http断点续传简单实现（java)

/* 0R5^p  
**SiteFileFetch.java  !QW 0  
*/ GlgORy=>  
package NetFox; +JAfHQm-  
import java.io.*; VBsFT2XiL  
import java.net.*; b:5%}  
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public class SiteFileFetch extends Thread { (:bCOEZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nP{sCH 1  
long[] nStartPos; //开始位置 tTh;.8
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long[] nEndPos; //结束位置 0CVsDVA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z0Z\d  
long nFileLength; //文件长度 7- 3N  
boolean bFirst = true; //是否第一次取文件 ocA'goI-  
boolean bStop = false; //停止标志 I1 R\Ts@  
File tmpFile; //文件下载的临时信息 c;8"vJ  
DataOutputStream output; //输出到文件的输出流 -f;j1bQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sa gBmA~  
public SiteFileFetch(SiteInfoBean bean) throws IOException s?;<F  
{ # pjyhH@  
siteInfoBean = bean; ic{.#R.BY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &0 )xvZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZJI1NCBZ  
if(tmpFile.exists ()) )av'u.]%c  
{ JU=\]E@8c  
bFirst = false; N" Jtg@w  
read_nPos(); MHr0CYyb.  
} XG\a-dq[  
else `\4
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{ Wh'_slDH+  
nStartPos = new long[bean.getNSplitter()]; ;GgQ@s@  
nEndPos = new long[bean.getNSplitter()]; ;aK !eD$  
} u388Wj   
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} zr;Y1Xt4  
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public void run() l;{N/cS  
{ NtA|#"^  
//获得文件长度 $6&GAJ
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//分割文件 z Jo#
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//实例FileSplitterFetch <E7Vbb9*  
//启动FileSplitterFetch线程 w{zJE]7  
//等待子线程返回 C`th^dqBV  
try{ B:A1W{l  
if(bFirst) qp~4KukL  
{ Sv~1XL W  
nFileLength = getFileSize(); 2c>H(t h=  
if(nFileLength == -1) Xv7U<
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{ JPTI6"/  
System.err.println("File Length is not known!"); [cTRz*\s  
} K@j^gF/0B  
else if(nFileLength == -2) $G-N0LV  
{ Xx y Bg!R  
System.err.println("File is not access!"); & L.PU@  
} _^xh1=Qr}n  
else |p8"9jN@}c  
{ {sfmWVp  
for(int i=0;i<nStartPos.length;i++) &t*8oNwSs  
{ TH(Lzrbg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ky'3z"  
} THbtu*E
l  
for(int i=0;i<nEndPos.length-1;i++) +zVcOS*-  
{ 2NArE@  
nEndPos = nStartPos[i+1]; sQ>B_
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} b!^M}s6  
nEndPos[nEndPos.length-1] = nFileLength; =@1R ozt  
} ;*)fO?TG)  
} e0|_Z])D  
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//启动子线程 cpF1XpvT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |?fW!y  
for(int i=0;i<nStartPos.length;i++) CNpe8M=/3  
{ HV$9b~(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .^W\OJ`G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (Xr_ np @  
nStartPos,nEndPos,i);  ENYF0wW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9#EHXgz  
fileSplitterFetch.start(); ;5Wx$Yfx  
} _86*.3fQG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :uIi ?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &Xn8oe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i>]<*w  
nEndPos = " + nFileLength); Av;q:x?  
// fileSplitterFetch[nPos.length-1].start(); 94p:|5@  
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//等待子线程结束 ^ =/?<C4  
//int count = 0; 6
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//是否结束while循环 sx[&4 k[  
boolean breakWhile = false; !0!U01SWa  
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while(!bStop) cz7CrK~5  
{ m<FWv2)^  
write_nPos(); y;{^Ln4{  
Utility.sleep(500); c9*1$~(v0I  
breakWhile = true; x:A-p..e  
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for(int i=0;i<nStartPos.length;i++) fd5ZaE#f  
{ H4}%;m%  
if(!fileSplitterFetch.bDownOver) l}Q"Nb)  
{ O:5Rp_?^  
breakWhile = false; jIx8k8  
break;  ^6)GS%R  
} m{bZRkt  
} jSwtf  
if(breakWhile) 5q(]1|Sei  
break; |P,zGy  
!^
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//count++; Sc4obcw%  
//if(count>4) sFQ4O- SM  
// siteStop(); tT@w%Sz57N  
} MG7 ?N #  
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}pl]9  
System.err.println("文件下载结束！"); ?fbgU  
} @pF fpHq?>  
catch(Exception e){e.printStackTrace ();} 5|<yfk8*J  
} eKZ@FEZ  
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%]a @A8o0  
//获得文件长度 hzT{3YtY2  
public long getFileSize() nabBU4;h  
{ 99l>CYXd  
int nFileLength = -1; v"P&`1=T  
try{ Pl rkgS0J  
URL url = new URL(siteInfoBean.getSSiteURL()); _pz,okO[V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K0EY<Ltq  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]6$,IKE7  
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int responseCode=httpConnection.getResponseCode(); 8sN#e(@  
if(responseCode>=400) V=j-Um;  
{ GBH_r0  
processErrorCode(responseCode); w/b>awI  
return -2; //-2 represent access is error =jg#fdM -  
} mR{CVU  
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String sHeader; Zg -]sp]  
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for(int i=1;;i++) !c3```*  
{ EMVk:Vt]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K0w<[CO  
//Utility.log(in.readLine()); nNt*} k  
sHeader=httpConnection.getHeaderFieldKey(i); X+=-f^)&  
if(sHeader!=null) Nls83 W  
{ E,{GU  
if(sHeader.equals("Content-Length")) -PNi^ K_  
{ )y9;OA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y/.AUN Z  
break; &+mV7o  
} V]79vC  
} aWyUu/g<A`  
else $4Z+F#mx  
break; di~]HUZh)  
} j|:dYt`WM  
} IByf_E;r  
catch(IOException e){e.printStackTrace ();} WtEI] WO  
catch(Exception e){e.printStackTrace ();} !ZFr7Xz  
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Utility.log(nFileLength); >[ eW">:>K  
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return nFileLength; o^3FL||P#r  
} >(X#<`  
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//保存下载信息（文件指针位置） JnfqXbE  
private void write_nPos() 4-mVB wq  
{ >~_Jq|KBB  
try{ 6+.>5e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S]}}A  
output.writeInt(nStartPos.length); n.*3,4.]  
for(int i=0;i<nStartPos.length;i++) \tY"BC4.  
{ i+g~ Uj}h  
// output.writeLong(nPos); ,V,f2W 4  
output.writeLong(fileSplitterFetch.nStartPos); =I2
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output.writeLong(fileSplitterFetch.nEndPos); 4SgF,ac3r  
} ?w-1:NWjt  
output.close(); RctU'T  
} |,b2b2v?  
catch(IOException e){e.printStackTrace ();} O|QUNr9  
catch(Exception e){e.printStackTrace ();} >R!"P[*  
} m6^ 5S  
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//读取保存的下载信息（文件指针位置） +R!zs  
private void read_nPos() ~g6"'Cya?k  
{ 7p
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try{ EIr@g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NmJ`?-Z  
int nCount = input.readInt(); OTj,O77k  
nStartPos = new long[nCount]; I,b9t\(6  
nEndPos = new long[nCount]; ?v:ZU~i  
for(int i=0;i<nStartPos.length;i++) IV'p~t
 
