http断点续传简单实现（java)

/* F G5e{  
**SiteFileFetch.java RBM(>lU:  
*/ 8jxs%N,aI  
package NetFox; PN@[k:5(  
import java.io.*; I~: AWS9  
import java.net.*; 0"O22<K3a  
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public class SiteFileFetch extends Thread { q9mYhT/Im  
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SiteInfoBean siteInfoBean = null; //文件信息Bean xs ^$fn\  
long[] nStartPos; //开始位置 ecgGl,{  
long[] nEndPos; //结束位置 ngC|BLT%h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q9`!T4,  
long nFileLength; //文件长度 q,H 0=\  
boolean bFirst = true; //是否第一次取文件 DU.nXwl]  
boolean bStop = false; //停止标志 P0N%77p>"  
File tmpFile; //文件下载的临时信息 zZ\2fKrpg  
DataOutputStream output; //输出到文件的输出流 A!
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %}%vey  
public SiteFileFetch(SiteInfoBean bean) throws IOException i'}Z>g5D  
{ (HZzA7eph  
siteInfoBean = bean; V3]"ROH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C)Ez>~Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?[K\X  
if(tmpFile.exists ()) 
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{ QA3q9,C"  
bFirst = false; Z*Qra4GBl]  
read_nPos(); V/jEMJNks  
} Q<F-l.q   
else _a3,Zuv  
{ ;2=H7dq  
nStartPos = new long[bean.getNSplitter()]; zXHCP.Rmg  
nEndPos = new long[bean.getNSplitter()]; (!0=~x|Z[  
} 5$ra4+k0  
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} X(;,-7Jw  
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public void run() ZxR
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{ Kpo{:a  
//获得文件长度 =os%22*  
//分割文件 UEvRK?mm=  
//实例FileSplitterFetch 9V%
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//启动FileSplitterFetch线程 Ba],ONM4k  
//等待子线程返回 *CH lg1  
try{ oKJj?%dHK9  
if(bFirst) PB 
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{ e Ert_@}  
nFileLength = getFileSize(); K 8gd?
88  
if(nFileLength == -1) 5r:SBt|/  
{ 9OC
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System.err.println("File Length is not known!"); n>Rt9  
} x@I(G "  
else if(nFileLength == -2) U&D"fM8  
{ )&j4F)  
System.err.println("File is not access!"); 7O)U(<70  
} [8VB"{{&  
else TuBl9 p'6  
{ ]tVU$9D   
for(int i=0;i<nStartPos.length;i++) tCk;tu!d  
{ W:7oGZ>4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q,JMmhWaT  
} 'j)xryw  
for(int i=0;i<nEndPos.length-1;i++) 0.~Pzg  
{ w6fVZY4  
nEndPos = nStartPos[i+1]; 76\ir<1up  
} eoS8e$}  
nEndPos[nEndPos.length-1] = nFileLength; \wxS~T<&L  
} ]Xur/C2A  
} R18jju>Zr  
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//启动子线程 n0T\dc~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u(7PtmV[!  
for(int i=0;i<nStartPos.length;i++) 5_@8g+~  
{ m q`EMOH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4*4s{twG  
nStartPos,nEndPos,i); ;R E|9GR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T<|B1jA  
fileSplitterFetch.start(); >5&'_  
} !79^M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wjF/c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;~
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S=>54!{`x  
nEndPos = " + nFileLength); S;[*5g6a&x  
// fileSplitterFetch[nPos.length-1].start(); &i8AB{OU  
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ec:?Q0  
//等待子线程结束 ISI\<qx  
//int count = 0; 0sv#* &0=  
//是否结束while循环 ;^}gC}tq  
boolean breakWhile = false; FY [WdZDZ  
0Ii* "?s  
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while(!bStop) r=<Oy1m/  
{ fQ5VRpWGn  
write_nPos(); C:/O]slH  
Utility.sleep(500); l@a>"\><i*  
breakWhile = true; :=BFx"Y
  
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ErK5iTSD  
for(int i=0;i<nStartPos.length;i++) -aDGXQM{~  
{  u%<Je  
if(!fileSplitterFetch.bDownOver) L'LZK  
{ $9DV}  
breakWhile = false; 
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break; wR\Y+Z
 
} Kv'2^B  
} \0iF <0oy  
if(breakWhile) VLuhURI)  
break; gnW`|-:\  
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V,<3uQD9a  
//count++; C9[Jr)QX  
//if(count>4) %|$h<~  
// siteStop(); B]dvX  
} tCAh?nR  
6eqxwj{S[  
<(dHh9$~  
System.err.println("文件下载结束！"); }>I|\Z0I  
} )<bgZ, v  
catch(Exception e){e.printStackTrace ();} _5
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} sK8=PZ\  
n=#AH;42  
7F OG^  
//获得文件长度 oa(R,{_*q  
public long getFileSize() nqNL[w6{  
{ ^s/HbCA  
int nFileLength = -1; !%{/eQFT4  
try{ B#Cb`b"  
URL url = new URL(siteInfoBean.getSSiteURL()); o(GXv3L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K,{P b?  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'M>QA"*48E  
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int responseCode=httpConnection.getResponseCode(); a>x3UVf_  
if(responseCode>=400) u}ULb F  
{ +;uP) "Q/L  
processErrorCode(responseCode); e^)+bmh  
return -2; //-2 represent access is error N
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} q}[
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String sHeader; dWbSrl  
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for(int i=1;;i++) `)Z"||8K  
{ (jbHV.]P9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2Wwzcvs@  
//Utility.log(in.readLine()); @v^;,cu'8  
sHeader=httpConnection.getHeaderFieldKey(i); 6-8,qk  
if(sHeader!=null) K.s\xA5`_  
{ qdkhfm2(K
 
if(sHeader.equals("Content-Length")) Bw _^"e8X  
{ h"Qp e'D}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &[u%ZL  
break; U$+EUDFi3_  
} 77D>;90>?  
