http断点续传简单实现（java)

/* Svs&?B\}{6  
**SiteFileFetch.java 0\eSiXs  
*/ Cq-99@&;  
package NetFox; Eok8+7g0&  
import java.io.*; z_8Bl2tl  
import java.net.*; =CL,+  
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public class SiteFileFetch extends Thread { j9cB<atL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean QqXaXx;  
long[] nStartPos; //开始位置 PC%_^BDW  
long[] nEndPos; //结束位置 B E#pHg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ol_&epG;ST  
long nFileLength; //文件长度 3;!a'[W&p  
boolean bFirst = true; //是否第一次取文件 'OMl9}M  
boolean bStop = false; //停止标志 SO~pe$c-  
File tmpFile; //文件下载的临时信息 472'P  
DataOutputStream output; //输出到文件的输出流 RaC6RH  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U)z1RHP|z  
public SiteFileFetch(SiteInfoBean bean) throws IOException dO-Zj#%7z8  
{ dtXtZ!g2  
siteInfoBean = bean; s GrI%3[e"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (8em5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9AD0|,g  
if(tmpFile.exists ()) ?w)A`G_  
{ i_I`  
bFirst = false; 475jmQ{q  
read_nPos(); J.0&gP V  
} TJ,?C$3  
else A~LTi  
{ 6\)u\m`7-l  
nStartPos = new long[bean.getNSplitter()]; T8j
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nEndPos = new long[bean.getNSplitter()]; V7+/|P_  
} ^q<EnsY  
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} y!j>_m){w  
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public void run() LBcqFvj{&  
{ %Wc$S]>i  
//获得文件长度 ;[|+tO_  
//分割文件 {|e7^_ke  
//实例FileSplitterFetch ikPr>  
//启动FileSplitterFetch线程 J/[PA[Rf  
//等待子线程返回 UG<<.1JL  
try{ V.o*`V  
if(bFirst) J!'IkC$>  
{ >Q)S-4iR  
nFileLength = getFileSize(); **ls 4CE<  
if(nFileLength == -1) zXd#kw;  
{ YIYuqtn
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System.err.println("File Length is not known!"); e"2x!(&n(  
} u5,vchZ  
else if(nFileLength == -2) \/r]Ra  
{ =e6!U5 f  
System.err.println("File is not access!");
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} (. ,{x)H  
else [bN_0T.YI  
{ v\XO?UEJ2  
for(int i=0;i<nStartPos.length;i++) Xd&oERJj  
{ L-e6
^
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); R7x*/?  
} _cbXzSYq&  
for(int i=0;i<nEndPos.length-1;i++) b+71`aD0  
{ W#9LK Jj  
nEndPos = nStartPos[i+1]; /NVyzM51V  
} WVL\|y728s  
nEndPos[nEndPos.length-1] = nFileLength; 57$/Dn  
} ;ZZmX]kz,M  
} 5WtI.7r  
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//启动子线程 o6r ^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jgw+c3^R_  
for(int i=0;i<nStartPos.length;i++) k6_
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{ QO|jdlg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^ =H 10A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C7Hgzc|U  
nStartPos,nEndPos,i); "l6Ob
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); COSQ  
fileSplitterFetch.start(); Z0Qh7xWve  
} 1sfs!b&E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [wUJ~~2#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mS]soYTQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '_xa>T}  
nEndPos = " + nFileLength); CWnRRZ}r  
// fileSplitterFetch[nPos.length-1].start(); JZD&u6tB   
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;7!u(XzN  
//等待子线程结束 T{ /\q 5  
//int count = 0; w)gMJX/0yw  
//是否结束while循环 ]tEH`Kl  
boolean breakWhile = false; o(xt%'L`t  
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while(!bStop) M,P:<-J  
{ hQDl&A  
write_nPos(); w{Y:p[}  
Utility.sleep(500); rVnolA*%  
breakWhile = true; <P c;8[  
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for(int i=0;i<nStartPos.length;i++) `mKK1x  
{ X!]p8Q y  
if(!fileSplitterFetch.bDownOver) ybgw#jv=  
{ m pM,&7}  
breakWhile = false; jiLt *>I  
break; Oxh.&  
} 97VS xhr  
} [JVUa2Sm  
if(breakWhile) T-lHlm  
break; "ODs.m oq  
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//count++; n UD;y}}n  
//if(count>4) gUv`G  
// siteStop(); HQ3kxOT  
} *lp{,  
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System.err.println("文件下载结束！"); ]N1gzHaS  
} |_wbxdq  
catch(Exception e){e.printStackTrace ();} 0bR})}a+Yg  
} :FI4GR*?  
