http断点续传简单实现（java)

/* IPr*pQ{;c  
**SiteFileFetch.java ~/]\iOL  
*/ c_D,MW\IC  
package NetFox; :$X4#k<  
import java.io.*; N9>'/jgZX  
import java.net.*; : .FfE  
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public class SiteFileFetch extends Thread { J*^,l`C/  
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{  
SiteInfoBean siteInfoBean = null; //文件信息Bean Wf+Cc?/4  
long[] nStartPos; //开始位置 Jnu}{^~  
long[] nEndPos; //结束位置 h~=\/vF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R4Gg|Bh  
long nFileLength; //文件长度 /pSUn"3  
boolean bFirst = true; //是否第一次取文件 =ihoVA:|  
boolean bStop = false; //停止标志 %0y3/W  
File tmpFile; //文件下载的临时信息 x1&b@u  
DataOutputStream output; //输出到文件的输出流 ;s!ns N  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #%=vy\r  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3ZJagJ\O  
{ kVG6\<c]  
siteInfoBean = bean; 7}iewtdy,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2A18hP`^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LK-K_!F  
if(tmpFile.exists ()) /Mi-lh^j-  
{ 9B?t3:  
bFirst = false; sgb+@&}9n  
read_nPos(); IW] 841  
} ;5JIY7t  
else }TAGr 0  
{ )2
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nStartPos = new long[bean.getNSplitter()]; 8ZDqqz^C0  
nEndPos = new long[bean.getNSplitter()]; 0u&?Zy9&  
} uYFcq  
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} ;o)`9<es!2  
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public void run() f)s_e  
{ {p lmFV  
//获得文件长度 Q\/":ISq1  
//分割文件 V[M$o  
//实例FileSplitterFetch coP$7Q .  
//启动FileSplitterFetch线程  j5VRv$P  
//等待子线程返回 lWyP[>*  
try{ 2I(@aB+  
if(bFirst) w]5f3CIm  
{ MF`k~)bDV  
nFileLength = getFileSize(); >.nt'BQ  
if(nFileLength == -1) "<n"A7e  
{ /x8C70W^  
System.err.println("File Length is not known!"); e5/DCz  
} N mjBJ_G  
else if(nFileLength == -2) rEpKX  
{ 1n5e^'z  
System.err.println("File is not access!");
Z :i"|;  
} j C1^>D  
else H7XxME  
{ 4[V6so0  
for(int i=0;i<nStartPos.length;i++) rgvc5p  
{ \z2hXT@D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OD
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} F]&J%i F[  
for(int i=0;i<nEndPos.length-1;i++) 2
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{ .2S
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nEndPos = nStartPos[i+1]; 1eR{~ ,  
} "ZPbK$+=yU  
nEndPos[nEndPos.length-1] = nFileLength; ]O(HZD%  
} c$SxDYG  
} }lvP|6Y: y  
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//启动子线程 Ywb)h^{!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &i}cC4i   
for(int i=0;i<nStartPos.length;i++) jnLu|W&  
{ Yiw^@T\H`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m?CjYqvf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d_|v=^;  
nStartPos,nEndPos,i); V@xnz)^t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fq!6#Usf;i  
fileSplitterFetch.start(); M@z/gy^  
} rW>'2m6HU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7Qztc?XK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G,* uj0g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,&l*AB!  
nEndPos = " + nFileLength); (%IstR|u:  
// fileSplitterFetch[nPos.length-1].start(); 0<Y&2<v  
jQlK-U=oi  
rG%_O$_dO  
//等待子线程结束 SmEd'YD!J  
//int count = 0; pq5H{  
//是否结束while循环 CxN@g'  
boolean breakWhile = false; rpI7W?hh  
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while(!bStop) _)H+..=  
{ cmLu T/oV  
write_nPos(); Ah
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Utility.sleep(500); c oz}VMp  
breakWhile = true; ]OUOL/J  
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for(int i=0;i<nStartPos.length;i++) `\uv+^x{  
{ pKlT.<X7  
if(!fileSplitterFetch.bDownOver) S|h  m  
{
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breakWhile = false; `^h##WaXap  
break; @G{DOxE*  
} |#kf.kN  
} gV>\lMc[-%  
if(breakWhile) i-W2!;G  
break; $1 \!Oe[i  
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8LKZ3Y|  
//count++; lLf01sa4  
//if(count>4) ]/naH#8G  
// siteStop(); J}u1\Id%  
} \ku{-^7  
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System.err.println("文件下载结束！"); 3"%44'  
} xeh|u"5  
catch(Exception e){e.printStackTrace ();} TzXl
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} vwD(J.;  
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//获得文件长度 ?wY.B  
public long getFileSize() gJv^v`X  
{ )ciHY6  
int nFileLength = -1; FaM~ 56Pa  
try{ ) O^08]Y g  
URL url = new URL(siteInfoBean.getSSiteURL()); ,i.P= o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wfzb:Aig`  
httpConnection.setRequestProperty("User-Agent","NetFox"); l.)!jWY  
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int responseCode=httpConnection.getResponseCode(); FZ/&[;E!  
