http断点续传简单实现（java)

/* l0sBXs`3b  
**SiteFileFetch.java q@6Je(H  
*/ by{ *R  
package NetFox; "KhVS  
import java.io.*; c8=@s#  
import java.net.*; 
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public class SiteFileFetch extends Thread { a=%QckR*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g218%i  
long[] nStartPos; //开始位置 BGSqfr1F  
long[] nEndPos; //结束位置 5"cYZvGkJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >_m4 idq1  
long nFileLength; //文件长度 RO9oO7S  
boolean bFirst = true; //是否第一次取文件 Q&;d7A.@  
boolean bStop = false; //停止标志 LqOjVQxz  
File tmpFile; //文件下载的临时信息 rjJ-ZRs\  
DataOutputStream output; //输出到文件的输出流 v."0igMO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DP-euz  
public SiteFileFetch(SiteInfoBean bean) throws IOException *K}j>A  
{ I8]q~Q<-P  
siteInfoBean = bean; <Ky6|&!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J@4,@+X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HbUadPr  
if(tmpFile.exists ()) $S(q;Y  
{ ]L?DV3N  
bFirst = false; (!iGQj(m  
read_nPos(); rQ!X  
} p#T^o]+  
else "v9i;Ba>+  
{ YJ[Jo3M@j0  
nStartPos = new long[bean.getNSplitter()]; c~=yD:$  
nEndPos = new long[bean.getNSplitter()]; FhyA_U%/nF  
} 5(}Qg9%  
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} {k#RWDespy  
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public void run() ?{bAyh/  
{ ?t{ 2y1  
//获得文件长度 nOE 1bf^l  
//分割文件 k
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//实例FileSplitterFetch "VfV;)]|w  
//启动FileSplitterFetch线程 4qc0QA%  
//等待子线程返回 3"pl="[*  
try{ TiF2c#Q*y  
if(bFirst) ;&9A Yh.  
{ |##rs  
nFileLength = getFileSize(); _?IP}}jA:  
if(nFileLength == -1) )ZP-t!).G#  
{ >aaHN1Ca  
System.err.println("File Length is not known!"); _H(:$=$Q  
} HR> X@g<c  
else if(nFileLength == -2) [61T$.  
{ WV8?zB1  
System.err.println("File is not access!"); lW8!_h"G`n  
} NL-<K  
else !]v&/  
{ NxyrP**j  
for(int i=0;i<nStartPos.length;i++) g^qbd$}  
{ FlPPz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +l,6}tV9  
} o3oA
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for(int i=0;i<nEndPos.length-1;i++) YV 5kzq  
{ ZvS|a~jO  
nEndPos = nStartPos[i+1]; E{-W#}#  
} KJf~9w9U  
nEndPos[nEndPos.length-1] = nFileLength; 5jYZ+OB  
} ny,a5zEnF  
} ^:yg,cS|Be  
pOz
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mAFVjSa2  
//启动子线程 npW1Z3n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vG7aT  
for(int i=0;i<nStartPos.length;i++) ^z^ UFW  
{ <f'2dT@6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xg>AW Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), j
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nStartPos,nEndPos,i); ji|`S\u#b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H:DTvv8e{  
fileSplitterFetch.start(); LE"t'R  
} Y.<&phv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p^s k?E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )L%i"=<Bdy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &>Ko}?w  
nEndPos = " + nFileLength); J6)&b7  
// fileSplitterFetch[nPos.length-1].start(); mOUIGlv  
GG}(*pOr  
J7C2:zj  
//等待子线程结束 SuHv{u45  
//int count = 0; s|1BqoE  
//是否结束while循环 k$hNibpkt  
boolean breakWhile = false; ;{Sgv^A  
e0#/3$\aSV  
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while(!bStop) VS:UVe  
{ cVR3_e{&H  
write_nPos(); =>0+BD  
Utility.sleep(500); #]@<YKoV{  
breakWhile = true; zP|y3`.52  
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for(int i=0;i<nStartPos.length;i++) LQnkpy3A  
{ jmAQ!y|W.  
