http断点续传简单实现（java)

/* 8]O#L}"  
**SiteFileFetch.java w\V<6_[vv.  
*/ 7s2*VKr  
package NetFox; 0tPw
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import java.io.*; %|f@WxNrU  
import java.net.*; TIaiJvo  
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public class SiteFileFetch extends Thread { 0AoWw-H6V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean TC@F*B;  
long[] nStartPos; //开始位置 sEZ2DnDI  
long[] nEndPos; //结束位置 |?MD>Pez  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #SjCKQ~  
long nFileLength; //文件长度 De>,i%`Q,D  
boolean bFirst = true; //是否第一次取文件 "GJ.`Hj  
boolean bStop = false; //停止标志 YB^m!A),I[  
File tmpFile; //文件下载的临时信息 ~XvMiWuo  
DataOutputStream output; //输出到文件的输出流 9(_n8br1  
9#~jlq(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） > %Hw008  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6x/o j`_[  
{ [biz[fm  
siteInfoBean = bean; +bb-uoZf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wqap~X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LcNI$g;}Yf  
if(tmpFile.exists ()) f'`y-]"V5)  
{ P=y1qqC  
bFirst = false; hAP2DeT$  
read_nPos(); \8vZZt  
} M9(lxu y1  
else "+ k}#<P4\  
{ fi&>;0?7  
nStartPos = new long[bean.getNSplitter()]; A8AeM`  
nEndPos = new long[bean.getNSplitter()]; 1-.i^Hal  
} 7qWa>fX  
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} T8W^qrx.v  
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public void run() <$#^)]Ts  
{ TQ[J,  
//获得文件长度 _.EM])b  
//分割文件 pE0@m-p  
//实例FileSplitterFetch vNZ"x)?  
//启动FileSplitterFetch线程 e ]2GAJLI  
//等待子线程返回 Z7?\ >4V  
try{ %j{*`}
 
if(bFirst) {W%XSE  
{ -b?s\X  
nFileLength = getFileSize(); hQvI}  
if(nFileLength == -1) NpbZt;%t  
{ M~Er6Zg  
System.err.println("File Length is not known!"); `}a-prT<f  
} XXD4T9Wy  
else if(nFileLength == -2) E%Ko[G  
{ o0dD  
System.err.println("File is not access!"); U><$p{)  
} whGtVx|zR
 
else zcio\P=^|B  
{ %.fwNS  
for(int i=0;i<nStartPos.length;i++) O>" |5wj  
{ xsvJjs;=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); li#ep?5h^  
} *w6F0>u  
for(int i=0;i<nEndPos.length-1;i++) 5F]2.<i  
{ '?3
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nEndPos = nStartPos[i+1]; muhu` k`C  
} |ss4pN0X  
nEndPos[nEndPos.length-1] = nFileLength; zIr-Rx'dL^  
} p>+Q6o9O
 
} $2Bll5!]  
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7dR]$~+*e  
//启动子线程 PMQlJ&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _!?a9  
for(int i=0;i<nStartPos.length;i++) WP^wNi ~>  
{ h66mzV:`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Odw9]`,T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X3~@U7DU  
nStartPos,nEndPos,i); @jZ1WHS_a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QQ %W3D@  
fileSplitterFetch.start(); Nkn2\w  
} #TB 3|=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /#?!9c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o Z%oP V:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pa?C-Xn^  
nEndPos = " + nFileLength); meGLT/   
// fileSplitterFetch[nPos.length-1].start(); E0u&hBd3_  
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//等待子线程结束 QM7BFS;  
//int count = 0; hK %FpGYA  
//是否结束while循环 tNYuuC%N  
boolean breakWhile = false; B
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while(!bStop) &&zsUAkS  
{ ,=: -&~?  
write_nPos(); HY(XI u  
Utility.sleep(500); eEYzA  
breakWhile = true; Fnd_\`9{  
4MCj*ok<  
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for(int i=0;i<nStartPos.length;i++) {??bJRT  
{ ^3QJv{)Q  
if(!fileSplitterFetch.bDownOver) {9cjitl  
{ zT>BC}~.b  
breakWhile = false; lx> ."rW  
break; N_l_^yD  
} 5!Ovd O}g  
} YU\k D
  
