http断点续传简单实现（java)

/* J`*iZvW#Bx  
**SiteFileFetch.java lHB
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*/ QjPj[c  
package NetFox; $t-n'Qh^2  
import java.io.*; jtm?z c  
import java.net.*; ]8;n{ }X  
#;#3%?  
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public class SiteFileFetch extends Thread { /VHi>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean bY~@}gC**@  
long[] nStartPos; //开始位置 rx:z#"?I  
long[] nEndPos; //结束位置 )$Z(|M4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P;]F=m+*V  
long nFileLength; //文件长度 [hRU&z;W  
boolean bFirst = true; //是否第一次取文件 :!zC"d
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boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 gX5&d\y  
DataOutputStream output; //输出到文件的输出流 s:y ^_W)d  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rp7W }P+uU  
public SiteFileFetch(SiteInfoBean bean) throws IOException VzlDHpG  
{ K^t?gt@k}  
siteInfoBean = bean; +'
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IK^~X{I?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7L:7/  
if(tmpFile.exists ()) insY(.N  
{ +[.Yy  
bFirst = false; W}'WA  
read_nPos(); ?nKF6f  
} /\Q*MLwD  
else =wq;@'U  
{ B ?%L  
nStartPos = new long[bean.getNSplitter()]; cyd~2\Kv~  
nEndPos = new long[bean.getNSplitter()]; qO`qJ/  
} C0x"pO7  
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} %zo= K}u  
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public void run() 4-v6=gz.  
{ 1QJBb \  
//获得文件长度 7k=fZ$+O  
//分割文件 !#?kWAU  
//实例FileSplitterFetch J0220 _  
//启动FileSplitterFetch线程 8rbG*6  
//等待子线程返回 ;Pb8YvG1$  
try{ K\Eo z]?  
if(bFirst) {b!7 .Cd=  
{ qS8B##x+=  
nFileLength = getFileSize(); w>~M}Ahj  
if(nFileLength == -1) 8)0L2KL'  
{ l*7?Y7FK  
System.err.println("File Length is not known!"); +'03>!V  
} J7i+c];!<  
else if(nFileLength == -2) g.Hio.fVd  
{ :wgfW .w  
System.err.println("File is not access!"); tjv\)Nn'  
} Q*O<@   
else v@u<Ww;=@  
{ ~S(^T9R  
for(int i=0;i<nStartPos.length;i++) mgkyC5)d  
{ V{Q kN7-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NyPd5m:  
} }C(5-7  
for(int i=0;i<nEndPos.length-1;i++) "<l<& qp  
{ G5'_a$  
nEndPos = nStartPos[i+1]; W."f8ow  
} fUcLf
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nEndPos[nEndPos.length-1] = nFileLength; &:#m&,tQ  
} WtX>Qu|  
} oO=o|w|T  
7!2 HNg  
h{]#ag5`  
//启动子线程 b1!@v+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O]nT>;PXX  
for(int i=0;i<nStartPos.length;i++) RIhOR8)  
{ jQt
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :%tuNJjj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F,v7ifo#f  
nStartPos,nEndPos,i); Bh`IXu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R,Ml&4pZ}  
fileSplitterFetch.start(); if~rp-\P  
} 68x}w Ae  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MTmO>V&O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qa!RH]B3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^9ng)  
nEndPos = " + nFileLength); 2@MN]
Low  
// fileSplitterFetch[nPos.length-1].start(); 7U:=~7GH  
6[==BbZ  
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//等待子线程结束 kX8=cL9G  
//int count = 0; =,Ttw>  
//是否结束while循环 Y%IJ8P^Y  
boolean breakWhile = false; ~b8a^6:R"  
]C *1
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while(!bStop) NJ$e6$g)  
{ koH4~m{  
write_nPos(); %D^bahf  
Utility.sleep(500); .C5@QKU  
breakWhile = true; T"W9YpZ  
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for(int i=0;i<nStartPos.length;i++) 4r*Pa(;y  
{ 6ojo##j  
if(!fileSplitterFetch.bDownOver) W/v|8-gcK  
{ `s}BXKIv}  
breakWhile = false; k|#Zy,  
break; #?m{YT{P  
} aJ2H.E  
} wD=am  
if(breakWhile) R$xY8+}V  
break; P^(.tr3t  
&|=?acv  
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//count++; o>!JrH  
//if(count>4) N5\{yV21",  
// siteStop(); $Q4=37H+  
} nW&$
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#`j][F@N  
]<X2AO1  
System.err.println("文件下载结束！"); .&(8(C  
} 4e/cqN6  
catch(Exception e){e.printStackTrace ();} 2v\W1VF  
}
9Dq.lr^  
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//获得文件长度 2f`xHI/@fj  
public long getFileSize() `Qq/F]  
{ s]bPV,"p  
int nFileLength = -1; X2P``YFV{  
try{ {_as!5l  
URL url = new URL(siteInfoBean.getSSiteURL()); bm6hZA|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bbs5f@E  
httpConnection.setRequestProperty("User-Agent","NetFox"); f+^c@0que  
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.Qk{5=l6P  
int responseCode=httpConnection.getResponseCode(); =kO@Gk?  
