http断点续传简单实现（java)

/* p<
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**SiteFileFetch.java {z>!Fw  
*/ |YLja87  
package NetFox; ;y(;7n_ a  
import java.io.*; 'u.Dt*.Uq  
import java.net.*; L!:NL#M  
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public class SiteFileFetch extends Thread { P7w RX F{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean , >WH)+a  
long[] nStartPos; //开始位置 \HB fM&  
long[] nEndPos; //结束位置 u43Mo\"<&%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `!cdxKLR  
long nFileLength; //文件长度 1{M?_~g4  
boolean bFirst = true; //是否第一次取文件 4 Y=0>FlY0  
boolean bStop = false; //停止标志 r]Hrz'C`  
File tmpFile; //文件下载的临时信息 $*eYiz3Ue  
DataOutputStream output; //输出到文件的输出流 ~+{*KPiD  
N&G'i.w/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oO;L l?~  
public SiteFileFetch(SiteInfoBean bean) throws IOException B!mHO*g  
{ At@0G\^  
siteInfoBean = bean; *m
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +7%?p"gEY\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y*@7/2,  
if(tmpFile.exists ()) v9H t~\>  
{ mW]dhY 3X  
bFirst = false; xp1/@Pw?  
read_nPos(); jUE:QOfRib  
} S$SCW<LuN  
else 2W0nA t  
{ ?8$`GyjS  
nStartPos = new long[bean.getNSplitter()]; +FNGRL  
nEndPos = new long[bean.getNSplitter()]; DSHvBFQ  
} jS]Saqd  
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} *i*\dl  
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public void run() mKtMI!FR  
{ TAh'u|{u2  
//获得文件长度  gwIR3u  
//分割文件 .pZYPKMaE  
//实例FileSplitterFetch Up%XBA  
//启动FileSplitterFetch线程 RNB-W%  
//等待子线程返回 
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try{ ~I N g9|  
if(bFirst) Ag T)J  
{ dlyGgaV*X  
nFileLength = getFileSize(); [&~x5l 8\C  
if(nFileLength == -1) .]exY i  
{ UQkd$w<  
System.err.println("File Length is not known!"); .qe+"$K'n  
} CV HKP[-  
else if(nFileLength == -2) An>ai N
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{ @G]*]rkKb  
System.err.println("File is not access!"); EyR/  
} D|U bh]  
else
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{ /Q9
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for(int i=0;i<nStartPos.length;i++) ^+%bh/2_W  
{ \aPH_sf,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V*JqC  
} [ {"x{;  
for(int i=0;i<nEndPos.length-1;i++) ({Yfsf,  
{ 3R$R?^G  
nEndPos = nStartPos[i+1]; Otr=+i ZI  
} hc$m1lLn  
nEndPos[nEndPos.length-1] = nFileLength; {pi_yr3  
} z( ^?xv  
} CUdpT$$x3  
PC"=B[OlJ  
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//启动子线程 w9u|E46  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KiMlbF.~V  
for(int i=0;i<nStartPos.length;i++) ]?}pJ28  
{ nQ'NS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V!*1F1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q7`)&^ Hx  
nStartPos,nEndPos,i); nT4Ryld  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bCTN^  
fileSplitterFetch.start(); 2T%sHp~qt  
} 0 GFho$f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /Xc9}~t6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .|DrXJ\c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w"D1mI!L 7  
nEndPos = " + nFileLength); TqS s*as5
 
// fileSplitterFetch[nPos.length-1].start(); e7n0=U0  
}VWUcALJV  
])
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//等待子线程结束 *>2FcoN;  
//int count = 0; !:xE X~  
//是否结束while循环 v}5YUM0H`  
boolean breakWhile = false; lV3k4iRH  
@ZYJY  
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while(!bStop) .`u8(S+  
{ 9I5AYa?  
