http断点续传简单实现（java)

/* &,zeBFmc  
**SiteFileFetch.java |wDCIHzQ  
*/ -g0>>{M'  
package NetFox; 0NxaQ`\  
import java.io.*; |{ kB`  
import java.net.*; scdT/|(U$  
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public class SiteFileFetch extends Thread { \1ZfSc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~J|0G6H  
long[] nStartPos; //开始位置 !duR7a  
long[] nEndPos; //结束位置 AF@C9s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -8IiQRS  
long nFileLength; //文件长度 o! 8X< o  
boolean bFirst = true; //是否第一次取文件 .qZ<ROZ  
boolean bStop = false; //停止标志 mS0W@#|K  
File tmpFile; //文件下载的临时信息 {'1,JwSmb  
DataOutputStream output; //输出到文件的输出流 4t":WutC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <*[(t;i  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ \21!NPXH2  
siteInfoBean = bean; PJ'l:IU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wNlp4Z'[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0^+W"O  
if(tmpFile.exists ()) mU!c;O  
{ }5K\l  
bFirst = false; -8
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read_nPos(); Px<;-H`  
} VD4(
  
else fA8 ,wy|>  
{ FX{Sb"  
nStartPos = new long[bean.getNSplitter()]; ^dro*a,  
nEndPos = new long[bean.getNSplitter()]; aePk^?KbB  
} 8W{R&Z7aL  
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} mz47lv1?  
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public void run() BwR)--75  
{ ='(:fHhhX  
//获得文件长度 )/UkJ/}j  
//分割文件 #(OL!B  
//实例FileSplitterFetch TV}H  
//启动FileSplitterFetch线程 Ta_#Rg*!  
//等待子线程返回 )Ipa5i>t  
try{ G=DRz F  
if(bFirst) SJ<nAX  
{ =oBV.BST u  
nFileLength = getFileSize(); OmsNo0OA  
if(nFileLength == -1) 7v{Dwg  
{ *t63c.S  
System.err.println("File Length is not known!"); ]`LMy
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} d;K,2  
else if(nFileLength == -2) %k9GoX
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{ {<V{0 s%  
System.err.println("File is not access!"); n;[d{bU  
} XOU 9r(  
else lwSA!W  
{ {q:6;yzxl  
for(int i=0;i<nStartPos.length;i++) wtK+\Qnb  
{ ->d3FR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); alyWp  
}  eGjEO&$  
for(int i=0;i<nEndPos.length-1;i++) G22u+ua  
{ `2G 0B@  
nEndPos = nStartPos[i+1]; +Y-Gp4"  
} >HyZ~M  
nEndPos[nEndPos.length-1] = nFileLength; cJMp`DQzc  
} W2'u]1bs  
} N^v"n*M0|  
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//启动子线程 :wtK'ld  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;O+= 6>W  
for(int i=0;i<nStartPos.length;i++) ka0MuQM  
{ <m'W{n%Pp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :>f}rq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JD9)Qelw^$  
nStartPos,nEndPos,i); :pq+SifP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~m3Q^ue  
fileSplitterFetch.start(); 1aDx 6Mq  
} \8g'v@$wG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NYw>Z>TD8c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W^k95%zBM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g%TOYZr!X  
nEndPos = " + nFileLength); E%LUJx}  
// fileSplitterFetch[nPos.length-1].start(); T\q:
  
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//等待子线程结束 )Vd^#p  
//int count = 0; ?fW['%  
//是否结束while循环 u.;l=tzz  
boolean breakWhile = false; i]9C"Kw$L  
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while(!bStop) YO&
@  
{ pmRm&VgE.  
write_nPos(); C cPOK2  
Utility.sleep(500); ZmI0|r}QbY  
breakWhile = true; 7>"dc+Fg  
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for(int i=0;i<nStartPos.length;i++) ^hNl6)hR  
{ 0 30LT$&!  
if(!fileSplitterFetch.bDownOver) \#4mPk_"  
{ #/_{(P  
breakWhile = false; 9TX2h0U?  
