http断点续传简单实现（java)

/* D67z6jep(  
**SiteFileFetch.java XZ<8M}Lg  
*/ E BSjU8  
package NetFox; nG%<n  
import java.io.*; Z>[n~{-,p  
import java.net.*; 0|kH0c,T-  
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public class SiteFileFetch extends Thread { j8+>E?nm  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -^JPY)\R  
long[] nStartPos; //开始位置 A{Qo}F<*  
long[] nEndPos; //结束位置 a-lF}P\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kDG?/j90D  
long nFileLength; //文件长度 /!sGO:  
boolean bFirst = true; //是否第一次取文件 Ya}}a  
boolean bStop = false; //停止标志 a@-bw4SD  
File tmpFile; //文件下载的临时信息 T^ - -:1  
DataOutputStream output; //输出到文件的输出流 ,<$rSvMfg  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5cb8=W-  
public SiteFileFetch(SiteInfoBean bean) throws IOException b3ys
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{ +R_s(2vz  
siteInfoBean = bean; Mp(;PbVD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yZ)-=H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !+DhH2;)F  
if(tmpFile.exists ()) b#*"eZj
 
{ S0ReT*I  
bFirst = false; s^k<r;'\  
read_nPos(); U,lO{J
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} `Ue5;<K-/  
else 7=s7dYlu  
{ zYM0?O8pJ~  
nStartPos = new long[bean.getNSplitter()]; CSH*^nk':O  
nEndPos = new long[bean.getNSplitter()]; gYloY=.Z$'  
} _YN C}PUU  
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}  &_-3>8gU  
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public void run() "N)InPR-  
{ 6!8uZ>u%Vg  
//获得文件长度 $~\Tl:!#?  
//分割文件 pktnX-Slt  
//实例FileSplitterFetch i(*fv(z  
//启动FileSplitterFetch线程 `6BQ6)7  
//等待子线程返回 g`~;"%u7cn  
try{ bP,K
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if(bFirst) " t?44[  
{ ],vid1E  
nFileLength = getFileSize(); c7R&/JV  
if(nFileLength == -1) JSx[V<7m  
{ ,1]VY/  
System.err.println("File Length is not known!"); _Fe=:q  
} MP.ye|i4Q  
else if(nFileLength == -2) l<'}`  
{ >U?#'e{qW  
System.err.println("File is not access!"); d[*NDMO  
} 4q(,uk&R[  
else eu?P6>urA  
{ s>[Oe|`  
for(int i=0;i<nStartPos.length;i++) KuEM~Q=  
{ n57mh5mixM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1lJ^$U  
} C%j@s|  
for(int i=0;i<nEndPos.length-1;i++) ylDfr){  
{ (cI@#x  
nEndPos = nStartPos[i+1]; E^m)&.+'M  
} S
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nEndPos[nEndPos.length-1] = nFileLength; %eGD1.R  
} e@&2q{Gi=  
}
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}WF6w+  
7M_GGjP  
//启动子线程 F=f9##Y?7M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :qV|rih_Q  
for(int i=0;i<nStartPos.length;i++) )bpdj,  
{ 8%xiHPVg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ju4wU;Nu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?%/*F<UVQ  
nStartPos,nEndPos,i); AJ6O>Euq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V#c=O}  
fileSplitterFetch.start(); 9WHarv2@  
} 2uMSeSx$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .Np!Qp1*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6)FM83zk)K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JD AX^]  
nEndPos = " + nFileLength); u/wWD@,  
// fileSplitterFetch[nPos.length-1].start(); ?}jjBJ&  
52F3r:Rk  
G {a;s-OA3  
//等待子线程结束 cCIs~*D  
//int count = 0; 7]hRAhJ8I  
//是否结束while循环 Lo"s12fr  
boolean breakWhile = false; $]?M[sL\N7  
"\M3||.!  
2#'"<n,G
 