if(breakWhile) $KS!vS7  
break; qTGi9OP6/  
gN]\#s@[  
~9@83Cs2  
//count++; HKVtO%&  
//if(count>4) VuD{t
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// siteStop(); :4r*Jju<V  
} [n3@*)q's  
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System.err.println("文件下载结束！"); mrig5{  
} Mt@Ma ]!  
catch(Exception e){e.printStackTrace ();} WYIv&h<h"  
} #K!"/,d@>J  
)^ PWr^  
I^[[*Bh*C  
//获得文件长度 ZzxWKIE'c  
public long getFileSize() eYevj[c;  
{ h-DHIk3/  
int nFileLength = -1; beNy5~M$  
try{ {HFx+<
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URL url = new URL(siteInfoBean.getSSiteURL()); 1Vs>G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3^-\=taN<m  
httpConnection.setRequestProperty("User-Agent","NetFox"); D&qJ@PR  
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int responseCode=httpConnection.getResponseCode(); aj<r=  
if(responseCode>=400) e%IbME]x  
{ jsP+,brO  
processErrorCode(responseCode); cM]ZYi
 
return -2; //-2 represent access is error m|v$F,Lv  
} ZKM@U?PK  
#$}A$sm  
5=8t<v1Bn  
String sHeader; !lBK!'0  
7}`FXB  
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for(int i=1;;i++) ex66GJQe1  
{ xqQK-?k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); ph~BxK )i6  
sHeader=httpConnection.getHeaderFieldKey(i); ux6p2Sk;K  
if(sHeader!=null) k *>"@  
{ 7xfS%'=y"  
if(sHeader.equals("Content-Length")) %"WhD'*z}  
{ \s!x;nw[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pF(6M3>IN  
break; #$F*.vQSs+  
} kdaq_O:s  
} M`E}1WNQ?]  
else 5Vai0Qfcu:  
break; Z;njSw%:  
} wJ"]H!r0  
} 4um^7Ns)7  
catch(IOException e){e.printStackTrace ();} unKgOvtj  
catch(Exception e){e.printStackTrace ();} UD9JE S,  
@Gy.p5J8  
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Utility.log(nFileLength); 9SJSUv:@  
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return nFileLength; d]MpE9@'v  
} C~C`K%7  
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//保存下载信息（文件指针位置） ) $0>L5d:  
private void write_nPos() mu5r
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{ HJP~ lg  
try{ WdB\n/BWB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ey=}bBx  
output.writeInt(nStartPos.length); X~SNkM  
for(int i=0;i<nStartPos.length;i++) "oyBF CW  
{ \xcf<y
3_  
// output.writeLong(nPos); ]wi0qc2{  
output.writeLong(fileSplitterFetch.nStartPos); 4Z5;y[k(  
output.writeLong(fileSplitterFetch.nEndPos); ?% A2  
} %0Qq~J@Lu  
output.close(); e1%kW1Z9  
} lD-2 5~YV  
catch(IOException e){e.printStackTrace ();} G6+6uWvl  
catch(Exception e){e.printStackTrace ();} Uv652DC  
} \A)Pcc}7  
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//读取保存的下载信息（文件指针位置） 9hh~u -8L  
private void read_nPos() n{&;@mgI  
{ w'E?L`c  
try{ b=U3&CV9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p#_5w  
int nCount = input.readInt(); *2rc
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nStartPos = new long[nCount]; tGzp=PyA  
nEndPos = new long[nCount]; ayQeT  
for(int i=0;i<nStartPos.length;i++) _O;4>  
{ CGkx_E]  
nStartPos = input.readLong(); B^/k`h6J  
nEndPos = input.readLong(); d={o|Mf  
} 3s67)n  
input.close(); <]X6%LX  
} 9X +dp  
catch(IOException e){e.printStackTrace ();} FFN Sn  
catch(Exception e){e.printStackTrace ();} [;4;.V  
} M'F<1(  
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private void processErrorCode(int nErrorCode) 6> z{xYat  
{ l(}MM|ka  
System.err.println("Error Code : " + nErrorCode); +\)Y,@cw  
} vU]n0)<KB  
g"(@+\XZH"  
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//停止文件下载 gVI`&W__,  
public void siteStop() %QEyvl4  
{ uG +ZR: _  
bStop = true; M&<qGV$A  
for(int i=0;i<nStartPos.length;i++) Px9 K  
fileSplitterFetch.splitterStop(); 9*huO#  
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%g{)K)$,ui  
} Pai8r%Zfu  
} ;r&Z?B$  
//负责部分文件的抓取 s9OW.i]zX  
**FileSplitterFetch.java 4nQ5zwiV  
*/ M ?AX:0  
package NetFox; 1ltW9^cF}  
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import java.io.*;
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import java.net.*; %5DM ew  
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e  
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public class FileSplitterFetch extends Thread { ?u/UV,";y  
{?2|rv)  
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String sURL; //File URL |lg jI!iK  
long nStartPos; //File Snippet Start Position <;O^3_'  
long nEndPos; //File Snippet End Position (DS"*4ty  
int nThreadID; //Thread's ID 8 H3u"  
boolean bDownOver = false; //Downing is over kFC*,  
boolean bStop = false; //Stop identical nc\2A>f`  
FileAccessI fileAccessI = null; //File Access interface 5Pxx)F9]  
.Eb]}8/}E  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4*Gv0#dga  
{ I%GQ3D"=  
this.sURL = sURL; j"aY\cLr t  
this.nStartPos = nStart; T93st<F=R  
this.nEndPos = nEnd;
4y?n62N8$  
nThreadID = id; C/#pK2xY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c:&8B/  
} \7>*ULP  
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public void run() xkax  
{ i3Bpim.  
while(nStartPos < nEndPos && !bStop) Dw
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{ URg;e M#  

