http断点续传简单实现（java)

/* S]9:3~  
**SiteFileFetch.java :I F&W=?9  
*/ Gc4N)oq)}b  
package NetFox; =@binTC4  
import java.io.*; sG0cN;I]t  
import java.net.*; 9 o-T#~i  
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public class SiteFileFetch extends Thread { =9
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SiteInfoBean siteInfoBean = null; //文件信息Bean (bH"x  
long[] nStartPos; //开始位置 2j4VW0:  
long[] nEndPos; //结束位置 X||oiqbY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {;Mcor3  
long nFileLength; //文件长度 .+ai dWd  
boolean bFirst = true; //是否第一次取文件 1<<`T%&  
boolean bStop = false; //停止标志 /Rx%}~x/m  
File tmpFile; //文件下载的临时信息 cpFw]w%]  
DataOutputStream output; //输出到文件的输出流 kdQ=%  
-C
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o,D>7|h  
public SiteFileFetch(SiteInfoBean bean) throws IOException {^"c>'R  
{ 0O
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siteInfoBean = bean; )`-9WCd&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A7+eWg{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r&1N8o  
if(tmpFile.exists ()) e@Z(z^V  
{ 6N
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bFirst = false; yXppu[=  
read_nPos();
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} %=S^{
A  
else rA8neO)  
{ = Yh>5A  
nStartPos = new long[bean.getNSplitter()]; ^z9ITGB~tV  
nEndPos = new long[bean.getNSplitter()]; m{_\@'q  
} vay_QxB5  
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} 8T
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public void run() lp!@uoN^T  
{ kIrME:  
//获得文件长度 ut& RKr3  
//分割文件 +S^Uw'L$=T  
//实例FileSplitterFetch zg)Z2?K|;u  
//启动FileSplitterFetch线程 t \DS}3pv  
//等待子线程返回 V2i*PK X  
try{ U,[vfSDGr  
if(bFirst) rbO9NRg>  
{ 9"=:\PE  
nFileLength = getFileSize(); B\KvKT|\  
if(nFileLength == -1) , YTuZS  
{ `Kpn@Xg
 
System.err.println("File Length is not known!"); o`M7:8G  
} Xy_+L_h^  
else if(nFileLength == -2) Z7K;~*  
{  #XQEfa  
System.err.println("File is not access!"); C[& \Xq  
} ,hT t]w  
else KNQX\-=  
{ b0PF7PEEQ  
for(int i=0;i<nStartPos.length;i++) QI=",vmau  
{ SD8Q_[rY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V. =!^0'A  
} BNQ~O^R0  
for(int i=0;i<nEndPos.length-1;i++) &=<x&4H+  
{ :f 1*-y  
nEndPos = nStartPos[i+1]; IObGmc  
} QC \8Zy  
nEndPos[nEndPos.length-1] = nFileLength; !RFl
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} ,K+K`"Oy  
} 8nt:peJ$+  
3"6lPUS  
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//启动子线程 ,Tvk&<!0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \n6#D7OV  
for(int i=0;i<nStartPos.length;i++) TW{.qed8^  
{ BV9B}IV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \P
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eqZ V/a  
nStartPos,nEndPos,i); :nCGqg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xl5mI~n_~  
fileSplitterFetch.start(); +]Po!bN@@  
} ht!o_0{~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a+uSCs[C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ",w@_}z:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^UEI`_HO0  
nEndPos = " + nFileLength); t}c ymX
~  
// fileSplitterFetch[nPos.length-1].start(); BCJo/m  
fp.,MIS  
rNO'0Ck=
 
