http断点续传简单实现（java)

/* P_7QZ0
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**SiteFileFetch.java M{(g"ha  
*/ G#uD CF,O  
package NetFox; S=f:-?N|  
import java.io.*; !]#@:Z  
import java.net.*; 7\;4 d4u  
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public class SiteFileFetch extends Thread { '.{tE*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [:Upn)9  
long[] nStartPos; //开始位置 q7#4e?1  
long[] nEndPos; //结束位置 }Mv$Up  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K$1(HbL  
long nFileLength; //文件长度 -e2f8PV?3  
boolean bFirst = true; //是否第一次取文件 ScCp88KpFI  
boolean bStop = false; //停止标志 ,`Yx(4!rR  
File tmpFile; //文件下载的临时信息 >IT19(J;A  
DataOutputStream output; //输出到文件的输出流 P* Z1Rs_  
%tK^&rw%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D*_Z"q_B  
public SiteFileFetch(SiteInfoBean bean) throws IOException r$Tu``z \  
{ Ia@!Nr2  
siteInfoBean = bean; 4{v?<x8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Vb57B.I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E[=#Rw!*  
if(tmpFile.exists ()) vB?(|  
{ >2^|r8l5  
bFirst = false; C CDO8  
read_nPos(); bxc!x>)  
} =".sCV9"N  
else S%6V(L|  
{
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nStartPos = new long[bean.getNSplitter()]; n/ CP2A  
nEndPos = new long[bean.getNSplitter()]; EYy|JT]B  
} @{ CP18~:  
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} !=[>r'+3  
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public void run() ?wCs&tM  
{ Y&GuDLUF  
//获得文件长度 Q.ukY@L.'  
//分割文件 l#xw.2bo  
//实例FileSplitterFetch q~O>a0f0  
//启动FileSplitterFetch线程 eEP( ).
 
//等待子线程返回 mf2Mx=oy  
try{ >3P9 i ;W  
if(bFirst) <+q$XL0  
{ $eX*  
nFileLength = getFileSize(); y\z > /q  
if(nFileLength == -1) q~h:<,5  
{ DxfMqH[vs  
System.err.println("File Length is not known!"); _z]v<,=3M  
} n_P(k-^U*  
else if(nFileLength == -2) iRs V#s  
{ ! Rvn'|!  
System.err.println("File is not access!"); GA@ Ue9  
} &I)\*Ue2t  
else b{pg!/N4  
{ O9e.
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for(int i=0;i<nStartPos.length;i++) Spo+@G  
{ TPK@*9rI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0x71%=4H^x  
} 2d~LNy  
for(int i=0;i<nEndPos.length-1;i++) t'aSF{%  
{ H"D5e  
nEndPos = nStartPos[i+1]; ?K<ZkYw?  
} D$hQyhz'  
nEndPos[nEndPos.length-1] = nFileLength; :H\&2/j  
}  f`J|>Vk  
} ~p^7X2% !  
`:4MMr91  
@H+~2;B,  
//启动子线程 i@6wO?Tv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \xeVDKJH+n  
for(int i=0;i<nStartPos.length;i++) j{"[Ec  
{ o8tS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]#5^&w)'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {XHk6w *-  
nStartPos,nEndPos,i); }$:#+ (17  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;dOs0/UM&  
fileSplitterFetch.start(); T3rn+BxF7  
} |z+9km7,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q"'V9m7 i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n}:t<  
nEndPos = " + nFileLength); NQR^%<hU  
// fileSplitterFetch[nPos.length-1].start(); N]u2ql&  

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//等待子线程结束 >HIt}Zh  
//int count = 0; 5H*>  
//是否结束while循环 3KT_AJ4}  
boolean breakWhile = false; 0d`5Gy_D%  
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while(!bStop) jE*Ff&]%m  
{ `VXZ khm  
write_nPos(); J&_3VKrN  
Utility.sleep(500); $l#{_~ "m7  
breakWhile = true; &SrGh$:X  
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for(int i=0;i<nStartPos.length;i++) Gql`>~  
{ ]<+3Vw  
if(!fileSplitterFetch.bDownOver) `I{tZ$iD  
{ Ge0Lb+<G  
breakWhile = false; pX^=be_  
break; F"v:}Vy|   
} ,02w@we5  
} cyHU\!Z*Zq  
if(breakWhile) %Gu][_.L  
break; W\NG>t  
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//count++; Zd+>  
//if(count>4) :t%)5:@A  
// siteStop(); 1I b_Kmb-  
} .8x@IWJD
 