if(responseCode>=400) @/iLC6QF  
{ FX 3[U+  
processErrorCode(responseCode); tB7aHZ|  
return -2; //-2 represent access is error )HE yTHLtJ  
} \H(,'w7H  
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String sHeader; :b-(@a7>  
3!x)LUWfWY  
=
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for(int i=1;;i++) jL1UPN  
{ h]$zub
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WI3!?>d  
//Utility.log(in.readLine()); P&;I]2#  
sHeader=httpConnection.getHeaderFieldKey(i); z{x -Vfd  
if(sHeader!=null) }J`Gm  
{ Lf9h;z>#  
if(sHeader.equals("Content-Length")) rz*Jmn b  
{ C5z4%,`f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Rz]bCiD3 B  
break; 7Cjrh"al"  
} tWuQKN`_  
} ?9"glzxr  
else {`> x"Y5  
break; fBmx +7  
} v\vn}/>*d  
} .v{ty  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} P+a&R<Dj4  
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Utility.log(nFileLength); o~B=[  
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return nFileLength; 0OXd*  
} wS
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//保存下载信息（文件指针位置） rxA<\h,A  
private void write_nPos() P^UcpU,  
{ uJizR F  
try{ nYY U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j#,O,\  
output.writeInt(nStartPos.length); _"=~aMXC.)  
for(int i=0;i<nStartPos.length;i++) "$_ypgRrSR  
{ 1mqFnVkf&+  
// output.writeLong(nPos); b,wO^07-3^  
output.writeLong(fileSplitterFetch.nStartPos); [B Al  
output.writeLong(fileSplitterFetch.nEndPos); u CXd% CzE  
} O{PRK5^h  
output.close(); gTT-7  
} 53A=Ogk8S  
catch(IOException e){e.printStackTrace ();} (,>`\\  
catch(Exception e){e.printStackTrace ();} bc-"If Z&  
} _"n4SXhq  
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//读取保存的下载信息（文件指针位置） TocqoYX{{  
private void read_nPos() k6XO-a f  
{ X'Oo ogu  
try{ 2B#\683  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %o-*~GQ@B  
int nCount = input.readInt(); 8eNGPuoL)  
nStartPos = new long[nCount]; 7^1ikmYY
 
nEndPos = new long[nCount]; O`eNuQSv  
for(int i=0;i<nStartPos.length;i++) v-o/zud]]  
{ m(Oup=\%b}  
nStartPos = input.readLong(); #AHIlUH"m  
nEndPos = input.readLong(); +_<#8v  
} 4dO>L"  
input.close(); u4Sa4o  
} lWR  
catch(IOException e){e.printStackTrace ();} v'uQ'CiH  
catch(Exception e){e.printStackTrace ();} IKt9=Tx  
} D~<GVp5T  
?~$y3<[  
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private void processErrorCode(int nErrorCode) {)+/w"^.  