if(responseCode>=400) =phiD&=  
{ fKYKW?g;)Z  
processErrorCode(responseCode); HPTHF  
return -2; //-2 represent access is error Y^5"qd|`  
} x-4J/tm  
u
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{jhcZ"#>\  
String sHeader; Yhk6Uog{4  
2+&R"#I  
tnL."^%A2I  
for(int i=1;;i++) 1g81S_T .  
{ 6puVw-X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z'e1"Y.  
//Utility.log(in.readLine()); O3&
|}:<  
sHeader=httpConnection.getHeaderFieldKey(i); S[.5n]  
if(sHeader!=null) TnxU/)  
{ i^/DiWdyf  
if(sHeader.equals("Content-Length")) .h!9wGi`  
{ r?afv.@L2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <>&89E%j'  
break; z0;9SZ9  
} 4)E|&)-fu8  
} }8 \|1@09  
else uegb;m  
break; @LHtt/&  
} F_ _H(}d  
} ?KCxrzf  
catch(IOException e){e.printStackTrace ();} x57'Cg \  
catch(Exception e){e.printStackTrace ();} -sx-7LKi  
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Utility.log(nFileLength); s8yCC#H"  
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return nFileLength; |zb`&tv}  
} sxt`0oE  
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&R0OeRToUb  
//保存下载信息（文件指针位置） Jtpa@!M  
private void write_nPos() \ bC}&Iz6  
{ n)Hk8)^8  
try{ RAdvIIQp:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GA7u5D"0  
output.writeInt(nStartPos.length); ^xmZ|f-  
for(int i=0;i<nStartPos.length;i++) at=D&oy4"+  
{ ?U$}Rsk{#  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); uH0#rgKt  
output.writeLong(fileSplitterFetch.nEndPos); E2-ojL[6  
} U* 4{"  
output.close(); &1oaZY w  
} >]^>gUmq
 
catch(IOException e){e.printStackTrace ();} Io09W^  
catch(Exception e){e.printStackTrace ();} 9ec0^T  
} E+:.IuXW$  
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X+d&OcO=q  
//读取保存的下载信息（文件指针位置） `)LIVi"(D  
private void read_nPos() /XjN%|  
{ 7<fL[2-  
try{ mQFa/7FX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :mzCeX8 *  
int nCount = input.readInt(); Cv0&prt  
nStartPos = new long[nCount]; QZ?O;K1|y  
nEndPos = new long[nCount]; '+tKvTU;  
for(int i=0;i<nStartPos.length;i++) HqB|SWyK  
{ i+U@\:=  
nStartPos = input.readLong(); Ko@zk<~"[  
nEndPos = input.readLong(); +tPx0>p;  
} }z8{B
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input.close(); B,w:
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} Tln9q0"W  
catch(IOException e){e.printStackTrace ();} w<v1N  
catch(Exception e){e.printStackTrace ();} 3.B4(9:>,  
} ]v<d0"2  
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private void processErrorCode(int nErrorCode) #"|"cYi,  
{ S!u6dz^[$X  
System.err.println("Error Code : " + nErrorCode);  dD:  
} ip<15;Z  
_r~!O$2  
IU7$%6<Y  
//停止文件下载 e21E_exM0  
public void siteStop() &3jBE--  
{ Lf[G>0t&n  
bStop = true; VjC*(6<Gj  
for(int i=0;i<nStartPos.length;i++) te4F"SEf  
fileSplitterFetch.splitterStop(); /A0 [_  
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} .MzOLv  
} mu 2 A%"7  
//负责部分文件的抓取 -
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**FileSplitterFetch.java @Q/x&BV  
*/ ?e"Wu+q~L  
package NetFox; \I'f3  
+SAk:3.#CV  
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import java.io.*; (s5<  
import java.net.*; >6*(}L9  
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public class FileSplitterFetch extends Thread { pk;ffq@  
kA;xAb+U3  
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String sURL; //File URL X\o/i\ C}  
long nStartPos; //File Snippet Start Position -J-3_9I  
long nEndPos; //File Snippet End Position }DJ|9D^yf  
int nThreadID; //Thread's ID VfQMFb',o  
boolean bDownOver = false; //Downing is over hTlnw[I  
boolean bStop = false; //Stop identical _)OA$  
FileAccessI fileAccessI = null; //File Access interface (y-x01H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SPfD2%jjC  
{ &oon'q5;  
this.sURL = sURL; /
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this.nStartPos = nStart; DZ%g^D
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this.nEndPos = nEnd; LvSP #$f  
nThreadID = id; b`(yu.{Jn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9`)w@-~~  
} .jvSAV5B  
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public void run() >{phyBy
I  
{ NvQY7C  
while(nStartPos < nEndPos && !bStop) |WD,\=J2  
{ #citwMW  
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try{ 9 Q0#We*  
URL url = new URL(sURL); _F}IF9{?G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S4#A#a2J  
httpConnection.setRequestProperty("User-Agent","NetFox"); N>uA|<b,  
String sProperty = "bytes="+nStartPos+"-"; S^3g]5YX  
httpConnection.setRequestProperty("RANGE",sProperty); l9M#]*{  
Utility.log(sProperty); f28gE7Y\a  
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/Ki0+(4  
InputStream input = httpConnection.getInputStream(); @ChN_gd
3!  