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System.err.println("文件下载结束！"); </fzBaTo  
} ^Tl|v'   
catch(Exception e){e.printStackTrace ();} Aam2Y,B  
} yVW)DQ4?  
! _QU-  
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//获得文件长度 J9o]$.e  
public long getFileSize() 0g1uM:;  
{ 3o1j l2n  
int nFileLength = -1; dfNNCPu]+  
try{ 1PWDK1GI8  
URL url = new URL(siteInfoBean.getSSiteURL()); 0s(G*D2%6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #jnb6v=5v  
httpConnection.setRequestProperty("User-Agent","NetFox"); T3bBc  
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int responseCode=httpConnection.getResponseCode(); Eg ;r]?|6  
if(responseCode>=400) (*#S%4(YX  
{ PJ);d>tz  
processErrorCode(responseCode); d!>PqPo  
return -2; //-2 represent access is error q$\KE4v"  
} VLRW,lR9O  
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String sHeader; 1;>J9  
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for(int i=1;;i++) Z/O5Dear/h  
{ hivWQ$6%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U1I2+;"#A  
//Utility.log(in.readLine()); M4`qi3I  
sHeader=httpConnection.getHeaderFieldKey(i); 'v?Z~"w=  
if(sHeader!=null) 3~Ah8
,  
{ c!b4Y4eJ  
if(sHeader.equals("Content-Length")) L,BuzU[1S  
{ ,|D<De\v&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kid@*.I  
break; u1rT:\G1  
} _pL:dKfy7  
} L~>pSP^a  
else (r.[b  
break; N_wB  
} W
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} }
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catch(IOException e){e.printStackTrace ();} [8[g_  
catch(Exception e){e.printStackTrace ();} uvi+#4~G  
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Utility.log(nFileLength); ]%pr1Ey  
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return nFileLength; (} ?")$.  
} ]sB-}n)  
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_ ZMoPEW  
//保存下载信息（文件指针位置） 0F/o  
private void write_nPos() HW"@~-\  
{ q-}qrg  
try{ z&Cz!HrS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vL}e1V:  
output.writeInt(nStartPos.length); h8'
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for(int i=0;i<nStartPos.length;i++) -Q9} gaH_  
{
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// output.writeLong(nPos); _TEjB:9eY  
output.writeLong(fileSplitterFetch.nStartPos); $bOiP  
output.writeLong(fileSplitterFetch.nEndPos); b@`h]]~:  
} (l}W\iB'd  
output.close(); }hRw{#*8  
} ,v,#f .  
catch(IOException e){e.printStackTrace ();} 05hjC  
catch(Exception e){e.printStackTrace ();} *3 8 u ~n  
} ^ZP $(a4  
#g=7fu{n:  
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//读取保存的下载信息（文件指针位置） 07b=Zhh  
private void read_nPos() lu vrvm  
{
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try{ zl $mt'\y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;S0Kf{DN2  
int nCount = input.readInt(); jzvrJ14  
nStartPos = new long[nCount]; gv\WI4"n  
nEndPos = new long[nCount]; \:y oS>G  
for(int i=0;i<nStartPos.length;i++) n37P$0  
{ |r['"6  
nStartPos = input.readLong(); s_o{w"3X  
nEndPos = input.readLong(); uHeKttR-  
} YpJJ]Rszg  
input.close(); w#}[=jy  
} ,i)wS1@  
catch(IOException e){e.printStackTrace ();} i/|}#yw8A  
catch(Exception e){e.printStackTrace ();} 3Zdwt\
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} g^I?u$&E  
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private void processErrorCode(int nErrorCode) fYhR#FVI  
{ jJVT_8J  
System.err.println("Error Code : " + nErrorCode); l>~`;W  
} %5h^`lp  
9k:W1wgH1  
kT^*>=1  
//停止文件下载 HK0::6n{  
public void siteStop() 1n'$Ji7  
{ uuSR%KK]|  
bStop = true; a jQqj.  
for(int i=0;i<nStartPos.length;i++) uxOJ3  
fileSplitterFetch.splitterStop(); X0WNpt&h  
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} Dz`k[mI  
} jJ aV  
//负责部分文件的抓取 M XZq  
**FileSplitterFetch.java 4.|-m.a  
*/ ,?g=U8y|  
package NetFox; ptpW41t}^  
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import java.io.*; ;8P_av}C  
import java.net.*; 5`{vE4A]q  
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public class FileSplitterFetch extends Thread { }:`5,b%Y_  
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String sURL; //File URL [pii  
long nStartPos; //File Snippet Start Position XOrcygb2  
long nEndPos; //File Snippet End Position I>A^I  
int nThreadID; //Thread's ID DVI7]+=nV  
boolean bDownOver = false; //Downing is over -(*nSD9  
boolean bStop = false; //Stop identical BhKO_wQ?:J  
FileAccessI fileAccessI = null; //File Access interface pOm@b`S%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,"Tjpdf  
{ |;P^clS3  
this.sURL = sURL; 0p-#f|ET  
this.nStartPos = nStart; .o}%~g<d  
this.nEndPos = nEnd; k oM]S+1  
nThreadID = id; 2M
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 -vV'Lw(  
} &5u BNpH  
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public void run() Ep mJWbU  
{ zmI5"K"
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while(nStartPos < nEndPos && !bStop) -Q$b7*"z(  
{ >AG^fUArH  
h*s`^W3
 