while(!bStop) nQn=zbZ3  
{ w2K>k/v{-  
write_nPos(); q@Zeu\T,*#  
Utility.sleep(500); ZKi?;ta=  
breakWhile = true; wqyF"^It"  
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for(int i=0;i<nStartPos.length;i++) G@<[fO|Iam  
{ 4=|oOIhgb  
if(!fileSplitterFetch.bDownOver) 7}tXF  
{ <,9rXjeRl  
breakWhile = false; +V#dJ[,8;.  
break;
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} ,LL=b-Es  
} w}x&wWM  
if(breakWhile) h6D1uM"o   
break; ^5-SL?E  
;]2d%Qt  
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//count++; quFNPdP  
//if(count>4) lK#uyag  
// siteStop(); c2yZvi  
} "}<baz  
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System.err.println("文件下载结束！"); N2Cf(  
} !Eb!y`jK  
catch(Exception e){e.printStackTrace ();} +^%
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} @$?*UI6y  
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//获得文件长度 H7Pw>Ta ;  
public long getFileSize() Wk]E6yz6  
{ j8ac8J,}c  
int nFileLength = -1; uecjR8\e  
try{ CbT ;#0  
URL url = new URL(siteInfoBean.getSSiteURL()); wd Di5-A4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tj tN<y  
httpConnection.setRequestProperty("User-Agent","NetFox"); &lB>G[t  
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int responseCode=httpConnection.getResponseCode(); "T6s;'k  
if(responseCode>=400) p%e/>N.P  
{ a,[NcdG  
processErrorCode(responseCode); N\x<'P4q  
return -2; //-2 represent access is error P)UpUMt;k  
} l,j0n0h.  
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String sHeader; /qXP\ a  
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for(int i=1;;i++) .H5^N\V|  
{ 0Y*Ag,S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v0+$d\mP4<  
//Utility.log(in.readLine()); ,v(ikPzd  
sHeader=httpConnection.getHeaderFieldKey(i); e{*z4q1  
if(sHeader!=null) Bv}nG|  
{ 8{p#Nl?U1  
if(sHeader.equals("Content-Length")) kT&GsR/  
{ ?O/!pUAu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dfd%Z;Yu  
break; 4I;$a;R!  
} E}|IU Pm  
} a.SxMF  
else vt}A6mF  
break; }/F9(m  
} ]#J-itO
  
} }yM!o`90  
catch(IOException e){e.printStackTrace ();} nkz^^q`5l7  
catch(Exception e){e.printStackTrace ();} %eE 6\f%g  
t` zPx#])  
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Utility.log(nFileLength); a8Z{-=)  
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return nFileLength; N
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} 6/L34VH  
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[L>AU; :  
//保存下载信息（文件指针位置） {OW.^UIq^  
private void write_nPos() BE," lX  
{ 2r#W#z%vS  
try{ <VmEXJIk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `
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output.writeInt(nStartPos.length); c]/&xRd  
for(int i=0;i<nStartPos.length;i++) ?uqPye1fc  
{ w0fFm"A|W  
// output.writeLong(nPos); /QVhT  
output.writeLong(fileSplitterFetch.nStartPos); O@,9a~Ghd  
output.writeLong(fileSplitterFetch.nEndPos); :-1 i1d  
} );ZxKGjc4  
output.close(); CrEC@5j  
} MH_3nN  
catch(IOException e){e.printStackTrace ();} uJL[m(G  
catch(Exception e){e.printStackTrace ();} Z~DR,:  
} Z<$y)bf  
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//读取保存的下载信息（文件指针位置） jftf]n&Z(q  
private void read_nPos() u/X1v-2  
{ }e&Z"H |  
try{ .
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T3^(I~03  
int nCount = input.readInt(); CYN|  
nStartPos = new long[nCount]; Y f;Slps  
nEndPos = new long[nCount]; l\~F0Z/O  
for(int i=0;i<nStartPos.length;i++) i^&^eg'.5  
{
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nStartPos = input.readLong(); O `a4 ")R  
nEndPos = input.readLong(); 5U%a$.yr  
} TllIs&MCe  
input.close(); O\)rp!i  
} A\~tr   
catch(IOException e){e.printStackTrace ();} <5l!xzvw  
catch(Exception e){e.printStackTrace ();} @#&y  
} UU]a).rz  
+[$ Q C*  
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private void processErrorCode(int nErrorCode) wm_o(Z}  
{ #N `Z)}Jm  
System.err.println("Error Code : " + nErrorCode); @(LEuYq}  
} 8hm|9  
!;;WS~no3  
0^&-j.9  
//停止文件下载 L:RMZp*bK  
public void siteStop() G,h=5y9_J  
{ e'1}5Ky  
bStop = true; Ra^GbT|Z
 
for(int i=0;i<nStartPos.length;i++) nn6&`$(Q~  
fileSplitterFetch.splitterStop(); c*`=o(S  
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} ':
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} hha^:,  
//负责部分文件的抓取 3+2cD  
**FileSplitterFetch.java e2$k %c~  
*/ o-%DL*^5  
package NetFox;  K na  
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import java.io.*; e-e*%  
import java.net.*; ,xsFBNCC  
)%]`uj>*[  
2/V9Or52  
public class FileSplitterFetch extends Thread { ![4<6/2gy  
) v^;"q"  
8.4+4Vxh   
String sURL; //File URL \*k}RKDwT  
long nStartPos; //File Snippet Start Position W=@]
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long nEndPos; //File Snippet End Position <hSrx7o  
int nThreadID; //Thread's ID b6A]/290x  
boolean bDownOver = false; //Downing is over nA>kJSL'$  
boolean bStop = false; //Stop identical [`Dv#  
FileAccessI fileAccessI = null; //File Access interface .3yxg}E>{  
kA%"-$3  
Q,z^eMk'd:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c@~j}(A  
{ 0NMekVi
 