{ >z2{D7  
System.err.println("Error Code : " + nErrorCode); -v:Y\=[\  
} *m7e>]-  
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//停止文件下载 W$y?~2  
public void siteStop() "H({kmR  
{ uo0(W3Q *  
bStop = true; r=vE0;7  
for(int i=0;i<nStartPos.length;i++) 2b<0g@~X  
fileSplitterFetch.splitterStop(); z}5XLa^  
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} eu~;G H  
} 4P.ry|2  
//负责部分文件的抓取 ixp%aRRP  
**FileSplitterFetch.java GRNH!:e  
*/ B::vOg77  
package NetFox; !"wIb.j}0  
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import java.io.*; *Hs5MXNu  
import java.net.*; Lczcz"t  
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public class FileSplitterFetch extends Thread { ALG +  
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String sURL; //File URL 35ng_,t$  
long nStartPos; //File Snippet Start Position </fzBaTo  
long nEndPos; //File Snippet End Position V3UEuA  
int nThreadID; //Thread's ID n4ISHxM  
boolean bDownOver = false; //Downing is over m~}nM|m%  
boolean bStop = false; //Stop identical }5A?WH_  
FileAccessI fileAccessI = null; //File Access interface yVW)DQ4?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jWm<!<~  
{ ;HW@ZI  
this.sURL = sURL; A;%fAI2Vr  
this.nStartPos = nStart; 'RPe5 vB  
this.nEndPos = nEnd; J[^-k!9M  
nThreadID = id; vnKUD
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 (h E^<jNR  
} v"^G9u  
[[Z*n/tr  
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public void run() J~~WV<6  
{ Alrk3I3{  
while(nStartPos < nEndPos && !bStop) zfS`@{;F`|  
{ *@D.=i>  
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try{ Er{yQIi0L  
URL url = new URL(sURL); V%"aU}   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }^=J
]  
httpConnection.setRequestProperty("User-Agent","NetFox"); (*#S%4(YX  
String sProperty = "bytes="+nStartPos+"-"; # TvY*D,  
httpConnection.setRequestProperty("RANGE",sProperty); 0Rj_l:d=  
Utility.log(sProperty); d!>PqPo  
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InputStream input = httpConnection.getInputStream(); 1Ztoj}!I  
//logResponseHead(httpConnection); WzF/wzR  
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byte[] b = new byte[1024]; D&.+Dx^G  
int nRead; LnLuWr<;}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i7iL[+f]Q  
{ t)5bHVx  
nStartPos += fileAccessI.write(b,0,nRead); O Qd,.m  
//if(nThreadID == 1) Qax=_[r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BeBa4s  
} hivWQ$6%  
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Wq]^1g_  
Utility.log("Thread " + nThreadID + " is over!"); M4`qi3I  
bDownOver = true; -_B*~M/vV`  
//nPos = fileAccessI.write (b,0,nRead); &kh-2#E  
} <"6}C)G  
catch(Exception e){e.printStackTrace ();} caS5>wk`R  
} oPl^tzO  
} rq>@0i  
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//打印回应的头信息 m$ "B=b2  
public void logResponseHead(HttpURLConnection con) \:8 >@Q  
{ m#ID%[hg$  
for(int i=1;;i++) $vx]\` ^  
{ L~>pSP^a  
String header=con.getHeaderFieldKey(i); wgY:W:y'N  
if(header!=null) ttgb"Wb%S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "OkJPu2!W  
Utility.log(header+" : "+con.getHeaderField(header)); N
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else !ouJ3Jn   
break; sZ_+6+ :  
} Ubv<3syR'  
} |pA3ZWm  
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public void splitterStop() *{6{ZKM  
{ xO{yr[x"L  
bStop = true; 5*C#~gd&F  
} O,u$L  
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} |<gYzb
q  
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/* E{*d`n  
**FileAccess.java 3,t3\`=  
*//文件访问(定位，写) h_n`E7&bG  
package NetFox; jY
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import java.io.*; $cflF@3  
d[=~-[  
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public class FileAccessI implements Serializable{ *d b,N'rK  
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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 },+ &y^  
RandomAccessFile oSavedFile; o!bV;]  
long nPos; j"1#n? 0  
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public FileAccessI() throws IOException OlI|.~  
{ dg-nv]7  
this("",0); b@`h]]~:  
} `|(S]xPHM  
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public FileAccessI(String sName,long nPos) throws IOException +VT/c  
{ C%H{"  
oSavedFile = new RandomAccessFile(sName,"rw"); )B)ecJJ_  
this.nPos = nPos; t>Lq "]1  
oSavedFile.seek(nPos); n<3qr}ZG^  
} RzhAXI=  
wNl{,aH@  
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public synchronized int write(byte[] b,int nStart,int nLen) t\S=u y  
{ xl>8B/Zmf#  
int n = -1; kn%i#Fz  
