http断点续传简单实现（java)

/* ~~fL`"  
**SiteFileFetch.java 4@W.{|2~  
*/ ftH 0aI  
package NetFox; jyT(LDsS  
import java.io.*; R1m18GHQ  
import java.net.*; vcSS+  
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public class SiteFileFetch extends Thread { ~,guw7F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *lTu-  
long[] nStartPos; //开始位置 wGxLs>| 4  
long[] nEndPos; //结束位置 9"aTF,'F/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #nxx\,i>  
long nFileLength; //文件长度 6x7=0}'  
boolean bFirst = true; //是否第一次取文件 r\1*N.O3|O  
boolean bStop = false; //停止标志 ]fc:CR  
File tmpFile; //文件下载的临时信息 Zuh
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DataOutputStream output; //输出到文件的输出流 GkO6r'MVE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E:tUbWVp  
public SiteFileFetch(SiteInfoBean bean) throws IOException Af%?WZlOq  
{ 2U+&F'&Q
 
siteInfoBean = bean; bpILiC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p?h;Sv/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LH8?0N[  
if(tmpFile.exists ()) E}GSii%S  
{ &ar}6eO  
bFirst = false; 4~/6d9f  
read_nPos(); :tgTYIF  
} 0T5>i 0/  
else ,jWd?-NH  
{ n" ~*9'  
nStartPos = new long[bean.getNSplitter()]; IY:O?M  
nEndPos = new long[bean.getNSplitter()]; R}VL UL$  
} LKZI@i)  
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} w~&]gyf  
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public void run() Hn~1x'$  
{ l_%~X9"  
//获得文件长度 NZuFxJ-`  
//分割文件 iQF}x&a<  
//实例FileSplitterFetch 6Ts`5$e  
//启动FileSplitterFetch线程 C] w< &o  
//等待子线程返回 ;cr6Xop#?  
try{  \_E.%K  
if(bFirst) {+:XVT_+  
{ u^9c`  
nFileLength = getFileSize(); jhG7sS|  
if(nFileLength == -1) {p 0'Lc<3n  
{ }v,THj  
System.err.println("File Length is not known!"); G#:!wI  
} Yn>zR I  
else if(nFileLength == -2) q1Sm#_7  
{ F21[r!3  
System.err.println("File is not access!"); Ol[gck|~  
} Ji[g@#  
else njMy&$6a##  
{ PuaosMn(9  
for(int i=0;i<nStartPos.length;i++) YkPt*?,P/  
{ GJs[m~`8#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c5e\ckqm^  
} F*}Q^%  
for(int i=0;i<nEndPos.length-1;i++) Xb*_LZAU  
{ dA/o4co  
nEndPos = nStartPos[i+1]; 7V (7JV<>  
} >` QX xTn  
nEndPos[nEndPos.length-1] = nFileLength; :, [!8QP  
} sVd_O[  
} D~OhwsL4  
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//启动子线程 "n }fEVJ,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j#P4Le[t  
for(int i=0;i<nStartPos.length;i++) ~@b}=+n  
{  /kU@S
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Az9J{
)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jA4v?(AO}#  
nStartPos,nEndPos,i); }#*zjMOz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &W+G{W{3  
fileSplitterFetch.start(); y~c[sW  
} oy bzD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KH>sCEt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !9LAXM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EJaaW&>[  
nEndPos = " + nFileLength); b[o"Uq@8?  
// fileSplitterFetch[nPos.length-1].start(); _8pkejg  
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rbun5&RCyW  
//等待子线程结束 PB<S
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//int count = 0; e=)
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//是否结束while循环 rI66frbj  
boolean breakWhile = false; 9Q7cUoxY  
1qKxg  
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while(!bStop) G%8)6m'3
 
{ < Gy!i/  
write_nPos(); Y1_6\zpA  
Utility.sleep(500); bc=u1=~w  
breakWhile = true; _B7?C:8Q-  
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*
 
