http断点续传简单实现（java)

/* )CdglPK  
**SiteFileFetch.java LUo3y'  
*/ rIge6A>I  
package NetFox; ej
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import java.io.*; #wM0p:<  
import java.net.*; ~Zaxn~u:  
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public class SiteFileFetch extends Thread { [mWo&Ph[-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e>z7?"N  
long[] nStartPos; //开始位置 8
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long[] nEndPos; //结束位置 \=yg@K?"AJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ubn5tN MK  
long nFileLength; //文件长度 6Mk@,\1  
boolean bFirst = true; //是否第一次取文件 C(,s_Ks  
boolean bStop = false; //停止标志 g4Hq<W"  
File tmpFile; //文件下载的临时信息 TF=S \ Q  
DataOutputStream output; //输出到文件的输出流 )b!q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wc__g8?'  
public SiteFileFetch(SiteInfoBean bean) throws IOException 31b-r[B{%  
{ 4vBbP;ELWq  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oTx#e[8f{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ARU
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if(tmpFile.exists ()) mDV 2vg  
{ 89 fT?tT  
bFirst = false; *Z/B\nb  
read_nPos(); SxH}/I|W  
} ,#WXAAmm  
else 3
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{ !%@n067  
nStartPos = new long[bean.getNSplitter()]; zNXkdw  
nEndPos = new long[bean.getNSplitter()]; 3`e1:`Hu  
} IRS^F;
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} ~Kb(
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public void run() :'!?dszS  
{ cL1cBWd  
//获得文件长度 7<1Y%|x`  
//分割文件 4]dPhsey  
//实例FileSplitterFetch m CdkYN#  
//启动FileSplitterFetch线程 E&K8hY%5  
//等待子线程返回 fp>o ^+VB  
try{ hF2 G{{8A  
if(bFirst) =lDmP|^  
{ TR%?U/_4;r  
nFileLength = getFileSize(); | c8u  
if(nFileLength == -1) CyXcA;H,.  
{ ^WD[>E~  
System.err.println("File Length is not known!"); mU\$piei  
} r%B5@+{so  
else if(nFileLength == -2) uP*>-s'm  
{ "?S#vUS+ 2  
System.err.println("File is not access!"); fO(.I  
} pxY5S}@  
else =_,OucKkYG  
{ 1MV^~I8Dd  
for(int i=0;i<nStartPos.length;i++) G3OQbqn  
{ 9X*q^u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ix$+NM<n  
} Jp,ohVRNq  
for(int i=0;i<nEndPos.length-1;i++) `\.n_nM  
{ 0`qq"j[6a  
nEndPos = nStartPos[i+1]; P4N{lQ.>  
} !.w S+  
nEndPos[nEndPos.length-1] = nFileLength; _@RW7iP>  
} cdGl[dQ/  
} ]kKsGch  
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//启动子线程 MBwp{ET!p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x208^=F\\  
for(int i=0;i<nStartPos.length;i++) |owhF  
{ (h%wO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `iY)3Rq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RdY#B;  
nStartPos,nEndPos,i); j5HOdy2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RI%l& Hm  
fileSplitterFetch.start(); SZ1C38bd,.  
} >i ~zG6H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y}WO`+Vf5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Lh,<q >t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Jq; }q63:  
nEndPos = " + nFileLength); Em?skUnG,  
// fileSplitterFetch[nPos.length-1].start(); /JfXK$`  
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>:Oo[{)  
//等待子线程结束 I7Eg$J&  
//int count = 0; M1g|m|H7  
//是否结束while循环 '"KK|]vJ  
boolean breakWhile = false; P]x@h  
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while(!bStop) x*)Wl!  
{ |0bSxPXn!  
write_nPos(); xGH%4J\  
Utility.sleep(500); 3NJH"amk  
breakWhile = true; ^wHO!$  
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for(int i=0;i<nStartPos.length;i++) EfUo<E  
{ Aqc(  
if(!fileSplitterFetch.bDownOver) 6D+k[oHZm  
{ # K-Q/*  
breakWhile = false; hQ\]vp7V  
break; /2U.,vw  
} !eO?75/  
} 
);*GOLka  
if(breakWhile) D0-e,)G}V,  
break; . =+7H`A  
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//count++;
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//if(count>4) VEn%_9(]  
// siteStop(); 1|]-F;b  
} un/R7"  
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System.err.println("文件下载结束！"); K~E]Fkw!;  
} Ue\&  
catch(Exception e){e.printStackTrace ();} 2V0R|YUt  
} f[v??^  
nOB ]?{X  
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//获得文件长度 Jv?e?U  
public long getFileSize() I2Us!W>6-  
{ }s|v-gRM{  
int nFileLength = -1; &]M<G)9  
try{ R5FjJ>JE  
URL url = new URL(siteInfoBean.getSSiteURL()); mB,7YZv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X >**M  
httpConnection.setRequestProperty("User-Agent","NetFox"); {
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7

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int responseCode=httpConnection.getResponseCode(); ,yT4(cMBk?  