} jFbj)!;  
else H9}z0VI  
break; ;}v#hKC~  
} "M#A `b  
} dm8
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catch(IOException e){e.printStackTrace ();} 86pujXjc'  
catch(Exception e){e.printStackTrace ();} lrqu%:q  
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Utility.log(nFileLength); {nvF>  
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return nFileLength; =-wF Brw  
} qWz%sT?C3L  
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//保存下载信息（文件指针位置） /-%0y2"7  
private void write_nPos() g{|F<2rd[m  
{ \4$V;C/n,  
try{ +i"^"/2f{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ncw)VH;_-  
output.writeInt(nStartPos.length); SI_u0j4%*  
for(int i=0;i<nStartPos.length;i++) uG-t)pej  
{ sz;B-1^6  
// output.writeLong(nPos); ykAZP[^'  
output.writeLong(fileSplitterFetch.nStartPos); F|mppY'<J  
output.writeLong(fileSplitterFetch.nEndPos); ViZ Tl~  
} xF4S  
output.close(); VcI'+IoR?  
} P){b"`f  
catch(IOException e){e.printStackTrace ();} $?x;?wS0V  
catch(Exception e){e.printStackTrace ();} -|F(qf  
} s{g^K#BoFi  
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//读取保存的下载信息（文件指针位置） ,xcm:;&  
private void read_nPos() KHnq%#  
{ 3|++2Z{},  
try{ |E]`rfr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 73C7g< Mx  
int nCount = input.readInt(); CuT~ Bj  
nStartPos = new long[nCount]; ENoGV;WG  
nEndPos = new long[nCount]; -/^a2_d[  
for(int i=0;i<nStartPos.length;i++) [f
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{ 3[_zz;Y*d  
nStartPos = input.readLong(); 9NXL8QmC8  
nEndPos = input.readLong(); 2TQyQ%  
} M
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input.close(); `^d[$IbDW  
} hCpX#rg?  
catch(IOException e){e.printStackTrace ();} \S5YS2,P  
catch(Exception e){e.printStackTrace ();} W20qn>{z  
} z5njblUz  
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8  
private void processErrorCode(int nErrorCode) IA6,P>}N  
{ qoZUX3{  
System.err.println("Error Code : " + nErrorCode); +"yt/9AO  
} $3yzB9\a"  
[hh
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ve3-GWT{C  
//停止文件下载 PiL[&_8g  
public void siteStop() Hl|EySno  
{ ^RIDC/B=V6  
bStop = true; GkU]>8E'"  
for(int i=0;i<nStartPos.length;i++) :o37 V!  
fileSplitterFetch.splitterStop(); Ca]V%
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v% c-El%  
} vx7wW<e%D  
} e&k=fV  
//负责部分文件的抓取 =6YffXa_s  
**FileSplitterFetch.java w *Txc}  
*/ A?zxF5rfp  
package NetFox; =NNA7E7c  
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import java.io.*; sUe<21:  
import java.net.*;
6+.8nx:9X  
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public class FileSplitterFetch extends Thread { c}u`L6!I3  
^2f2g>9j_C  
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String sURL; //File URL #cCR\$-~  
long nStartPos; //File Snippet Start Position <jz\U7TBf  
long nEndPos; //File Snippet End Position be+]kp  
int nThreadID; //Thread's ID yN/
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boolean bDownOver = false; //Downing is over i w(4!,4~  
boolean bStop = false; //Stop identical b^dBX  
FileAccessI fileAccessI = null; //File Access interface 9zKbzT]  
=5kTzH.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException z~0f[As.  
