http断点续传简单实现（java)

/* b;!
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**SiteFileFetch.java %qja:'k  
*/ -!;vX @  
package NetFox; H@aCo(#  
import java.io.*; RA.@(DN&  
import java.net.*; ?7a<V+V:  
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public class SiteFileFetch extends Thread { |U7{!yy%MF  
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}z
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0Vy* 0\{S  
long[] nStartPos; //开始位置 S@_@hFV jd  
long[] nEndPos; //结束位置 \?qXscq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UK&E#i  
long nFileLength; //文件长度 I X\&lV  
boolean bFirst = true; //是否第一次取文件 @X\nY</E#M  
boolean bStop = false; //停止标志 8oA6'%.e  
File tmpFile; //文件下载的临时信息 `5GJ,*{z  
DataOutputStream output; //输出到文件的输出流 C: e}}8i  
*+@/:$|U  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8^< -;  
public SiteFileFetch(SiteInfoBean bean) throws IOException by8d18:it  
{ +;;fw |/  
siteInfoBean = bean; R 8Iac[N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y`(I};MO  
if(tmpFile.exists ()) Jw {:1  
{ <w2Nh eM 3  
bFirst = false; v8pUt\m"  
read_nPos(); sV[|op  
} 1/1P;8F@G  
else q{ctHsQ(9  
{ ) mv}u~  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; \=5CNe  
} W:EXL@  
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} \t!+]v8f8  
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}3?M0:  
public void run() X.UIFcK^  
{ RbrvY  
//获得文件长度 .s2d  
//分割文件 I[e7Up  
//实例FileSplitterFetch PK+][.6H  
//启动FileSplitterFetch线程 3q1O:b^eo  
//等待子线程返回 /n"A%6S  
try{ 4|:{a
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if(bFirst) =#+Z KD  
{ "[#jq5> :  
nFileLength = getFileSize(); ^kXDEKm  
if(nFileLength == -1) wh~~g qi9  
{ :Z< 5iLq  
System.err.println("File Length is not known!"); s;5PHweWf  
} *~:@xMa  
else if(nFileLength == -2) zBjqYqZ<+  
{ ueWG/`ig  
System.err.println("File is not access!"); a.] !  
} gE$dz#t.  
else pH"LZ7)DI0  
{ ZE=~ re  
for(int i=0;i<nStartPos.length;i++) :+R||qi  
{ "3hw]`a}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2nEj X\BY  
} @9c^{x\4  
for(int i=0;i<nEndPos.length-1;i++) ' !_44  
{ 0{B5C[PTG  
nEndPos = nStartPos[i+1]; <R!qOQI  
} y'zEaL&SI@  
nEndPos[nEndPos.length-1] = nFileLength; +h9CcBd  
} Cu|n?Uk  
} NGxii$F  
_5X}&>>lhF  
2ag]p  
//启动子线程 zg5u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UW>~C  
for(int i=0;i<nStartPos.length;i++) [I^SKvM  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;N/c5+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |H@M-  
nStartPos,nEndPos,i); Z]Qm64^I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \ _i`=dx  
fileSplitterFetch.start(); D!X{9q}S1  
} Dn6DkD!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q% dpGI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d-?~O~qD|!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
a.Mp1W  
nEndPos = " + nFileLength); Cu`ZgKLQ  
// fileSplitterFetch[nPos.length-1].start(); xpS#l"dr  
nrf%/L  
kKjYMYT6  
//等待子线程结束 @L~
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//int count = 0; jV7q)\uu^  
//是否结束while循环 w6E?TI  
boolean breakWhile = false; rVN|OLh  
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v)pdm\P  
while(!bStop) Tok"-
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{ W&*{j;e9%I  
write_nPos(); =T\pq8  
Utility.sleep(500); X0U6:  
breakWhile = true; JN8k x;@  
j&&^PH9ZY  
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for(int i=0;i<nStartPos.length;i++) p,4z;.s$  
{ SOUA,4  
if(!fileSplitterFetch.bDownOver) UGN. ]#"#  
{ R4v=i)A~Z  
breakWhile = false; zO+nEsf^O  
break; U}5uy9A  
} \u)(+t{  
} #A))#sT'R  
if(breakWhile) kB8
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break; |MRxm"]A   
5(F!*6i>  
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//count++; 2GD%=rP2]  
//if(count>4) Z@h]dU5%a  
// siteStop(); Jz-f1mhQV  
} Fj5^_2MU:  
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8.  