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for(int i=0;i<nStartPos.length;i++)  !QW 0  
{ }V#9tWW  
if(!fileSplitterFetch.bDownOver) VBsFT2XiL  
{ lyH X#]  
breakWhile = false; m>-^K  
break; OK2/k_jXN'  
} 9Bvn>+_K  
} p9 ,\{Is  
if(breakWhile) a0/n13c?G  
break; t
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I1 R\Ts@  
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//count++; {L-aXe{  
//if(count>4) # /,2MQ  
// siteStop(); k5%0wHpk=  
} +yP[(b/  
Up/u|A$0V  
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System.err.println("文件下载结束！"); >[%.h(h/%  
} }!yD^:[5  
catch(Exception e){e.printStackTrace ();} A]O5+"mc  
} u388Wj   
vu'!-K=0  
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//获得文件长度 ND55`KT4  
public long getFileSize() vPl6Dasr  
{ _Dcc<-.  
int nFileLength = -1; wp]7Lx?F  
try{ Th;gps%b  
URL url = new URL(siteInfoBean.getSSiteURL()); &b@!DAwAJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8T.5Mhx0jS  
httpConnection.setRequestProperty("User-Agent","NetFox"); \l=KWa3Q  
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int responseCode=httpConnection.getResponseCode(); mb~=Xyk&  
if(responseCode>=400) :U-US|)(2  
{ 6PQJgki  
processErrorCode(responseCode); |!xfIR>=F  
return -2; //-2 represent access is error =4M.QA@lI!  
}  uRB)g  
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l  
\{MrQ2jd  
String sHeader; pT ocqJ22  
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for(int i=1;;i++) 9OQ0Yc!3  
{ EYJi6#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2*-ENW2  
//Utility.log(in.readLine()); ~*PK080N}  
sHeader=httpConnection.getHeaderFieldKey(i); 1 ~B<  
if(sHeader!=null) X
8,7_D$  
{ .n)!ZN  
if(sHeader.equals("Content-Length")) R!_8jD:$  
{ !}L~@[v,uL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1|l)gfc
P  
break; 94p:|5@  
} =;k+g?.@I  
} +C'TW^  
else 9Ew:.&d  
break; !0!U01SWa  
} wzDk{4U  
} :Er^"9'A2  
catch(IOException e){e.printStackTrace ();} _[$T29:8\]  
catch(Exception e){e.printStackTrace ();} U=&^H!LVY  
*
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Utility.log(nFileLength); E
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return nFileLength; cD'HQ3+  
} LL= Z$U $  
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//保存下载信息（文件指针位置） *]}CSZ[>  
private void write_nPos() M1/M}~  
{ H{\.g=01  
try{ tb:,Uf>E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @pF fpHq?>  
output.writeInt(nStartPos.length); `2xH7
a-  
for(int i=0;i<nStartPos.length;i++) %1-K);SJ  
{ sJ))<,e5I  
// output.writeLong(nPos); N|!MO{sB  
output.writeLong(fileSplitterFetch.nStartPos); T3USNc51  
output.writeLong(fileSplitterFetch.nEndPos); W>5vRwx00  
} aN^]bs?R  
output.close(); ,:#,}w_HyO  
} @uI?  
catch(IOException e){e.printStackTrace ();} (O)\#%,@R  
catch(Exception e){e.printStackTrace ();} /9x{
^  
} C5O5S:|'  
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}x
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//读取保存的下载信息（文件指针位置） kzZDtI)  
private void read_nPos() doP$N3Zm  
{ ?z2jk  
try{ Tub1Sv>J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); s kN9O"^A  
nStartPos = new long[nCount]; -PNi^ K_  
nEndPos = new long[nCount]; T n"e  
for(int i=0;i<nStartPos.length;i++) yXJ]U \ %  
{ ?e F@Q!h  
nStartPos = input.readLong(); KcC!N{  
nEndPos = input.readLong(); +c^_^Z$_4o  
} &
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input.close(); 9n1ZVP.a
g  
} >[ eW">:>K  
catch(IOException e){e.printStackTrace ();} kOw=c Gt  
catch(Exception e){e.printStackTrace ();} \|CPR6I  
} 7;&(}  
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private void processErrorCode(int nErrorCode) =M7TCE  
{ cAD[3b[Gk  
System.err.println("Error Code : " + nErrorCode); D^Te%qnW  
} \tY"BC4.  
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//停止文件下载 pet~[e%!  
public void siteStop() I%oRvg|q  
{ }g~g50ci  
bStop = true; MDJc[am  
for(int i=0;i<nStartPos.length;i++) ; e@gO  
fileSplitterFetch.splitterStop(); iOXZ]Xj5  
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} NmJ`?-Z  
} 5F2_xH$5  
//负责部分文件的抓取 %SAw;ZtQ:  
**FileSplitterFetch.java F/>*Ifs  
*/ CEuWw:)  
package NetFox; owvS/"@  
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import java.io.*; }Dn^d}?s||  
import java.net.*; i31<].|kA*  
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public class FileSplitterFetch extends Thread { 8$0\J_  
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String sURL; //File URL !^e =P%S  
long nStartPos; //File Snippet Start Position .h4\{|  
long nEndPos; //File Snippet End Position rEdY>\'  
int nThreadID; //Thread's ID Tk*w3c"$  
boolean bDownOver = false; //Downing is over 54{q.I@n  
boolean bStop = false; //Stop identical 03k?:D+5  
FileAccessI fileAccessI = null; //File Access interface w7FoL  
c pk^!@c  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ](#&.q%5!  
{ lwT9~Hyp  
this.sURL = sURL; &fwS{n;U  
this.nStartPos = nStart; ?P/AC$:|I  
this.nEndPos = nEnd; x&Cp> +i  
nThreadID = id; \}5p0.=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (u hd "  
} H6K`\8/SeN  
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public void run() vi!YN|}\  
{ G_ >G'2  
while(nStartPos < nEndPos && !bStop) e)H!uR
 