write_nPos(); 55`p~:&VQ  
Utility.sleep(500); X16O9qsh  
breakWhile = true; usKP9[T$  
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for(int i=0;i<nStartPos.length;i++) 2u0B=0x  
{ it>Bf;  
if(!fileSplitterFetch.bDownOver) 1f"}]MbLR  
{ 3DCR n :  
breakWhile = false; A#Ga!a  
break;
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} Bn.R,B0PL  
} Dbx zqd  
if(breakWhile) gs.+|4dv  
break; <)_#6)z:  
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//count++; V3|" v4  
//if(count>4) HsRoiqo  
// siteStop(); z 36Y/{>[  
} VWYNq^<AT  
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System.err.println("文件下载结束！"); s/3sOb}sA  
} (Xzq(QV  
catch(Exception e){e.printStackTrace ();} pvWj)4e  
} o8A8fHl  
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//获得文件长度 :YLYCVi|  
public long getFileSize() "WPWMQ+  
{ q+;lxR5D  
int nFileLength = -1; RZ9_*Lq7+  
try{ 1} _<qk9  
URL url = new URL(siteInfoBean.getSSiteURL()); @.dM1DN)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LF(S"Of  
httpConnection.setRequestProperty("User-Agent","NetFox"); P;X0L{u0H  
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int responseCode=httpConnection.getResponseCode(); +,i_G?eX  
if(responseCode>=400) .G<Or`K^i  
{ }`2+`w%uZ  
processErrorCode(responseCode); Ir
- 1@_1Q  
return -2; //-2 represent access is error V6Of(;r  
} Pc+,iK>
 
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String sHeader; ,d HAD  
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for(int i=1;;i++) =*UVe%N4  
{ b$*G&d5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F"tM?V.|  
//Utility.log(in.readLine()); -O@/S9]S)  
sHeader=httpConnection.getHeaderFieldKey(i); %u Dd#+{  
if(sHeader!=null) !:_krLB<  
{ ?Qpi(Czbpq  
if(sHeader.equals("Content-Length")) 5a&gdqg]  
{ ILHn~d IC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )%: W;H  
break; F=UW[zy/[  
} h`tf!MD]  
} bvJ*REPL?  
else {PL,3EBG  
break; K$$%j"s
 
} ;~}!P7z  
} iZ(p]0aP7  
catch(IOException e){e.printStackTrace ();} (d[JMO^@8  
catch(Exception e){e.printStackTrace ();} YIl,8! z~  
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Utility.log(nFileLength); #vR5a}BAk  
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return nFileLength; <.@w%rvG  
} c[?&;# feV  
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//保存下载信息（文件指针位置） <@v|~AO4~  
private void write_nPos() I=8M
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{ j2#B l  
try{ }sfvzw_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p"n3JV.~k+  
output.writeInt(nStartPos.length); ve*6WDK,H  
for(int i=0;i<nStartPos.length;i++) fp"GdkO#}i  
{ ,0n=*o@W  
// output.writeLong(nPos); c{/KkmI  
output.writeLong(fileSplitterFetch.nStartPos); B=i%Z_r]w  
output.writeLong(fileSplitterFetch.nEndPos); ,\PTn7_  
} 2u}ns8wn  
output.close(); >DR/lBtL  
} &([yI>%  
catch(IOException e){e.printStackTrace ();} Sr6?^>A@t  
catch(Exception e){e.printStackTrace ();} .@Jos^rxgJ  
} leJ3-w{ 2  
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//读取保存的下载信息（文件指针位置） N*Xl0m(Q  
private void read_nPos() ??Dv\yLZI  
{ xb^M33-y  
try{ K`cy97  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q".p5(<  
int nCount = input.readInt(); .@f)#2  
nStartPos = new long[nCount]; UeSPwY  
nEndPos = new long[nCount]; IpsV4nmnz-  
for(int i=0;i<nStartPos.length;i++) n,|YJ,v[  
{ FVoKNaK-  
nStartPos = input.readLong(); yc@:*Z  
nEndPos = input.readLong(); 9CHn6 v ~)  
} toC|vn&P  
input.close(); !%G;t$U=M  
} ;0E[ ; L!  
catch(IOException e){e.printStackTrace ();} T;B/Wm!x  
catch(Exception e){e.printStackTrace ();} a~`,zQ -@  
} sQa9M  
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private void processErrorCode(int nErrorCode) yI$MqR  
{ -<q@0IYyi  
System.err.println("Error Code : " + nErrorCode); Zq\ p%AU9  
} -<gQ>`(0  
>4AwjS}H  
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//停止文件下载 1s#GY<<  
public void siteStop() Y@V6/D} 1  
{ %J|xPp)  
bStop = true; 4fdO Ow  
for(int i=0;i<nStartPos.length;i++) q|R$A8)L.  
fileSplitterFetch.splitterStop(); ZZF\;  
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} <x1H:8A  
} bR|1*<  
//负责部分文件的抓取 }zV#?;}  
**FileSplitterFetch.java kZvh<NFh_  
*/ m?Dk(DJ  
package NetFox; -*&C "%e  
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import java.io.*; fsVr<m  
import java.net.*; u=p-]?  