//等待子线程结束 V~+Oil6sa  
//int count = 0; Q\<C9%a  
//是否结束while循环 ,gUSW  
boolean breakWhile = false; &UEr4RK;I  
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while(!bStop) i`z1if6O  
{ ?y>P  
write_nPos(); vYKKv%LE  
Utility.sleep(500); Urm&4&y  
breakWhile = true; [v^T]L  
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for(int i=0;i<nStartPos.length;i++) K;k_MA310  
{ /$|
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if(!fileSplitterFetch.bDownOver) 4;<?ec(dc  
{ W.r0W2))(  
breakWhile = false; <ZSH1~<{6  
break; V\W?@V9g-  
} x{*g^f  
} kl?U2A.=  
if(breakWhile) re2M!m6k5  
break; 4`I2tr  
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fFMGpibkM  
//count++; -Ds}kdxw  
//if(count>4) ['~3"lK^O  
// siteStop(); }TzMWdT  
} .__XOd}K  
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IL}  
)D{L<.i_  
System.err.println("文件下载结束！"); b^~ keQ  
} A5S9F8Q/]  
catch(Exception e){e.printStackTrace ();} 1p[C5j3  
} 64%P}On  
` .|JTm[  
[a:yKJ[  
//获得文件长度 ,|D_? D)U  
public long getFileSize() 5Ev9u),D+v  
{ ]JVs/  
int nFileLength = -1; t3|If@T  
try{ k@L},Td  
URL url = new URL(siteInfoBean.getSSiteURL()); ~Z9Eb|B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lr'h  
httpConnection.setRequestProperty("User-Agent","NetFox"); !8lG"l|,l  
"1FPe63\*O  
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int responseCode=httpConnection.getResponseCode(); |`+kZ-M*  
if(responseCode>=400) ]v(8i3P84  
{ Jz&a9  
processErrorCode(responseCode); Cc/h|4  
return -2; //-2 represent access is error ,m;S-Im_Xr  
} Jr$,w7tQn@  
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String sHeader; L.ScC  
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for(int i=1;;i++) 
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{ d[E~}Dq3#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N[~{'i  
//Utility.log(in.readLine()); Xb?:dlu3  
sHeader=httpConnection.getHeaderFieldKey(i); {; #u~e(W  
if(sHeader!=null) H=Scrvfx  
{ }{T9`^V:h  
if(sHeader.equals("Content-Length")) )hs"P%Zg  
{ ;\ ^'}S|3Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dk8 O*B
 
break; eG&\b-%  
} d3-F?i 5d  
} 2l]*><q|  
else t5t,(^;f  
break; 3*)<Y}Tc  
} w^OV;gp  
} R[KF${X4  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} jBZlNEw  
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Utility.log(nFileLength); > %h7)}U  
% `Q
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return nFileLength; iO1ir+B\  
} Z6s-n$dSm  
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//保存下载信息（文件指针位置） ~puXZCatN  
private void write_nPos() b3R1L|@  
{ 7k,pUC-w7c  
try{ ,;;7+|`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NwAvxN<R(f  
output.writeInt(nStartPos.length); <;Q1u,Mc  
for(int i=0;i<nStartPos.length;i++) @Wgd(Ezd  
{ DJ_[{WAV  
// output.writeLong(nPos); wcr3ugvT  
output.writeLong(fileSplitterFetch.nStartPos); s
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output.writeLong(fileSplitterFetch.nEndPos); eS#kDa/ %  
} 5Ku=Xzvq  
output.close(); x}\x3U  
} O[}{$NXw  
catch(IOException e){e.printStackTrace ();} {1?94rz  
catch(Exception e){e.printStackTrace ();} U*sjv6*T  
} LGnb"ZN  
)/HbmtXqI  
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//读取保存的下载信息（文件指针位置） [|iWLPO1&k  
private void read_nPos() +85#`{ D  
{ y7CC5S?  
try{ 5k:SD7^b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o\/&05rp]  
int nCount = input.readInt();  NOY`1i  
nStartPos = new long[nCount]; k=]#)A(#C  
nEndPos = new long[nCount]; {!RDb'Zp  
for(int i=0;i<nStartPos.length;i++) f3yH4r?;w  
{ U ?iw  
nStartPos = input.readLong(); %MG{KG=&o  
nEndPos = input.readLong(); E_q/*}]pE  
} L hp  
input.close(); jej.!f:H  
} ~[8n+p+&X  
catch(IOException e){e.printStackTrace ();} rR Kbs@1M  
catch(Exception e){e.printStackTrace ();} q+iG:B/Z  
} %G0J]QY{(x  
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private void processErrorCode(int nErrorCode) Vz.G!*>Dg  
{ _V2^0CZ  
System.err.println("Error Code : " + nErrorCode); Eep~3U  
} %x'}aTa  
m:}PVJ-"  
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//停止文件下载 mM9aT0_w  
public void siteStop() \;XDPC j  
{ VSx9aVPkC  
bStop = true; [T |P|\M  
for(int i=0;i<nStartPos.length;i++) N5PW]  
fileSplitterFetch.splitterStop(); J#.f%V
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} ^VC/tJ  
}
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//负责部分文件的抓取 }Q2v~eD  
**FileSplitterFetch.java 7xF)\um  
*/ ]?< wUd  
package NetFox; U g:  
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import java.io.*; FR9w0{o  
import java.net.*; HNJR&U t  
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public class FileSplitterFetch extends Thread { Z";&1cK  
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String sURL; //File URL OV G|WC  
long nStartPos; //File Snippet Start Position ^4b;rLfk@  
long nEndPos; //File Snippet End Position Iuyq!R4:7  
int nThreadID; //Thread's ID ZUyS+60  
boolean bDownOver = false; //Downing is over m?<^b_a}  
boolean bStop = false; //Stop identical ~8 B]  
FileAccessI fileAccessI = null; //File Access interface f+cN'jH E  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]'NL-8x">  
{ nt&"? /s  
this.sURL = sURL; 57fl<IM  
this.nStartPos = nStart; 4wMZNa<S
x  
this.nEndPos = nEnd; y Nc@K|  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 aD(3.=[R  
} t$Bu<frQ  
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public void run() /[=Yv!  
{ Za
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while(nStartPos < nEndPos && !bStop) qzj.N$9]  
{ +v2)'?BS  
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HA J[Y3d<  
try{ sYq:2Wn>8Q  
URL url = new URL(sURL); yV~TfTJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A`--*$8\  
httpConnection.setRequestProperty("User-Agent","NetFox"); +CVB[r#hu  
String sProperty = "bytes="+nStartPos+"-"; M}! qH.W  
httpConnection.setRequestProperty("RANGE",sProperty); Z0/$XS9|h;  
Utility.log(sProperty); |KR8=-!7  
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~.tl7wKkR/  
InputStream input = httpConnection.getInputStream(); \.aKxj5
  