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System.err.println("文件下载结束！"); 'Gc6ZSLM  
} =uvv|@Z  
catch(Exception e){e.printStackTrace ();} Xr~r`bR=  
} =X1$K_cN  
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//获得文件长度 oFsMQ Py  
public long getFileSize() ;WzT"yW)T  
{ <8y8^m`P9  
int nFileLength = -1; ]xS< \{og  
try{ BHU[Rz7x  
URL url = new URL(siteInfoBean.getSSiteURL()); I{2e0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p"X\]g^jA>  
httpConnection.setRequestProperty("User-Agent","NetFox"); r&H>JCRZ<=  
5
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A1Zu^_y'  
int responseCode=httpConnection.getResponseCode(); WL7:22nSHa  
if(responseCode>=400) `
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{ q)%C
|  
processErrorCode(responseCode); ZNx{7]=a  
return -2; //-2 represent access is error g3qtWS  
} S=my;M-  
 10DS  
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String sHeader; (V+(\<M  
9sRP8Nj|  
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for(int i=1;;i++) UIyOn` d"  
{ S^n:O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); K'71uW>  
sHeader=httpConnection.getHeaderFieldKey(i); d }]b  
if(sHeader!=null) 8Za
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{ ))MP]j9 T  
if(sHeader.equals("Content-Length")) H)4Rs~;{'g  
{ ~PV>3c3l=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AUN Tc3  
break; hR?rZUl2M  
} Y /wvn8~C  
} 36j
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else 8pk5[=3Z  
break; KYeA=  
} ?Z.YJXoKZ  
} mg3jm  
catch(IOException e){e.printStackTrace ();} 0!?f9kJq  
catch(Exception e){e.printStackTrace ();} uIba{9tM"P  
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Utility.log(nFileLength); k20H|@g2  
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return nFileLength; |l~ADEg  
} k'\RS6M`L  
{vU '>pp  
:3G9YjzC}  
//保存下载信息（文件指针位置） f8n'9HOw>  
private void write_nPos() h&Sl8$jVp  
{ "JGaw_o  
try{ g)"6|Z?D"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]:f1r8<3p  
output.writeInt(nStartPos.length); .)o5o7H  
for(int i=0;i<nStartPos.length;i++) 1DBzD%@Oz  
{ ,`w
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// output.writeLong(nPos); TX 87\W.  
output.writeLong(fileSplitterFetch.nStartPos); wgufk{:  
output.writeLong(fileSplitterFetch.nEndPos); vXf#gX!Y  
} B O"+m  
output.close(); Ylf6-FbF  
} 0|U<T#t8?  
catch(IOException e){e.printStackTrace ();} &fTCY-W[  
catch(Exception e){e.printStackTrace ();} O-|3k$'\z  
} DnTM#i:  
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;J_d%  
//读取保存的下载信息（文件指针位置） h0gT/x  
private void read_nPos() ,rN7X<s54  
{ \K4
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try{ Z,2
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8=e\^Q+  
int nCount = input.readInt(); 1n,JynJ  
nStartPos = new long[nCount]; HgMDw/D(  
nEndPos = new long[nCount]; :r6 bw  
for(int i=0;i<nStartPos.length;i++) E6US  
{ Xak~He  
nStartPos = input.readLong(); '3xSzsDn  
nEndPos = input.readLong(); >!wwXhH(  
} duM>(y  
input.close(); 1-,l|K  
} g_q{3PW.  
catch(IOException e){e.printStackTrace ();} #a0 (Wh7  
catch(Exception e){e.printStackTrace ();} F |GWYw'%  
} M5q7` }>G  
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private void processErrorCode(int nErrorCode) rUuM__;d  
{ vbWX`skU  
System.err.println("Error Code : " + nErrorCode); UR\*KR;yM  
} 4v{gc/g  
n.T [a  
&2g1Oy~  
//停止文件下载 [`:\(( 8  
public void siteStop() S5XFYQ  
{ 6Y=$7%z  
bStop = true; Axcm~!uf  
for(int i=0;i<nStartPos.length;i++) 'tdjPdw  
fileSplitterFetch.splitterStop(); Vw,dHIe(3  
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} +XQS -=  
} Nc7YMxk'H  
//负责部分文件的抓取 P3:hGmk8|j  
**FileSplitterFetch.java [bZXzV(  
*/ =A,i9Z&  
package NetFox; )UxF lp;\  
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import java.io.*; /2YI!U@A  
import java.net.*; i JQS@2=A  
*l5/q\D  
tn}9(Oa)  
public class FileSplitterFetch extends Thread { OW6i2>Or  
@NNN&%  
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String sURL; //File URL X09&S4  
long nStartPos; //File Snippet Start Position 1|Fukx<@J<  
long nEndPos; //File Snippet End Position :lcoSJ  
int nThreadID; //Thread's ID jPFA\$To  
boolean bDownOver = false; //Downing is over WyO10yvR  
boolean bStop = false; //Stop identical |{Oe&j3|  
FileAccessI fileAccessI = null; //File Access interface -()CgtSR  
=i `o+H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;]'mx  
{ cm-!6'`  
this.sURL = sURL; o8Tt|Lxb$8  
this.nStartPos = nStart; _TkiI.'  