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try{ K~I?i/P=z  
URL url = new URL(sURL); zy n
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `j9\]50Z>  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xt$P!~Lu  
String sProperty = "bytes="+nStartPos+"-"; R=&-nC5e  
httpConnection.setRequestProperty("RANGE",sProperty); 8iOHav4  
Utility.log(sProperty); Y:L[Iz95o  
]8DTk!  
 s2wDJ|  
InputStream input = httpConnection.getInputStream(); F:q8.^HTJ  
//logResponseHead(httpConnection); DR:DXJc  
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byte[] b = new byte[1024]; UnP<`z#  
int nRead; D,[Nn_N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]'M B3@T  
{ G &NK  
nStartPos += fileAccessI.write(b,0,nRead); ZfH>UHft  
//if(nThreadID == 1) NN1}P'6Ha  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nqo1+OR  
} UZrEFpi  
O(!;7v}  
#+V4<o  
Utility.log("Thread " + nThreadID + " is over!"); cL~WDW/  
bDownOver = true; -,T!/E  
//nPos = fileAccessI.write (b,0,nRead); T*PEUq  
} dcD#!v\0  
catch(Exception e){e.printStackTrace ();} EU%v |]  
} .UQ|k,,t  
} 7pQ5`;P  

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j BBl{  
//打印回应的头信息 -]Su+/3(,  
public void logResponseHead(HttpURLConnection con) r|DIf28MIq  
{ C=@4U}  
for(int i=1;;i++) (=;'>*L(  
{ <tZZ]Y]  
String header=con.getHeaderFieldKey(i); eOF*|9  
if(header!=null) =b>TFB=*N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qHdUnW  
Utility.log(header+" : "+con.getHeaderField(header)); , QWu
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else W02z}"#  
break; P5oS 1iu*  
} #$-?[c$>  
} oYTLC@98}  
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public void splitterStop() j~K(xf  
{ ;nQ=! .#Q  
bStop = true; Z_xQ2uH$:  
} n8=Dzv0  
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} 4K~=l%l  
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/* ng9e)lU~*b  
**FileAccess.java ]=%qm;  
*//文件访问(定位，写) buN@O7\  
package NetFox; wv."  
import java.io.*; ^uN[rHZ*u  
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public class FileAccessI implements Serializable{ OUF%DMl4  
gj @9(dk%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LO)!Fj4|  
RandomAccessFile oSavedFile; Y z&!0Hfd  
long nPos; d7[^pN  
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public FileAccessI() throws IOException t,JX6ni  
{ R@z`  
this("",0); 2p\xgAW?  
} wn!=G~nB  
2&n6:"u|  
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public FileAccessI(String sName,long nPos) throws IOException X5VNj|IE  
{ |C z7_Rn  
oSavedFile = new RandomAccessFile(sName,"rw"); )1M
2}11uS  
this.nPos = nPos; ,3T"fT-(  
oSavedFile.seek(nPos); Uoe;=P@  
} so$(-4(E O  
{R(CGrI  
{cOx0=  
public synchronized int write(byte[] b,int nStart,int nLen) 7`t"fS  
{ >| ,`E  
int n = -1; gveJ1P  
try{ k89N}MA   
oSavedFile.write(b,nStart,nLen); abUO3 Y{  
n = nLen; IJ2'  
} {TpbUj0  
catch(IOException e) 76@W:L*J$J  
{ `G\Gk|4;2  
e.printStackTrace (); 0{z8pNrc  
} QJ(%rvn3  
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return n; XK3O,XM  
} Sv/P:r _  
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} ZwLr>?0$ p  
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/* eg}g}a  
**SiteInfoBean.java Z+y'w#MZL  
*/ a dr\l5pWQ  
package NetFox; '%ilF1#  
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b:hta\%/2  
public class SiteInfoBean { ydO+=R0M  
EF\OM?R  
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private String sSiteURL; //Site's URL *w(n%f  
private String sFilePath; //Saved File's Path t :YZua  
private String sFileName; //Saved File's Name ;xz_H$g  
private int nSplitter; //Count of Splited Downloading File nfHjIYid  
bk<Rp84vL  
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public SiteInfoBean() c:.5@eq^  
{//nSplitter的缺省值为5 "kFH*I+v  
//default value of nSplitter is 5 r1-MO`6  
this("","","",5); 6}I X{nQI  
} EniV-Uj\D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ya\:C]   
{ dGOFSH  
sSiteURL= sURL; tmS2%1o  
sFilePath = sPath; ( `bb1g
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sFileName = sName; j]kgdAq>  
this.nSplitter = nSpiltter; )GVTa4}p  
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8=L"rekV_  
} {v]L|e%{  
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public String getSSiteURL() 0{ mm%@o  
{ F<p`)?  
return sSiteURL; vLN KX;9  
} rD <T  
H%Vf$1/TF  
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public void setSSiteURL(String value) mm+V*L{x  
{ 5)XUT`;'){  
sSiteURL = value; ynM~&]fk#k  
} &t<gK D  
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}W:Z>vam+  
public String getSFilePath() 8,IF%Z+LI  
{ e16H@  
return sFilePath; t{iRCj  
} k-n`R)p:  
-~
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public void setSFilePath(String value) &t8,326;  
{ < r~hU*u  
sFilePath = value; CUH u=  
} `K+%/|!  
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|s/N?/qi  
public String getSFileName() Nkj$6(N=zJ  
{ U"8Hw@  
return sFileName; #2%V  
} 0~BaQ, A@  
7O*Sg2B  
Cn5"zDK$  
public void setSFileName(String value) ;E 9o%f:o  
{ fK=0?]s}I  
sFileName = value; qypF}Pw  
} *s 4Ym
  