if(!fileSplitterFetch.bDownOver) 0V:DeX$bZ  
{ :jFKTG  
breakWhile = false; !"dbK'jb^  
break; SQZUkKfb  
} u I \zDR  
} ||lI_B  
if(breakWhile) .o2]ndT/J  
break; iZVMDJ?(Z]  
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//count++; tkG0xRH  
//if(count>4) bs%lMa.o  
// siteStop(); CXQPbt[5  
} 4@wH4H8  
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System.err.println("文件下载结束！"); Y{ho[%  
} \qrSJ=}t  
catch(Exception e){e.printStackTrace ();} R7L:U+*V"  
} +b7}R7:AFH  
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//获得文件长度 ,=9e]pQ  
public long getFileSize() Dm=Em-ST6  
{ [U]ouh)  
int nFileLength = -1; sI u{_b  
try{ [Z5Lgg&  
URL url = new URL(siteInfoBean.getSSiteURL()); hm%'k~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2>.2H  
httpConnection.setRequestProperty("User-Agent","NetFox"); R|%R-J]  
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int responseCode=httpConnection.getResponseCode(); P}%0YJ$6  
if(responseCode>=400) J{gqm  
{ Sd3KY9,  
processErrorCode(responseCode); 4DVkycM  
return -2; //-2 represent access is error u#8J`%g  
} b"ypS7 _  
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u7=jtB   
String sHeader; VK*2`Z1  
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for(int i=1;;i++) U8Pnt|0M  
{ H<M ggs-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]U]22I'+$2  
//Utility.log(in.readLine()); C*}TY)8  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) ^KU:5Bn  
{ i>9/vwe  
if(sHeader.equals("Content-Length")) CjzfU*G  
{ o|7]8K=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rAdYBr=0  
break; B/i`  
} web=AQ5I4  
} jb' hqz  
else p%A(
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break; BX|+"AeF  
} "+REv_:  
} L%8>deE>;D  
catch(IOException e){e.printStackTrace ();} p_$03q>oQ  
catch(Exception e){e.printStackTrace ();} `eIX*R  
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Utility.log(nFileLength); 5#zwdoQ  
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return nFileLength; Ve,_;<F]S  
} 1NO<K`  
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//保存下载信息（文件指针位置） \o^M,yI  
private void write_nPos() K?_4|  
{ }N_9&I
 
try{ _/"m0/,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uc?QS~H&w  
output.writeInt(nStartPos.length); k;p:P ?s5Y  
for(int i=0;i<nStartPos.length;i++) H1uNlPT  
{ MOJ-q3H^W  
// output.writeLong(nPos); 6&=xu|M<x=  
output.writeLong(fileSplitterFetch.nStartPos); ]@op  
output.writeLong(fileSplitterFetch.nEndPos); (9h{7<wD`  
} fW Vd[zuD4  
output.close(); D-.XSIEMu  
} Ox"4 y  
catch(IOException e){e.printStackTrace ();} ?aInn:FE  
catch(Exception e){e.printStackTrace ();} k/vE|  
} Q)}sX6TB  
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//读取保存的下载信息（文件指针位置） Bv$;yR  
private void read_nPos() tw8@&8"  
{ yV:DR  
try{ <CL0@?*i9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D"F5-s7  
int nCount = input.readInt(); jxL5L[  
nStartPos = new long[nCount]; Ys10r-kDS  
nEndPos = new long[nCount]; +XU*NAD,!  
for(int i=0;i<nStartPos.length;i++) s> JmLtT  
{ VdR5ZP  
nStartPos = input.readLong(); CTt3W>'=+  
nEndPos = input.readLong(); 06I'#:]  
} $|!VP'VI  
input.close(); {A4"KX(U  
} A%n l@`s,  
catch(IOException e){e.printStackTrace ();} M_V\mYC8I  
catch(Exception e){e.printStackTrace ();} M'D;2qo  
} c"%XE#D  
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private void processErrorCode(int nErrorCode)
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{ -^8gZk/(W  
System.err.println("Error Code : " + nErrorCode); t&u,Od  
} $Q1:>i@I|g  
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//停止文件下载 -p`hevRr  
public void siteStop() KcVCA   
{ 4E:HO\  
bStop = true; ]yN]^%PYH  
for(int i=0;i<nStartPos.length;i++) OWCd$c_(  
fileSplitterFetch.splitterStop(); mFOuE5  
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} !z
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} /ocd
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//负责部分文件的抓取 +Ij>\;vM"  
**FileSplitterFetch.java 8QDRlF:;<  
*/ -MoI{3a  
package NetFox; RX:\@c&  
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import java.io.*; PdJtJqA8h\  
import java.net.*; }:YS$'by  
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public class FileSplitterFetch extends Thread { F<X)eO]tk  
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String sURL; //File URL V@<tIui$  