//logResponseHead(httpConnection); 0HO'%'Ga*  
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byte[] b = new byte[1024]; <NEz{1Z  
int nRead; =@nE:uto]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5DpvMhc_  
{ J-|&[-Z  
nStartPos += fileAccessI.write(b,0,nRead); 4@+
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//if(nThreadID == 1) Q>q-6/|UX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R XCjYzt  
} ?I8r2M]  
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Utility.log("Thread " + nThreadID + " is over!"); }rvX}   
bDownOver = true; gg/ts]$  
//nPos = fileAccessI.write (b,0,nRead); V'tqsKQ
!  
} EKD#s,(V*X  
catch(Exception e){e.printStackTrace ();} !F:mDZeY  
} A^E 6)A=  
} r#A*{4wz  
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//打印回应的头信息 -e_
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public void logResponseHead(HttpURLConnection con) ]h#QA;  
{ id588
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for(int i=1;;i++) fP[S.7F+No  
{ '`YZJ  
String header=con.getHeaderFieldKey(i); k*u6'IKi.4  
if(header!=null) joDqv,iW8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &"?99E>  
Utility.log(header+" : "+con.getHeaderField(header)); Dpwqg3,  
else M}j[{wW3  
break; Q_Br{ `c  
} s3T7M:DM4  
} <$@I*xk[  
,N_/J4Us  
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public void splitterStop() J0 dY%pH#  
{ Vo6+|ztk|  
bStop = true; vsyg u  
} n=PfV3B  
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} 1l/t|M^I  
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/* 8{]nS8i  
**FileAccess.java @ze2'56F}  
*//文件访问(定位，写) Q lA?dXQ  
package NetFox; 5HsF#  
import java.io.*; J>k 6`gw  
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public class FileAccessI implements Serializable{ , O/IY  
:5['V#(o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u;]xAr1  
RandomAccessFile oSavedFile; `a:3S@n(}  
long nPos; k$ T  
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public FileAccessI() throws IOException qo$ls\[X  
{ yoJ.[M4q  
this("",0); `|Hk+V  
} '!ks $}$`h  
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public FileAccessI(String sName,long nPos) throws IOException SB08-G2  
{ o<iU;15  
oSavedFile = new RandomAccessFile(sName,"rw");
1<fW .Q)  
this.nPos = nPos; *sZH3:  
oSavedFile.seek(nPos); 6-uLK'E  
} -%]1q#C>@  
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public synchronized int write(byte[] b,int nStart,int nLen) \@yJbhk  
{ {;E
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int n = -1; A^p{Cq@E  
try{ 9gdK&/ulR  
oSavedFile.write(b,nStart,nLen); (X Oz0.W  
n = nLen; UlXxG|  
} >d=pl}-kOQ  
catch(IOException e) _9t1aP5  
{ XXhN;-p  
e.printStackTrace ();
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} _'ebXrbZB  
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return n; ~,ozhj0f/  
} Rzh.zvxTp  
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} Z\Ur F0  
 T&MhSJf#  
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/* @&EIH,c  
**SiteInfoBean.java ,Pcg+^A  
*/ [FrLxU  
package NetFox; czU"  
V2`Ud[  
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public class SiteInfoBean { Z]R#F0"U  
}% q-9  
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private String sSiteURL; //Site's URL cV0CI&  
private String sFilePath; //Saved File's Path ,c^nW  
private String sFileName; //Saved File's Name "OK[uug  
private int nSplitter; //Count of Splited Downloading File ypG*41  
1AN$s  
ppNMXbXR  
public SiteInfoBean() NN=^4Xpc:  
{//nSplitter的缺省值为5 z'$1$~I  
//default value of nSplitter is 5 qbeUc5`1  
this("","","",5); p%&$%yz$  
} aA52Li
  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (YYg-@IO  
{
GVJ||0D  
sSiteURL= sURL; ;Su-Y!&%  
sFilePath = sPath; W[*xr{0V  
sFileName = sName; H\a"=&M  
this.nSplitter = nSpiltter; [2Zy~`*y{  
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} S} OO)  
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public String getSSiteURL() Dqii60  
{ |u^S}"@3sU  
return sSiteURL; 5|*`} ;/y  
} N'9T*&o+  
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<\<o#Vq  
public void setSSiteURL(String value) C$PS@4'U  
{ 'UWkJ2:!  
sSiteURL = value; {9}CU~R  
} '!`\!=j-`  
(^y"'B  
OVDuF&0  
public String getSFilePath() oV0 45G  
{ &=jPt%7#M  
return sFilePath; 6Q