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try{ @`wn<%o$  
URL url = new URL(sURL); s~J=<)T*6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^av6HFQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); XJSa]P^B1  
String sProperty = "bytes="+nStartPos+"-"; D{p5/#|r  
httpConnection.setRequestProperty("RANGE",sProperty); txq~+'A:+  
Utility.log(sProperty); BwxnDeG)  
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InputStream input = httpConnection.getInputStream(); *Y%Jl o  
//logResponseHead(httpConnection); 2n|CD|V$ux  
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byte[] b = new byte[1024]; kUa)smh
 
int nRead; !>n|c$=;qk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NZk&JND  
{ 3qi_]*dD  
nStartPos += fileAccessI.write(b,0,nRead); ^ve14mbF#.  
//if(nThreadID == 1) sDC*J\X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B +Aj*\Y.  
} S~)w\(r  
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Utility.log("Thread " + nThreadID + " is over!"); C\Vg{&'  
bDownOver = true; uS<_4A;sD,  
//nPos = fileAccessI.write (b,0,nRead); cin2>3Z$  
} 7I}P*%(f  
catch(Exception e){e.printStackTrace ();} `8:Kp  
} pSfYu=#f  
} m"d/b~q  
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j~`\XX{>  
//打印回应的头信息 a#0;==#  
public void logResponseHead(HttpURLConnection con) |`O7nOM  
{ P)6lu8zQ  
for(int i=1;;i++) S8vV!xO  
{ Br5o7(AE  
String header=con.getHeaderFieldKey(i);
&@v<nO-  
if(header!=null) o3N]`xD'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Yr+23Ro  
Utility.log(header+" : "+con.getHeaderField(header)); Tum_aI  
else $t/rOo9cV  
break; xT*d/Oaw  
} nFM@@oA  
} h<6UC%'ac  
0g=`DSC<(  
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public void splitterStop() izZ=d5+K  
{ oxz{ ejd{  
bStop = true; uB!kM  
} *x)Ozfe  
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} 2o>)7^9|#<  
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/* p>_;^&>&  
**FileAccess.java RI
68
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*//文件访问(定位，写) m*$|GW9  
package NetFox; MxyN\Mq'  
import java.io.*; n}s~+USZX  
_+ .\@{c  
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public class FileAccessI implements Serializable{ ,39aF*r1Q  
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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 FQ>`{%>  
RandomAccessFile oSavedFile; 0i8LWX_M  
long nPos; >vuY+o;B  
# O4gg  
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public FileAccessI() throws IOException CgzD$`~  
{ Q5%#^ZdsTd  
this("",0); CRbdAqofV  
} Hcc"b0>}{  
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4A9{=~nwT  
public FileAccessI(String sName,long nPos) throws IOException O@?kT;B  
{ 7Sz?S_N/j  
oSavedFile = new RandomAccessFile(sName,"rw"); PQ@L+],C  
this.nPos = nPos; T97]P-}  
oSavedFile.seek(nPos); w`l{LHrR  
} `bc;]@"  
[frq 'c  
*m2=/Sh  
public synchronized int write(byte[] b,int nStart,int nLen) #z1H8CFL"  
{ 0(_l|PScF  
int n = -1; O$IjNx  
try{ IF]lHB  
oSavedFile.write(b,nStart,nLen); &i!vd/*WlD  
n = nLen; D5~n/.B"  
} h
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4  
catch(IOException e) "TH6o:x  
{ :{(w3<i  
e.printStackTrace (); ~
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} si4don  
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return n; 97)/"i e  
} uI
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} MQKfJru7  
LL$_zK{  
@(C1_  
/* #Wu*3&a]yU  
**SiteInfoBean.java fL]Pztsk+  
*/ +{]xtQB=,{  
package NetFox; zS]8V?`  
:rP#I#,7w  
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/  
public class SiteInfoBean { fb da  
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private String sSiteURL; //Site's URL id?h>g  
private String sFilePath; //Saved File's Path I}2P>)K  
private String sFileName; //Saved File's Name jjM{]  
private int nSplitter; //Count of Splited Downloading File W[+|}
 
