http断点续传简单实现（java)

/* .XY
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**SiteFileFetch.java #Wh"_zpM+  
*/ h*d&2>"0m?  
package NetFox; 0( /eSmet  
import java.io.*; [,G]#<G?q  
import java.net.*; `Mp]iD{  
8 rnr>Ee@  
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public class SiteFileFetch extends Thread { zBqr15  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ,!u^E|24  
long[] nStartPos; //开始位置 1 5rE|m^  
long[] nEndPos; //结束位置 .KK"KO5k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sveFxI  
long nFileLength; //文件长度 tA'i-D&  
boolean bFirst = true; //是否第一次取文件 <>
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boolean bStop = false; //停止标志 h`Y t4-Y  
File tmpFile; //文件下载的临时信息 ?Y
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DataOutputStream output; //输出到文件的输出流 Fda<cS]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5.5dB2w  
public SiteFileFetch(SiteInfoBean bean) throws IOException w;{k\=W3Ff  
{ zg|yW6l)9  
siteInfoBean = bean; 2lXsD;[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "52wa<MVJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pOw4H67  
if(tmpFile.exists ()) }]tSWVb*  
{ 0H;dA1
  
bFirst = false; =XudL^GF  
read_nPos(); ITq+Hk R  
} Auv/w}zrr  
else ?Cmb3pX^\  
{ *)u
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nStartPos = new long[bean.getNSplitter()]; @{XN}tWDOp  
nEndPos = new long[bean.getNSplitter()]; ?CM,k0  
} uK): d&]Ux  
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} vWzNsWPK"{  
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public void run() NL2n\%n  
{ r}03&h~Hc&  
//获得文件长度 213D{#2  
//分割文件 s9O] tk  
//实例FileSplitterFetch 9-pd{Z~l  
//启动FileSplitterFetch线程 lL%7lO
 
//等待子线程返回 G{ F>=z"(l  
try{ r_ r+&4n  
if(bFirst) 2c9@n9Vx3a  
{ {`l]RIig  
nFileLength = getFileSize(); IcaIB
)  
if(nFileLength == -1) f{^n<\Jh  
{ c|ZZ+2IYd  
System.err.println("File Length is not known!"); _VR4|)1g  
} x{Gih
1  
else if(nFileLength == -2) zM[WbB+"m  
{ |oO0%#1H  
System.err.println("File is not access!"); bu@Pxz%_  
}
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else nc@ul')  
{ x-Xb4?{  
for(int i=0;i<nStartPos.length;i++)
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{ "B)DX*-\?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ia>qVM0  
} ^JYR^X>_  
for(int i=0;i<nEndPos.length-1;i++) t}NxD`8  
{ & }k=V4L  
nEndPos = nStartPos[i+1]; l\MiG Na  
} aU#8W.~  
nEndPos[nEndPos.length-1] = nFileLength; M
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} <2|x]b8  
} 5Ko
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//启动子线程 ho^1T3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0!+ab'3a  
for(int i=0;i<nStartPos.length;i++) zse!t  
{ S,Tm=} wj  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I|iI ,l/9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), swlxV@NQ  
nStartPos,nEndPos,i); f ( UcJx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Fi*6ud\n!  
fileSplitterFetch.start(); r@s, cCK9?  
} ]l+2Ca:-[j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ub.pJJlC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yu}4L'e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,{zvGZ|  
nEndPos = " + nFileLength); MQ,$'Y5~H  
// fileSplitterFetch[nPos.length-1].start(); | b@?]M  
|Zkcs]8M!  
!K`;fp!  
