http断点续传简单实现（java)

/* =~,2E;#X  
**SiteFileFetch.java Rw63{
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*/ W}k/>V_  
package NetFox; hVz]',  
import java.io.*; qm9=Ga5  
import java.net.*; aU.!+e%_  
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public class SiteFileFetch extends Thread { 'aeuL1mz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean GAs.?JHd  
long[] nStartPos; //开始位置 svt3gkR0  
long[] nEndPos; //结束位置 7uu\R=$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Oku7&L1  
long nFileLength; //文件长度 g%)cyri  
boolean bFirst = true; //是否第一次取文件 39pA:3iTd  
boolean bStop = false; //停止标志 Q7zpu/5?  
File tmpFile; //文件下载的临时信息 N3)n**  
DataOutputStream output; //输出到文件的输出流 d|gfp:Z`a  
8X? EB6=c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oOLj? 0t  
public SiteFileFetch(SiteInfoBean bean) throws IOException [T3%Xt'4  
{ X-CoC   
siteInfoBean = bean; |NTqJ j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8"[{[<-   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "ChJR[4@  
if(tmpFile.exists ()) lQRtsmZ0  
{ w}97`.Kt!n  
bFirst = false; D)[(  
read_nPos(); yr.sfPnJK  
} y34<B)Wy  
else 5]kv1nQ  
{ }dU!PZ9N)  
nStartPos = new long[bean.getNSplitter()]; 4,=;:#n,J  
nEndPos = new long[bean.getNSplitter()]; =<TJ[,h et  
} VTX6_&Hc1g  
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} #7YJ87<E  
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public void run() m*lcIa  
{ yI-EF)A@;  
//获得文件长度 oykb8~u}}  
//分割文件 5CfD/}{:#I  
//实例FileSplitterFetch W]>%*n  
//启动FileSplitterFetch线程 iJKGzHvS  
//等待子线程返回 UQP>yuSx  
try{ D mky!Cp
 
if(bFirst) y M-k]_  
{ P*ZMbAf.  
nFileLength = getFileSize(); =L?2[a$2;  
if(nFileLength == -1) ^oE#;aS  
{ u2[L^]|  
System.err.println("File Length is not known!"); d+ [2Sm(7  
} ZC^NhgX  
else if(nFileLength == -2) uA t{WDHm  
{ _ib @<%  
System.err.println("File is not access!"); e)XnS'  
} iG=Di)O  
else }{&;\^i  
{ CHCT e  
for(int i=0;i<nStartPos.length;i++) [;~"ctf{  
{ nuA 0%K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F]0 qt$GO  
} o?IrDQ2gmh  
for(int i=0;i<nEndPos.length-1;i++) .Ep&O#  
{ s+=':Gcb(C  
nEndPos = nStartPos[i+1]; p3T:Y_  
} rJRg4Rog  
nEndPos[nEndPos.length-1] = nFileLength; ##alzC  
} /?S^#q>m%  
} xm=$D6O:  
& Yx12B\  
}iUpBn  
//启动子线程 _lm^v%J$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zdfh*MHMg  
for(int i=0;i<nStartPos.length;i++) B;piO-hH  
{ =NNxe"Kd;U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3kwkU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W|s";EAM  
nStartPos,nEndPos,i); OpK_?XG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NnU`u.$D  
fileSplitterFetch.start(); vWa\8yf  
} h 'Hnq m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <zAYq=IU  
nEndPos = " + nFileLength); ip1gCH/?_+  
// fileSplitterFetch[nPos.length-1].start(); N8J(RR9O  
S a
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//等待子线程结束 @*|T(068&  
//int count = 0; UG}2q:ST  
//是否结束while循环 P^<to(|  
boolean breakWhile = false; D`KaIqLz  
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f=S2O_Ee  
while(!bStop) Imq-5To#  
{ T{yJL<  
write_nPos(); VC%.u.< F  
Utility.sleep(500); $3%+N|L  
breakWhile = true; hMV>5Y[s  
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| :i
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for(int i=0;i<nStartPos.length;i++) ,g,Hb\_R)  
{ Vobq|Rd/%  
if(!fileSplitterFetch.bDownOver) i` ay9J8N  
{ ,@Kn@%?$  
breakWhile = false; Hk(=_[S  
break; 2Vw2r@S/  
} 'G>9iw  
} g=
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if(breakWhile) qOnGP{   
break; TNK1E  
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//count++; eg1F[~YL/  
//if(count>4) BL"7_phM,  
// siteStop(); @X560_x[q  
} JO90TP $  
k1s5cg=n(  
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System.err.println("文件下载结束！"); :M<] 6o  
} >VX'`5r>uw  
catch(Exception e){e.printStackTrace ();} ZE~zs~z|  
} GQQp(%T  
:F@goiuC  
A r>BL2@  
//获得文件长度 UP%6s:>:  
public long getFileSize() "^;h'  
{ .0~uM!3y  
int nFileLength = -1; ]]3rSXs2}J  
try{ j]vEo~Bbh  
URL url = new URL(siteInfoBean.getSSiteURL()); Nd{U|k3pL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j2.7b1s  
httpConnection.setRequestProperty("User-Agent","NetFox"); S kB*w'k  
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int responseCode=httpConnection.getResponseCode(); ik;F@kdm`  
if(responseCode>=400) Chx+p&!  