{ 
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try{ kM/Te{<  
URL url = new URL(sURL); %0,-.(h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x;LzG t:w  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]]0,|My7  
String sProperty = "bytes="+nStartPos+"-"; 1[;;sSp  
httpConnection.setRequestProperty("RANGE",sProperty); `_v
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Utility.log(sProperty); VsK>6S\T  
2HD]?:Fk7  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection);  d
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byte[] b = new byte[1024]; @U{<a#  
int nRead; <7_KeOLJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (`BSVxJH  
{ r?/A?DMe  
nStartPos += fileAccessI.write(b,0,nRead); )$Mmn  
//if(nThreadID == 1) @n&<B`/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L';MP^  
} 23!;}zHp  
? "/ fPV-  
7nU6k%_%  
Utility.log("Thread " + nThreadID + " is over!"); ->^~KVh&  
bDownOver = true; S8d8%R~1=h  
//nPos = fileAccessI.write (b,0,nRead); Ih}1%Jq  
} Kl{>jr8B3  
catch(Exception e){e.printStackTrace ();} 8.J(r(;>  
} V/d/L3p  
} U69u'G:  
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}[+!$#  
//打印回应的头信息 YevyN\,}V!  
public void logResponseHead(HttpURLConnection con)  p?D2)(  
{ iIT8H\e  
for(int i=1;;i++) (>4aibA'P  
{ TjMe?p  
String header=con.getHeaderFieldKey(i); !" #9<~Q,p  
if(header!=null) qBV x6MI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _@mRb^  
Utility.log(header+" : "+con.getHeaderField(header)); 2&'|Eqk  
else D4Al3fe  
break; D_mL,w  
} j$UV/tp5T  
} KlV:L 4a~  
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public void splitterStop() {Gq*e/  
{ SzwQOs*  
bStop = true; gWABY%!}  
} `@d<n  
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} j*"3t^|-  
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/*
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**FileAccess.java ;*ix~taL%  
*//文件访问(定位，写) DFhXx6]  
package NetFox; 9Zry]$0~R
 
import java.io.*; >Rvx[`|O!m  
5u
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public class FileAccessI implements Serializable{ ] Z8Vj7~  
<FMq>d$\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `Y-|H;z  
RandomAccessFile oSavedFile; CQel3Jtt.  
long nPos; ?D,=37  
} VJfJ/  
{3})=>u:S  
public FileAccessI() throws IOException oH
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{ *
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this("",0); PJxH7|GSi  
} U
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,+`61J3W  
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public FileAccessI(String sName,long nPos) throws IOException @ '@:sM_  
{ hcVJBK  
oSavedFile = new RandomAccessFile(sName,"rw"); :o:e,WKxb  
this.nPos = nPos; ^F?&|clM/  
oSavedFile.seek(nPos); qE'9QQ>:b  
} >!_Xgw  
OD']:  
3@5=+z~CW  
public synchronized int write(byte[] b,int nStart,int nLen) QwhRNnE=  
{ omWJJ
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int n = -1; +T9:Udi  
try{ ~|wbP6</:-  
oSavedFile.write(b,nStart,nLen); LZM
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n = nLen; 0$7.g!h?  
} Y+K|1r
 
catch(IOException e) %OgS^_tu  
{ Bgmn2-  
e.printStackTrace (); >0p$(>N]  
} NrP0Ep%V  
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return n; [{C )LDN  
} Ltjbxw"Qd  
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} G,;,D9jO7  
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/* +cU>k}  
**SiteInfoBean.java 5SkW-+$  
*/ 1Bxmm#  
package NetFox; AkOO)0  
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public class SiteInfoBean { qY 4#V k  