this.sURL = sURL; *FrlzIAom  
this.nStartPos = nStart; yUzpl[*e^o  
this.nEndPos = nEnd; 1lLL9l{UVw  
nThreadID = id; 0413K_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U k*HRudt  
} Z 7s (g]  
vTY+J$N__  
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public void run() .,5N/p"aV  
{ Y>i?nC%*  
while(nStartPos < nEndPos && !bStop) 0755;26Bx  
{ WN%KATA  
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try{ *iVCHQ
~  
URL url = new URL(sURL); WbW@V_rr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bhWH  
httpConnection.setRequestProperty("User-Agent","NetFox"); WYklS<B[  
String sProperty = "bytes="+nStartPos+"-"; ]5}C@W@_  
httpConnection.setRequestProperty("RANGE",sProperty); 251^>x.R  
Utility.log(sProperty); DYKJVn7w  
'Bv)UfZ  
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InputStream input = httpConnection.getInputStream(); !9knFt43  
//logResponseHead(httpConnection); O>j_xW]V  
<i(<|/$  
` kG}NJf  
byte[] b = new byte[1024]; J` J^C  
int nRead; kt*""&R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
 8DsXw@o  
{ 1IRlFC  
nStartPos += fileAccessI.write(b,0,nRead); 5VG[FY6Pl  
//if(nThreadID == 1) #A '|O\RGP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U,wJ8  
} vhQIkB8  
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Utility.log("Thread " + nThreadID + " is over!"); E1uyMh-dy  
bDownOver = true; w[S!U<9/  
//nPos = fileAccessI.write (b,0,nRead); 8~>5k  
} DL0i  
catch(Exception e){e.printStackTrace ();} k[p7)ec  
} 5 UQbd8  
} NY`$D}Bi  
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//打印回应的头信息 <s7OY`(8   
public void logResponseHead(HttpURLConnection con) *$I5_A8,.  
{ D+ )R_  
for(int i=1;;i++) =E?!!EIq.  
{ |E YJbL;1%  
String header=con.getHeaderFieldKey(i); ]'2;6%.4
 
if(header!=null) SCZ6:P"$qX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~K-c-Zs#z  
Utility.log(header+" : "+con.getHeaderField(header)); }yfSF|\  
else !F_BLHig  
break; DFKumw>!  
} CAhkv0?8  
} Gw5j6  
i,Q{Z@,  
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public void splitterStop() m.}Yn,
  
{ 5g{F-  
bStop = true; :bhpYEUMx  
} Rt[zZv  
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} lo%:$2*'p  
n
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/* X(Wd  
**FileAccess.java vIi#M0@N  
*//文件访问(定位，写) 5ZRO{rf  
package NetFox; MifPZQ  
import java.io.*; \[Dxg`;4  
IU8/B+hM~  
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public class FileAccessI implements Serializable{ Ie[8Iot?bn  
tCJ+OU5/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4\.1phe$a  
RandomAccessFile oSavedFile; 4nfpPNt  
long nPos; 9bL`0L  
fJb<<6C  
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public FileAccessI() throws IOException ~ "^]\3#  
{ 5f:Mb|.?  
this("",0); }CiB+  
} me+F0:L  
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43"`gF]  
public FileAccessI(String sName,long nPos) throws IOException @o[C Xrz  
{ /a?*Ap5"  
oSavedFile = new RandomAccessFile(sName,"rw"); xMAfa>]{n  
this.nPos = nPos; Q!%4Iq%jr  
oSavedFile.seek(nPos); "t-u=aDl-.  
} b#:Pl`n6u  
$rAHtr  
|]dA`e&y  
public synchronized int write(byte[] b,int nStart,int nLen) "gcHcboU5$  
{ S+mZ.aFS0z  
int n = -1; ~i4h
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try{ _k0X)N+li  
oSavedFile.write(b,nStart,nLen); q"|,HpQ  
n = nLen; \a|FhhI  
} P,2FH2Eyj  
catch(IOException e) Hqel1J  
{ ~VRt6C  
e.printStackTrace (); j{i3lGaN  
} 7gLN
7_2  
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return n; T+OQa+E@P  
} \,-t]$9  
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} 5Iv3B|u  
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/* FCC9Ht8U?  
**SiteInfoBean.java }/ p>DMN  
*/ 9t.u9C=!F  
package NetFox; QJL%J  
DS@ZE Q`F  
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public class SiteInfoBean { U#I8Rd I,  
p7UdZOi2  
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private String sSiteURL; //Site's URL 7X h'VOljB  
private String sFilePath; //Saved File's Path J33enQd  
private String sFileName; //Saved File's Name 3;wAm/Z:Q  
private int nSplitter; //Count of Splited Downloading File }r}$8M+1  
H
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public SiteInfoBean() wj-=#gyAoo  
{//nSplitter的缺省值为5 }9&Z#1/  
//default value of nSplitter is 5 @a08*"lbp  
this("","","",5); 2yu\fu  
} V &K:~[M  
#1INOR9  
5
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j-egsKR  
{ wA+QUN3#n  
sSiteURL= sURL;  O "jX|5  
sFilePath = sPath; U*G8}W  
sFileName = sName; Y#>'.$(Az  
this.nSplitter = nSpiltter; C@{#OOa  
wABaNB=9;  
+d7s
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} n+C]&6-b  
qSB]Zm<  
HLL[r0P`F  
public String getSSiteURL() 'y
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{ ea"!:cL(g  
return sSiteURL; o"^+i#H!  
} b51{sL  
V Ae@P  
B0_[bQoc1  
public void setSSiteURL(String value) Ck71N3~W  
{ s*"Yi~
  