break; AXF 1{  
} DL`8qJ'mJs  
} /yHjds  
if(breakWhile) eSQkW  
break; ]~2iducB,  
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//count++; da<>a  
//if(count>4) Unvl~lm6  
// siteStop(); Idb*,l|<  
} -L+kt_>  
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System.err.println("文件下载结束！"); D&i\dgbK  
} LaO8)lqR  
catch(Exception e){e.printStackTrace ();} To}eJ$8*5  
} EsGf+-}|!0  
yX4Vv{g  
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//获得文件长度 v^ "qr?3V  
public long getFileSize() <o/!M6^:  
{ Q7rBc wm5  
int nFileLength = -1; MA,*$BgZ  
try{ R\|,GZ!`+  
URL url = new URL(siteInfoBean.getSSiteURL()); =* G3Khz!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G<M0KU(  
httpConnection.setRequestProperty("User-Agent","NetFox"); "]#Ij6ml  
{;DAKWm@T  
5CZyA`3V^5  
int responseCode=httpConnection.getResponseCode(); +@=V}IO  
if(responseCode>=400) %ggf|\-e  
{ `Jk0jj6Z  
processErrorCode(responseCode); & ?xR  
return -2; //-2 represent access is error dpTsTU!\  
} M#; ks9  
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String sHeader;  ][wb4$2  
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for(int i=1;;i++) iP0m1  
{ lhKn&U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V_:`K$  
//Utility.log(in.readLine()); 6LBdTnzUd  
sHeader=httpConnection.getHeaderFieldKey(i); ]:OrGD"  
if(sHeader!=null) O;~e^ <*  
{ j@>D]j  
if(sHeader.equals("Content-Length")) H"FK(N\  
{ gom!dB0J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qtExd~E  
break; sFc\L94  
} T9 /;$6s*  
} >E>yA d  
else "iA0hA  
break; @khFk.LBD  
} 1Ng+mT  
} `Gqe]ZE#"  
catch(IOException e){e.printStackTrace ();} |Y>Jf~SN  
catch(Exception e){e.printStackTrace ();} SLKplLO  
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Utility.log(nFileLength); C`hdj/!A  
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return nFileLength; S MWXP  
} wb0$FZzh  
&"^F;z/  
'OsZD?W{  
//保存下载信息（文件指针位置） I8Aq8XBw  
private void write_nPos() lI<jYd 0fZ  
{ =]%JTGdp(  
try{ U?UU]>Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); krUtOVI  
output.writeInt(nStartPos.length); +/ZIs|B4,z  
for(int i=0;i<nStartPos.length;i++) Y;/@[AwF  
{ BS9VwG<Z  
// output.writeLong(nPos); vqSpF6F q  
output.writeLong(fileSplitterFetch.nStartPos); JT?u[pQ^  
output.writeLong(fileSplitterFetch.nEndPos); J8qFdNK  
}  >Uw:cq  
output.close(); QQrldc(I  
} N d].(_  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} Fw 0m(7  
} fpR|+`k  
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//读取保存的下载信息（文件指针位置） NoiB98g  
private void read_nPos() ek][^^4o  
{ .PB!1C.}@  
try{ |V a:*3u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S(gr>eC5  
int nCount = input.readInt(); 5#GMp  
nStartPos = new long[nCount]; 'H530Y\  
nEndPos = new long[nCount]; ("8Hku?  
for(int i=0;i<nStartPos.length;i++) g(@F`W[  
{ t7f(%/] H0  
nStartPos = input.readLong(); w?ugZYwX*  
nEndPos = input.readLong(); ^&qK\m_A  
} zjmoIE  
input.close(); tu\XuDky  
} sY;h~a0n  
catch(IOException e){e.printStackTrace ();} 7m2iL#5[  
catch(Exception e){e.printStackTrace ();} ,X|Oe@/  
} 2R\K!e  
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private void processErrorCode(int nErrorCode) w!m4>w  
{ 9<gW~ s>  
System.err.println("Error Code : " + nErrorCode); ?w:\0j5~  
} }b456J  
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//停止文件下载 SY,ns*>1F  
public void siteStop() In?rQiD9  
{ ?/.])'&b  
bStop = true; #:?:gY<  
for(int i=0;i<nStartPos.length;i++) TAYh#T=S  
fileSplitterFetch.splitterStop(); DGHSyB^+1  
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} =F\Xt "  
} y6$a:
6  
//负责部分文件的抓取 _ s 3aaOL  
**FileSplitterFetch.java QBa+xI_ J  
*/ b$@I(.X:  
package NetFox; L(
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import java.io.*; 
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import java.net.*; XpANaqH\  
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public class FileSplitterFetch extends Thread { ,u}wW*?,sT  
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String sURL; //File URL a<-aE4wdm  
long nStartPos; //File Snippet Start Position X+Sqw5rH  
long nEndPos; //File Snippet End Position -7!L]BcZ.  
int nThreadID; //Thread's ID !>F70  
boolean bDownOver = false; //Downing is over ~C{:G;Iy0  
boolean bStop = false; //Stop identical E{)X ;kN=  
FileAccessI fileAccessI = null; //File Access interface f}yRTR GJv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :?UcD_F  
{ %oqKpD+  
this.sURL = sURL; 4Q!