this.nEndPos = nEnd; 6)Kg!.n%f  
nThreadID = id; rFGbp8(2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x|1OGbBK  
} 9CxU:
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public void run() \QQw1c+  
{ 2y,f  
while(nStartPos < nEndPos && !bStop) `2}Mz9mk  
{ ](B+ilr   
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)88z=5.  
try{ LKTIwb>  
URL url = new URL(sURL); #5=Yg5   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QYDSE  
httpConnection.setRequestProperty("User-Agent","NetFox"); >DPC}@Wl  
String sProperty = "bytes="+nStartPos+"-"; `cCsJm$V"  
httpConnection.setRequestProperty("RANGE",sProperty); +Y6=;*j$  
Utility.log(sProperty); O*X]oX  
' FF@I^O  
P @G2F:}  
InputStream input = httpConnection.getInputStream(); pFx7URZA  
//logResponseHead(httpConnection); up#W"`"  
x}{/) ?vC  
EH=[!iW;  
byte[] b = new byte[1024]; t*iKkV^aE  
int nRead; I& DEF*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JN,4#,  
{ GU([A@;  
nStartPos += fileAccessI.write(b,0,nRead); ~ep-XO  
//if(nThreadID == 1) TY"8.vd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0NL~2Qf_4  
} j KGfm9|zj  
p D-k<8|
 
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Utility.log("Thread " + nThreadID + " is over!"); !:]CKbG  
bDownOver = true; .nl!KzO6g  
//nPos = fileAccessI.write (b,0,nRead); #rD0`[pz  
}
3"FvYv{  
catch(Exception e){e.printStackTrace ();} @y]ek/  
} P{-j^'y  
} f#f<Ii  
<Nwqt[.  
:#7"SEud}  
//打印回应的头信息 M#Kke
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public void logResponseHead(HttpURLConnection con) iI.pxo s  
{ <NKmLAfX  
for(int i=1;;i++) u
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{ o^+2%S`]  
String header=con.getHeaderFieldKey(i); g\%;b3"#  
if(header!=null) /Z^"[Ke  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [ICFPY6  
Utility.log(header+" : "+con.getHeaderField(header)); n/9.;9b$I  
else EdcbWf7  
break; KTtB!4by  
} #!?jxfsFa  
} n#$sLXVy  
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public void splitterStop() p+7G  
{ -d>2&)5  
bStop = true; yM}~]aQ y  
} ^#( B4l!  
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} I-Q@
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.q90+9Ek=  
/*
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**FileAccess.java r{cmw`WA/P  
*//文件访问(定位，写) / <C{$Gu  
package NetFox; <?Ln`,Duk  
import java.io.*; kz_gR;"(Z  
z`}z7e'>  
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public class FileAccessI implements Serializable{ |lCS^bA3  
cslZ;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =fRC$  
RandomAccessFile oSavedFile; ^r
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long nPos; `.z"Q%uz  
~] &yHzp2  
]z#+3DaH  
public FileAccessI() throws IOException -1{f(/  
{ Rtu"#XcBw+  
this("",0); m]+~F_/  
} /8#e < p  
G{.[o6>  
@cr/&  
public FileAccessI(String sName,long nPos) throws IOException ,<=gPs;x  
{ {^D; ($lm  
oSavedFile = new RandomAccessFile(sName,"rw"); tzShds  
this.nPos = nPos; w/z 
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oSavedFile.seek(nPos); [g bFs-B2/  
} u`CHM:<<?  
S zNZY&8 f  
9^u}~e #(  
public synchronized int write(byte[] b,int nStart,int nLen) \G#_z|'dN  
{ ~GE|,Np  
int n = -1; 6gabnW3  
try{ U!{~L$S  
oSavedFile.write(b,nStart,nLen); 3$?nzKTW\  
n = nLen; :_,a%hb+8  
} ;Fo7 -kK  
catch(IOException e) Yq
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{ <.#jp([W>  
e.printStackTrace ();
.i {yW  
} s#'Vasu  
6oa>\PDy   
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return n; &xt[w>/i  
} 7H*,HZc@=  
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} sSf;j,7V  
k')H5h+Q=  
6.9C4  
/* g&S>Wq%L  
**SiteInfoBean.java S}fQis  
*/ cuC' o\f  
package NetFox; ZbiC=uh  
!rs }83w!  
