http断点续传简单实现（java)

/* fn
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**SiteFileFetch.java XTW/3pB  
*/ )sNtwSl^  
package NetFox;
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import java.io.*; +oQ@E<)H  
import java.net.*; ;ejC:3yO  
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public class SiteFileFetch extends Thread { yY_]YeeR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean cVulJ6  
long[] nStartPos; //开始位置 ^O892
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long[] nEndPos; //结束位置 2N)vEUyDV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `VBjH]$  
long nFileLength; //文件长度 .WG@"2z|  
boolean bFirst = true; //是否第一次取文件 Hh!x&;x}  
boolean bStop = false; //停止标志 o_G.J4 V  
File tmpFile; //文件下载的临时信息 T,?^J-h^  
DataOutputStream output; //输出到文件的输出流 T 86}^=-5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 89 (k<m  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5gJQr%pS  
{ ?on3z  
siteInfoBean = bean; b$gDFNa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Uc9Uj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6K<vyr40  
if(tmpFile.exists ()) j@9nX4Z  
{ #),QWTl3  
bFirst = false; oN _%oc  
read_nPos(); {I2jLc  
} kc"U)>  
else \*_a#4a  
{ t5e(9Yhj  
nStartPos = new long[bean.getNSplitter()]; ! B)Em  
nEndPos = new long[bean.getNSplitter()]; C8G['aQ  
} =~HX/]zF  
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} n7{c0;)$  
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public void run() +qS$t  
{ vk#xCggK  
//获得文件长度 _wHqfj)  
//分割文件 p(x[zn+%Y  
//实例FileSplitterFetch fwl RwH(  
//启动FileSplitterFetch线程 Pel3e ~?t  
//等待子线程返回 %HSoQ?qA  
try{ \<z{@  
if(bFirst) ;2X1qw>  
{ &2) mpY8xQ  
nFileLength = getFileSize(); }D|"$*  
if(nFileLength == -1) }QC:!e,yG  
{ +*|E%pq  
System.err.println("File Length is not known!"); ?SQT;C3j(  
} cxmr|-^  
else if(nFileLength == -2) oHa6fi  
{ lv8tS-  
System.err.println("File is not access!"); bo@1c0  
} "kN5AeRg  
else q+m&V#FT%  
{ -i;#4@^t  
for(int i=0;i<nStartPos.length;i++) +$<m;@mZ  
{ *?i~AXJm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); n ~ =]/  
} n$~RgCf  
for(int i=0;i<nEndPos.length-1;i++) _|s{G  
{ 2KPXRK  
nEndPos = nStartPos[i+1]; 8ztY_"]3p  
} &i!.6M2  
nEndPos[nEndPos.length-1] = nFileLength; Mv;7kC7]  
} [(dAv7YbN  
} 02=eE|Y@  
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//启动子线程 F!N
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :/1WJG:!  
for(int i=0;i<nStartPos.length;i++) IXC: Q  
{ 7qnw.7p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +i K.+B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,':?3| $c  
nStartPos,nEndPos,i); O"{NHNG\oT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pG|DT ?  
fileSplitterFetch.start(); 1g|H8CA  
} <K2 )v~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fHe3 :a5+W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7ZJYT#>b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fw-LZ][  
nEndPos = " + nFileLength); Pw+cpM8<  
// fileSplitterFetch[nPos.length-1].start(); L%=u&9DmU  
;H}?8L  
_\u'~wWl  
//等待子线程结束 :@n e29,}  
//int count = 0; /)v X|qtIY  
//是否结束while循环 \bfNki  
boolean breakWhile = false; XV!P8n  
:]?I|.a  
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while(!bStop) :x16N|z  
{ 8vchLl#  
write_nPos(); R|5w:+=z  
Utility.sleep(500); HPu nNsA  
breakWhile = true; k2O==IG]
6  
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for(int i=0;i<nStartPos.length;i++) tn:tM5m  
{ M|e@N  
if(!fileSplitterFetch.bDownOver) Nhuw8Xv  
{ r1t  TY?  
breakWhile = false; c!6.D  
break; rw58bkh6  
} QCMt4`%'u  
} Q?Q!D+~mND  
if(breakWhile) P PmE.%_  
break; {:!*1L  
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7  
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//count++; y/ vE  
//if(count>4) hoPCbjkov  
// siteStop(); hfVJg7-  
} 9D-PmSnv  
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System.err.println("文件下载结束！"); ^|OxlfS  
} j].XVn,  
catch(Exception e){e.printStackTrace ();}
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} 7!z0)Ai_>=  
!~PV\DQN  
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//获得文件长度 _18) XR  
public long getFileSize() dd_n|x1  
{ i.6c;KU  
int nFileLength = -1; UG 9uNgzQ/  
try{ %nT!u!#  
URL url = new URL(siteInfoBean.getSSiteURL()); 0<
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1@;Dn'  
httpConnection.setRequestProperty("User-Agent","NetFox"); "){"{~  
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int responseCode=httpConnection.getResponseCode(); '\=aSZVO  
if(responseCode>=400) `BF+)fs  
{ V+-%$-w>  
processErrorCode(responseCode); FAo\`x  
return -2; //-2 represent access is error Jro)  
} 8FU8E2zo  
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String sHeader; [Vc8j&:L  
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for(int i=1;;i++) !CY:XQm  
{ q\/ph(HF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'HzF/RKh  
//Utility.log(in.readLine()); 5{L~e>oS9  
sHeader=httpConnection.getHeaderFieldKey(i); <0T|RhbY  
if(sHeader!=null) 6 -N 442  
{ :)p\a1I[*  
if(sHeader.equals("Content-Length")) 4*P#3 B'@V  
{ 2V:`':  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !%?O`+r  
break; *3d+ !#;rG  
} :[kfWai#(  
} YZMSiDv[e  
else xG/B$DLn  
break; `zwXfY,%  
} kZ>_m&g  
} X@RS /  
catch(IOException e){e.printStackTrace ();} [+ Kjun_  
catch(Exception e){e.printStackTrace ();} ,K 8R
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Utility.log(nFileLength); ose(#n40  
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return nFileLength; -Aaim`06bv  
} 0"}J!c<g  
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}"\1  
//保存下载信息（文件指针位置） t-B5,,`  
private void write_nPos() ~@=(#tO.  
{ n+MWny  
try{ =h0vdi%{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :e/*5ix  
output.writeInt(nStartPos.length); h!=h0  
for(int i=0;i<nStartPos.length;i++) cD6S;PSg  
{ hz:h>Hwy  
// output.writeLong(nPos); i'V("  
output.writeLong(fileSplitterFetch.nStartPos); =HMa<"-8  
output.writeLong(fileSplitterFetch.nEndPos); M#nlKj<  
} *,& 2?E8  
output.close(); J/LsL k  
} Kv0V`}<Yc  
catch(IOException e){e.printStackTrace ();} lg"aB  
catch(Exception e){e.printStackTrace ();} 5.1z9[z  
} <yl%q*gls  
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,2YZB*6h{  
//读取保存的下载信息（文件指针位置） /|q.q  
private void read_nPos() ysapvQN_6  
{ VWq]w5oQO  
try{ vMd3#@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o1`\*]A7J  
int nCount = input.readInt(); ;3x*pjLG:Q  
nStartPos = new long[nCount]; b:Z&;A|"{  
nEndPos = new long[nCount]; Xii>?sA5Z"  
for(int i=0;i<nStartPos.length;i++) y+3+iT@i  
{ t:MSV?  
nStartPos = input.readLong(); v5>A1\  
nEndPos = input.readLong(); [?%q,>F  
} <qg4Rz\c]  
input.close(); J2<kOXXJ9  
} ijsoY\V50  
catch(IOException e){e.printStackTrace ();} p8Z?R^$9H  
catch(Exception e){e.printStackTrace ();} pHT]2e#  
} sYjhQN=Y*  
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private void processErrorCode(int nErrorCode) '2GnAws^  
{ nv0\On7wd  
System.err.println("Error Code : " + nErrorCode); #
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} o^XDG^35`  
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lu utyK!  
//停止文件下载 /:|vJ|dJ  
public void siteStop() >P6"-x,["  
{ awLvLkQb{  
bStop = true; WtSs:D  
for(int i=0;i<nStartPos.length;i++) K#"=*p,  
fileSplitterFetch.splitterStop(); ,p2UshOmd
 