try{ 6 );8z!+  
oSavedFile.write(b,nStart,nLen); x,L<{A`z  
n = nLen; v(=?@tF}E  
} zi%Ql|zI~  
catch(IOException e) P@| W\  
{ $Y`oqw?g+^  
e.printStackTrace (); JCO+_d#x  
} Gu@n1/m@o  
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return n; Q?xA))0  
} [3D*DyQt  
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} V$0mcwH  
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/* C2 4"H|D  
**SiteInfoBean.java 'Y2ImSWj  
*/ z;wOtKl5r  
package NetFox; N2 4J!L  
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public class SiteInfoBean { hU'h78bt(  
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private String sSiteURL; //Site's URL X~g U$  
private String sFilePath; //Saved File's Path  T_)G5a  
private String sFileName; //Saved File's Name Lo,uH`qU  
private int nSplitter; //Count of Splited Downloading File {^":^N)  
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public SiteInfoBean() tJ$gH;  
{//nSplitter的缺省值为5 2Y>#FEW/  
//default value of nSplitter is 5 4ibOVBG:*,  
this("","","",5); #?"^:,Y  
} OMfw#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r(j:C%?}C  
{ 'C7$,H'  
sSiteURL= sURL; +?)R
}\\  
sFilePath = sPath; #(7^V y&  
sFileName = sName; 'pj*6t1~  
this.nSplitter = nSpiltter; >t#5eT`_ w  
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} ^ 6b27_=  
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public String getSSiteURL() R =kXf/y  
{ =&Z#QD"vl  
return sSiteURL; W#&BU-|2  
} XM f>B|
  
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public void setSSiteURL(String value) ZiW&*nN?M  
{ i
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sSiteURL = value; |@5G\N-  
} `*WzHDv5p  
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public String getSFilePath() ;;S9kNp^v  
{ }Qa  
return sFilePath; H1c>3c  
} ;Wg
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public void setSFilePath(String value) T]x]hQ  
{ $px1D$F!  
sFilePath = value; _Un*x5u2O  
} ?f= ~Pn+  
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public String getSFileName() ivg W[]  
{ 3aw-fuuIb  
return sFileName; 9^7z"*@#  
} 4k!>JQor  
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public void setSFileName(String value) y[ZVi5) ,  
{ ,zEPdhTX  
sFileName = value; T_[5 ZYy  
} }Te+Rv7{E  
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public int getNSplitter() lS|F&I5j  
{ {A~3/M%74;  
return nSplitter; (%'`t(<  
} woa|h"T  
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public void setNSplitter(int nCount) H#M;TjR  
{ 1{Ik.O)  
nSplitter = nCount; @=OX7zq\h-  
} _7b4+ L  
} h.\p+Qw.  
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MoXai0d%  
/* jX.'G   
**Utility.java YZAQt*x
 
*/ liBFx6\"S  
package NetFox; Wr@q+Whq  
zSjZTA/Z  
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public class Utility { 85q!FpuH  
{]%7-4E  
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public Utility() uqVarRi$  
{ CDY3+!  
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} K#Xl)h}y7  
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//线程睡眠 .e4upTGU  
public static void sleep(int nSecond) r)B55;*Fh  
{ XT
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try{ w4FYd  
Thread.sleep(nSecond); IH`7ou{  
} !C(PfsrR/  
catch(Exception e) 7X8*7'.2  
{ #7"";"{z|  
e.printStackTrace (); J\FLIw4  
} N;DE,[:<  
} fymmAfaR  
 c& $[a%s  
//日志 mKoDy`s  
public static void log(String sMsg) `QZKW  
{ (:^YfG~e  
System.err.println(sMsg); {L \TO,  
} Vh^ :.y  
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,."wxP2u  
public static void log(int sMsg) s`pdy
$  
{ @V&HE:P  
System.err.println(sMsg); IpM"k)HR  
} \mZB*k)+  
} Nrq/Pkmy  
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/* qiq=v)  
**TestMethod.java O|+$9#,  
*/ VbNN1'a-  
package NetFox; e(FT4KD~  
>p`i6_P0P/  
\=$G94%  
public class TestMethod { :2+z_+k}<  
3#aLCpVla  
^5)=)xVF  
public TestMethod() {E}D6`{  
{ ///xx/weblogic60b2_win.exe 8Pva]Q  
try{ 7jr+jNsowj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $GOF'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @1qdnU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nfv` )n@  
fileFetch.start(); e.Jaq^Gw|  
} 1/syzHjbY  
catch(Exception e){e.printStackTrace ();} w
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9Z"WV5o  
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} zn0%%x+!g  
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public static void main(String[] args) ;iQw2XhT  
{ y-S23B
(  
new TestMethod(); :GFK |  
} I]42R;Sc  
} q"WfKz!U  
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