I ]o|mjvs  
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public int getNSplitter() AYY(<b  
{ | 8mWR=9fs  
return nSplitter; akr2Os  
} G?Gf,{#K  
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public void setNSplitter(int nCount) *cWHl@4  
{ 7Ji'7$  
nSplitter = nCount; )C?H m^#  
} ej_u):G*  
} %$zak@3%'  
;5X~"#%U_  

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/* ]>[TF'pIAx  
**Utility.java 0'F/z%SMj  
*/ vS~tr sI  
package NetFox; LWqKSNE;  
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public class Utility { SPlt=*C#_  
/ S' +  
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public Utility() o NA ]G]  
{ $S<B\\ %  
 /d|:  
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} j"~"-E(79  
~{{S<S v  
//线程睡眠 x#SE%j?  
public static void sleep(int nSecond) ^g(qPtQ  
{ ?`xF>P]M  
try{ t{},Th  
Thread.sleep(nSecond); M}X
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} pJe!~eyHm  
catch(Exception e) S+.>{0!S"  
{ ^`lDw  
e.printStackTrace (); |X1axRO  
} 'L3MHTM>[  
} a_+3, fP  
G|nBja8vm  
//日志 ]}'bRq*]  
public static void log(String sMsg) 4"eFR'g  
{ /PSXuVtu5  
System.err.println(sMsg); L7<30"7  
} `-U?{U}H  
LyvR].p=5*  
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public static void log(int sMsg) %`s#p` Ol1  
{ R%n*wGi_6b  
System.err.println(sMsg);  ]XlBV-@b  
} 7=yM40  
} @0EY5{&  
b7^q(}qE  
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/* {Lv"wec*x  
**TestMethod.java :F6dXW  
*/ dr"$@  
package NetFox; nl(GoX$vRQ  
jcJ@A0]  
V/\Y(Mxc  
public class TestMethod { g?xXX /Qe  
I:DAn!N-A*  
DFZ0~+rh  
public TestMethod() w3 vZ}1|  
{ ///xx/weblogic60b2_win.exe 1l)j(,Zd*  
try{ 7&P70DO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pFMjfWD,C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5V(#nz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LFi{Q{E)  
fileFetch.start(); F|+B8&-v  
} $'>iNMtK{p  
catch(Exception e){e.printStackTrace ();} 2Jiy`(P  
*"_W1}^  
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} }sqFvab<  
6:}n}q,V  
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public static void main(String[] args) uAnL`
 
{ }@ U}c6/  
new TestMethod(); $D65&R  
} $$p +~X  
} I8@leT\9M  
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