if(responseCode>=400) jgYiuM3c\  
{ $@NZ*m%?JQ  
processErrorCode(responseCode); r({(;  
return -2; //-2 represent access is error *kIJv?%_}  
} C$hsR&  
<FJ#Hy+  
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String sHeader; vS0P]AUo  
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for(int i=1;;i++) _Nj;Ni2rD  
{ f(C0&"4e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h>n;A>k@N  
//Utility.log(in.readLine()); }Yt0VtL
t  
sHeader=httpConnection.getHeaderFieldKey(i); v3/cNd3  
if(sHeader!=null) QO k%Q$^G  
{ B;@yOm=  
if(sHeader.equals("Content-Length")) 5M(?_qj  
{ FxUH?%w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SAoqq  
break; ^\CQWgY(  
} (&B
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} |fA[s7)  
else MHbRG_zW  
break; Rl)/[T  
} <E^:{J95  
} x?%vqg^r  
catch(IOException e){e.printStackTrace ();} tsk}]@W  
catch(Exception e){e.printStackTrace ();} RsY<j& f  
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Utility.log(nFileLength); |9Y9pked8  
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return nFileLength; XI0O^[/n{  
} X3"V1@-i4$  
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//保存下载信息（文件指针位置） |hpm|eZG"h  
private void write_nPos() NBeGmC|  
{ o1Xk\R{  
try{ m$o|s1t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XJlun l)(K  
output.writeInt(nStartPos.length); Jd%#eD*k9  
for(int i=0;i<nStartPos.length;i++) V^0*S=N
 
{ $'&5gFr9  
// output.writeLong(nPos); 55;xAsG  
output.writeLong(fileSplitterFetch.nStartPos); _zOzHc?Q  
output.writeLong(fileSplitterFetch.nEndPos); /Ly%-py-$  
} IlE! zRA  
output.close(); p7k0pS
t  
} $0 li"+  
catch(IOException e){e.printStackTrace ();} [qy@g5`  
catch(Exception e){e.printStackTrace ();} F|PYDC  
} &o8\ $A  
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//读取保存的下载信息（文件指针位置） 9xSAWKr,l  
private void read_nPos() 5~sJ$5<,  
{ 'UB<;6wy  
try{ eg}|%GG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1xx-}AIH#  
int nCount = input.readInt(); 1{,WY(,c  
nStartPos = new long[nCount]; N\vc<Zpn  
nEndPos = new long[nCount]; !qcR5yk`2  
for(int i=0;i<nStartPos.length;i++) R1SEv$  
{ 8IX6MfR}C  
nStartPos = input.readLong(); mxWaXb  
nEndPos = input.readLong(); UA/3lH}  
} 3QF!fll^  
input.close(); q/Gy&8 K  
} [<%yUy  
catch(IOException e){e.printStackTrace ();} <y!BO  
catch(Exception e){e.printStackTrace ();} QQ?` 1W  
} B!Qdf8We  
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private void processErrorCode(int nErrorCode) #v v k7  
{ -_2=NA?t  
System.err.println("Error Code : " + nErrorCode); gy>2=d  
} BBp
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//停止文件下载 LA
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public void siteStop() YY.;J3C  
{ #v`G
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bStop = true; ?W#! S  
for(int i=0;i<nStartPos.length;i++) ;bZ)q  
fileSplitterFetch.splitterStop(); J|I|3h<T  
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} 1.';:/~(  
} ;[6u79;I  
//负责部分文件的抓取 Bg#NB  
**FileSplitterFetch.java GI~;2 `V  
*/ 7f`jl/   
package NetFox; F\
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import java.io.*; `j<'*v zo  
import java.net.*; ucMl>G'!gX  
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public class FileSplitterFetch extends Thread { LN7;Yr  
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String sURL; //File URL [szwPNQ_  
long nStartPos; //File Snippet Start Position ."h;H^5  
long nEndPos; //File Snippet End Position B[Tw0rQ  
int nThreadID; //Thread's ID 0.Iw/e   
boolean bDownOver = false; //Downing is over CjO/q)vV  
boolean bStop = false; //Stop identical #4|?;C)u\  
FileAccessI fileAccessI = null; //File Access interface =|jOio=s:  
v=/V<3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H%/$Rqg  
{ ^%_LA't'R  
this.sURL = sURL; on(W^ocnD  
this.nStartPos = nStart; L ~  
this.nEndPos = nEnd; ?49wq4L;a  
nThreadID = id; O'p7^"M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &'(:xjN  
} zL>nDnL 4  
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public void run() 'T.> oP0>  
{ kDm=Cjxv  
while(nStartPos < nEndPos && !bStop) z~X]v["d  
{ ]{;K|rCR-  
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try{ nhy3E  
URL url = new URL(sURL); H{+U; 6b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NcPzmW{#;g  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9,F(f}(t  
String sProperty = "bytes="+nStartPos+"-"; LxG :?=O.  