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} b,!C8rJ  
} !R{IEray  
//负责部分文件的抓取 JsaXI:%1  
**FileSplitterFetch.java \!KE_7HRu  
*/ ?Y=aO(}=h  
package NetFox; 1]xk:u4LA  
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import java.io.*; n Ja!&G&  
import java.net.*; IsXNAYj  
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public class FileSplitterFetch extends Thread {  }D1x%L  
zLJ>)v$81  
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String sURL; //File URL w\C1Bh!  
long nStartPos; //File Snippet Start Position j?T'N:Qd  
long nEndPos; //File Snippet End Position 7UT
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int nThreadID; //Thread's ID `IHP_IfR  
boolean bDownOver = false; //Downing is over )Q
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boolean bStop = false; //Stop identical t~2oEwTm  
FileAccessI fileAccessI = null; //File Access interface f\&X$
g  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2mY!gVi  
{ <^S\&v1C_  
this.sURL = sURL; Bc>j5^)8w  
this.nStartPos = nStart; m\teE]8x  
this.nEndPos = nEnd; 4[ uqsJB  
nThreadID = id; e=]SIR()`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |mT%IR  
} _{|a<Keq|  
hY}Q|-|  
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public void run() _|~Dj)z  
{ "&L8d(ZuA  
while(nStartPos < nEndPos && !bStop) ,%!m%+K9a  
{ VH7
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try{ T!/o^0w  
URL url = new URL(sURL); xd?=#d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NKY|Z\  
httpConnection.setRequestProperty("User-Agent","NetFox"); n6Oz[7M  
String sProperty = "bytes="+nStartPos+"-"; B>{%$@4  
httpConnection.setRequestProperty("RANGE",sProperty); ^^q&VL  
Utility.log(sProperty);  %:26v  
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InputStream input = httpConnection.getInputStream(); zAB= >v  
//logResponseHead(httpConnection); .zb  
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byte[] b = new byte[1024]; 7i5B=y7b  
int nRead; P"c@V,.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `IN!#b+Eo  
{ ?K$&|w%{3  
nStartPos += fileAccessI.write(b,0,nRead); FNGa4  
//if(nThreadID == 1) WcmX"{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^y,h0?Z9  
} [;m@A\F  
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Utility.log("Thread " + nThreadID + " is over!"); x,nl PU  
bDownOver = true; LhG\)>Y%  
//nPos = fileAccessI.write (b,0,nRead); {S0-y  
} av'D
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catch(Exception e){e.printStackTrace ();} CU=sQfE  
} D5gj*/"  
} `%YMUBaI  
|s3;`Nxu7  
"#)|WVa=BM  
//打印回应的头信息 /xX7:U b  
public void logResponseHead(HttpURLConnection con) f@}>:x  
{ f y2vAwl  
for(int i=1;;i++) cb-IRGF  
{ y&(#
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String header=con.getHeaderFieldKey(i); %??v?M*  
if(header!=null) Gf8^nfr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2: QT`e&  
Utility.log(header+" : "+con.getHeaderField(header)); MKbcJZe  
else \.2i?<BC  
break; I<}% L V  
} lIyMNw  
} 9L$OSy|  
tR51Pw  