//logResponseHead(httpConnection); mXxZM;P[  
@4G.(zW  
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byte[] b = new byte[1024]; se<i5JsSV  
int nRead; =fKhXd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `ENlV9  
{ 7V9%)%=h|  
nStartPos += fileAccessI.write(b,0,nRead); gi1}5DR  
//if(nThreadID == 1) o|rGy5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O\|C,Epm  
} K[iY{  
Y|hzF:ll  
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Utility.log("Thread " + nThreadID + " is over!"); Q\&AlV  
bDownOver = true; ki[;ZmQqY  
//nPos = fileAccessI.write (b,0,nRead); +Fu@I{"A  
} ]%NO"HzF~  
catch(Exception e){e.printStackTrace ();} NYSj^k;^(z  
} -IpV'%nX;  
} H B::0l<  
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W _PM!>8`  
//打印回应的头信息 _9}x
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public void logResponseHead(HttpURLConnection con) m NUN6qVP~  
{ LU-#=1Q  
for(int i=1;;i++) qP7&LtU  
{ . 1{vpX  
String header=con.getHeaderFieldKey(i); }Q{ =:X9  
if(header!=null) ?#VP)A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fl pXVtsQ  
Utility.log(header+" : "+con.getHeaderField(header)); b9
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else syWv'Y[k?  
break; e.3sAUHZ-  
} 5~`|)~FA  
} IQ(]66c,  
$Nt=gSWw5  
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public void splitterStop() '_TJ"lOZ  
{ >)AE|j`  
bStop = true; /tId#/Y  
} Ev$-PX  
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|1_
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} w*&n(zJF>  
'T&=$9g7  
? e9XVQ*  
/* P+*rWJ8gQ  
**FileAccess.java gTmUK{y'  
*//文件访问(定位，写) c~^]jqid]  
package NetFox; aIzp\$NWVK  
import java.io.*; [#STR=_f  
)+jK0E1  
9a"Y,1  
public class FileAccessI implements Serializable{ SU_]C+  
[T}%q"<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %#S"~)  
RandomAccessFile oSavedFile; r|JiGj^om  
long nPos; g|GvJ)VX  
 r
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public FileAccessI() throws IOException l ))~&  
{ 6]@|7|N>X  
this("",0); wB1|r{  
} U&Sbm~Qi  
K=!ZI/+ju  
^ RcIE (  
public FileAccessI(String sName,long nPos) throws IOException ReHd~G9  
{ \V"PmaP\  
oSavedFile = new RandomAccessFile(sName,"rw"); 07T;IV3#C5  
this.nPos = nPos; uDy>xJ|  
oSavedFile.seek(nPos); "a0u-}/D  
} ~kSnXJ
v  
V(''p{  
H/^TXqQ8  
public synchronized int write(byte[] b,int nStart,int nLen) lH,]ZA./  
{ +AgkPMy  
int n = -1; *Lb(urf  
try{ 0?5%  
oSavedFile.write(b,nStart,nLen); },n,P&M\`  
n = nLen; ard3yNQt  
} 'n>3`1E,  
catch(IOException e) J1c&"Oh  
{ lkSz7dr@  
e.printStackTrace (); (8@hF#N1  
} :ET3&J L  
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|;Se$AdT#  
return n; :~0^ib<v;  
} 9(N)MT5F  
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} njwR~aL`|  

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O=#/DM;  
/* &,Zz  
**SiteInfoBean.java 3@Zz-~4Td  
*/ V'.eesN  
package NetFox; bWC~Hv  
yqVaA 'w5  
*OGXu07 !  
public class SiteInfoBean { @E"+qPp.3  
;@7#w  
p^zEfLTU  
private String sSiteURL; //Site's URL d_WnK{  
private String sFilePath; //Saved File's Path Wf`OyeRz  
private String sFileName; //Saved File's Name :#W>S
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private int nSplitter; //Count of Splited Downloading File Hs4zJk  
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r"u(!