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5E\&O%W"  
//获得文件长度 ro@`S:  
public long getFileSize() @*~cmf&FIQ  
{ 8x<; AL|`  
int nFileLength = -1; |'12Kv]#Xa  
try{ </7?puVR  
URL url = new URL(siteInfoBean.getSSiteURL()); VXu1YxY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >J@hqW  
httpConnection.setRequestProperty("User-Agent","NetFox"); `T$CUlt6  
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int responseCode=httpConnection.getResponseCode(); Vu1X@@
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if(responseCode>=400) {@<EV
w  
{ jX{t/8v/s4  
processErrorCode(responseCode); =h}IyY@o  
return -2; //-2 represent access is error J"]P"`/  
} {K+]^M  
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String sHeader; '~kAsn*/  
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for(int i=1;;i++) NxQ+z^o\  
{ pL)o@-k#%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qi-!iT(fe  
//Utility.log(in.readLine()); h8
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sHeader=httpConnection.getHeaderFieldKey(i); +"2IQme5  
if(sHeader!=null) i^u5j\pfY*  
{ l+i9)Fc<i  
if(sHeader.equals("Content-Length")) EU-=\Y  
{ TZ%u;tBH:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iMr/i?`i  
break; O[#pB. 4  
} MzO4Yv"A  
} BF>3CW7  
else 3~^}R  
break; >gTrui{,  
} mkOj&Q  
} l*C(FPw4  
catch(IOException e){e.printStackTrace ();} uWKc .  
catch(Exception e){e.printStackTrace ();} O U3KB  
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Utility.log(nFileLength); !<xeAo%8  
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return nFileLength; q!+m, !M  
} t9B]V  
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//保存下载信息（文件指针位置） .I&]G  
private void write_nPos() _4jRUsvjY  
{ @I^LmB9*  
try{ <kr%ylhIu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nWAx!0G  
output.writeInt(nStartPos.length); DU/WB  
for(int i=0;i<nStartPos.length;i++) 8P'zQ:#RV  
{ -hIDL'5u-I  
// output.writeLong(nPos); Ou<Vg\Mu  
output.writeLong(fileSplitterFetch.nStartPos); 2qD80W<1  
output.writeLong(fileSplitterFetch.nEndPos); a,sU-w!X'  
} i-4pdK u  
output.close(); DpaPRA)x  
} F&om^G'U  
catch(IOException e){e.printStackTrace ();} Jr4^@]78o<  
catch(Exception e){e.printStackTrace ();} p%v+\T2r  
} 'rwnAr  
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//读取保存的下载信息（文件指针位置） T};fy+iq  
private void read_nPos() E#=slj@  
{ Jm+;A^;  
try{ ;8 D31OT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,!?&LdPt>  
int nCount = input.readInt(); k )T;WCia  
nStartPos = new long[nCount]; h)qapC5z,  
nEndPos = new long[nCount]; sKT GZA  
for(int i=0;i<nStartPos.length;i++) )0I;+9:D=  
{ mw1|>*X&R  
nStartPos = input.readLong(); kU5chltGF  
nEndPos = input.readLong(); wv8WqYV  
} sinnHQ  
input.close(); *VFUC:  
} |-c)OS3#D  
catch(IOException e){e.printStackTrace ();} /~
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catch(Exception e){e.printStackTrace ();} Q!<b"8V]  
} qUY QN2wG  
]#N~r&hmQ  
+)4_1i4"x  
private void processErrorCode(int nErrorCode) jHj*S9:`  
{ {Y! -]_5  
System.err.println("Error Code : " + nErrorCode); 8N|y  
} lxpi  
=sk]/64h``  
}.x&}FqXE  
//停止文件下载 OJUH".o  
public void siteStop() jc|"wN]  
{ 5!T\L~tyt  
bStop = true; i(XcNnn6  
for(int i=0;i<nStartPos.length;i++) *LbRLwt  
fileSplitterFetch.splitterStop(); 5X5&(S\  
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} bt/u^E  
} }-:s9Lt  
//负责部分文件的抓取 `)[bu  
**FileSplitterFetch.java tU02t#8  
*/ Wv]NFHe#  
package NetFox; IG1+_-H:  
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import java.io.*; , wT$L3  
import java.net.*; 4%TY` II  
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public class FileSplitterFetch extends Thread { i6p0(OS&D  
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 2L~[dn.s  
String sURL; //File URL .FS`Fh;  
long nStartPos; //File Snippet Start Position vt3yCS  
long nEndPos; //File Snippet End Position _ FcfNF  
int nThreadID; //Thread's ID {"dU?/d  
boolean bDownOver = false; //Downing is over X#
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boolean bStop = false; //Stop identical ,nJYYM   
FileAccessI fileAccessI = null; //File Access interface C%8jWc  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C<GS._V&  
{ lZ5 lmsCU  
this.sURL = sURL; mJaWzR  
this.nStartPos = nStart; }];8v+M  
this.nEndPos = nEnd; M~Yho".  
