http断点续传简单实现（java)

/* AX%}ip[PC  
**SiteFileFetch.java 1ig*Xp[  
*/ ja~Dp5  
package NetFox; G u_\ySV/y  
import java.io.*; /*>}y$  
import java.net.*; %7 yQ0'P  
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public class SiteFileFetch extends Thread { kr~n5WiAZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _q1\8y  
long[] nStartPos; //开始位置 4)OOj14-V  
long[] nEndPos; //结束位置 QW,:'\G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AD<>
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long nFileLength; //文件长度 TfkGkVR  
boolean bFirst = true; //是否第一次取文件 62,dFM7  
boolean bStop = false; //停止标志 iX{2U lF7  
File tmpFile; //文件下载的临时信息 WkE="E}  
DataOutputStream output; //输出到文件的输出流 o6;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） YLTg(*  
public SiteFileFetch(SiteInfoBean bean) throws IOException DiOd!8Y  
{ z9OpMA  
siteInfoBean = bean; 4Eu'_
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,g}$u'A+d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fap]`P~#L  
if(tmpFile.exists ()) %L]sQq,  
{ Kw;gQk~R!  
bFirst = false; G1e_pszD{o  
read_nPos();
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} 0M&n3s{5I  
else #k)z5vZ$h  
{ r ~UDK]?V  
nStartPos = new long[bean.getNSplitter()]; @:PMb Ub  
nEndPos = new long[bean.getNSplitter()]; u0arJU_.)  
} '"\n,3h  
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} Spx%`O<  
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public void run() CP;<B1  
{ "u4x#7n|  
//获得文件长度 Gvdok<o  
//分割文件 G8__6v~  
//实例FileSplitterFetch @w.DN)GPo  
//启动FileSplitterFetch线程 }T\.;$f  
//等待子线程返回 ;>6~}lMgJ  
try{ Y7g%nz[[  
if(bFirst) ({C[RsY=6  
{ D=3Z] 'A  
nFileLength = getFileSize(); fg
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if(nFileLength == -1) # }}6JM  
{ O%>*=h`P  
System.err.println("File Length is not known!"); Zazs".  
} sUc[!S:/  
else if(nFileLength == -2) <Fx%P:d  
{ CEw%_U@8  
System.err.println("File is not access!"); yF6AI@y  
} nIlTzrf6  
else pL[3,.@WA  
{ oLX[!0M^  
for(int i=0;i<nStartPos.length;i++) @XtrC|dkkE  
{ MbInXv$q2/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); n CX{tqy   
} `p* 43nV  
for(int i=0;i<nEndPos.length-1;i++) ]u-bJ  
{ PIo@B|W-SX  
nEndPos = nStartPos[i+1]; nu1XT 1q1  
} sxRKWM@4  
nEndPos[nEndPos.length-1] = nFileLength; S},Cz  
} ]ke9ipj]:  
} &v;fK$=2C  
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//启动子线程 5HHf3E [  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j-**\.4a~  
for(int i=0;i<nStartPos.length;i++) ,\&r\!=  
{ w{L9-o3A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m(9I+
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I2RXw  
nStartPos,nEndPos,i); j82w 3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Srmr`[i  
fileSplitterFetch.start(); i g7|kl  
} i={4rZOD^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a;IOL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y7qQ`|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {4/*2IRN9h  
nEndPos = " + nFileLength); k}nGgd6XD  
// fileSplitterFetch[nPos.length-1].start(); E.Th}+
  
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//等待子线程结束 ?
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//int count = 0; ZWS:-]P.  
//是否结束while循环 _](y<O^9yO  
boolean breakWhile = false; 8mdVh\i!Kf  
8|\ -(:v  
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while(!bStop) : 4-pnn  
{ kxEq_FX  
write_nPos(); #Q["[}flVv  
Utility.sleep(500); II _CT=  
breakWhile = true; {%k[Z9*tO  
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for(int i=0;i<nStartPos.length;i++) c'VCCXe  
{ bk=;=K  
if(!fileSplitterFetch.bDownOver) $'d,X@}8  
{ $\]Mvd  
breakWhile = false; )Kl@dj  
break; nwfu@h0G  
} bYem0hzOe  
} !@P{s'<:  
if(breakWhile) 6nsb)7a  
break; dG~U3
\!  