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public void splitterStop() P!-RZEt$  
{ >5O~S
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bStop = true; aOvqk ^  
} cfmLErkp  
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} :2lpl%/  
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/* ?|,:;^2l1  
**FileAccess.java H+*3e&  
*//文件访问(定位，写) 6uD<E  
package NetFox; 4dixHpq'  
import java.io.*; 4prJ!k  
(uX?XX^  
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public class FileAccessI implements Serializable{ H!*ypJ  
FS}b9sQ)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }etdXO_^  
RandomAccessFile oSavedFile; +iQ@J+k  
long nPos; k, N{  
F]M-r{  
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public FileAccessI() throws IOException YM`T"`f  
{ uD/@d'd_4L  
this("",0); N3$1f$`  
} 3li$)S1z  
CUJq [  
6y!U68L;B  
public FileAccessI(String sName,long nPos) throws IOException ~!ooIwNNz  
{ Q u2 ~wp<  
oSavedFile = new RandomAccessFile(sName,"rw"); lU 62$2  
this.nPos = nPos; uxyj6(  
oSavedFile.seek(nPos); 7c"Csq/]I  
} R'sNMWM  
.@):
 Uh  
J4ZHE\  
public synchronized int write(byte[] b,int nStart,int nLen) j7)mC4o:%  
{ %%ouf06.|  
int n = -1; (Yz[SK=U}  
try{ o/3.U=px~  
oSavedFile.write(b,nStart,nLen); [.4{s  
n = nLen; e1g3a1tnWl  
} /4O))}TX  
catch(IOException e) WowT!0$  
{ $y6 <2w%b  
e.printStackTrace (); U;/2\Ii  
} %16Lo<DPm  
WOZuFS13  
%|e)s_%XE  
return n; -E1-(TS  
} nrY)i_\  
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} -TVwoK  
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3!8(A/YP;  
/* 4Q0ZY(2 EO  
**SiteInfoBean.java `(HvD] l  
*/ `Pc6 G*p  
package NetFox; :pM8Q1:B  
YzjRD:  
c#TY3Z|  
public class SiteInfoBean { PS"rXaY  
?o[h$7`o6  
^2}HF/  
private String sSiteURL; //Site's URL Ho&:Zs  
private String sFilePath; //Saved File's Path f2[R2sto@  
private String sFileName; //Saved File's Name q{`1[R  
private int nSplitter; //Count of Splited Downloading File M?YNK]   
5IUdA?  
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public SiteInfoBean() ]+Lr'HF  
{//nSplitter的缺省值为5 2$Xof  
//default value of nSplitter is 5 |l8=z*v<  
this("","","",5); (m
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} IDn<5#  
lIS`_H}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;U>nj],uv  
{ IQU1 JVkZ  
sSiteURL= sURL; @]q^OMLY  
sFilePath = sPath; Bc.de&Bxz_  
sFileName = sName; K?J_cnJ`  
this.nSplitter = nSpiltter; ke8g tbm  
-XXsob}/8  
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} r QiRhp  
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public String getSSiteURL() Eo2`Vr9g  
{ )Mdddz4  
return sSiteURL; #1U>  
} 3v
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%JrZ
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}| MX=:@*  
public void setSSiteURL(String value) f|VCibI  
{ Z@1kx3Wx$  
sSiteURL = value; d7](fw@c  
} rl7up  
7P2n{zd,  
f$QkzWvr  
public String getSFilePath() i[9yu-  
{ V K6D  
return sFilePath; xgMh@@e  
} l#enbQ`-~  
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public void setSFilePath(String value) i<F7/p "
-  
{ eMnK@J  
sFilePath = value; mP\V.^  
} .F8[;+  
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Lo'pNJH;$  
public String getSFileName() Oe1WnS 7(]  
{ KGM__ZO.  
return sFileName; N<i5X.X  
} oaqH@`  
m|W17LhW{  