<)pPq+  
public class SiteInfoBean { n*ROlCxV  
,na}' A@a`  
*o5[P\'6  
private String sSiteURL; //Site's URL #D#kw*c  
private String sFilePath; //Saved File's Path ju5o).!bg  
private String sFileName; //Saved File's Name 'gXD?ARW  
private int nSplitter; //Count of Splited Downloading File KwV!smi2  
E=8GSl/Jx  
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public SiteInfoBean() Tay$::V  
{//nSplitter的缺省值为5 !4`:(G59  
//default value of nSplitter is 5 RX%)@e/@  
this("","","",5); </Y(4Xwf=  
} w#hg_RK(Jr  
m,"-/)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =>lX brJ  
{ FaWDAL=Vhk  
sSiteURL= sURL; 4%zy$,|e  
sFilePath = sPath; p^}`^>OL  
sFileName = sName; R!%HQA1U  
this.nSplitter = nSpiltter; N34-z|"q  
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AbhR*  
} ~(^pGL3<  
<KK.f9^o(  
pEz^z9  
public String getSSiteURL() tBfmjxv  
{ OiXO<1'$  
return sSiteURL; 9BpxbU+L;  
} JWaWOk(t=?  
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YjnQ@IfIH  
public void setSSiteURL(String value) T)%6"rPL3!  
{ A`JE(cIz3  
sSiteURL = value; 0>Td4qr+u  
} D vvi)/<  

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l`l6Y>c*]  
public String getSFilePath() s3m\  
{ ~4Gc~"  
return sFilePath; %o4v} mzV  
} T iL.py,  
8m=R" %h  

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public void setSFilePath(String value) -BI!ZsC'  
{ ]\ !ka/%  
sFilePath = value; rQlQ^W$=?  
} g 8uq6U  
9B;WjXSe  
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public String getSFileName() ?<^8,H  
{ 1kpw*$P0  
return sFileName; 4i{Xs5zk  
} Ipq0 1 +  
*P9"1K+  
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public void setSFileName(String value) @VW1^{.do^  
{ 0SWqC@AR%  
sFileName = value; "_LqIW1  
} 6;:D!},'c  
l1lYb;C  
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public int getNSplitter() YLTg(*  
{ DiOd!8Y  
return nSplitter; (0#$%US\  
} xRgdU+,Mj  
s@"|o3BX  
8rS;}Bt  
public void setNSplitter(int nCount) F)X`CG ;t  
{ ~+0IFJ`}  
nSplitter = nCount; =y@0il+V  
} &v*4AZ['  
} `?R{sNr.  
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~
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/* ogQfzk  
**Utility.java x=xo9wEg  
*/ Mb[4_D
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package NetFox; ;A@DE@^5w  
0AffD:  
Spx%`O<  
public class Utility { #yR&|*@  
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public Utility() X[tB^`  
{ hGrX,.zj  
X)iI]  
o[ks-C>jw  
} +FadOx7X$  
+:ms`Sr>  
//线程睡眠 }PBL  
public static void sleep(int nSecond) A'~mJO/  
{ j0~c2  
try{ c-(dm:  
Thread.sleep(nSecond); tw<Oy^i  
} Dzu//_u  
catch(Exception e)
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{ Z?=o(hkd  
e.printStackTrace (); CYE[$*g6y  
} `W+-0F@Y?@  
} . 70=xH  
xYv;l\20.  
//日志 pL[3,.@WA  
public static void log(String sMsg) /Ta-3Eh!  
{ yl@Nyu  
System.err.println(sMsg); _{#K  
} l
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Cc{{9Ud  
LVdR,'lS  
public static void log(int sMsg) sm{0o$\Z  
{ g
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System.err.println(sMsg); iJoY
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} s1::\&`za  
} cU ?F D  
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/* v,QvCozOz  
**TestMethod.java {`M\}(E  
*/ l"`VvW[  
package NetFox; =Gzs+6A8  
 03zt^<  
D{\o*\TN  
public class TestMethod { l8+)Xk>  
W(Sni[c{  
WH39=)D%u  
public TestMethod() y!x[N!a  
{ ///xx/weblogic60b2_win.exe J[Mj8ee#  
try{ 9a]o?>`E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V*2*5hx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i!UT =  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4 Cd5-I  
fileFetch.start(); 0iR?r+|  
} }m^^6h  
catch(Exception e){e.printStackTrace ();} ?
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_](y<O^9yO  
( [a$Z2m  
} ?F$#t6Q  
$`\qY ^.(  
jxm#4  
public static void main(String[] args) :~W(#T,$E  
{ K+M\E[1W  
new TestMethod(); ONpvx5'#  
} rB]2qk`/'  
} SD%3B!cpX  
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