{ H$!+A  
nStartPos = input.readLong(); Z7fg 25  
nEndPos = input.readLong(); hq=,Z1J  
} <47k@Ym   
input.close(); 7h%4]  
} *m9{V8Yi2  
catch(IOException e){e.printStackTrace ();} LN4qYp6)G  
catch(Exception e){e.printStackTrace ();} 4S|=/f  
} k;k}qq`d  
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private void processErrorCode(int nErrorCode) ks*Y9D*=  
{ q*,Q5  
System.err.println("Error Code : " + nErrorCode); uRE*%d>  
} )P?IqSEA%  
?7 \\e;j}  
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//停止文件下载 0"78/6XIs  
public void siteStop() _T5)n=|  
{ p~&BChBl!=  
bStop = true; SRZL\m}  
for(int i=0;i<nStartPos.length;i++) 5u r)uz]w8  
fileSplitterFetch.splitterStop(); UZGDdP  
}g|nz8
  
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} Tkw;pb  
} LH2PTW\b!6  
//负责部分文件的抓取
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**FileSplitterFetch.java |S&5es-yW  
*/ KB!5u9  
package NetFox; i0:>Nk  
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import java.io.*; +f>cxA  
import java.net.*; glE^t6)  
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public class FileSplitterFetch extends Thread { e4`uVq5  
6?qDdVR~]  
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String sURL; //File URL 9Ma0^_  
long nStartPos; //File Snippet Start Position rv>^TR*,!  
long nEndPos; //File Snippet End Position oFDz;6  
int nThreadID; //Thread's ID gd7^3q[$h  
boolean bDownOver = false; //Downing is over hIYTe  
boolean bStop = false; //Stop identical Ub_4yN;  
FileAccessI fileAccessI = null; //File Access interface yHeEobvb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ibpzeuUl  
{ Pf<[|yu4?  
this.sURL = sURL; oH#v6{y  
this.nStartPos = nStart; geM6G$V&  
this.nEndPos = nEnd; RO&H5m r%@  
nThreadID = id; ^B/9{0n'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4-R^
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} N@xg:xr  
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public void run()
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{ p`F9Amb  
while(nStartPos < nEndPos && !bStop) `_v
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{ V0*3;n  
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try{ _Ov;4nt!  
URL url = new URL(sURL); 445o DkG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MFt*&%,JX  
httpConnection.setRequestProperty("User-Agent","NetFox"); zR;X*q"T$4  
String sProperty = "bytes="+nStartPos+"-"; ?4 S+edX  
httpConnection.setRequestProperty("RANGE",sProperty); #]]Su91BA  
Utility.log(sProperty); ]y@F8$D!  
*Dmx&F=3,5  
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InputStream input = httpConnection.getInputStream(); dRi5hC$  
//logResponseHead(httpConnection); B@y(.  
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byte[] b = new byte[1024]; e@#kRklV&  
int nRead; 5J2=`=FK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1ocJ+  
{ )$Mmn  
nStartPos += fileAccessI.write(b,0,nRead); B,WTHU[AV  
//if(nThreadID == 1) BvD5SBa}"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $wB^R(f@  
} bFS>)
 
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Utility.log("Thread " + nThreadID + " is over!"); S
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bDownOver = true; kc `V4b%  
//nPos = fileAccessI.write (b,0,nRead); uC3:7  
} SOZPZUUEJ  
catch(Exception e){e.printStackTrace ();} errH>D~  
} &fC!(Oy  
} ao" %WX  
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:1ecx$  
//打印回应的头信息 :}:3i9e*2  
public void logResponseHead(HttpURLConnection con) mmXm\]r>4  
{ V/d/L3p  
for(int i=1;;i++) AK!hK>u`  
{ }n_p$g[Nj/  
String header=con.getHeaderFieldKey(i); ;Q;[*B=kE  
if(header!=null) l_tw<`Ep  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %V`F!D<D  
Utility.log(header+" : "+con.getHeaderField(header)); #H?t!DU  
else !$;a[Te  
break; $~0Q@):  
} WE6a'  
} B