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-  
public void setSFileName(String value) T+nID@"36  
{ =tD*,2]  
sFileName = value; Y]L4,V  
} avq$aq(3&  
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public int getNSplitter() OiQf=Uz\  
{ :wS&3:h  
return nSplitter; NH|I>vyN  
} AwNr}9`  
"W"^0To  
vcd
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public void setNSplitter(int nCount) 3!l>\#q6  
{ 9{OO'at?  
nSplitter = nCount; 6Yn>9llo}=  
} (*$F7oO<  
} 2pdeJ  
]Z5m_-I  
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/* Qz(2Iu{E]  
**Utility.java c+3`hVV  
*/ QO}~"lMj  
package NetFox; SM8N*WdiU  

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public class Utility { A .&c>{B7  
w@^J.7h^  

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public Utility() Mc.{I"c@  
{ |gI>Sp%Fu  
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} $x'jf?zs!  
pL1ABvBB  
//线程睡眠 R
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public static void sleep(int nSecond) x3cjyu<K  
{ r%f Q$q>
 
try{ %]}JWXof  
Thread.sleep(nSecond); :|s;2Y  
} C33Jzn's  
catch(Exception e) GP c B(  
{  Kg';[G\  
e.printStackTrace (); l%2VA  
} fX`u"`o5  
} 4Y?2u  
m@XX2l9:9  
//日志 B{&W|z{$  
public static void log(String sMsg) |1!fuB A  
{ tV(
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System.err.println(sMsg); -:%QoRCy  
} C/Q20  
yS~Y"#F!.  
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public static void log(int sMsg) g)czJ=T2  
{ \JM6zR^Ef  
System.err.println(sMsg); m8F$h-  
}
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} aeUgr!  
6d]4 %QT  
a%Q`R;W  
/* ;SU<T^a  
**TestMethod.java ?h4[yp=w  
*/ %cn1d>M+I  
package NetFox; 6"G(Iq'2t3  
Y^Buz<OiG  
&*OwoTgk+  
public class TestMethod { :ir#7/  
%U{sn\V  
E~}H,*)  
public TestMethod() $a~  
{ ///xx/weblogic60b2_win.exe N9M}H#  
try{ P1[.[q/-e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4j3_OUwWZx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ivgX o'=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;xiN<f4B  
fileFetch.start(); )8oyo~4?  
} .t\J@?Z  
catch(Exception e){e.printStackTrace ();} 9ia&/BT7"z  
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ks.p)F>]  
} _m?i$5  
&6CDIxH{  
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public static void main(String[] args) YaS!YrpI  
{ Q.$8>)  
new TestMethod(); R?)Yh.vi=t  
} 5/P. 4<c7  
} X'$H'[8;C  
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