http断点续传简单实现（java)

/* h jWRU#  
**SiteFileFetch.java '}LH,H:%G  
*/ (w4#?_  
package NetFox; m[]pIXc(  
import java.io.*; P?\rRB  
import java.net.*; NAHQ:$  
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public class SiteFileFetch extends Thread { 7ugmZO}lL  
@
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SiteInfoBean siteInfoBean = null; //文件信息Bean G74<sD  
long[] nStartPos; //开始位置 fM \T^X  
long[] nEndPos; //结束位置 W
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 3p$ZHH.UP  
long nFileLength; //文件长度 Qa(u+  
boolean bFirst = true; //是否第一次取文件 ~r&Q\G  
boolean bStop = false; //停止标志 "fS9Nx3  
File tmpFile; //文件下载的临时信息 _U/etlDTO  
DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {n #  
public SiteFileFetch(SiteInfoBean bean) throws IOException $F;$-2  
{ dID]{  
siteInfoBean = bean; sRt|G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P4Wd=Xoz6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (47jop0RDQ  
if(tmpFile.exists ()) CK'Cf{S  
{ Ff%m.A8d,4  
bFirst = false; )QFT$rmX  
read_nPos(); ;k(|ynXv  
} >/ HC{.k  
else (f $Y0;v>}  
{ E8#y
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nStartPos = new long[bean.getNSplitter()]; j3sUZg|d  
nEndPos = new long[bean.getNSplitter()]; q>!T*BQ  
} UyTq(7uo  
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} )<IbQH|_  
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public void run() #d(6q$IE  
{ XlDVJx<&J  
//获得文件长度 # |w,^tV  
//分割文件  p^\>{  
//实例FileSplitterFetch H*;J9{  
//启动FileSplitterFetch线程 - stSl*  
//等待子线程返回 ur9-F^$  
try{ !Z<Z"R/  
if(bFirst) w[:5uo(  
{ ~O|j*T  
nFileLength = getFileSize(); tJ2l_M^  
if(nFileLength == -1) qt/"$
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{ <$,iYx  
System.err.println("File Length is not known!"); 8t9sdqM/C  
} E5-8tHV   
else if(nFileLength == -2) r(%#@?&  
{ :mL\KQ  
System.err.println("File is not access!"); :t^=~xO9  
} !OC?3W:^_  
else |) THuE(  
{ qd!$nr  
for(int i=0;i<nStartPos.length;i++) |;9OvR> A  
{ q'",70"\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^=.|\ YM  
} PN+,M50;1  
for(int i=0;i<nEndPos.length-1;i++) nLdI>c9R  
{ };29'_.."x  
nEndPos = nStartPos[i+1]; k&yy_r   
} JFR,QUT  
nEndPos[nEndPos.length-1] = nFileLength; TS-m^Y'R  
} b>Vs5nY!  
} BU]9eF!>h  
?HZ+fS,-  
:%!=Ej.J  
//启动子线程 )k0bP1oGS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >:KPvq!0  
for(int i=0;i<nStartPos.length;i++) dRas9g  
{ Lr40rLx;u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |Z#)1K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;y4 "wBX  
nStartPos,nEndPos,i); oA_AnD?G+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |F9/7 z\5+  
fileSplitterFetch.start(); B@.U\.  
} w}oH]jVKL6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l&;#`\s!V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z}u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c>=[|F{{e  
nEndPos = " + nFileLength); wyvs#T  
// fileSplitterFetch[nPos.length-1].start(); 6i=m1Yk  
(p^q3\
 
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//等待子线程结束 f0MHh5  
//int count = 0; R"=G?d)  
//是否结束while循环 @qg=lt|(F  
boolean breakWhile = false; \HTXl]  
@i6D&e=  
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while(!bStop) Ms^,]Q1{  
{ 3u+~
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write_nPos(); E83{4A4  
Utility.sleep(500);  1=W>zC  
breakWhile = true; RHVMlMX  
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#sAEIk/  
for(int i=0;i<nStartPos.length;i++) %|l*=v  
{ &ATjDbW*(  
if(!fileSplitterFetch.bDownOver) }g>&l.2X  
{ ]>*Z 1g;
  
breakWhile = false; _g$6vx&  
break; {9_CH<$W%U  
} <=^YIp  
} QJ>+!p*  
if(breakWhile) g0_8:Gs}^  
break; z4_>6sf{  
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//count++; o`hF1*yp  
//if(count>4) %UgyGQeo  
// siteStop(); LxsB.jb-  
} T9N /;3  
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System.err.println("文件下载结束！"); PlTY^N6Hn  
} OW1[Y-o[  
catch(Exception e){e.printStackTrace ();} el-%#0
  