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//count++; ^e_uprZWm  
//if(count>4) iKaS7lWH  
// siteStop(); N|@tP:j  
} !U2<\!_  
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System.err.println("文件下载结束！"); G#NbLj`h  
} KX!/n`2u  
catch(Exception e){e.printStackTrace ();} yD!GgnW  
} z,dFDl$  
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//获得文件长度 Dh#5-Kf%  
public long getFileSize() wpQp1){%Q  
{ n) HV:8j~  
int nFileLength = -1; qyy.&+  
try{ YFj#{C.  
URL url = new URL(siteInfoBean.getSSiteURL()); 9X#]Lg?b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >XuPg(Ow  
httpConnection.setRequestProperty("User-Agent","NetFox"); j3+ hsA/(k  
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int responseCode=httpConnection.getResponseCode(); 6Qz=g t%I=  
if(responseCode>=400) vt(
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{ vs$
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processErrorCode(responseCode); S @!z'$&  
return -2; //-2 represent access is error rt)[}+ox  
} v-!Spf  
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#X{lV]Z  
String sHeader; S&cN+r  
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for(int i=1;;i++) [z;}^3b  
{ 4/S3hH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fv* $=m  
//Utility.log(in.readLine()); ,CqGO %DY  
sHeader=httpConnection.getHeaderFieldKey(i); _IxYnm`pc  
if(sHeader!=null) \l5G   
{ aqi]5,  
if(sHeader.equals("Content-Length"))
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{ j&8GtE1b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n7n-uc  
break; brqmi<*9"[  
} i{HzY[  
} }C=+Tn  
else \vL{f;2J  
break; (J(SwL|  
} zE}ry!{  
} 00Ye ]j_  
catch(IOException e){e.printStackTrace ();} [8WG  
catch(Exception e){e.printStackTrace ();} \K Kt&bKL  
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Utility.log(nFileLength); 69odE+-X.  
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return nFileLength; o7v9xm+  
} X:(t,g*7  
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//保存下载信息（文件指针位置） G{a_\'7  
private void write_nPos() qUQP.4Z95  
{ PnI_W84z  
try{ ZRa~miKyM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uxW<Eh4H*  
output.writeInt(nStartPos.length); iYr*0:M  
for(int i=0;i<nStartPos.length;i++) Y5mk*Q#q  
{ [bBPs&7u  
// output.writeLong(nPos); +xYg<AFS  
output.writeLong(fileSplitterFetch.nStartPos); E@Yq2FBpnn  
output.writeLong(fileSplitterFetch.nEndPos); ^|cax|
>  
} 0A75)T=lQ  
output.close(); J$yJ2G  
} J p0j  
catch(IOException e){e.printStackTrace ();} S^5Qhv  
catch(Exception e){e.printStackTrace ();} "3Ckc"G@  
} o
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CG
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//读取保存的下载信息（文件指针位置） YE-}1&8  
private void read_nPos() !~}@Eoii4  
{ <;!#+|L/  
try{ ^`9O$.'@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L5]uT`Twa  
int nCount = input.readInt(); 6k ]+DbT  
nStartPos = new long[nCount]; B(R$5Xp  
nEndPos = new long[nCount]; R)]+>M-.  
for(int i=0;i<nStartPos.length;i++) lMjeq.5nP  
{ @u-CR8^  
nStartPos = input.readLong(); f(c#1AJE53  
nEndPos = input.readLong(); uNvdlY]  
} Cuom_+wV&  
input.close(); 8+&Da  
} Fma#`{va  
catch(IOException e){e.printStackTrace ();} \8Yv}wQ  
catch(Exception e){e.printStackTrace ();} AK$i0Rn;pm  
} >ti)m >f  
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private void processErrorCode(int nErrorCode) bxAHzOB(\  
{ j=PM]  
System.err.println("Error Code : " + nErrorCode); ] N7(<EV/  
} 8qv>C)~~
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#>">fs]  
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//停止文件下载 )1Z @}o 9  
public void siteStop() T$o;PJc  
{ |h2=9\:]  
bStop = true; nm@.] "/  
for(int i=0;i<nStartPos.length;i++) D'"l%p  
fileSplitterFetch.splitterStop(); d+IN-lR(  
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} `_<O_  
} aj$&~-/ R  
//负责部分文件的抓取 d'e\
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**FileSplitterFetch.java tx}=c5  
*/ E.^F:$2  
package NetFox; RWXN  
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import java.io.*; LOe l6Ui  
import java.net.*; VI8/@A1Gv  
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public class FileSplitterFetch extends Thread { a} :2lL%  
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String sURL; //File URL Md>9Daa~  
long nStartPos; //File Snippet Start Position ~p\r( B7G  
long nEndPos; //File Snippet End Position }ZfdjF8N
!  