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public class FileSplitterFetch extends Thread { FuZLE%gP  
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String sURL; //File URL }=^Al;W  
long nStartPos; //File Snippet Start Position p`LPO  
long nEndPos; //File Snippet End Position p9$=."5  
int nThreadID; //Thread's ID e.^Y4(  
boolean bDownOver = false; //Downing is over r$.v"Wh)  
boolean bStop = false; //Stop identical wKs-<b%;  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7Ke#sW.HN  
{ 2wG4"  
this.sURL = sURL; 2VNfnk  
this.nStartPos = nStart; K=C).5=U  
this.nEndPos = nEnd; )Y+?)=~  
nThreadID = id; )IP{yL8c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cxQ8/0^  
} /!Kl  
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public void run() Ev;ocb,  
{ !56gJJ-r  
while(nStartPos < nEndPos && !bStop) RDu'N  
{ `L=$,7`  
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try{ :+>:>$ao  
URL url = new URL(sURL); 35[8XD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (^Kcyag4  
httpConnection.setRequestProperty("User-Agent","NetFox"); b(~ gQM  
String sProperty = "bytes="+nStartPos+"-"; #dgWXO  
httpConnection.setRequestProperty("RANGE",sProperty); '{:Yg3K  
Utility.log(sProperty); nC5  
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InputStream input = httpConnection.getInputStream(); ?=uw0~O[  
//logResponseHead(httpConnection); z<F.0~)jb  
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byte[] b = new byte[1024]; oGLSk(T&I  
int nRead; L.xzI-I@D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hFjXgpz5  
{ F W# S.<  
nStartPos += fileAccessI.write(b,0,nRead); Pl }dA  
//if(nThreadID == 1) THmX=K4=?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^m   
} 2Ax HhD.  
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Utility.log("Thread " + nThreadID + " is over!"); 1& k_&o  
bDownOver = true; 6#k Ap+g7  
//nPos = fileAccessI.write (b,0,nRead); imtW[y+4  
} %
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catch(Exception e){e.printStackTrace ();} (r^IW{IndX  
} WQ]~TGW  
} y\Z-x  
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1px:(8]{  
//打印回应的头信息 .JpYZ |  
public void logResponseHead(HttpURLConnection con) >29eu^~nh  
{ 5|-(Ic  
for(int i=1;;i++) NDRk%_Eu(  
{ {cv,Tz[Q>  
String header=con.getHeaderFieldKey(i); i)0*J?l=  
if(header!=null) C<6IiF[>%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =ot`V; Q>  
Utility.log(header+" : "+con.getHeaderField(header)); U3^T.i"R  
else ,7pO-:*g  
break; Uc}L/ax  
} &,fBg6A%  
}  -[a0\H  
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public void splitterStop() eR8qO"%2:  
{ f
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bStop = true; Ckvm3r\i2  
} / GJ"##<  
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} ?S0VtHQ  
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/* `2NL'O:  
**FileAccess.java x-U^U.i@  
*//文件访问(定位，写) d<qbUk3;  
package NetFox; d?&?$qf[  
import java.io.*; y3$' gu|  
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public class FileAccessI implements Serializable{ 89@89-_mC  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )u]<8  
RandomAccessFile oSavedFile; t_,iV9NrZ  
long nPos; CQ"IL;y  
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public FileAccessI() throws IOException J(M0t~RZ  
{ *D,+v!wG9  
this("",0); rEdr8qw  
} Roy`HU ;0a  
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public FileAccessI(String sName,long nPos) throws IOException #JO#PV%  
{ Y#{KGVT<  
oSavedFile = new RandomAccessFile(sName,"rw"); ERGDo=j  
this.nPos = nPos; YIfPE{,  
oSavedFile.seek(nPos); n1uJQt  
} >}u?{_s *0  
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public synchronized int write(byte[] b,int nStart,int nLen) )Ah  
{ WqY:XE+?\  
int n = -1; G5=(3V%  
try{ ?8! 4!P%n  
oSavedFile.write(b,nStart,nLen); Ej
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n = nLen; A0O$B7ylQ  
} qg:1  
catch(IOException e) s4MP!n?gB  
{ vT%rg r  
e.printStackTrace (); -hp,O?PM  
} T_jwj N  
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return n; \~jt7 Q  
} Mk|h ><Q"  
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} :;{U2q+  