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public SiteInfoBean() 'Qs3  
{//nSplitter的缺省值为5 %:be{Y6  
//default value of nSplitter is 5 RZ
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this("","","",5); ]=86[A-2N  
} UTK.tg  
;qVEI/  
>;'1k'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;@ll  
{ ,QHx*~9  
sSiteURL= sURL; M#lVPXS  
sFilePath = sPath; 5rHnU<H@y  
sFileName = sName; &J&w4"0N'  
this.nSplitter = nSpiltter; '/yx_RK2?  
sNk>0 X[  
eFXi )tl  
} HDW\S#  
1z};"A  
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public String getSSiteURL() qq9tBCk

 
{ RP@idz  
return sSiteURL; t1RwB23  
} 8#Z\}gGz  
%dk$K!5D0  
^qzT5W\@  
public void setSSiteURL(String value) MlC-
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{ K`_E>k  
sSiteURL = value; gH{\y5%rO  
} C#?d
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b1>$sPJ+  
4qSS<SqY  
public String getSFilePath() qYu!:xa8  
{ C@?e`=9(  
return sFilePath; %`T^qh_dE  
} *(SBl}f4l  
A$"$`)P!  
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public void setSFilePath(String value) Ff#N|L'9_  
{ fN*4(yw  
sFilePath = value; ubCJZ"!  
} aXK
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7quwc'!  
r+#V{oE_  
public String getSFileName() {}_Oo%IVGK  
{ Y`O}]*{>8R  
return sFileName; ah6F^Kpl{  
} f?<M3P  
$E~Lu$|  
CL}I:/zRB  
public void setSFileName(String value) `SS~=~WY  
{ I{g2q B$6  
sFileName = value; ?e_}X3{  
} R?9Plzt5  
WlLZtgq  
k;:u| s8NS  
public int getNSplitter() 36Z`.E>~L  
{ ^nm!NL{z^  
return nSplitter; Boj{+rE0  
} owY_cDzrH  
cSs
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0!'M#'m  
public void setNSplitter(int nCount) 7/OOq=z  
{ 3]]6z K^i  
nSplitter = nCount; !RUo:b+  
} &$z1
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} a3 _0F@I  
g$T_yT''  
>93{=+  
/* qF6%XKbh=  
**Utility.java ZE(RvPW  
*/ Sl<-)a:  
package NetFox; NCM{OAjS5U  
!zJ67-G  
];}|h|q/{}  
public class Utility { /sC[5G%  
Vq7 kA "  
"yq;{AGOGl  
public Utility() \w_[tPz}  
{ >E,L"&_j  
BHE =Zo  
np>!lF:  
} KeO
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be  
<fxjj  
//线程睡眠 J&Qy$itqg  
public static void sleep(int nSecond) {}C7VS1  
{ -Jrc'e4K  
try{ 1:s~ ]F@  
Thread.sleep(nSecond); ;Wh[q*A  
} [^=8k2  
catch(Exception e) `IRT w"  
{ ?&nz  
e.printStackTrace (); L#@$Mtc  
} w>UV\`x  
} )ZU#19vr7  
lz0]p  
//日志 KIY_EE$?  
public static void log(String sMsg) 8=Y|B5  
{ qq%_ksQ  
System.err.println(sMsg); ^[z\KmUqt  
} )3\rp$]1  
ZU@jtqq  
~9;mZi1-  
public static void log(int sMsg) *7V{yK$O|  
{ {Om3fSk:  
System.err.println(sMsg); ^g){)rz|  
} g\nL n#  
} A"ph!* i{  
kRa$jD^?  
"m)O13x  
/* .7Bav5 ;  
**TestMethod.java kV%y%l(6  
*/ ,^66`C[G  
package NetFox; ywtDz8!^u  
+W
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&|FG#.2yw  
public class TestMethod { yXl.Gq>]{  
s/^=WV  
DYk->)   
public TestMethod() h4xdE0  
{ ///xx/weblogic60b2_win.exe 62'0)Cy^  
try{ J@{Bv%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (8F?yBu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s_?*R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,qh  
fileFetch.start(); [~J
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} >Nqkz?67  
catch(Exception e){e.printStackTrace ();} '~=xP  
ky"7 ^  
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} l{{ #tW  
4[j) $!l`  
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public static void main(String[] args) md_s2d  
{ p)]^>-L  
new TestMethod();  0d)n}fm  
} &1n0(qB  
} I`lH6hHp  
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