//等待子线程结束 @,zBZNX y  
//int count = 0; $o]suF;3  
//是否结束while循环 EXb{
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boolean breakWhile = false; %y8w9aGt  
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j:{<    
while(!bStop) & qd:o}  
{
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write_nPos(); W,wg@2  
Utility.sleep(500); |#!25qAT  
breakWhile = true; G-,PsXSwe  
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for(int i=0;i<nStartPos.length;i++) ?]5wX2G^|J  
{ |k?,4 Pk  
if(!fileSplitterFetch.bDownOver) [C7:Yg7  
{ .fQDj{  
breakWhile = false; TzX>d<x  
break; 5'oWd e  
} E 8,53$  
} EHo"y.ODg  
if(breakWhile) Qj3UO]>  
break; zxwpS  
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//count++; qZ8lU   
//if(count>4) rV2}> k  
// siteStop(); _$Z46wHmB  
} Do2y7,jv  
S"N@.n[  
LU;ma((yy[  
System.err.println("文件下载结束！"); D(Xv shQ  
} |mci-ZT  
catch(Exception e){e.printStackTrace ();} 5|H?L@_9  
} vz@QGgQ9~2  
~Bu~?ZJmd  
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//获得文件长度 G.<9K9K  
public long getFileSize() C'zMOR6c  
{ CsuSg*#X+  
int nFileLength = -1; H<1C5-  
try{ %J+$p\c  
URL url = new URL(siteInfoBean.getSSiteURL()); "gK2!N|#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sy>Pn  
httpConnection.setRequestProperty("User-Agent","NetFox"); q$EVd9aN  
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int responseCode=httpConnection.getResponseCode(); cl)MI,/>  
if(responseCode>=400) G%'h'AV"  
{ ]=]'*Z%  
processErrorCode(responseCode); $dwv1@M2  
return -2; //-2 represent access is error %iJ6;V4  
} L6Ynid.k  
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String sHeader; Ww8C![ ,  
u# %7>=  
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for(int i=1;;i++) egP3q5~  
{ kW-5H;>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #!,xjd  
//Utility.log(in.readLine()); T,H]svN
5p  
sHeader=httpConnection.getHeaderFieldKey(i); XP{ nf9&  
if(sHeader!=null) ;gW~+hW^  
{ qTffh{q V  
if(sHeader.equals("Content-Length")) dB_\,%vAd  
{ b_wb!_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J^t=.-a|  
break; U*6-Y%7  
} e=2;z  
} Ulktd^A\  
else 75^-93  
break; jhg!K.A  
} mZq*o<kTA  
} =8tduB  
catch(IOException e){e.printStackTrace ();} !gT6So  
catch(Exception e){e.printStackTrace ();} !;R{-  
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Utility.log(nFileLength); qqkZbsN  
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return nFileLength; rylllJz|L:  
} Gg-<3z  
,t)mCgbcO  
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//保存下载信息（文件指针位置） ? 4.W _  
private void write_nPos() y()#FRp7  
{ .Hgiru&  
try{ HP?e?3.T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A:p0p^*  
output.writeInt(nStartPos.length); VQ}=7oe%q  
for(int i=0;i<nStartPos.length;i++) ,'ndQ{\9  
{ XeZv%` ?  
// output.writeLong(nPos); PE4{;|a }  
output.writeLong(fileSplitterFetch.nStartPos); [{Y$]3?}  
output.writeLong(fileSplitterFetch.nEndPos); KNK0w5  
} @j^qT-0M  
output.close(); 1TbKnmTx  
} | C2k(  
catch(IOException e){e.printStackTrace ();} xt3IR0  
catch(Exception e){e.printStackTrace ();} 6\E |`  
} pq4+n'uO  
Y %<B,3  
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//读取保存的下载信息（文件指针位置） _ H@pYMNH  
private void read_nPos() H
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{ jMw;`yh  
try{ 3$y]#
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z#oo8  
int nCount = input.readInt(); 6 #QS5  
nStartPos = new long[nCount]; 1F$a My?  
nEndPos = new long[nCount]; YemOP9  
for(int i=0;i<nStartPos.length;i++) {8UBxFIM(  
{ ^U`[P@T  
nStartPos = input.readLong(); ;>CmVC'/  
nEndPos = input.readLong(); "ENgu/A!  
} Ay2|@1e  
input.close(); YJ:CqTy  
} Duz}e80  
catch(IOException e){e.printStackTrace ();} >iG`  
catch(Exception e){e.printStackTrace ();} 2+Fq'!  
} >\@6i s  
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private void processErrorCode(int nErrorCode) 5E.cJ{  
{ sN;U,{  
System.err.println("Error Code : " + nErrorCode); yJKez
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} +J#H9>To!  
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//停止文件下载 g/Qr]:;  
public void siteStop() kvo741RO6  
{ kmP0gT{Sj  
bStop = true; 0TVO'$Gvi  
for(int i=0;i<nStartPos.length;i++) 5))?,YkrrI  
fileSplitterFetch.splitterStop(); |5Z@7  
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} ^:DlrI$  
} - +>
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//负责部分文件的抓取 9g 2x+@5T^  
**FileSplitterFetch.java =fRP9`y  
*/ -`Z5#8P  
package NetFox; xXHz)w  
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import java.io.*; SmtH2%yI  
import java.net.*; q Rt
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public class FileSplitterFetch extends Thread { S&]JY  
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String sURL; //File URL m_St"`6 .  
