一ơ完全的垃圾攉?br />
(tng) (tng) 使用-XX:MaxPerSize标志来增加永久域搭大。在WebLogic Server应用E序加蝲较多cLQ经帔R要增加永久域的最大倹{当jvm加蝲cLQ永久域中的对象急剧增加Q从而jvm不断调整怹域大。ؓ(f)?jin)避免调_(d)可?XX:PerSize标志讄初始倹{?br /> (tng) (tng) 下面把永久域初始D|成32mQ最大D|成64m?br /> (tng) (tng) (tng) (tng)java -Xms512m -Xmx512m -Xmn128m -XX:PermSize=32m -XX:MaxPermSize=64m
(tng) (tng) (tng) (tng)默认状态下QHotSpot在新域中使用复制攉器。该域一般分Z个部分。第一部分为EdenQ用于生成新的对象。另两部分称为救助空_(d)当Eden充满Ӟ攉器停止应用程序，把所有可到达对象复制到当前的from救助I间Q一旦当前的from救助I间充满Q收集器则把可到辑֯象复制到当前的to救助I间。From和to救助I间互换角色。维持活动的对象在救助I间不断复制Q直到它们获得用期q{入旧域。?XX:SurvivorRatio可控制新域子I间的大?br />
(tng) (tng) (tng) (tng)同NewRation一PSurvivorRation规定某救助域与EdenI间的比倹{比如，以下命o(h)把新域设|成64mQEden?2mQ每个救助域各占16mQ?br /> (tng) (tng) (tng) (tng)java -Xms256m -Xmx256m -Xmn64m -XX:SurvivorRation =2
(tng) (tng) (tng) (tng)如前所qͼ默认状态下HotSpotҎ(gu)域用复制收集器Q对旧域使用标记Q清除－压羃攉器。在新域中用复制收集器有很多意义，因ؓ(f)应用E序生成的大部分对象是短寿命的。理想状态下Q所有过渡对象在UdEdenI间时将被收集。如果能够这L(fng)话，q且UdEdenI间的对象是长寿命的Q那么理Z可以立即把它们移q旧域，避免在救助空间反复复制。但是，应用E序不能适合q种理想状态，因ؓ(f)它们有一部分中长寿命的对象。最好是保持q些中长寿命的对象ƈ攑֜新域中，因ؓ(f)复制部分的对象L压羃旧域廉h(hun)。ؓ(f)控制新域中对象的复制Q可?XX:TargetSurvivorRatio控制救助I间的比例（该值是讄救助I间的用比例。如救助I间?MQ该?0表示可用500KQ。该值是一个百分比Q默认值是50。当较大的堆栈用较低的sruvivorratioӞ应增加该值到80?0Q以更好利用救助I间。用-XX:maxtenuring threshold可控制上限?br />
(tng) (tng) 为放|所有的复制全部发生以及(qing)希望对象从eden扩展到旧域，可以把MaxTenuring Threshold讄?。设|完成后Q实际上׃再用救助空间了(jin)Q因此应把SurvivorRatio设成最大g最大化EdenI间Q设|如下：(x)
(tng) (tng) java ?-XX:MaxTenuringThreshold=0 –XX:SurvivorRatioQ?0000 ?/span>
]]>
Wecould try something like
window.opener.name="opener728";
form.target="opener728";
however, I suspect the window.name property is read-only.
Alternatively, if We are certain that the opener already has a name then this might work
form.target=window.opener.name;
It's also possible that browsers assign unique names to otherwise unnamed windows, so the above would always work - I've never checked this.
]]>
tomcat5.5出来后，jndi的配|方法是大大地节省，而且很简z，个h觉得比以前的版本好很多。这里大概给Z个配|例子。tomcat数据库连接池jndi配置有两U，一U是全局的，一U是context的，下面主要是讲全局的，q且以一个实例jdbc/byisdbZ?br /> (tng) (tng) (tng)
一、tomcat5.0配置Ҏ(gu)
1、首先在server.xml里面配置Q找C面的配置
(tng) <!-- Global JNDI resources -->
(tng) <GlobalNamingResources>
(tng)</GlobalNamingResources>
2、在里面增加一个Resource
(tng) (tng) (tng) (tng) (tng) (tng)<Resource (tng)name="jdbc/byisdb" (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)auth="Container" (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)type="javax.sql.DataSource"/>3、在下面增加属?br />
(tng) (tng)<ResourceParams (tng)name="jdbc/byisdb"> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng)<name>factory</name> (tng) (tng) (tng) (tng) (tng) (tng)<value>org.apache.commons.dbcp.BasicDataSourceFactory</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<!-- (tng)Maximum (tng)number (tng)of (tng)dB (tng)connections (tng)in (tng)pool. (tng)Make (tng)sure (tng)you (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)configure (tng)your (tng)mysqld (tng)max_connections (tng)large (tng)enough (tng)to (tng)handle (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)all (tng)of (tng)your (tng)db (tng)connections. (tng)Set (tng)to (tng)0 (tng)for (tng)no (tng)limit. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng)<name>maxActive</name> (tng) (tng) (tng) (tng) (tng) (tng)<value>100</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<!-- (tng)Maximum (tng)number (tng)of (tng)idle (tng)dB (tng)connections (tng)to (tng)retain (tng)in (tng)pool. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)Set (tng)to (tng)-1 (tng)for (tng)no (tng)limit. (tng) (tng)See (tng)also (tng)the (tng)DBCP (tng)documentation (tng)on (tng)this (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)and (tng)the (tng)minEvictableIdleTimeMillis (tng)configuration (tng)parameter. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng)<name>maxIdle</name> (tng) (tng) (tng) (tng) (tng) (tng)<value>30</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<!