{ <c!I\y  
this.sURL = sURL; u^X,ASkQ  
this.nStartPos = nStart; a? <Ar#)j  
this.nEndPos = nEnd; eb*w$|y6"  
nThreadID = id; n38l!m(.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6Gj69Lr  
} 0s2@z5bfX  
R=m9[TgBm  
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public void run() =N?K)QD`  
{ ;n2b$MB?nM  
while(nStartPos < nEndPos && !bStop) WoSJp5By$  
{ iS#m{1m$$  
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\
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try{ ] RLEyDB  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O{&wqV5m"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7a#zr_r  
String sProperty = "bytes="+nStartPos+"-"; B,NHy C1i  
httpConnection.setRequestProperty("RANGE",sProperty); !fT3mI6u\  
Utility.log(sProperty); _usi~m  
<&87aDYz  
r$/.x6g//  
InputStream input = httpConnection.getInputStream(); R1j)0b6cQ%  
//logResponseHead(httpConnection); R2B0?fu  
=>u9k:('9  
];7/DM#Np  
byte[] b = new byte[1024]; wPRs.(]_  
int nRead; Zt{\<5j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )an,-EIX%  
{ V+dFL9  
nStartPos += fileAccessI.write(b,0,nRead); =7P(T`j  
//if(nThreadID == 1) #fkOm Y7X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4SGF8y@WU  
} t=6Wk4  
SHt#%3EU  
8pE0ANbq  
Utility.log("Thread " + nThreadID + " is over!"); MoP,a9p  
bDownOver = true; j|c6BdROl  
//nPos = fileAccessI.write (b,0,nRead); M\w%c5  
} R3!3TJ  
catch(Exception e){e.printStackTrace ();} &-B&s.,kj  
} Q!(qL[o  
} .=% ,DT"  
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//打印回应的头信息 nq3B(  
public void logResponseHead(HttpURLConnection con) 99mo]1_  
{ @uzzyp r>  
for(int i=1;;i++) ;=oGg%@aP  
{ KRN{Ath.  
String header=con.getHeaderFieldKey(i); 2Hj;o  
if(header!=null) K26x,m]p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1u\kxlZ  
Utility.log(header+" : "+con.getHeaderField(header)); x}*Y =Xh  
else r\f|r$i  
break; }RPeAcbU_  
} !tr /$  
} .0H!B#9  
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,`nl";Zc  
public void splitterStop() qW(_0<E  
{ $KGpcl  
bStop = true; o7#Mr`6H  
} S&w(H'4N  
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/*2sg>e'QF  
} cQ<* (KU  
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\y*,N^wu  
/* ukH?O)0O  
**FileAccess.java *iW$>Yjb  
*//文件访问(定位，写) M!E#T-)  
package NetFox; |Je+y;P7  
import java.io.*; M_monj}Z  
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public class FileAccessI implements Serializable{ c-, 6k  
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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 ko<iG]Dv'  
RandomAccessFile oSavedFile; -ipfGb  
long nPos; TPeBb8v8D  
{cF>,T  
`9yR,Xk=l  
public FileAccessI() throws IOException \mt>R[  
{ X/!37  
this("",0); 7h3JH  
} FeM,$&G:  
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S.kFs{;1x  
public FileAccessI(String sName,long nPos) throws IOException dPfDPb  
{ _-.~>C  
oSavedFile = new RandomAccessFile(sName,"rw"); !1M=9 ~$!  
this.nPos = nPos; 7L=V{,,v  
oSavedFile.seek(nPos); r31H Zx1^  
} /Dn  
\jcEEIEi  
b2vc  
public synchronized int write(byte[] b,int nStart,int nLen) >X(,(mKi  
{ RZ:i60  
int n = -1; d{LQr}_o$$  
try{ rH<iUiA?O  
oSavedFile.write(b,nStart,nLen); $CYB&|d  
n = nLen; 8(Y=MW;g  
} [@_zsz,`L  
catch(IOException e) 7:_\t!]  
{ V,@Y,  
e.printStackTrace (); ?8LRd5LH  
} /rqaUC)A  
-}?