httpConnection.setRequestProperty("RANGE",sProperty); zS?L3*u  
Utility.log(sProperty); N-5lILuJJ  
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InputStream input = httpConnection.getInputStream(); wlkS+$<  
//logResponseHead(httpConnection); 1*=[% d7  
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byte[] b = new byte[1024]; i/WYjo  
int nRead; D'</eJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =b;v:HC  
{ c[Y7tj%y  
nStartPos += fileAccessI.write(b,0,nRead); O[-wm;_(=*  
//if(nThreadID == 1) ZL@7Mr!e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )ll}hGS  
} #%x4^A9 q  
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Utility.log("Thread " + nThreadID + " is over!"); 9m8`4%y=  
bDownOver = true; tFb49zbk  
//nPos = fileAccessI.write (b,0,nRead); 8XTVpf4  
} BV7GzJ2([{  
catch(Exception e){e.printStackTrace ();} }-Zfljj  
} ;}:"[B3$  
}  EI+.Q  
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//打印回应的头信息 C YnBZ  
public void logResponseHead(HttpURLConnection con) r{Xh]U&>k  
{ /LJ?JwAvg5  
for(int i=1;;i++) f9#B(4Tgi  
{ BPC$ v\a  
String header=con.getHeaderFieldKey(i); g*8sh  
if(header!=null) )L^WD$"'Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :egSW2"5S  
Utility.log(header+" : "+con.getHeaderField(header)); ,Kdvt@vle  
else R`/nsou  
break; 3"q%-M|+Q  
} R{4O*i8#  
}
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public void splitterStop() :y]l`Mo -  
{ _{-GR-  
bStop = true; T0Y=g
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} 6)Oe]{-  
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} .-nA#/2-  
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/* )M}bc1 _  
**FileAccess.java ` R^[s56wp  
*//文件访问(定位，写) 3A'd7FJ0G  
package NetFox; =TyN"0@  
import java.io.*; *}yW8i}36  
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public class FileAccessI implements Serializable{ G!%1<SLi.  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /I: d<A  
RandomAccessFile oSavedFile; ~!Onz wmO  
long nPos; ^${-^w@,%V  
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public FileAccessI() throws IOException <y~`J`-  
{ Lt=#tu&d  
this("",0); AvhmN5O=  
} u},<On  
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public FileAccessI(String sName,long nPos) throws IOException 2D&t
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{ KWU#Swa`  
oSavedFile = new RandomAccessFile(sName,"rw"); 6\'v_A O  
this.nPos = nPos; 5P+
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oSavedFile.seek(nPos); V .