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16SOIT  
public SiteInfoBean() E\;ikX&1  
{//nSplitter的缺省值为5 `>o?CIdp  
//default value of nSplitter is 5 y$<Vha  
this("","","",5); %6--}bY^  
} 7H>@iI"?  
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21RP=0Q:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KN"S?i]X  
{ nL:SG{7  
sSiteURL= sURL; N8`?t5  
sFilePath = sPath; w-@6|o,S  
sFileName = sName; H'F6$ypoS  
this.nSplitter = nSpiltter; 1N2,mo?2  
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6oSQQhge  
} m
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public String getSSiteURL() !.1%}4@Q]  
{ ^`f*'Z  
return sSiteURL; _lW+>xQ  
} 6dAEM;$_Z  
5X.e*;  
{G*A.$-d  
public void setSSiteURL(String value) t:LcNlN|  
{ 1y^K/.5-  
sSiteURL = value; 9z?oB&5  
} {K#NB_*To  
-G,^1A
L>  
}bU8G '  
public String getSFilePath() qNyzU@  
{ oPc\<$  
return sFilePath; 0N=X
74  
} C6_@\&OA  
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public void setSFilePath(String value) 97!>%d[0  
{ p (FlR?= S  
sFilePath = value; 27ckdyQx  
} bN^O}[  
0tk#Gs[  
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public String getSFileName() YJxw 'U >P  
{ hl&-\dc+  
return sFileName; avp;*G}  
} ,a?\MM9$  
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public void setSFileName(String value) 8&"(WuZ@  
{ 8 6QE/M  
sFileName = value; t)oapIeIe  
} 1G~S|,8p  
!A8^Xmz"  
BcA31%  
public int getNSplitter() zBf-8]"^  
{ ;evCW$G=  
return nSplitter; G)>W'yxQ  
} o-7>eE}+  
Q Z8QQ`*S  
v;y0jD
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public void setNSplitter(int nCount) 64Gi8|P  
{ `P+(&taT  
nSplitter = nCount; =j0x.fSe  
} !/K8xD$  
} "EpH02{i  
4V9BmVS|Th  
qb;b.P?~D$  
/* ASdW!4.p  
**Utility.java w<~[ad}  
*/ X0L\Ewm  
package NetFox; f@`|2wG  
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.$s']' =  
public class Utility { j3&q?1  
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public Utility() ^W sgAyCB  
{ E q4tcZ  
V]Te_ >E;w  
xbi\KT`~  
} <cZ/_+H%
C  
z4 =OR@ h  
//线程睡眠 f:46.)Wj<  
public static void sleep(int nSecond) >NPK;Vu  
{ r?u4[ Oe#  
try{ Qq6'[Od  
Thread.sleep(nSecond); 0e&&k  
} X> 98`  
catch(Exception e) t;Z9p7rk  
{ Jqzw94  
e.printStackTrace (); K. B\F)K  
} q~#>MB}".  
} #do%u"q  
5mV!mn:H:  
//日志 ;1yF[<a  
public static void log(String sMsg) 5MG4S  
{ Xl1%c7r.1  
System.err.println(sMsg); u ]y[g  
} =^p}JhQ  
u`wD6&y*  
/$clk=  
public static void log(int sMsg) Z^Um\f  
{ /":/DwI'  
System.err.println(sMsg); ?f9M59(l  
} ..h@QQ  
} ">!pos`<C  
R`$Y]@i&B  
S]=.p-Am  
/* > dVhIbG  
**TestMethod.java Jw=7eay$F  
*/ U]+IP;YS  
package NetFox; Kg~D~ +j  
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"*/IP9?]  
public class TestMethod { lH?jqp
  
y+Nw>\|S  
_\yR/W~  
public TestMethod() _t"[p_llo  
{ ///xx/weblogic60b2_win.exe %}H 2  
try{ \:@7)(p\;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L_9uwua.B~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T^MY w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F0&ubspt\  
fileFetch.start(); LUxDP#~7  
} \:s%;s51  
catch(Exception e){e.printStackTrace ();} E@otV6Wk[@  
!4#qaH-Q  
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} jmgkY)rb R  
;=IJHk1&  
^ )"Il  
public static void main(String[] args) ` ;mQ"lO  
{ {HM[ )t0  
new TestMethod(); y5=,q]Qjk[  
} _'"whZ)2  
} Z:2a_Atm  
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