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/* X-oou'4<  
**SiteInfoBean.java ]4uIb+(S  
*/ i0p"q p  
package NetFox; ^"6xE nA]  
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pl q$t/.U;  
public class SiteInfoBean { :$/lGIz  
{U^mL6=&v  
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private String sSiteURL; //Site's URL i7e{REBXb  
private String sFilePath; //Saved File's Path  `U(A
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private String sFileName; //Saved File's Name <&l3bL  
private int nSplitter; //Count of Splited Downloading File _~L
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public SiteInfoBean() HOykmx6$  
{//nSplitter的缺省值为5 Om>6<3n  
//default value of nSplitter is 5 ~+3f8%   
this("","","",5); 1v`<Vb%"}T  
} S
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w`>xK sKW>  
{ Qkr'C n  
sSiteURL= sURL; nV:.-JR  
sFilePath = sPath; -k$rkKHZ(  
sFileName = sName; Am kHVg  
this.nSplitter = nSpiltter; qG=`'%,m  
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} 0qJ(3N  
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#
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public String getSSiteURL() 20%xD e  
{ 8{Zgvqbb  
return sSiteURL; &)xoR4!2  
} v,+2CVdW  
##k=='dR  
[(#ncR8B  
public void setSSiteURL(String value) I!# 42~\  
{ 7|,5
;  
sSiteURL = value; )2bPu[U  
} o5Pq>Y2T  
? 76jz>;b  
=H!u4  
public String getSFilePath() 9-bDgzk   
{ KS(s<ip|  
return sFilePath; *QAK9mc  
} YdE$G>
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public void setSFilePath(String value) l)XzU&Sc~  
{ xQaN\):^8  
sFilePath = value; r%_)7Wk*  
} z4{|?0=C  
]<z>YyBA  
s)ZL`S?</  
public String getSFileName() 9O@eJ$  
{ 0%'&s)#  
return sFileName; 7z F29gC  
} Zf?>:P  
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public void setSFileName(String value) 8Jxo;Y  
{ X<Vko^vlj  
sFileName = value; e[R364K  
} lm]4zs /A  
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public int getNSplitter() _?O'65  
{ XQlK}AK  
return nSplitter; |*OS;FD5  
} v0=^Hym  
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tR0o6s@v/<  
public void setNSplitter(int nCount) R2t5T-8`c  
{ ETjlq]@j  
nSplitter = nCount; #/5jW
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} IY,&/MCh  
} ha3 Qx  
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/* a.wRJ  
**Utility.java "E8-76n  
*/ hD # Yz<  
package NetFox; #N@sJyIN  
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^  
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public class Utility { K^s!0[6  
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public Utility() |2{y'?,  
{ xJN Jv
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} &xrm;pO  
9[6xo!  
//线程睡眠 $>8+t>|  
public static void sleep(int nSecond) _@jl9<t=_  
{ 8$xg\l0?KK  
try{ u|O5ZV-cd  
Thread.sleep(nSecond); xREqcH,vU  
} D8BK/E-  
catch(Exception e) KzI$GU3  
{ 1ciP+->$  
e.printStackTrace (); IWuR=I$t  
} :}e*3={4  
} Aj SIM.  
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//日志 ;:8_H0X'K  
public static void log(String sMsg)  4\dc  
{ I_'vVbK+>  
System.err.println(sMsg); byyz\>yAVq  
} +%$!sp?  
!$qNugLg  
}qi6K-,oU  
public static void log(int sMsg) WI](a8bm  
{ 6>SP5|GG  
System.err.println(sMsg); Y-gjX$qGo  
} <y(>z*T;  
} CPFd 33  
<P(d%XEl  
-"<H$  
/* dB^J}_wp  
**TestMethod.java +:mj]`=
  
*/ fPZBm&`C  
package NetFox; o5i?|HJ  
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public class TestMethod { 8/ZJkI  
vn6/H8  
3)EslBA7i  
public TestMethod() CZxQz  
{ ///xx/weblogic60b2_win.exe >.\G/'\?  
try{ {~[H"h537t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4YXtl+G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FavU"QU&|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [ C]=p  
fileFetch.start(); It(8s)5  
} Czid"Ih-  
catch(Exception e){e.printStackTrace ();} k_-=:(Z  
=}Bq"m  
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} ipw_AC~  
aVO5zR./)  
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public static void main(String[] args) (GMKIw2  
{ ^qIp+[/'  
new TestMethod(); +}I[l,,xy  
} HC?yodp^  
} c zL[W2l  
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