} XZIj' a0d  
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//获得文件长度 GZ*cV3Y`&  
public long getFileSize() viY _Y.Yjy  
{ F9-xp7T  
int nFileLength = -1; b_cD >A  
try{ <:>a51HBX  
URL url = new URL(siteInfoBean.getSSiteURL()); :2K0/@<x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z`q?pE>R  
httpConnection.setRequestProperty("User-Agent","NetFox"); gbQrSJs!Zh  
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int responseCode=httpConnection.getResponseCode(); CXvL`d"  
if(responseCode>=400) lE$X9yIt  
{ 60^dzi!vs  
processErrorCode(responseCode); Dgp"RUP  
return -2; //-2 represent access is error QTtcGU  
} ewY+a ,t  
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String sHeader; N\<M4fn  
a:v&pj+|<  
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for(int i=1;;i++) Fag%#jxI  
{ `?91Cw=`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {p1#H`  
//Utility.log(in.readLine()); ^5j9WV  
sHeader=httpConnection.getHeaderFieldKey(i); !W .ooy5(  
if(sHeader!=null) m~#98ZJ^  
{ F.
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if(sHeader.equals("Content-Length")) >$?$&+e}  
{ ([tbFI}A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }\P9$D+  
break; `NyvJt^<  
} _z{:Q  
} +hV7o!WxC  
else b":cj:mxL  
break; YM/GSSq  
} Rb|\!  
} Th'6z#h:U  
catch(IOException e){e.printStackTrace ();} :hCp@{  
catch(Exception e){e.printStackTrace ();} g' H!%<  
8L6!CP_!  
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Utility.log(nFileLength); UR:cBr  
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return nFileLength; ;r"YZs&Xd  
} ^szCf|SM  
K"#np!Y)  
[|Jzs[  
//保存下载信息（文件指针位置） )TBBYCL3  
private void write_nPos() O: :X$O7  
{ ixE72bX  
try{ d%u|) =7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ef:.)!;jy  
output.writeInt(nStartPos.length); H'&x
4[J:  
for(int i=0;i<nStartPos.length;i++) >N{K)a  
{ rRly0H  
// output.writeLong(nPos); wh[XJ_xY  
output.writeLong(fileSplitterFetch.nStartPos); 31Y+bxQ  
output.writeLong(fileSplitterFetch.nEndPos); ]'EtLFv)  
} bL]*K$  
output.close(); qOqQt=ObU  
} R
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catch(IOException e){e.printStackTrace ();} WENPS*0oS]  
catch(Exception e){e.printStackTrace ();} ZG
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} A +e ={-*  
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//读取保存的下载信息（文件指针位置） {ajaM'x  
private void read_nPos() 0!eZ&.h?4  
{ oV&AJ=|\  
try{ q1.w8$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y4w{8;Mh  
int nCount = input.readInt(); t+|c)"\5h  
nStartPos = new long[nCount]; (kK6=Mrf  
nEndPos = new long[nCount]; ^8ZVB.Fv  
for(int i=0;i<nStartPos.length;i++) a=.A/;|0*  
{ "z1\I\ ^  
nStartPos = input.readLong(); $*\[I{Zau}  
nEndPos = input.readLong(); jyb/aov  
} )F8G q,  
input.close(); WIa4!\Ky!  
} \|L ~#{a  
catch(IOException e){e.printStackTrace ();} !X e  
catch(Exception e){e.printStackTrace ();} pGc_Klq  
} OjCTTz
 