long nStartPos; //File Snippet Start Position 5KU}dw>*g  
long nEndPos; //File Snippet End Position 13s!gwE)  
int nThreadID; //Thread's ID >+R`3|o '  
boolean bDownOver = false; //Downing is over q~.\NKc  
boolean bStop = false; //Stop identical Q4-d2I>0  
FileAccessI fileAccessI = null; //File Access interface qHg\n)R"x!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mgX0@#wFn  
{ `DO`c>>K  
this.sURL = sURL; YEAiLC+q  
this.nStartPos = nStart; uXW<8( %W  
this.nEndPos = nEnd; |4
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nThreadID = id; Fs<kMT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -DhF> 4f  
} '
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public void run() S1wt>}w0$  
{ Nqp%Z7G  
while(nStartPos < nEndPos && !bStop) / O6n[qj|  
{ z}yntY]n  
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try{ 3zY"9KUN  
URL url = new URL(sURL); ?s#DD,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "P.7FD  
httpConnection.setRequestProperty("User-Agent","NetFox"); VR2BdfKU,  
String sProperty = "bytes="+nStartPos+"-"; ,\4@Ao  
httpConnection.setRequestProperty("RANGE",sProperty); \TkBV?W  
Utility.log(sProperty); pNr3u  
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InputStream input = httpConnection.getInputStream(); SQWwxFJ  
//logResponseHead(httpConnection); EU TTeFp  
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byte[] b = new byte[1024]; 2X;,s`)  
int nRead; BgJ;\NV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /A[AHJ<[?  
{ ' ~lC85  
nStartPos += fileAccessI.write(b,0,nRead); YN9ug3O+  
//if(nThreadID == 1) FVT_%"%C9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]plg@  
} T/MbEqAf  
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Utility.log("Thread " + nThreadID + " is over!"); c^}gJ  
bDownOver = true; yAG4W[  
//nPos = fileAccessI.write (b,0,nRead); :)t1>y>3  
} Qr1%"^4  
catch(Exception e){e.printStackTrace ();}  nsij
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} i*..]!7e  
} z<ptrH  
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//打印回应的头信息 ueZ`+g~gg  
public void logResponseHead(HttpURLConnection con) 5[]7baO)h1  
{ \=v7'Hp  
for(int i=1;;i++) XUfj 0  
{ "]JE]n}Ulg  
String header=con.getHeaderFieldKey(i); N-]h+Cnyu  
if(header!=null) x&+/da-E/5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~0>g 4 D.  
Utility.log(header+" : "+con.getHeaderField(header)); iW+ZI6@  
else  r75,mX  
break; {6~v oVkj  
} C^K?"800  
} Q?L-6]pg  
fxXZ^#2wX  
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public void splitterStop() 4&!`Yi_1L  
{ }I}RqD:`  
bStop = true; x,@cU}D  
} Jj*XnL*  
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} 2Prr:k  
~A}"s-Kq5  
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/* &sh %]o8  
**FileAccess.java 0SwWLq  
*//文件访问(定位，写) J1YP-:  
package NetFox; ,m{Zn"?kS  
import java.io.*; ]L^X}[SH  
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public class FileAccessI implements Serializable{ 1&ZG6#16q  
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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 BOrfKtG\  
RandomAccessFile oSavedFile; ~zi6wu(3  
long nPos; @ >%I\  
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public FileAccessI() throws IOException 1mwb&j24n3  
{ @E{c P%fv  
this("",0); vK!,vKa.  
} F/tBr%RV  
4gG&u33RrE  
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public FileAccessI(String sName,long nPos) throws IOException ={~`0,  
{ Z`o}xV  
oSavedFile = new RandomAccessFile(sName,"rw"); [~`; .7~  
this.nPos = nPos; A 7'dD$9  
oSavedFile.seek(nPos); J)oa:Q  
} cT`x,2  
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public synchronized int write(byte[] b,int nStart,int nLen) eY"y[  
{ `E8m>q Ss  
int n = -1; ]QJLES  
try{ L}P<iB   
oSavedFile.write(b,nStart,nLen); 2shr&Mfp[  
n = nLen; m@;X%wf<U  
} UN'hnqC  
catch(IOException e) CtTG`)"|  
{ _Fe
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e.printStackTrace ();  4>uz'j<  
} @C0{m7q
 
) 2wof(  
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return n; 4C/  
} 1u:OzyJy  
# 5v 2`|)  
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} :iD([V  
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/* R;.zS^LL  
**SiteInfoBean.java sEt5!&  
*/ #*BcO-N  
package NetFox; QKL5! L9`  
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public class SiteInfoBean { HTao)`.  