sSiteURL = value; O~E6"vQ  
} 334UMH__  
y\=(;]S'  
V'kCd4  
public String getSFilePath() :xn/9y+s  
{ S7{L-"D=y  
return sFilePath; IO,ddVO  
} v!\\aG/  
<M(Jqb cWa  
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public void setSFilePath(String value) 5Ocd2T'  
{ +(v<_#wR-  
sFilePath = value; qH3<,s*  
} G+k[.  
mN5`Fct*A>  
pF)}<<C  
public String getSFileName() e(;1XqLM  
{ z:RclDm  
return sFileName; +~gqPk  
} _R&}CP  
!ke_?+8sY  
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public void setSFileName(String value) v35wlt^}  
{ -&4W0JK9  
sFileName = value; yv.Y-c=  
} W<J".2D  
-P|EV|8=  
oV4+w_rrLc  
public int getNSplitter() S >E|A%  
{ 1b4aY> Z  
return nSplitter; RYU(z;+0p  
} ,XD'f  
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s[
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public void setNSplitter(int nCount) =5NM =K  
{ TTg>g~t`  
nSplitter = nCount; @]*b$6tt  
} v&BKl  
} gv&%2e}_  
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/* .'3&!#3  
**Utility.java JNQiCK,)}M  
*/ l `D>h2]  
package NetFox; z^+`S:  
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public class Utility { w28!Yj1Q  
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public Utility() fz%I'
+!  
{
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rlj @'  
} ;]ojfR=?%  
]B;GU  
//线程睡眠 r 5!ie!5gE  
public static void sleep(int nSecond)  Vf:w.G A  
{ "CYh"4]@rD  
try{ ldjypEa}  
Thread.sleep(nSecond); T[mo PD5  
} 13oR-Stj|  
catch(Exception e) nC^|83  
{ V^O dTM  
e.printStackTrace (); ow
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} j, SOL9yg  
} (kpn"]^
'  
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//日志 y`"b%P)+T  
public static void log(String sMsg) m'Jk!eo  
{ C$X )I~M  
System.err.println(sMsg); +\SNaq~&  
} OiB*,TWV  
%9z N U  
zd)2@jX=  
public static void log(int sMsg) %w <59d6  
{ E?c)WA2iH  
System.err.println(sMsg); wGd4:W  
} V K/;ohTTP  
} W~15[r0  
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/* TH_Vw,)  
**TestMethod.java 9N(<OY+Dgm  
*/ Dq/ _#&S  
package NetFox; %B^nQbNDM  
<VP@#  
|yE_M-Nc
 
public class TestMethod { F...>%N$  
qXPT1%+)y  
zz ^2/l  
public TestMethod() "0pH@_8o{  
{ ///xx/weblogic60b2_win.exe B_FfXFQm<  
try{ f =H,BQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4:$?u}9[:[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :3qA7D}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &1hJ?uM01  
fileFetch.start(); ]=A=VH&  
} 28l",j)S  
catch(Exception e){e.printStackTrace ();} ],ow@
}  
,B
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9*!C|gC9Ia  
} 3VJoH4E!6  
\0%)eJ  
q7}$F]UM"  
public static void main(String[] args) "hRw_<  
{ vkmTd4g  
new TestMethod(); @kR/=EfS  
} V1R=`  
} .
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