{ N]6t)Zv  
processErrorCode(responseCode); fGRV]6?V  
return -2; //-2 represent access is error 4"\cA:
9a  
} .aVtd [  
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String sHeader; G#^0Bh&  
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for(int i=1;;i++) xgpf2y!{  
{ Dg{d^>T!_x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N^@:+,<3  
//Utility.log(in.readLine()); ;[(d=6{hc]  
sHeader=httpConnection.getHeaderFieldKey(i); het<#3Bo  
if(sHeader!=null) J_-fs#[x  
{ {IaDZ/XS6  
if(sHeader.equals("Content-Length")) '3WtpsKA  
{ ^w2 HF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n;Q8Gg2U  
break; \iP@|ay9  
} Ym!e}`A\F  
} HEIg_6sb  
else Xtz:^tg  
break; \g h |G  
} _L$a[zH  
} QCE7VV1Rw  
catch(IOException e){e.printStackTrace ();} 0Oc?:R'$  
catch(Exception e){e.printStackTrace ();} 5b*kn
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Utility.log(nFileLength); TsGx2[  
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return nFileLength; u*rP8GuS  
} '[%#70*  
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//保存下载信息（文件指针位置） 6Io}3}3  
private void write_nPos() L/`1K_\l  
{ w D r/T3  
try{ :zLf~W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T<?kH  
output.writeInt(nStartPos.length); FO:L+&hr?>  
for(int i=0;i<nStartPos.length;i++) &}
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{ =!xX{o?64  
// output.writeLong(nPos); D&D6!jz  
output.writeLong(fileSplitterFetch.nStartPos); "QiR  
output.writeLong(fileSplitterFetch.nEndPos); PPIO<K 3`  
} $?bD55  
output.close(); kLZVTVSJt  
} ]+W){W=ai  
catch(IOException e){e.printStackTrace ();} V K 7  
catch(Exception e){e.printStackTrace ();} ,w H~.LHi  
} F P|cA^$<  
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//读取保存的下载信息（文件指针位置） [H>u'fy:C  
private void read_nPos() 3?I!  
{ FiUwy/,ZV  
try{ "QxULiw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \y]K]iv  
int nCount = input.readInt(); n$r`s`}  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; >RAg63!`  
for(int i=0;i<nStartPos.length;i++) 4n7Kz_!SVf  
{ ,_Bn{T=U  
nStartPos = input.readLong(); NR1M W^R  
nEndPos = input.readLong(); 3Z=yCec]  
} ;p`to"6IFD  
input.close(); ~uty<fP  
} QOS
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catch(IOException e){e.printStackTrace ();} P=jsOuW  
catch(Exception e){e.printStackTrace ();} jYRSV7d  
} nW7: ]  
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private void processErrorCode(int nErrorCode) K4<"XF1A:  
{ 9n{Y6I x:  
System.err.println("Error Code : " + nErrorCode); dX@ic,?  
} ;M4[Liw~O  
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//停止文件下载 %\HPYnIe  
public void siteStop() 8Sj<,+XFq  
{ wGKxT ap  
bStop = true; <TtPwUX  
for(int i=0;i<nStartPos.length;i++) a
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fileSplitterFetch.splitterStop(); qpYgTn8l7  
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4=Ru{ewRV  
} xL"J?Gy  
}
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//负责部分文件的抓取 ;'8P/a$  
**FileSplitterFetch.java d\]KG(T  
*/ %bN{FKNN  
package NetFox; LkS tU)  
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import java.io.*;
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import java.net.*; Jcze.t  
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/  
public class FileSplitterFetch extends Thread { VPYLDg.'  