int nThreadID; //Thread's ID ;^ YpQP  
boolean bDownOver = false; //Downing is over 88A,ll%  
boolean bStop = false; //Stop identical wo\O0?d3{  
FileAccessI fileAccessI = null; //File Access interface a- 7RJ.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h%Uq  
{ muIJeQ.C  
this.sURL = sURL; :hDv^D?3  
this.nStartPos = nStart; 5ih5=qX  
this.nEndPos = nEnd; :VlMszy}B3  
nThreadID = id; rh6 e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k3&/Ei5  
} \}; 4rm}V  
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public void run() G PL^!_  
{ 921s'"  
while(nStartPos < nEndPos && !bStop) e}2[g  
{ ZKVM9ofXRi  
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try{ Kj#h9e  
URL url = new URL(sURL); yUg'^SEbLk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :-cqC|Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); d@{#F"o  
String sProperty = "bytes="+nStartPos+"-"; nC#SnyUO  
httpConnection.setRequestProperty("RANGE",sProperty); &IkHP/  
Utility.log(sProperty); MG3xX;  
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InputStream input = httpConnection.getInputStream(); *)Pb-c
 
//logResponseHead(httpConnection); tCQf `  
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byte[] b = new byte[1024]; @mEB=X(-l=  
int nRead; ]v0=jm5A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KZ|p_{0&  
{ 7h\U}!  
nStartPos += fileAccessI.write(b,0,nRead); /@6T~XY M  
//if(nThreadID == 1) (b+o$C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zO6Sl[)  
} - 4B&{P  
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Utility.log("Thread " + nThreadID + " is over!"); Gvc/o$_  
bDownOver = true; C59H| S  
//nPos = fileAccessI.write (b,0,nRead); {$v>3FG  
} ,ydn]0SS  
catch(Exception e){e.printStackTrace ();} /mnV$+BE  
} )D ':bWP  
} yH.Z%*=xQa  
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//打印回应的头信息 S|T*-?|  
public void logResponseHead(HttpURLConnection con) i^V3u  
{ 10r9sR  
for(int i=1;;i++) ?# )\SQ  
{ 0Yfz?:
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String header=con.getHeaderFieldKey(i); i{k v$ir!  
if(header!=null) n;~6'fxe  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6?= ^8  
Utility.log(header+" : "+con.getHeaderField(header)); )Z63 cr/  
else : W0;U  
break; VBe&of+  
} 4m6%HV8{}[  
} 8<Ex`  
n)R[T.E)+  
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public void splitterStop() D~@lpcI  
{ e)]DFP[n  
bStop = true; _kQOax{c/  
} tMr$N[@r  
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} 2m2$jp0  
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/* g (V_&Y  
**FileAccess.java WmZ,c_  
*//文件访问(定位，写) -A1:S'aN-  
package NetFox; "S3U]zw0_  
import java.io.*; _)^`+{N<  
'jBtBFzP-  
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public class FileAccessI implements Serializable{ anFl:=  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mp17d$R-  
RandomAccessFile oSavedFile; n|!O .+\b  
long nPos; [,q^\T  
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public FileAccessI() throws IOException ;($ 3,d8  
{ hV"2L4/E  
this("",0); ((tWgSZ3  
} R5'_il  
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[
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public FileAccessI(String sName,long nPos) throws IOException mNr<=Z%b  
{ Zz56=ZX*_  
oSavedFile = new RandomAccessFile(sName,"rw"); ,4kipJ!,yK  
this.nPos = nPos;
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oSavedFile.seek(nPos); 'pl){aL`@u  
} jX 6+~  
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public synchronized int write(byte[] b,int nStart,int nLen) aKkY)  
{ cUM#|K#6  
int n = -1; Gm'Ch}E  
try{ p|R]/C0f  
oSavedFile.write(b,nStart,nLen); C'CdVDmX  
n = nLen; ekO*(vQ~  
} p?eQN Y  
catch(IOException e) bL18G(5  
{ S[oRq   
e.printStackTrace (); X.<2]V7!  