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private void processErrorCode(int nErrorCode) z v*hA/  
{ 2$V]XSe  
System.err.println("Error Code : " + nErrorCode); ^dJ/>?1  
} yCwBZ/C  
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//停止文件下载 Q"h/o"-h  
public void siteStop() 2,{m>fF  
{ E=_M=5]  
bStop = true; Mm;kB/1  
for(int i=0;i<nStartPos.length;i++) b*+Od8r  
fileSplitterFetch.splitterStop(); /U4F\pZl  
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} /59jkcA+  
} 7hlgm7^  
//负责部分文件的抓取 7q&Ru|T33  
**FileSplitterFetch.java !_3RdS  
*/ zYvf}L&]h  
package NetFox; 8$xd;+`y'  
mJ2>#j;5f  
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import java.io.*; N,0l5fD~T  
import java.net.*; C!6?.\U/:c  
P:eY>~m<;  
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public class FileSplitterFetch extends Thread { D(yU:^L  
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O8%+5l`T!  
String sURL; //File URL =;#+8w=^  
long nStartPos; //File Snippet Start Position 3xj ?}o  
long nEndPos; //File Snippet End Position JL5 )  
int nThreadID; //Thread's ID C_mPw  
boolean bDownOver = false; //Downing is over j"{|* _6E_  
boolean bStop = false; //Stop identical A.8{LY;  
FileAccessI fileAccessI = null; //File Access interface -r)Q|U  
2R66 WKQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4
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{ uH!uSB2  
this.sURL = sURL; JKN0:/t7Q  
this.nStartPos = nStart; klm
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this.nEndPos = nEnd; vPz$jeA  
nThreadID = id; xdGm
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 l*V]54|ON3  
} t}n:!v"|+O  
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public void run() xfZ.  
{ 9y"R,  
while(nStartPos < nEndPos && !bStop) 6c>cq\~E  
{ 96x$Xl;  
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try{ 1AiqB Rs  
URL url = new URL(sURL); 8@pY:AY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y7g
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httpConnection.setRequestProperty("User-Agent","NetFox"); lf3QMr+  
String sProperty = "bytes="+nStartPos+"-"; Jn!-Wa,  
httpConnection.setRequestProperty("RANGE",sProperty); f86
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Utility.log(sProperty); \Jq$!foYx  
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}q7rR:g  
InputStream input = httpConnection.getInputStream(); ;;#28nV  
//logResponseHead(httpConnection); Y%eFXYk.  
/R\]tl#2j  
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byte[] b = new byte[1024]; wq+%O,  
int nRead; b{q-o <Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b|F4E{{D^  
{ #D4gNQg@R  
nStartPos += fileAccessI.write(b,0,nRead); {8`V5:  
//if(nThreadID == 1) 6vy(@z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U-!
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} Zt;3HY=y  
B'<k*9=Nv8  
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Utility.log("Thread " + nThreadID + " is over!"); GIG\bQSv2  
bDownOver = true; z !2-
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//nPos = fileAccessI.write (b,0,nRead); Y7{|iw(#  
} J=v" HeVm  
catch(Exception e){e.printStackTrace ();} Vm\ly;v'R  
} QCjC|T9  
} 5~)m6]-6  
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%N``EnF2  
//打印回应的头信息 6xI9%YDy  
public void logResponseHead(HttpURLConnection con) 2UqLV^ZY  
{ EMK>7 aks  
for(int i=1;;i++) B. '&[A  
{ "*E06=fiG  
String header=con.getHeaderFieldKey(i); YhQ;>Ko  
if(header!=null) {-?^j{O0.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nmu;+{19M  
Utility.log(header+" : "+con.getHeaderField(header)); YB?yi( "yL  
else J" :R,w`  
break; ;;|S QX  
} =@BVO@z@  
} W>[0u3  
;J<K/YdI  
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public void splitterStop() .%Pt[VQ  
{ 5MU-Eu|*>  
bStop = true; dZ]['y%  
} e0rh~@E  
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} vq(ElXTO  
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%<[?;  
/* /4K ^-  
**FileAccess.java BF >678h  
*//文件访问(定位，写) D=ZH? d  
package NetFox; "}/$xOl"  
import java.io.*; :<Z>?x  
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public class FileAccessI implements Serializable{ i6Zsn#Z7)  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $eqwn&$n  
RandomAccessFile oSavedFile; p>9-Ga  
long nPos; {c|{okQ;Q  
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public FileAccessI() throws IOException kx3?'=0;5  
{ :U>[*zE4&  
this("",0); jEaU;  
} /^Ckk  
(j>a?dKDS  
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public FileAccessI(String sName,long nPos) throws IOException mT:Z!sS  
{ "~:AsZ"7  
oSavedFile = new RandomAccessFile(sName,"rw"); o=%pR|  
this.nPos = nPos; ^/`W0kT  
oSavedFile.seek(nPos); G&7!3u  
} qHQWiu%h  
;^yR,32F  
4 C7z6VWg  
public synchronized int write(byte[] b,int nStart,int nLen) LN!e_b  
{ hv4om+  
int n = -1; B:?MMXB  
try{ cUB+fH<B2  
oSavedFile.write(b,nStart,nLen); }hoyjzv]L  
n = nLen; }={TVs^  
} P
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catch(IOException e) !=/w
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{ K*"Wq:T;B  
e.printStackTrace (); Y<vHL<G  
} cM|!jnKm  