*m+FMyr  
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String sURL; //File URL Yz_}*  
long nStartPos; //File Snippet Start Position KYm8|]'g  
long nEndPos; //File Snippet End Position s0f+AS|}  
int nThreadID; //Thread's ID )__sw  
boolean bDownOver = false; //Downing is over -6kX?sNl)X  
boolean bStop = false; //Stop identical D5P-$1KPt  
FileAccessI fileAccessI = null; //File Access interface Kgr<OL}VJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException } u;{38~  
{ oOpEpQ}}q  
this.sURL = sURL; lt6wmCe  
this.nStartPos = nStart; ue@/o,C>  
this.nEndPos = nEnd; 9S@x  
nThreadID = id; scH61Y8`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /g{*px|  
} ="& GU%$  
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public void run() K $- *  
{ IeYNTk&<  
while(nStartPos < nEndPos && !bStop) e&VC}%m  
{ zl:by?  
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try{ M> WWP3  
URL url = new URL(sURL); z.-yL,Rc`-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |w|c!;,  
httpConnection.setRequestProperty("User-Agent","NetFox"); |> STb\  
String sProperty = "bytes="+nStartPos+"-"; 94#,dA,M  
httpConnection.setRequestProperty("RANGE",sProperty); ~F'6k&A^q  
Utility.log(sProperty); !\R5/-_UU  
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InputStream input = httpConnection.getInputStream(); $J4\jIipL  
//logResponseHead(httpConnection); by @qg:  
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byte[] b = new byte[1024]; k37?NoT  
int nRead; p]RQ-0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &SbdX  
{ ';FJ
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nStartPos += fileAccessI.write(b,0,nRead); G|Et'k.F4  
//if(nThreadID == 1) u.X]K:Yow  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [E a{);  
} u>lt}0  
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Utility.log("Thread " + nThreadID + " is over!"); h6D4CT  
bDownOver = true; )mm0PJF~q  
//nPos = fileAccessI.write (b,0,nRead); yor'"6)i  
} MQwxQ{  
catch(Exception e){e.printStackTrace ();} }qECpKa0  
} zBy} >Jx  
} .yy*[56X  
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//打印回应的头信息 \HLo%]A@M  
public void logResponseHead(HttpURLConnection con) {UP[iw$~  
{ ; oa+Z:;f  
for(int i=1;;i++) h^=;
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{ Ak@!F6~  
String header=con.getHeaderFieldKey(i); zJw5+ +  
if(header!=null) pmB {b  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  aO<7a 6  
Utility.log(header+" : "+con.getHeaderField(header)); hc q&`Gun  
else %oa@2qJ^  
break; WBWW7
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} ]?=87w  
} ,1mL=|na  
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public void splitterStop() $f3IO#N  
{ <)T| HKx  
bStop = true; ?3BcjD0  
} >(a35 b$  
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} w~6UOA8}  
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/* >IaGa!4  
**FileAccess.java oI
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*//文件访问(定位，写) 4aOz=/x2  
package NetFox; !2!Zhw2u  
import java.io.*; *`+zf7-f  
`qhT  
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public class FileAccessI implements Serializable{ 2@tnOs(*  
9k;,WU(K<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aU(.LC  
RandomAccessFile oSavedFile; !rRBy3&  
long nPos; z9S (<  
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7/~=[#]*  
public FileAccessI() throws IOException iG54 +]  
{ KUU{X~w  
this("",0); =O
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} }lp37,
 
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public FileAccessI(String sName,long nPos) throws IOException I;'{X_9$a  
{ Nt$4;  
oSavedFile = new RandomAccessFile(sName,"rw"); ]YI9  
this.nPos = nPos;
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oSavedFile.seek(nPos); 0
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} WCsf_1  
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public synchronized int write(byte[] b,int nStart,int nLen) ^o5;><S]  
{ rB".!b  
int n = -1; 1+*sEIC"  
try{ 5/nL[4Z  
oSavedFile.write(b,nStart,nLen); 2ul8]=  
n = nLen; sA?8i:]O:  
} iKo2bC:.&  
catch(IOException e) iz-z?)%  
{ q~9-A+n  
e.printStackTrace (); 
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} imif[n+]}d  
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return n; EFC+7L(j  
} Ni>Ns=n  

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} a,oTU\m C  
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/* Sa<(F[p`  
**SiteInfoBean.java 1?&|V1
vc  
*/ eXKEx4rU  
package NetFox; ;&=jSgr8  
SN@>mpcJS  
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public class SiteInfoBean { 1J9p1_d5  
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private String sSiteURL; //Site's URL X:s~w#>R  
private String sFilePath; //Saved File's Path OD~Q|I(j  
private String sFileName; //Saved File's Name t4UK~ {gh  
private int nSplitter; //Count of Splited Downloading File HY5R  
}o:LwxNO  
"mBM<rEn*  
public SiteInfoBean() (UkDww_!  