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this.nStartPos = nStart; %f<>Kwr`2  
this.nEndPos = nEnd; B*:I-5  
nThreadID = id; `Ij EwKra  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bGwOhd<.  
} jwjLxt  
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public void run() &yP|t":HWX  
{ r\QV%09R  
while(nStartPos < nEndPos && !bStop) v#gXXO[P1  
{ ktPM66`b  
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try{ ts<\n-f  
URL url = new URL(sURL); gaC4u,Zb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 48z%dBmTT*  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zr
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String sProperty = "bytes="+nStartPos+"-"; &bq1n_  
httpConnection.setRequestProperty("RANGE",sProperty); G(?1 Urxi  
Utility.log(sProperty); 4RctYMz  
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InputStream input = httpConnection.getInputStream(); 8D>5(Dg-  
//logResponseHead(httpConnection); 5MG4S  
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:Z/\U*6~  
byte[] b = new byte[1024]; _1RvK? ;.{  
int nRead; =p5]r:9W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O`Qke
Z}  
{ )-"<19eu  
nStartPos += fileAccessI.write(b,0,nRead); MB:[: nX  
//if(nThreadID == 1) s[a\m,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q_p&~PNy5  
} phG*It}  
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Utility.log("Thread " + nThreadID + " is over!"); q{G8Po$z'  
bDownOver = true; .Y2H
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//nPos = fileAccessI.write (b,0,nRead); oQpGa>6U&  
} E$z-|-{>  
catch(Exception e){e.printStackTrace ();} PSv 5tQhm  
} Y,L[0%  
} Z,AY<
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//打印回应的头信息 l z"o( %D  
public void logResponseHead(HttpURLConnection con) g||EjCsp  
{ L|<j/bP  
for(int i=1;;i++) $bp$[fX(e  
{ &,8Q
e;  
String header=con.getHeaderFieldKey(i); b3_P??yp  
if(header!=null) PX?%}~ v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z" H;t\P  
Utility.log(header+" : "+con.getHeaderField(header)); Lp"OXJ*es  
else d 4tL  
break; D=vw0Q_3Y3  
} )uAY_()/  
} sZ&6g<8#y  
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public void splitterStop() 49>b]f,Vc  
{ R+ \%  
bStop = true; EKcPJ\7  
} yKrbGK*=_  
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} Oq% TW|a#  
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-3? <Ja  
/* p*g)-/mA  
**FileAccess.java wXp:XZ:]T  
*//文件访问(定位，写) +\%]<YO  
package NetFox; <]%6x[  
import java.io.*; iex%$> "  
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public class FileAccessI implements Serializable{ 3B%7SX  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -,;woOG  
RandomAccessFile oSavedFile; G Wa6F
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long nPos; ~a3u['B  
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public FileAccessI() throws IOException aqqo>O3 s  
{ Oprfp^L  
this("",0); @+zWLq!1pB  
} CeOA_M  
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M
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public FileAccessI(String sName,long nPos) throws IOException E<! L^A M`  
{ <G<5)$ S  
oSavedFile = new RandomAccessFile(sName,"rw"); 2 KH
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this.nPos = nPos; [S]q'c)  
oSavedFile.seek(nPos); ??B!UXi4R  
} 5CcX'*P  
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}m?Ut|  
public synchronized int write(byte[] b,int nStart,int nLen) ;c]O*\/  
{ kk<%VKC  
int n = -1; ;aD~1;q  
try{ saZK+kD4I  
oSavedFile.write(b,nStart,nLen); _8K8Ai-~.>  
n = nLen; C_ d|2C6  
} ]Z\W%'q+  
catch(IOException e) oF+yh!~mM  
{ G6>sAOf  
e.printStackTrace (); ,Js_d  
} Uv.Xw}q  
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return n; 9cN@y<_I  
} O"TVxP:  
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} bvZD@F`2  
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;}S_PnwC@  
/* +RpCh!KP  
**SiteInfoBean.java Fq+Cr?-  
*/ B[8RBTsA  
package NetFox; AriV4 +  
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public class SiteInfoBean { T$r/XAs  
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private String sSiteURL; //Site's URL RB
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private String sFilePath; //Saved File's Path im:[ViR {  
private String sFileName; //Saved File's Name x7l}u`N4  
private int nSplitter; //Count of Splited Downloading File \&V[<]  
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public SiteInfoBean() c; .y  
{//nSplitter的缺省值为5 q |Pebe=  
//default value of nSplitter is 5 cJwe4c6.m  
this("","","",5); oliVaavj  
} &l{ctP%q  
FChW`b&S  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u|ih
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{ :|I"Em3R  
sSiteURL= sURL; O7Jp;  
sFilePath = sPath; \KpJIHkBRy  
sFileName = sName; &2@Rc?!6_P  
this.nSplitter = nSpiltter; E:\#Ur2  
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*}(
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} `+TC@2-?  