-- (tng)Maximum (tng)time (tng)to (tng)wait (tng)for (tng)a (tng)dB (tng)connection (tng)to (tng)become (tng)available (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)in (tng)ms, (tng)in (tng)this (tng)example (tng)10 (tng)seconds. (tng)An (tng)Exception (tng)is (tng)thrown (tng)if (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)this (tng)timeout (tng)is (tng)exceeded. (tng) (tng)Set (tng)to (tng)-1 (tng)to (tng)wait (tng)indefinitely. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng)<name>maxWait</name> (tng) (tng) (tng) (tng) (tng) (tng)<value>10000</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<!-- (tng)MySQL (tng)dB (tng)username (tng)and (tng)password (tng)for (tng)dB (tng)connections (tng) (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng)<name>username</name> (tng) (tng) (tng) (tng) (tng)<value>una_oa</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng)<name>password</name> (tng) (tng) (tng) (tng) (tng)<value>una_oa</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng)<!-- (tng)Class (tng)name (tng)for (tng)the (tng)old (tng)mm.mysql (tng)JDBC (tng)driver (tng)- (tng)uncomment (tng)this (tng)entry (tng)and (tng)comment (tng)next (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)if (tng)you (tng)want (tng)to (tng)use (tng)this (tng)driver (tng)- (tng)we (tng)recommend (tng)using (tng)Connector/J (tng)though (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng) (tng)<name>driverClassName</name> (tng) (tng) (tng) (tng) (tng) (tng) (tng)<value>org.gjt.mm.mysql.Driver</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng) (tng)--> (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)<!-- (tng)Class (tng)name (tng)for (tng)the (tng)official (tng)MySQL (tng)Connector/J (tng)driver (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng) (tng)<name>driverClassName</name> (tng) (tng) (tng) (tng) (tng) (tng) (tng)<value>oracle.jdbc.driver.OracleDriver</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)<!-- (tng)The (tng)JDBC (tng)connection (tng)url (tng)for (tng)connecting (tng)to (tng)your (tng)MySQL (tng)dB. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)The (tng)autoReconnect=true (tng)argument (tng)to (tng)the (tng)url (tng)makes (tng)sure (tng)that (tng)the (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)mm.mysql (tng)JDBC (tng)Driver (tng)will (tng)automatically (tng)reconnect (tng)if (tng)mysqld (tng)closed (tng)the (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)connection. (tng) (tng)mysqld (tng)by (tng)default (tng)closes (tng)idle (tng)connections (tng)after (tng)8 (tng)hours. (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng) (tng)--> (tng) (tng) (tng) (tng)<parameter> (tng) (tng) (tng) (tng) (tng) (tng)<name>url</name> (tng) (tng) (tng) (tng) (tng) (tng)<value>jdbc:oracle:thin:@192.168.1.210:1521:byisdb</value> (tng) (tng) (tng) (tng)</parameter> (tng) (tng)</ResourceParams>4、在你的应用的web.xml里面增加
<resource-ref> (tng)<description>postgreSQL (tng)Datasource (tng)example</description> (tng)<res-ref-name>jdbc/byisdb</res-ref-name> (tng)<res-type>javax.sql.DataSource</res-type> (tng)<res-auth>Container</res-auth></resource-ref>OK,到此配置完毕Q可以用下面的几D代码进行测?br />
Context (tng)initContext (tng)= (tng)new (tng)I(yng)nitialContext();Context (tng)envContext (tng) (tng)= (tng)(Context)initContext.lookup("java:/comp/env");DataSource (tng)ds (tng)= (tng)(DataSource)envContext.lookup("jdbc/byisdb");Connection (tng)conn (tng)= (tng)ds.getConnection();out.println("conn (tng)is:"+conn);二、tomcat5.5配置
1、打开conf/context.xml里面
(tng) d下面的配|?br />
(tng) (tng) (tng) (tng)<Resource (tng)name="jdbc/byisdb" (tng)auth="Container" (tng)type="javax.sql.DataSource" (tng)driverClassName="oracle.jdbc.driver.OracleDriver" (tng)url="jdbc:oracle:thin:@192.168.1.210:1521:byisdb" (tng)username="una_oa" (tng)password="una_oa" (tng)maxActive="20" (tng)maxIdle="10" (tng)maxWait="10000"/>(tng)
2在你的应用的web.xml里面增加
<resource-ref> (tng)<description>postgreSQL (tng)Datasource (tng)example</description> (tng)<res-ref-name>jdbc/byisdb</res-ref-name> (tng)<res-type>javax.sql.DataSource</res-type> (tng)<res-auth>Container</res-auth></resource-ref>同样Q可以用上面的代码进行测试?img src ="http://www.tkk7.com/jspark/aggbug/62989.html" width = "1" height = "1" />
]]>