nThreadID = id; o:<gJzg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Jb'M/iG  
} `CP}1W>  
[.O3z*[9#  
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public void run() ]~:9b[G2  
{ :?VM1!~ga  
while(nStartPos < nEndPos && !bStop) E4^zW_|xE  
{ Z_oBZs  
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try{ XY]|OZ7(  
URL url = new URL(sURL); xeqAFq=9?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3"HpM\A{A=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Nj Ng=q  
String sProperty = "bytes="+nStartPos+"-"; 5Uc!;Gd?b  
httpConnection.setRequestProperty("RANGE",sProperty); rULrGoM  
Utility.log(sProperty); w\U fq  
}VlX!/42  
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InputStream input = httpConnection.getInputStream(); B1]dub9  
//logResponseHead(httpConnection); V#:`:-$$+  
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byte[] b = new byte[1024]; _C3l2v'I$  
int nRead; P>/n!1c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >E&mNp  
{ A+Nf](
[  
nStartPos += fileAccessI.write(b,0,nRead); U$j*{`$4  
//if(nThreadID == 1) W8:?y*6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iq>PN:mr  
} ?:(BkY,K5  
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Utility.log("Thread " + nThreadID + " is over!"); "oX@Z^  
bDownOver = true; Hf( d x\5  
//nPos = fileAccessI.write (b,0,nRead); _Y'+E  
} kK2x';21  
catch(Exception e){e.printStackTrace ();} #M;Cw}pW  
} -I7"9}j3  
} -,NiSh}A  
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+;7Rz_.6f  
//打印回应的头信息 4-@D`,3L  
public void logResponseHead(HttpURLConnection con) Z `FqC  
{ 9H~3&-8&  
for(int i=1;;i++) LMchNTL  
{ ZzA4iT=KO  
String header=con.getHeaderFieldKey(i); [,s{/OM  
if(header!=null) Gma)
8X#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )v&r^DR_  
Utility.log(header+" : "+con.getHeaderField(header)); b&BSigrvou  
else +@),
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break; [ay~l%x  
} }Wf\\  
} ^J3\ U{B  
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public void splitterStop() N>?R,XM V  
{ XJl2_
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bStop = true; *rPUVhD_  
} 5a1)`2V2M  
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} -`FPR4;  
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/* qP<wf=wY  
**FileAccess.java y#HDJ=2  
*//文件访问(定位，写) "71@WLlN  
package NetFox; ,6U
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import java.io.*; A+d&aE}3V  
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public class FileAccessI implements Serializable{ Sns`/4S?6Z  
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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 Gj]*_"T  
RandomAccessFile oSavedFile; j,")c'r&dD  
long nPos; y=)Cid  
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public FileAccessI() throws IOException .b*%c
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{ a=*
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this("",0); #% PnZ /  
} J1kG'cH05  
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public FileAccessI(String sName,long nPos) throws IOException i9?$BZQ[R  
{ (rV#EA+6[`  
oSavedFile = new RandomAccessFile(sName,"rw"); aW-'Jg=@H^  
this.nPos = nPos; Bi?+e~R  
oSavedFile.seek(nPos); Wh4`Iv\.  
} U5 ~L^  
AW;"` ].  