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} >WG$!o+R  
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public synchronized int write(byte[] b,int nStart,int nLen) 3"&6rdF\jB  
{ q!}&<w~|  
int n = -1; 5Ss=z  
try{ .wYx_  
oSavedFile.write(b,nStart,nLen); %z1WdiC  
n = nLen; IOt!A  
} jr'O4bo%  
catch(IOException e) ^d-`?zb  
{ >|H=25N>;  
e.printStackTrace (); dH?;!sJ  
} jG8ihi  
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return n; |jc87(x<  
} AVHn7olG  
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} ~h0SD(  
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/* CEZ*a 0}=  
**SiteInfoBean.java aRg- rz  
*/ aY8>#t?  
package NetFox; !!dNp5h`  
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public class SiteInfoBean { )|'? uN7  
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private String sSiteURL; //Site's URL h dPKeqg7  
private String sFilePath; //Saved File's Path rzY7f: '  
private String sFileName; //Saved File's Name "X"DTP1b  
private int nSplitter; //Count of Splited Downloading File A5B 5pJ  
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public SiteInfoBean() Cz m`5  
{//nSplitter的缺省值为5 0M-Zp[w\-  
//default value of nSplitter is 5 X~%Wg*Hm  
this("","","",5); 0 UjT<t^F  
} &c?-z}=G  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3mpEF<z  
{ Fg`r:,(a  
sSiteURL= sURL; GfPe0&h  
sFilePath = sPath; Ku56TH!Py  
sFileName = sName; Dy0cA| E  
this.nSplitter = nSpiltter; cAAJ7?  
V=\&eS4^"  
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} H&`p9d*(e  
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public String getSSiteURL() h"M}Iz~|V?  
{ `N ;!=7y7Y  
return sSiteURL; x-(?^g  
} ,$7LMTVDrE  
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public void setSSiteURL(String value) 3-~_F*%ST  
{ ]:Ocu--  
sSiteURL = value; J1P82=$,  
} {Km|SG[-q  
X
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public String getSFilePath() +TA(crD  
{ ,Ix7Yg[  
return sFilePath; JKGUg3\~  
} <iv9Mg
}  
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public void setSFilePath(String value) J1yy6Wq3
[  
{ 1 NLawi6  
sFilePath = value; 5{[3I|m{  
} .V 9E@_(  
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public String getSFileName() c[@>#7p`o  
{ j+PW9>Uh  
return sFileName; `:?padZG  
} fh:=ja?bM3  
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public void setSFileName(String value) "f3, w   
{ 31<hn+pE&  
sFileName = value; u,4,s[  
} ,TeDJ\k  
^ D?;K8a-l  
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public int getNSplitter() X*}S(9cg\i  
{ &h8+-  
return nSplitter; M'R^?Jjb  
} qm@c[b  
Vy&F{T;$  
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public void setNSplitter(int nCount) 2m/
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{ |#f P8OK  
nSplitter = nCount; Z:)\j.  
} 7Ja^d-F7  
} ~u/Enl7\-  
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at ]Lz_\  
/* _f{'&YhUU  
**Utility.java GDZe6*  
*/ dcYUw]  
package NetFox; 0'c<EJ  
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public class Utility { rQ@,Y"  
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public Utility() S!up2OseW  
{ `"Tx%>E(U  
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v
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} 6n45]?  
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//线程睡眠 ;'p X1T  
public static void sleep(int nSecond) ?v8B;="#w  
{ VL7zU->  
try{ OfbM]:}<3  
Thread.sleep(nSecond); u L/*,[}'  
} f*bs{H'5  
catch(Exception e) 33s.p'  
{ 5 S7\m5  
e.printStackTrace (); .'L@$]!G  
} _+.z2} M  
} b?h"a<7  
r6*0H/*  
//日志 i,$*+2Z  
public static void log(String sMsg) D{PO!WzW  
{ u`R  
System.err.println(sMsg); xa5I{<<U  
} D.
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,hYUxh45  
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public static void log(int sMsg) b"/P  
{ [;h@q}  
System.err.println(sMsg); HVh+Zk  
} mY |$=n5X  
} ~,m6g&>R  
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/* E.}T.
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**TestMethod.java Y]^[|e8  
*/ M5[AA/@  
package NetFox; "72 _Sw  
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public class TestMethod { h9 [ov)  
\b{=&B[Q$'  
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public TestMethod() \;$j "i&  
{ ///xx/weblogic60b2_win.exe !!DHfAV]  
try{ zl4Iq+5~6Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,^`+mP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =cX&H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oju4.1  
fileFetch.start(); P0 hC4Sxf  
} GyRU/0'BME  
catch(Exception e){e.printStackTrace ();} "qMd%RP  
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}+,1G!?z  
} )LKutN?tBy  
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public static void main(String[] args) mst-:F[h  
{ 2PAotD4+I  
new TestMethod(); '<4/Md[  
} FJ}/g ?  
} x_s9DkX  
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