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return n; I=;.o>  
}
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} 8*$HS.Db'  
*PF}L%K(?  
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/* iYPlgt/Y!  
**SiteInfoBean.java z\F#td{r  
*/ *IGCFZbp41  
package NetFox; Lo{g0~?x*  
ORdS|y;:  
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public class SiteInfoBean { e]!`Cl-f80  
9P7^*f:E  
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private String sSiteURL; //Site's URL P #PRzt  
private String sFilePath; //Saved File's Path 7kT&}`g.  
private String sFileName; //Saved File's Name }M0GPpv  
private int nSplitter; //Count of Splited Downloading File g]mR
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rYn)E=FG/  
8mh@C6U  
public SiteInfoBean() C)z?-f  
{//nSplitter的缺省值为5 J^y}3ON  
//default value of nSplitter is 5
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this("","","",5); U)sw IisE  
} nD
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EjF2mkA*  
{ @ =XJ<  
sSiteURL= sURL; E&_q"jJRi  
sFilePath = sPath; ?cvV~&$gc  
sFileName = sName; r`OC5IoQ   
this.nSplitter = nSpiltter; 0nu&JQ  
b;2[E/JKB  
+qiI;C_P\  
} -(FhjIr  
n@PXC8}  
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public String getSSiteURL() >U9JbkeF  
{ Ij{ K\{y  
return sSiteURL; +YFAZv7`  
} t3VZ
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n~mP7X%wE7  
]*&`J4i  
public void setSSiteURL(String value) G)8H9EV  
{ ;4s7\9o  
sSiteURL = value; ny'wS  
} VEGp!~D  
W2T-TI,>PC  
$ vt6~nfI  
public String getSFilePath() Sa 8T'%W  
{ S0]JeP+3!  
return sFilePath; |e+r|i]  
} 0/4"Jh$t  
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}xb?C""q^q  
public void setSFilePath(String value) zPyN2|iFah  
{ "IA:,j.#g  
sFilePath = value; tm|YUat$]r  
} NxGSs_7  
GS@Zc2JPF  
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public String getSFileName() .*~t2 :  
{ a
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return sFileName; pm>$'z!.):  
} 3[cGSI"+  
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public void setSFileName(String value) 3:mZ1+  
{ /DGEI&}&:u  
sFileName = value; DWXHx  
} Uip-qWI  
~LU$ no^  
!S}d?8I6  
public int getNSplitter() MY>*F[~ 2  
{ ~gA^tc3G  
return nSplitter; qbq.r&F&  
} >E\U$}WCG  
bqcwZ6r<  
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public void setNSplitter(int nCount) OeYZLC(  
{ #8CeTR23cw  
nSplitter = nCount; d]I3zSIC  
} i~i ?M)  
} >mUSRf4  
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/* Gg# 1k TK  
**Utility.java J_}Rsp ED  
*/ iVZX  
package NetFox; m_C#fR /I  
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public class Utility { u_'XUJ32!  
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eEZZ0NNe;  
public Utility() 
{D`_q
|  
{ s#4Q?<65u  
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g..&x]aS(  
} qE@H~&  
#``Alh8  
//线程睡眠
::
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public static void sleep(int nSecond) y*vg9`$k  
{ Y5R|)x  
try{ ]\6*2E{1m  
Thread.sleep(nSecond); /:+MUw7~  
} v%4zP%4Ak[  
catch(Exception e) * am
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{ 4Pkl()\c  
e.printStackTrace (); :} N;OS_  
} }:1*@7eR  
} 6SP!J*F  
['DYP-1J  
//日志 fIii  
public static void log(String sMsg) N/8_0]Gf  
{ txFcV  
System.err.println(sMsg); %~EOq\&  
} ~n{lu'SIX2  
6e4A|<  
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public static void log(int sMsg) sL4+O P-
 
{ q?=_{oH9  
System.err.println(sMsg); Ox^VU2K;&.  
} KF}_|~~T  
} ?,oE_H  
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evro]&N{  
/* #|^yWw^  
**TestMethod.java VdE$ig@  
*/ M2piJ'T4u  
package NetFox; W&p f%?  
!+Zso&  
+1>\o|RF  
public class TestMethod { 3fq'<5 ^  
EE,C@d!*k7  
P%y$e0  
public TestMethod() d'!abnF[d  
{ ///xx/weblogic60b2_win.exe <I.{meDg  
try{ 3 adF) mh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %Zi}sm1t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a{+;&j[!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [9,34/i  
fileFetch.start(); my*E7[  
} ,%$Cfu  
catch(Exception e){e.printStackTrace ();} fk'DJf[M  
6UAw9 'X8  
Je#vu`.\\  
} Ie'iAY  
jFGY`9Zw0  
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public static void main(String[] args)  Dac ,yW  
{ >+F +"NAN  
new TestMethod(); 9ve)+Lk  
} R/ 3#(5  
} H':0  
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