long nStartPos; //File Snippet Start Position mX"z$  
long nEndPos; //File Snippet End Position R?I(f(ib   
int nThreadID; //Thread's ID Q<78<#I  
boolean bDownOver = false; //Downing is over Mg;;o  
boolean bStop = false; //Stop identical R;,&CQUl  
FileAccessI fileAccessI = null; //File Access interface rl6vt*g  
5M*ZZ+YX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }TYCF@  
{ a+J :1'  
this.sURL = sURL; V{a7@_y  
this.nStartPos = nStart; .Sb|+[{  
this.nEndPos = nEnd; J.El&Dev  
nThreadID = id; -;Hd_ ~O>j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;E#
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} wd1*wt  
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public void run() eo,m ^&  
{ 44S<(Re  
while(nStartPos < nEndPos && !bStop) M,mj{OY~x  
{ "-I>  
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try{ k*^.-v  
URL url = new URL(sURL); ;r`[6[AG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9hLPo  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;/e!!P]jP  
String sProperty = "bytes="+nStartPos+"-"; A03PEaZO  
httpConnection.setRequestProperty("RANGE",sProperty); fC(lY4,H3R  
Utility.log(sProperty); ko  ~iDT  
} |sP;Rpu  
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InputStream input = httpConnection.getInputStream(); ~6@~fhu  
//logResponseHead(httpConnection); `~*q
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byte[] b = new byte[1024]; 8zZR%fZ  
int nRead; lOZ.{0{f,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A0&~U0*(~  
{ ~;U!?  
nStartPos += fileAccessI.write(b,0,nRead); &_!BMzp4  
//if(nThreadID == 1) >~XX'}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o F@{&  
} >Z>*Iz,LP  
#7'ww*+  
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Utility.log("Thread " + nThreadID + " is over!"); ^DIN(0u)  
bDownOver = true; }g(aZ  
//nPos = fileAccessI.write (b,0,nRead); ?#]c{Tlpz  
} YB)1dzU  
catch(Exception e){e.printStackTrace ();} %L~X\M:Qk  
} m>UJ; F  
} !Ng^k>*h  
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//打印回应的头信息 +5^*c
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public void logResponseHead(HttpURLConnection con) o#w6]Fmc  
{ Ry/NfF=  
for(int i=1;;i++) ^S, "iV  
{ #<se0CJB  
String header=con.getHeaderFieldKey(i); h=)Im)  
if(header!=null) l`,`N+FG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `&
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Utility.log(header+" : "+con.getHeaderField(header)); Wx:_F;  
else Gb~q:&IUr  
break; )5]z[sE  
} I,?bZ&@8  
} }eB\k,7L  
to,=Q8)0  
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public void splitterStop() g]jtVQH']  
{ kqHh@]Z0'  
bStop = true; zSkM8LM2  
} >} aykz*g  
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} _+^3<MT  
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/* 5X~ko>  
**FileAccess.java V
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*//文件访问(定位，写) )P|Ql-rE4  
package NetFox; ]kc_wFT<  
import java.io.*; BRH:5h  
vtr:{   
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public class FileAccessI implements Serializable{ Yh"Z@D[d  
/G84T,H  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 So!1l7b  
RandomAccessFile oSavedFile; iY(hGlV  
long nPos; G+5G,|}  
P.[>x  
~=#jO0dE|  
public FileAccessI() throws IOException -=g`7^qa>  
{ HWe.|fH:  
this("",0); 3V,X=  
} yy#Xs:/  
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public FileAccessI(String sName,long nPos) throws IOException
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{ !!` zz  
oSavedFile = new RandomAccessFile(sName,"rw"); 2$3BluK  
this.nPos = nPos; Mzb_o2^(  
oSavedFile.seek(nPos); O;,k~  
} sIELkF?.  
{CGk5`g~  
8YYY *>  
public synchronized int write(byte[] b,int nStart,int nLen) KY_qK)H  
{ .h*
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int n = -1; 29GejLg|  
try{ Y
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oSavedFile.write(b,nStart,nLen); r3*wH1n  
n = nLen; g%\e80~1(  
} p
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catch(IOException e) I5 2wTl0  
{ 4P`\fz  
e.printStackTrace ();  sRoZvp5  
} t+h"YiT  
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+)7NWR\  
return n; {0QA+[Yd&!  