@ eqVug  
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private String sSiteURL; //Site's URL 5JK{dis]k  
private String sFilePath; //Saved File's Path b7E=
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private String sFileName; //Saved File's Name Bcg\p}  
private int nSplitter; //Count of Splited Downloading File '!]ry<  
5u'"m<4  
^Jcs0c @\  
public SiteInfoBean() yBXdj`bV  
{//nSplitter的缺省值为5 ^:5;H=.  
//default value of nSplitter is 5 %a<N[H3NV@  
this("","","",5); sw6]Bc  
} A-aukJg9  
/k|y\'<  
'uGn1|Pvy  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^*#5iT8/  
{ ?;i O  
sSiteURL= sURL; TFb9gOTJ  
sFilePath = sPath; 51;V#@CsQ  
sFileName = sName; X@:pys 8@  
this.nSplitter = nSpiltter; 9n]zh-  
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} U 3aY =8B  

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public String getSSiteURL() }_u1'  
{ &, hhH_W  
return sSiteURL; vQ2kL`@  
} AYeA)jk  
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public void setSSiteURL(String value) ;g?oU"YM  
{ U=\ZeYK.  
sSiteURL = value; x[U/ 8#f&  
} "X4OUk  
?DzKqsS'  
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public String getSFilePath() cod__.  
{ r03
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return sFilePath; oFB~)}f<v  
} V%g$LrLVe  
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public void setSFilePath(String value) A6v02WG_1T  
{ (zIP@ H  
sFilePath = value; UX}ZE.cV  
} k(+EY%  
K??%Qh5l+C  
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public String getSFileName() v!27q*;8H  
{ U']DB h  
return sFileName; |&eZ[Sy(=l  
} *&9_+F8ly  
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public void setSFileName(String value) -lV]((I&  
{ G7yCGT)vQ  
sFileName = value; lyNa(3  
} X1?7}VO  
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public int getNSplitter() Q*&>Ui[&  
{ CMB:%  
return nSplitter; `% k9@k.  
} <^snS,06  
\W=~@k  
ivYHq#b59  
public void setNSplitter(int nCount) fw$/@31AP?  
{ ;wwhW|A  
nSplitter = nCount; 8!2NZOZOS  
} 3}e-qFlV8,  
} CG*eo!Nw  
3B!lE(r%J  
B{$4s8XU  
/* j&,,~AZm  
**Utility.java `WQz_}TqB  
*/ /yPFts_q  
package NetFox; ,~u5SR  
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JwG$lGNJ  
public class Utility { S&_Z,mT./  
`T7gfb%1-3  
)w(
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public Utility() 4Xt.}S!  
{ }tA77Cm)45  
j hf%ze  
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} mz$)80ly  
QxZYy}2  
//线程睡眠 <9z2:^  
public static void sleep(int nSecond) (8qD'(@  
{ 1Q"w)Ta  
try{ R#gt~]x6k  
Thread.sleep(nSecond); nt.A X  
} B64L>7\>`  
catch(Exception e) ,<R/jHZP9  
{ 0NrUB  
e.printStackTrace (); C1&~Y.6m  
} Gx/sJ(  
} _^K)>  
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//日志 Xg
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public static void log(String sMsg) jkCa2!WQ'i  
{ e/hA>  
System.err.println(sMsg); *`$Y!uzG:\  
} q-gp;Fm  
H8.Aq\2S  
J&Ig%&/  
public static void log(int sMsg) ;D.a |(Q  
{ le60b@2G0  
System.err.println(sMsg); S.&=>   
} =j#1HI=Fe  
} [&12`!;j  
j#L"fW^GM  
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/* eGcc'LBr;  
**TestMethod.java iR}3 [  
*/ _`3'D`s  
package NetFox; }dcXuX4{r  
Age  
&Ui*w%  
public class TestMethod { IxN0m7  
_2uRY  
!bs{/?  
public TestMethod() V&nTf100  
{ ///xx/weblogic60b2_win.exe EGpN@  
try{ >K:| +XbH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /g$cQ=c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yF2|w=!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BkywYCWZ )  
fileFetch.start(); |dNJx<-  
} FvpaU\D  
catch(Exception e){e.printStackTrace ();} ,@I_b  
B-'oB>|  
(=#[om(A  
} u\-
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$Ro]]NUz|  
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public static void main(String[] args) tFlLKziU  
{ u /PaXQ  
new TestMethod(); cHqT1EY  
} t6-He~  
} fKEZlrw  
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