{//nSplitter的缺省值为5 hiVa\s  
//default value of nSplitter is 5 ({rcH.:  
this("","","",5); ]^"Lc~w8&  
} }Ecv6&G  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w?_8OJ  
{ w
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sSiteURL= sURL; \r:*`Z*y  
sFilePath = sPath; GkU_01C  
sFileName = sName; !$l<'K$  
this.nSplitter = nSpiltter; Brxnl,%\  
5!A:xV]6]  
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} /#vt\I<x  
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public String getSSiteURL() BGi'UL,  
{ p7> 9 m  
return sSiteURL; % WDTnEm  
} .iR<5.  
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2 )o2d^^  
public void setSSiteURL(String value) Ut2T:%m{  
{ qZ!kVrmg&  
sSiteURL = value; ykbfK$jz  
} T&[6  
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public String getSFilePath() TXM/+
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{ H^kOwmSzh  
return sFilePath; O$,
 
} X[h{g`  
})] iN"  
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public void setSFilePath(String value) g8E5"jpXx3  
{ a^LckHPI>  
sFilePath = value; ZB1%Kn#zo4  
} (5]
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public String getSFileName() =XQGg`8<LB  
{ j_,/U^Ws|f  
return sFileName; .X3n9]  
} =_=%1rI~  
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public void setSFileName(String value) l4T[x|')M  
{ `#iL'ND[  
sFileName = value; `=p
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} rNhS\1-  
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[|  
public int getNSplitter() sHPAr}14  
{ GmNCw5F  
return nSplitter; e~gNGr]L/  
} ^`#7(S)a/  
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public void setNSplitter(int nCount) ;iYCeL(  
{ .BxQF  
nSplitter = nCount; 6, j60`f)  
}  kVZs:  
} 3c#^@Bj(-e  
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/* f{2UL ?y  
**Utility.java +a,#
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*/ #QsJr_=  
package NetFox; u
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public class Utility { yz0#0YG7  
g]h@U&`~u_  
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public Utility() E8PwA.  
{ *MfH\X379  
'wFhfZB1!B  
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} I/upiqy  
k;<@2C  
//线程睡眠 OH`zeI,[*  
public static void sleep(int nSecond) RLex#j  
{ !W,LG$=/  
try{ -wH0g^Ed  
Thread.sleep(nSecond); R#Yj%$E1  
} E4\HI+  
catch(Exception e) lGK7XAx,  
{ ,)U%6=o#}  
e.printStackTrace (); eQyc<  
} SN")u  
} ^& *;]S`  
*GYLj
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//日志 "D>/#cY1/  
public static void log(String sMsg) S=kO9"RB]  
{ WF~x`w&\  
System.err.println(sMsg); f uU"  
} r
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public static void log(int sMsg) D&K9!z"]  
{ nF]E":  
System.err.println(sMsg); %OHWGac"i  
} c1i[1x%
  
} ?z|Bf@TJ[+  
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/* <]z4;~/&  
**TestMethod.java IC"ktv bHz  
*/ 2h<_?GM\s  
package NetFox; si~zg\uY  
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public class TestMethod { (gE<`b  
6b2h\+AP  
^o>WCU=  
public TestMethod() OXZK|C;M}  
{ ///xx/weblogic60b2_win.exe *C|*{!  
try{ 90F.9rh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /Dc54Un  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `=V1w4J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S
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fileFetch.start(); G3!O@j!7w$  
} F@ pf._c  
catch(Exception e){e.printStackTrace ();} DfGq m-c  
oP
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!]7b31$M_  
} t{s>B]i^_w  
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public static void main(String[] args) ]X7_ji(l,  
{ .i?{h/9y  
new TestMethod(); N&G(`]  
} (6H7?nv  
} P!j*4t  
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