,e`n2)  
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public String getSSiteURL() 1dp8'f5^  
{ l!j=em@  
return sSiteURL;  UiK)m:NU  
} `N}'5{I  
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public void setSSiteURL(String value) @
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{ Pa|*Jcr  
sSiteURL = value; 3v#F0s|  
} m9D*I1  
g
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!,7)ZW?*8  
public String getSFilePath() Esj1Vv#  
{ KUq(&H7  
return sFilePath; 1Sns$t%b  
} +y-3tcI)  
G [yI[7=d  
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public void setSFilePath(String value) 6k37RpgH  
{ j{ri]?p  
sFilePath = value; !*"#*)S.  
} O6q5qA  
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?%Pi#%P  
public String getSFileName() \/Zo*/  
{ UD2l!)rW  
return sFileName; 01%0u8U  
} 3?&P^{  
e&<=+\ul  
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public void setSFileName(String value) sa"!ckh  
{ ZtI@$ An  
sFileName = value; Nfl5tI$U:  
} 7zNfq.Ni~  
j#VR>0oC]\  
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public int getNSplitter() 2.a{,d  
{ !,DA`Yt  
return nSplitter; HIlTt  
} w(odgD  
~\O,#j`_  
]#FQde4]5  
public void setNSplitter(int nCount) > mP([]  
{ EuD$^#  
nSplitter = nCount; \%#
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} 7z+Ngt' !  
} ~y:?w(GD  
*W4~.peoE  
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/* 55Ye7P-d  
**Utility.java OV7SLf  
*/ 6.3qux9  
package NetFox; 2cv=7!K4Uv  
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%/K;!'7  
public class Utility { C7MCM
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public Utility() ~H626vT37  
{ 4m_CPe  
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} SiT5QJe  
v-}D>)M^W  
//线程睡眠 n!?u/[@  
public static void sleep(int nSecond) -lI6!a^  
{ '&iAPc4=  
try{ 8wzQr2:  
Thread.sleep(nSecond); 2,'%G\QT  
} '# J/e0o@  
catch(Exception e) k{+Gv}Y  
{ ;#dzw!+Y  
e.printStackTrace (); .:TSdusr~  
} t",b.vki\z  
} ,mD{4 >7  
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//日志 S(5&%}QFQ  
public static void log(String sMsg) ap.L=vn  
{ >L88`  
System.err.println(sMsg); j:J7
  
} >T
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h Ap(1h#m  
public static void log(int sMsg) wO*x0$  
{ o<i\1<eI  
System.err.println(sMsg); ~5wT
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} <FU1|  
} [!>DQE  
e4Jx%v?_P  
#TG.weT
C  
/* }FT8[m<  
**TestMethod.java JReJlDu  
*/ 6^hCW`jG  
package NetFox; s7na!A[  
=
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public class TestMethod { bRK[u\,  
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public TestMethod() bWfT-Jewh  
{ ///xx/weblogic60b2_win.exe aA&}=lm  
try{ 'n4 iW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); DeRC_ [  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CC{{@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Jnf@u  
fileFetch.start(); qb7ur;  
} PitDk 1T  
catch(Exception e){e.printStackTrace ();} )w&k&TY4H  
}
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}
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" )/febBS  
public static void main(String[] args) ]R8JBnA  
{ KeE)9e   
new TestMethod(); 6`sS8Ar&u  
} wA7^  
} u
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