+2 Af&~T  
4Jx"A\5*G  
private String sSiteURL; //Site's URL XD"_Iq!  
private String sFilePath; //Saved File's Path !%dN
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private String sFileName; //Saved File's Name VbBPB5 $q  
private int nSplitter; //Count of Splited Downloading File =)|-?\[w  
>vo=]cw  
tE7[Smzuf  
public SiteInfoBean() M:5b4$Qh<  
{//nSplitter的缺省值为5 V]90  
//default value of nSplitter is 5 %kgkXc~6|x  
this("","","",5); ^k<oT'89  
} Ytg
j|@jsp  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /PsnD_s]5  
{ h;3cd0  
sSiteURL= sURL; )& u5IA(  
sFilePath = sPath; 8b0d]*q  
sFileName = sName; ]vuwkn+)  
this.nSplitter = nSpiltter; {&Q9"C  
SM@QUAXO  
:_QCfH  
} fU!<HDh  
qTQBt}  
)Pv9_XKJ  
public String getSSiteURL() 3MRc4UlB  
{ Qyy.IPTP  
return sSiteURL; [LRLJ_~g5  
} c_elShK8#  

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t]Xw{)T  
public void setSSiteURL(String value) Uk\Id~xLV  
{ VsA'de!V4[  
sSiteURL = value; Uo2GK3nT  
} |<O9Sb_  
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public String getSFilePath() D.mHIsX6\  
{ 3N_"rNKD  
return sFilePath; <\;#jF%V  
} S%`0'lzzj  
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p ]d]QMu  
public void setSFilePath(String value) rylzcN9RM$  
{ JY6 Qp  
sFilePath = value; &~W:xg(jN  
} 9*a=iL*Nw  
:kGU,>BN  
HbW0wuI  
public String getSFileName() >KJ+-QuO&  
{ H<3I 5Kgt  
return sFileName; y '!m4-  
} ^yOZArc'r  
*BR^U$,e  
@9"J|}  
public void setSFileName(String value) f%*/c
pA)  
{
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sFileName = value; [KxF'mz9  
} LGtIm7  
,{mCf^  
>FkWH7  
public int getNSplitter() ZMq6/G*fD  
{ YD7Oao4:o  
return nSplitter; q|),`.eh\  
} O6OP =K!t:  
y`=]T>X&x  
8e(\%bX  
public void setNSplitter(int nCount) /~<@
*-'  
{ y~\oTJb  
nSplitter = nCount; -(=eM3o-9m  
} }B1!gz$YNO  
} Z+=@<
i''  
1Yn +<I  
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/* n<u $=H  
**Utility.java r! MWbFw|X  
*/ &mx)~J^m  
package NetFox; <q@a~'Ai?!  
v%iflCK  
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public class Utility { c-0#w=  
T]c%!&^_  
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public Utility() nX`u[ks  
{ $F5 b  
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*vwbgJG! *  
} q1KZ5G)6GJ  
s|y "WDyx5  
//线程睡眠 BNs@n"k  
public static void sleep(int nSecond) jIyB  
{ TJR:vr  
try{ @W"KVPd  
Thread.sleep(nSecond);  cHk)i  
} @/ohg0  
catch(Exception e) LF& z  
{ 1 P!Yxeh  
e.printStackTrace (); |M,iM]  
} 8p:e##%  
} b?lD(fa&  
.E8_Oz  
//日志 /~$WUAh  
public static void log(String sMsg) :x4|X8>  
{ U ^5Kz-5.  
System.err.println(sMsg); ~yW4)4k;b  
} S(*sw 0O@+  
?q{,R"  
1oWED*B  
public static void log(int sMsg) Xx0hc 8qd  
{ WGZ9B^A  
System.err.println(sMsg); r w2arx  
} =k^Y?.  
} os:A]  
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/* 'R'*kxf  
**TestMethod.java 1;Cyz)  
*/ 3 0
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package NetFox; ZJzt~ H  
P"IPcT%Ob%  
&;[Io  
public class TestMethod { xRzFlay8  
Q/(K$6]j  
9CWF{"  
public TestMethod() <oT^A|JFj  
{ ///xx/weblogic60b2_win.exe /-_h1.!   
try{ R6kD=JY/!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rrBsb -
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KyYMfC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;Q OBBF3HG  
fileFetch.start(); ;5S9y7[i|  
} KWowN;  
catch(Exception e){e.printStackTrace ();} /_AnP  
i1NY9br  
"$+Jnc!!  
} ?mFv0_!O
 
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4ew" %Cs*  
public static void main(String[] args) 5 ZGNz1)?V  
{ `1$@|FgyC  
new TestMethod(); 1PQ~jfGi  
} k;AD`7(=  
} [q
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