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7dG79H  
public void splitterStop() *OJ/V O  
{ -|k)tvAm  
bStop = true; Kv'n:z7Md  
} WtulTAfN  
[#Lc]$  
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} eN?Y7  
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/* `;
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**FileAccess.java ^9OUzTF  
*//文件访问(定位，写) [D-Q'"'A  
package NetFox; 9^"b*&>P  
import java.io.*; g"s$}5{8:  
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public class FileAccessI implements Serializable{ u's`*T@.  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A1)wo^,  
RandomAccessFile oSavedFile; u] :m"LM  
long nPos; 9SlNq05G
7  
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public FileAccessI() throws IOException f4-a?bp  
{ E:zF/$tG  
this("",0); J:uW`R  
} LE5.b]tv2  
:@W.K5  
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public FileAccessI(String sName,long nPos) throws IOException [,n c  
{ @`tXKP$so  
oSavedFile = new RandomAccessFile(sName,"rw"); 2!&&|Mh}  
this.nPos = nPos; /525w^'pd  
oSavedFile.seek(nPos); ? J}r  
} I;5R2" 3  
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1O].v&{  
public synchronized int write(byte[] b,int nStart,int nLen) }$MN|s  
{ )X4K2~k*  
int n = -1; 08X_}97#WF  
try{  +`7KSwa  
oSavedFile.write(b,nStart,nLen); hA\K</h.  
n = nLen; G}5#l  
} 0 a]/%y3V  
catch(IOException e) +&zYZA8v  
{ &//wSlL3  
e.printStackTrace (); {`2R,Jb%S  
} ^[%%r3"$C  
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+<,gB $j  
return n; tXJUvish  
} G-9iowS/A  
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} BBcV9CGU  
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6}FO[  
/* pP(XIC  
**SiteInfoBean.java cRX~z  
*/ uEc<}pV  
package NetFox; JCAq8=zM  
}|%eCVB  
7d92Pe  
public class SiteInfoBean { @( n^T  
'!f5?O+E  
r>bJ%M}  
private String sSiteURL; //Site's URL i#%aTRKHd6  
private String sFilePath; //Saved File's Path ;S xFp  
private String sFileName; //Saved File's Name 1s1=rZ!  
private int nSplitter; //Count of Splited Downloading File s+:=I e  
k+1|I)z  
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public SiteInfoBean() 7)h[Zy,A  
{//nSplitter的缺省值为5 {BHI1Uw  
//default value of nSplitter is 5 qY 4#V k  
this("","","",5);
+2 Af&~T  
} Wu)>U  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o:V|:*1Q  
{ ]({~,8s  
sSiteURL= sURL; 1>L(ul(qGF  
sFilePath = sPath; tE7[Smzuf  
sFileName = sName; /  g 2b  
this.nSplitter = nSpiltter; V`@>MOw^d  
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.5  
} OT&k.!=  
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public String getSSiteURL() ZoArQ(YFy  
{ trE{FT  
return sSiteURL; 8b0d]*q  
} 5c8x: e@  
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cO9Aw!  
public void setSSiteURL(String value) {VG6m Hw  
{ ,~#hHhR_  
sSiteURL = value; (WvA9s{/  
} Dl{Pd`D  
W!*vO>^1W  
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public String getSFilePath() u.6%n.g  
{
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return sFilePath; \BW(c)Q  
} =_Rd0,  
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public void setSFilePath(String value) 4tjRju?  
{ c/RG1w  
sFilePath = value; q`hg@uwA{`  
} \z 'noc  
_[W=1bGJ  
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public String getSFileName() (!s[~O6  
{ UpILr\3U  
return sFileName; 5|Qr"c$p  
} 4)_ [)MZ\j  
q2y:bqLWl  
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public void setSFileName(String value) W2RS G~|  
{ !k:j+h/  
sFileName = value; s6I]H  
} sdLFBiR  
@,]v'l!u  
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public int getNSplitter() -nW-I\d%  
{ qF?S[Z;  
return nSplitter; hf[K\aAk  
} ;1KhUf;&F  
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public void setNSplitter(int nCount) L>B0%TP^  
{ UxW~