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return n; 4gNF;  
} Cq0S8Or0  
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} &2!F:L  
.7nr:P  
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/* "w\Iz]  
**SiteInfoBean.java W]v[Xm$q  
*/ Je6=N3)  
package NetFox; oVc l (  
r|WoM39bp  
0*.> >rI  
public class SiteInfoBean { :K)=Hf2y  
9N[vNg<n  
*<**rY*  
private String sSiteURL; //Site's URL AjQ^ {P  
private String sFilePath; //Saved File's Path M zLx2?  
private String sFileName; //Saved File's Name 7 vS]O$w<4  
private int nSplitter; //Count of Splited Downloading File ?=]*r>a3  
Q(}TN,N  
3ppY@_1  
public SiteInfoBean() |x AwiF_  
{//nSplitter的缺省值为5 wghz[qe  
//default value of nSplitter is 5 3psCV=/z  
this("","","",5); &!3=eVg  
} 3d{v5. C#X  
Y.Er!(pz  
jnK8 [och  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kd9GHN;7  
{ G
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sSiteURL= sURL; 1{-W?n  
sFilePath = sPath; _cZ`7]Z  
sFileName = sName; &B^vHH  
this.nSplitter = nSpiltter; %KeQp W  
G~{xTpL  
X^#.4:>.  
} o%Lk6QA$  
Z:#-4CiP  
H>-?/H  
public String getSSiteURL() {V!Jj6n  
{ =#i#IF42?  
return sSiteURL; j${:Y$V
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} UC^Bn1  
#lax0IYY=  
#zcp!WE.OI  
public void setSSiteURL(String value) <%JRZYZ  
{ ]]s_ 8u3  
sSiteURL = value; sX3Vr&r  
} j~G^J  
G6zFCgFJ^y  
gz[Ng> D+  
public String getSFilePath() V 'Gi2gNaP  
{ p;VqkSQ76  
return sFilePath; N,w;s-*  
} qVF
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|67j__XC  
U/M(4H3>H  
public void setSFilePath(String value) x7J|  
{ rbnu:+!  
sFilePath = value; UcMe("U  
} C"/
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N1I1!!$K;%  
HnVUG4yZTD  
public String getSFileName() EjB<`yT  
{ n%Xw6qV:  
return sFileName; =VlO53Hy{  
} /|y3M/;F  
}[PbA4l.g  
Y9m'RFZr  
public void setSFileName(String value) {=7W;uL  
{ HLAYmXX"w  
sFileName = value; V9"Kro  
} 0.nS306  
q+32|k>)  
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public int getNSplitter() dCcV$BX,K  
{ P_t8=d  
return nSplitter; o><~.T=d&  
} _c%]RE  
 !+IxPn  
U<eVLfSij  
public void setNSplitter(int nCount) Y[;Pl$  
{ )%C482GO-  
nSplitter = nCount; J=TbZL4y}4  
} )^)VyI`O  
} IgC)YIhd  
4(&00#Yxg2  
=[`wyQe`_  
/* U;KH
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**Utility.java <P( K,L?r  
*/ LaJc;Jt$  
package NetFox; G`w,$:,  
-nO('(t  
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public class Utility { 7(~^6Ql!  
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3O
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public Utility() 7 .+kcqX  
{ S'Q$N-Dy  
Y_%\kM?7  
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} "[H9)aAj7  
sb(,w  
//线程睡眠 " %|CD"
@  
public static void sleep(int nSecond) {Y'DUt5j  
{ RgQ\Cs24Q  
try{ AUoi$DF(@  
Thread.sleep(nSecond); M.d{:&@`%  
} 622mNY  
catch(Exception e) ms ;RJT2O'  
{ 3Du&KZ  
e.printStackTrace (); u!nt0hS  
} I_#)>%H  
} UNYU2ze'  
RGLwtN  
//日志 KEYM@,'  
public static void log(String sMsg) yN~=3b>  
{ "6pjkEt4  
System.err.println(sMsg); ;pb~Zk/[,w  
} 8.jd'yp*J  
V* fDvr0  
Dw[w%
uz  
public static void log(int sMsg) ClVMZ  
{ 43:~kCF[s  
System.err.println(sMsg); sj. eJX"z  
} Bh2m,=``  
} vn0XXuquzC  
f|6%71  
?ArQ{9c  
/* |=38t8Ge&  
**TestMethod.java o|alL-  
*/ Cj5M  
package NetFox; ~v,LFIT  
)OH!<jW  
i>,5b1x~  
public class TestMethod { RLulz|jC  
A1%V<im@Z  
kf-ZE$S4  
public TestMethod() N4fuV?E`  
{ ///xx/weblogic60b2_win.exe 3QUe:8
 
try{ D9H|]W~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <ze'o.c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l*'jqR')h^  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); qg.[M*  
} !h&hPY1  
catch(Exception e){e.printStackTrace ();} _vU,avw  
g-}Vu1w0{6  
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} ,Z>RvLl  
_7$j>xX  
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public static void main(String[] args) Jz:d\M~j5  
{ s977k2pp-  
new TestMethod(); lrq !}\aX  
} 2[M:WZ.1  
} &g) `  
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