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} >FwK_Zd'  
|r Aot2  
Sk>=C0f:  
public void setSFilePath(String value) !pw)sO~  
{ Vi-Ph;6[  
sFilePath = value; f+uyO7  
} +"<+JRI(M5  
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F[Mwd &P@  
public String getSFileName() fxPg"R!1i  
{ gAdqZJR%]  
return sFileName; f%@~|:G:  
} =dDPQZEin  
`sT;\  
,P`NtTN-  
public void setSFileName(String value)
/
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{ ?@$xLUHR4  
sFileName = value; .cQO?UKK  
} Wy7w zt  
G/Sp/I<d  
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public int getNSplitter()  XyE$0i~t  
{ ^ZQMRNP{r  
return nSplitter; *}lLV.+A  
} [QgP6f]=  
}#H,oy;Dz  
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public void setNSplitter(int nCount) 8CZfz!2  
{ O;<wDh)Yt  
nSplitter = nCount; M['O`^  
} 77O$^fG2  
} [m0X kvd  
3< ?+Yhq  
>bf.T7wy  
/* mW%8`$rVEO  
**Utility.java F6[F~^9D  
*/ uW!XzX['  
package NetFox; zFExYYd   
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public class Utility { n>q!m@ }<  
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public Utility() Tt)z[^)%  
{ 0<\|D^m=&h  
R#4l"  
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} OA3J(4!"W  
;F"!$Z/  
//线程睡眠 MIIl+   
public static void sleep(int nSecond) y ;[~(Yg[  
{ js81@WX!c  
try{ H u;"TG  
Thread.sleep(nSecond); G9Uc }z  
} Z\CvaX  
catch(Exception e) BeVDTk:  
{ <C'_:&M  
e.printStackTrace (); /"gRyv  
}  80@\e  
} Bgm8IK)6  
a(A~S u97  
//日志 /\/^= j  
public static void log(String sMsg) O0qG 6a  
{ [G|.  
System.err.println(sMsg); ``WTg4C(Y  
} '2r  
<x^$Fu
 
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public static void log(int sMsg) sq_>^z3T  
{ c]|vg=W  
System.err.println(sMsg); n;Oe-+oSC  
} 5Z!$?J4Rl  
} nd8<*ru$  
)_jboaNzwI  
_:m70%i  
/* FQ<x(&/NF  
**TestMethod.java _Rii19k  
*/
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package NetFox; OOSf<I*>  
7y|U!r"Y  
D j9aTO  
public class TestMethod { 7@;*e=v  
3k)xzv%r`  
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public TestMethod() _h-agn4[i  
{ ///xx/weblogic60b2_win.exe 3<r7"/5  
try{ ,IPt4EH$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;\0|1Eem`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vTK%8qoZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k2D*`\ D  
fileFetch.start(); tw$EwNI[  
} J=3{<Xl  
catch(Exception e){e.printStackTrace ();} 4P3RRS  
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~DK.Y   
} x *I'Ar  
0(y*EJA$  
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public static void main(String[] args) V|'@D#\  
{ "mJo<i}  
new TestMethod(); \|Af26  
} .z,-ThTH@\  
} ElW\;C:K*  
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