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nSplitter = nCount; HwHI$IB  
} &>-Cz%IV  
} 3]'3{@{}H  
sEoS|"  
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/* |^ qW   
**Utility.java , Le_PJY)  
*/ ZrTq)BZ  
package NetFox; 7 ir T6O<.  
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!MbRI  
public class Utility { V#=N?p  
k
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3yTBkFI!  
public Utility() ^3el-dZ  
{ w:qwU\U>x  
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} \UXQy{Ex  
&?~> I[^~  
//线程睡眠 2-$R@ SVy  
public static void sleep(int nSecond) l!
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{ +Y.As  
try{ 6:e0?R^aD"  
Thread.sleep(nSecond); ~sM334sQ  
} zP5HTEz  
catch(Exception e) tvd/Y|bV=  
{ ;N)qNiJY  
e.printStackTrace (); jildi
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} Ngg (<ZN  
} 2^|*M@3r  

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//日志 f5'+F-`N  
public static void log(String sMsg) " I:j a7  
{ ](%-5G1<  
System.err.println(sMsg); ^.k}YSWut  
} oqG 0 @@  
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public static void log(int sMsg) W4Zi?@L>'  
{ zV%U4P)Dao  
System.err.println(sMsg); `2GHB@S"k  
} :c c#e&BO  
} (d@lG*K  
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=T9QmEBm  
/* VNF@)!l  
**TestMethod.java {gzL}KL  
*/ =EFF2M`F  
package NetFox; %|4Nmf$:Og  

o4tQ9X=}  
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public class TestMethod { &d=j_9   
*V5R[   
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public TestMethod() g;vG6!;E\  
{ ///xx/weblogic60b2_win.exe :+; UW \  
try{ @MTm8E6au  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GJU84Xn7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M~=9ym  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Kh}#At^C8e  
fileFetch.start(); 9>%ti&_-jt  
} o|$l+TC  
catch(Exception e){e.printStackTrace ();} eNpGa0 eG  
le`fRq8f&  
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} NO8)XJ3s  
YR^J7b\  
,)|nxX  
public static void main(String[] args) pq*W;6(-  
{ #zyEN+  
new TestMethod(); *6?h,Dt L  
} ZXh6Se4o  
} 0ERA(=w5  
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