} h*?/[XY  
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return n; 6'vt '9  
} 3W}xYYs]^  
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} 3?oj46gP  
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E| =~rIKN  
/* Oz_|pu  
**SiteInfoBean.java RVb}R<yU+  
*/ -YP>mwSN?  
package NetFox; e8<[2J)P&  
@Xe[5T  
+{S^A)  
public class SiteInfoBean { S
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j=,]b6(  
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private String sSiteURL; //Site's URL {BKr/) H  
private String sFilePath; //Saved File's Path /4n:!6rt  
private String sFileName; //Saved File's Name k,nRC~Irh  
private int nSplitter; //Count of Splited Downloading File $N1UEvC%Q  
<sq@[\l}a  
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public SiteInfoBean() S\O6B1<:  
{//nSplitter的缺省值为5 ^~%zPlv  
//default value of nSplitter is 5 B?tO&$s  
this("","","",5); tkGJ!aUt  
} &Kgl\;}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z[{: `  
{ ]o]*&[C  
sSiteURL= sURL; hup<U+p  
sFilePath = sPath; ^.9I[Umua  
sFileName = sName; ard<T}|N  
this.nSplitter = nSpiltter; 2!35Tj"RFE  
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} Lh5d2}tcO  
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public String getSSiteURL() WwF4`kxT
 
{ @ 0RB.-  
return sSiteURL; nVC:5ie  
} -B-nTS`  
.hxcx>%  
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public void setSSiteURL(String value) +89s+4Jn  
{ XKU+'Tz  
sSiteURL = value; -/.Xf<y58  
} )k8=< =s  
YEWHr>&Z  
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public String getSFilePath() s}d1 k  
{ #Pulbk8  
return sFilePath; jy] hP?QG  
} XK (y ?Y1  
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public void setSFilePath(String value) -k p~pe*T  
{ ~R]E=/m|  
sFilePath = value; d))(hk:  
} y#AwuC K  
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public String getSFileName() yWACIaj  
{ .-;K$'YG  
return sFileName; Oph4&Ip[w  
} \]U@=w  
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public void setSFileName(String value) l[O!_bH  
{ hv'~S  
sFileName = value; I)E+  
} )
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public int getNSplitter() <R7*
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{ {}?s0U$5  
return nSplitter; S<f&?\wK=v  
} "aN<3
b  
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public void setNSplitter(int nCount) #D3e\(  
{ @5H1Ni5/o@  
nSplitter = nCount; :b;2
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} J.:"yK""  
} e| (jv<~r  
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9  
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/* -gh',)R  
**Utility.java !%NxSJ  
*/ p8
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package NetFox; L1`^~m|  
_> .TB\  
1 ,oC:N  
public class Utility { #6_?7 (X  
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public Utility()
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{ bslv_OxJ  
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} uJMF\G=nb  
+Bv{A3E9  
//线程睡眠 "j3Yu4_ks  
public static void sleep(int nSecond) bOux8OHt*  
{ [X)+(-J  
try{ 3j0/&ON  
Thread.sleep(nSecond); N{iBVl  
} y<k-d
br  
catch(Exception e) e}f!zA  
{ _x z_D12  
e.printStackTrace (); P /wc9Yt  
} OCo=h|qBp  
} p{!aRB%  
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//日志 'rHkJ  
public static void log(String sMsg) 9+9}^B5@A  
{ )qD%5} t  
System.err.println(sMsg); 8;p6~&).C~  
} G?e,Q$  
{{f%w$r(  
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public static void log(int sMsg) \Yz>=rY  
{ XV)ej>A-V  
System.err.println(sMsg); Lh"Je-x<<  
} ~m[^|w  
} >t'/(y  
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/* HvK<>9  
**TestMethod.java gx4`pH;B\  
*/ f'aUo|^?  
package NetFox; ep3_G\m  
7&:gvhw  
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public class TestMethod { YQ4;X8I`r  
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public TestMethod() W&}R7a@:<~  
{ ///xx/weblogic60b2_win.exe d vkA-9  
try{ 7zVaj"N(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -}MWA>an8
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %xyt4}-)m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Xl2Fgg}#  
fileFetch.start(); '-4);:(^  
} [}9R9G>"  
catch(Exception e){e.printStackTrace ();} _V1O =iu-  
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k
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} $[VKM|Zjw  
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public static void main(String[] args) zr\I1v]?1#  
{ u#\=g:  
new TestMethod(); Zu_m$Mx  
} 68*h#&  
} )j4]Y dJ  
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