} WG^D$L
:  
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} ,U<Ku*}B  
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/* eueXklpg+  
**SiteInfoBean.java mCq*@1Lp9  
*/ ? th+~dE  
package NetFox; -'8|D!>v2  
uAJ_`o[  
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public class SiteInfoBean { ~" $9auQtC  
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private String sSiteURL; //Site's URL fnXl60C%  
private String sFilePath; //Saved File's Path sH&8"5BT%  
private String sFileName; //Saved File's Name 0 TS:o/{(a  
private int nSplitter; //Count of Splited Downloading File bUqO.FZ[  
AV8TP-Ls+  
*:d_~B?Tn  
public SiteInfoBean() :A 1,3g  
{//nSplitter的缺省值为5 `rs1!ZJ,  
//default value of nSplitter is 5 5hD
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this("","","",5); *Pq`~W_M7  
} MM5#B!
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _VMJq9.  
{ ! q1Ql18n  
sSiteURL= sURL; {+`ep\.$&  
sFilePath = sPath; Wh4lz~D\@  
sFileName = sName; "Dy&`  
this.nSplitter = nSpiltter; X0=R @_KY  
'kUrSM'*$N  
$MsM$]~  
} [jLx}\]  
nl?|X2?C  
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public String getSSiteURL() zd;xbH//)b  
{ w'qV~rN~tc  
return sSiteURL; rhUZ9Fdv  
} 89 lPeF
Q`  
o<!#1#n+:  
pcEB-boI9  
public void setSSiteURL(String value) JHMj4Zkp  
{ LBM:>d5  
sSiteURL = value; dYO87
n  
} yBr{nFOgdY  
4H " *.l  
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public String getSFilePath() ;N,7#l|wi  
{ "n05y}  
return sFilePath; iu:e>r  
} }- +;{u  
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;j52a8uE'}  
public void setSFilePath(String value) =|G PSRQ  
{ 5N[Y
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sFilePath = value; M.l;!U!}  
} Ao]F
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public String getSFileName() \(A>~D8Fo  
{ u(lq9; ;Th  
return sFileName;   ()SG  
} koie  
X'3F79`  
>%W"u`Q  
public void setSFileName(String value) 0u0Hl%nl  
{ D1Fc7!TV  
sFileName = value; !-7(.i-  
} [Q%3=pm_  
{<|
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public int getNSplitter() > h:~*g  
{ MZ+"Arzb  
return nSplitter; $MR{3-  
} }wUF#  
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oZzE.Q1T  
public void setNSplitter(int nCount) xAoozDj  
{ )_&<u\cm L  
nSplitter = nCount; &2Y>yFB ,  
}
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} S ":-5S6  
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#  
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/* >o[T#U  
**Utility.java f^]2qoN  
*/ bGSgph  
package NetFox; U 26Iz  
/Ia#udkNMp  
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public class Utility { 3*'!,gK~[  
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}LE/{]A  
public Utility() 
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{ )qxL@w.  
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} DLz~$TF^  
w.V8-9{  
//线程睡眠 8 {QvB"w  
public static void sleep(int nSecond) =6%0pu]0  
{ Eu0_/{:  
try{ 8d>OtDLa  
Thread.sleep(nSecond); 3|~(9b{+  
} !u=[/>  
catch(Exception e) t<`BaU  
{ ?HBc7$nW  
e.printStackTrace (); ?Jx8z`(  
} ?=fJu\;  
} gFW1Nm_DJ  
PgxU;N7Y  
//日志 ;1o"Oij  
public static void log(String sMsg) E>7[ti_p5  
{ 0phGn+"R  
System.err.println(sMsg); h?idRaN_  
} b0 5h,  
%]:u^\7  
.E@yB`AR  
public static void log(int sMsg) AMkjoy3+]  
{ @F=4B0=  
System.err.println(sMsg); \K>6-0r|  
} }$OQw'L[  
} _@HMk"A  
T}zOM%]]  
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/* gjwp' GN  
**TestMethod.java O
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*/ 0BBWuNF.  
package NetFox; '|6j1i0x  
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V%3K")  
public class TestMethod { nGg>lRL
  
;[*7UE+#7  
F02NnF  
public TestMethod() 4sG^bZ,  
{ ///xx/weblogic60b2_win.exe Dzp9BRS 2f  
try{ sKNN ahGjh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :vm*miOF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VdYu| w;v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?}O\'Fa8
 
fileFetch.start(); 7$/ O{GBJ  
} k%.IIVRx  
catch(Exception e){e.printStackTrace ();} fRq2sK;+  
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} p6>3 p  
qex.}[  
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public static void main(String[] args) I]zCsT.  
{ )|*HkdF`  
new TestMethod(); Q
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} ;K`qSX;;c(  
} ;i\i+:=  
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