}r:H7&|&  
public synchronized int write(byte[] b,int nStart,int nLen) EAYx+zI  
{ j#e^PK <  
int n = -1; IM:*uv  
try{ .[Ezg(U}ze  
oSavedFile.write(b,nStart,nLen); .c~`{j}  
n = nLen; Z'EXq.hk  
} dLQV>oF  
catch(IOException e) L1;IXCc=  
{ 9$F '*{8  
e.printStackTrace (); g7G=ga  
} GmoY~}cg~  
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return n; O?|st$g  
} Ym~*5|  
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} |7XV!D!\g  
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/* 6A$ \I44  
**SiteInfoBean.java cl s-x@ Kd  
*/ Q$_S/d%*  
package NetFox; G%N3h'zDi  
u`Kjs}F'  
_:|/4.]`_  
public class SiteInfoBean { \Q[u?/TF  
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private String sSiteURL; //Site's URL vr#_pu)f4  
private String sFilePath; //Saved File's Path p-QD(+@M  
private String sFileName; //Saved File's Name fyat-wbb  
private int nSplitter; //Count of Splited Downloading File K1c@]]y)  
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s UX%{|T_  
public SiteInfoBean() pq0F!XmU  
{//nSplitter的缺省值为5 *gHGi(U(U  
//default value of nSplitter is 5 =sVB.P  
this("","","",5); :

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} >% a^;gk(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _B4H"2}[Y  
{ {VOLUC o 4  
sSiteURL= sURL; ZsjDe{TH  
sFilePath = sPath; }Xv2I$J  
sFileName = sName; @?,iy?BSG  
this.nSplitter = nSpiltter; )LESdX  
~x`BV+R  
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} '{9nQDgT  
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9L+dN%C  
public String getSSiteURL() z&!n'N<C  
{ (9bFIvMc  
return sSiteURL; !9+xKr99  
} '5j$wr zt  
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public void setSSiteURL(String value) 5AV5`<r.  
{ P~Cx#`#(V  
sSiteURL = value; ~4YU  
} %<cfjo  
*^]Hqf(`  
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public String getSFilePath() Z["[^=EP  
{ JY4sB8  
return sFilePath; H4#|f
n  
} ;E? Z<3{  
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public void setSFilePath(String value) DpG|Kl|d  
{ 7;H!F!K]  
sFilePath = value; \%fl`+`  
} EMyMed_  
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public String getSFileName() "PO>@tY  
{ `/en&l  
return sFileName; -X#Zn>#  
} =bt/2nPV  
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public void setSFileName(String value) z:C VzK,  
{ u_+64c_7  
sFileName = value; FM\yf]'  
} Qs(WyP#  
gWcl@|I;\  
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public int getNSplitter() ^_dYE]t  
{ d;GF<bz  
return nSplitter; iY @MnnX  
} nqX)+{wAXe  
nSWW^ ;  
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public void setNSplitter(int nCount) ?2D1gjr  
{ D@:w/W  
nSplitter = nCount; sB|>\O#-
 
} iQryX(z  
} hrsMAh!  
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5$C4Ui{<E'  
/* BJzNh>-#=  
**Utility.java e))fbv&V  
*/ 3K Y-+ k  
package NetFox; .<Y7,9;YEF  
1k&**!S]%  
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public class Utility { &p>VTD  
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public Utility() `Mj>t(  
{ Y](kMNUSg  
B J,U,!  
2%0J/]n\A"  
} PGTi-o}  
` drds  
//线程睡眠 p$r=jF&  
public static void sleep(int nSecond) -[\+~aDH,  
{ DIx!Sw7EC  
try{ i"eUacBz/-  
Thread.sleep(nSecond); Y*!J +A#  
} 6.X| .N  
catch(Exception e) q/I':a[1  
{ 3C8cvi[IS  
e.printStackTrace (); JO*}\
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} ,Jqi J?,4C  
} =pQ'wx|>|  
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//日志 {FV_APL9_  
public static void log(String sMsg) Ja$Ple*XU8  
{ k%UE^
 
System.err.println(sMsg); ]xhZJ~"@u  
} 5X
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public static void log(int sMsg) 3LT[?C]H$  
{ s zgq7  
System.err.println(sMsg); s d-5AE  
} ["N{6d&Q  
} qo2/?
]  
/%W&zd
=%#  
>lZ9Y{Y4v  
/* xWNB/{F  
**TestMethod.java \>}G|yL  
*/ TL%2?'G  
package NetFox; oA_T9uh[  
e;QPn(  
{<\[gm\X
 
public class TestMethod { -)S(eqq1  
g=8}G$su{%  
)?@X{AN&  
public TestMethod() /5@4}m>Z@  
{ ///xx/weblogic60b2_win.exe @EPO\\C"f  
try{ P)VysYb?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sn.Xvk%75  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3vs;ZBM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zq(R!a6  
fileFetch.start(); Q&p'\6~  
} A
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catch(Exception e){e.printStackTrace ();} r!DUsE  
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} }E?{M~"<  
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public static void main(String[] args) nq9|cS%-  
{ }jF67c->  
new TestMethod(); 8Ja't8  
} D;~c`G "f  
} 4d\1W?i-  
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