http断点续传简单实现（java)

/* |} 9GHjG  
**SiteFileFetch.java b8e*Pv/  
*/ YOlH*cZtg  
package NetFox; klo^K9!  
import java.io.*; YiO3<}Uf  
import java.net.*; U#$:\fT  
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public class SiteFileFetch extends Thread { ^:U;rHY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %27G2^1  
long[] nStartPos; //开始位置 | 4%v"
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long[] nEndPos; //结束位置 >LCjtm\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]svw CPu C  
long nFileLength; //文件长度 zM)M_L  
boolean bFirst = true; //是否第一次取文件 8vu2k>  
boolean bStop = false; //停止标志 vo.EM1x  
File tmpFile; //文件下载的临时信息 78gob&p?  
DataOutputStream output; //输出到文件的输出流 eNivlJ,K|@  
}:"R-s  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ELD +:b  
public SiteFileFetch(SiteInfoBean bean) throws IOException P0Aas)!  
{ sbpu qOL  
siteInfoBean = bean; ,qYf#fU#7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w zdxw$E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z^"?sd  
if(tmpFile.exists ()) $/os{tzjd  
{ k:W=5{[  
bFirst = false; m/cx|b3hqv  
read_nPos(); vDWr|M%``l  
} n/Or~@pHD  
else Scf.4~H 0  
{ &,F elB0*  
nStartPos = new long[bean.getNSplitter()]; PaA6Z":  
nEndPos = new long[bean.getNSplitter()]; 1ME|G"$;  
}
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} BR%{bY^ 5p  
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public void run() D_zcOq9  
{ ;Kt'Sit  
//获得文件长度 Y{`3`Pg&N  
//分割文件 qNhH%tYQ
 
//实例FileSplitterFetch D~XU`;~u  
//启动FileSplitterFetch线程 7Z9.z4\  
//等待子线程返回 Bc5YW-QD  
try{ 01'y^`\xQ  
if(bFirst) pFG]IM7o/u  
{ 6 bYC  
nFileLength = getFileSize(); Al)lWD}j2g  
if(nFileLength == -1) }7otuO(pRo  
{ F%9e@{  
System.err.println("File Length is not known!"); lrq>TJEcx  
} 9$n+-GSK  
else if(nFileLength == -2) 7O]J^H+7  
{ Q=dw 6  
System.err.println("File is not access!"); oA5<[&~<  
} -wJ  
else q|?`Gsr  
{ 8|fLe\"  
for(int i=0;i<nStartPos.length;i++) {H/8#y4qp&  
{ V}j%gy`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "tEj`eR  
} \z&03@Sw  
for(int i=0;i<nEndPos.length-1;i++) wV7@D[8  
{ CD*f4I#d  
nEndPos = nStartPos[i+1]; f6@^
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} n U+pnkMj  
nEndPos[nEndPos.length-1] = nFileLength; ^U R-#WaQ  
} >aNbp  
} B:B0p+$I  
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]t
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//启动子线程 sDW"j\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {Q}!NkF1  
for(int i=0;i<nStartPos.length;i++) U&tfl/  
{ yd\5Z[iEp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Krt$=:m|1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IptB.bYc  
nStartPos,nEndPos,i); ^\xCqVk_R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FF5tPHB  
fileSplitterFetch.start(); N[- %0  
} nL "g23  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kxt\{iy4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9/@FAD
h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~R
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nEndPos = " + nFileLength); BYhmJC|  
// fileSplitterFetch[nPos.length-1].start(); PmuEL@'^ U  
N` @W%  
7-g]A2N  
//等待子线程结束 $%N;d>[U,  
//int count = 0; 3sd{AkD^  
//是否结束while循环 9Ba%=  
boolean breakWhile = false; JNU"5sB  
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while(!bStop) n23%[#,r  
{ ^K1~eb*K  
write_nPos(); :HQ8M*o  
Utility.sleep(500); C}dKbs^g|  
breakWhile = true; _stI?fz*4k  
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for(int i=0;i<nStartPos.length;i++) a>;3 j  
{ +xoyKP!  
if(!fileSplitterFetch.bDownOver) 1Xk{(G<\  
{ c+)36/; X  
breakWhile = false; kMfc"JXF  
break;
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} M6o xtt4  
} (9WL+S  
if(breakWhile) e _SoM!;  
break; (1saof*p%  
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//count++; VuJfo9 `E  
//if(count>4) e>ZbZy?  
// siteStop(); [="g|/M)  
} W07-JHV%  
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System.err.println("文件下载结束！"); 02]8|B(E90  
} Fyi?,,  
catch(Exception e){e.printStackTrace ();} PU]7c2.y  
} 5p#o1I
 
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//获得文件长度 @M1yBN  
public long getFileSize() &CxyP_  
{ 2Q`PUXj  
int nFileLength = -1; L~?,6  
try{ 8S[<[CH  
URL url = new URL(siteInfoBean.getSSiteURL()); )sY$\^'WY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9^b7jw  
httpConnection.setRequestProperty("User-Agent","NetFox"); )n[`Z#  
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int responseCode=httpConnection.getResponseCode(); 1%]{0P0?[  
if(responseCode>=400) kp#c:ym  
{ )Bm^aMVl3  
processErrorCode(responseCode); f//j{P[  
return -2; //-2 represent access is error oJ4mxi@|#  
} n{qa]3  
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String sHeader; 0IT20.~  
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for(int i=1;;i++) {=pP`HD0  
{ {
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Muc*?wB`  
//Utility.log(in.readLine()); ]/<Qn-BbU  
sHeader=httpConnection.getHeaderFieldKey(i); y$r?t0
 
if(sHeader!=null) #Kb)>gzT  
{ I2Or& _  
if(sHeader.equals("Content-Length")) )P(d66yq'u  
{ {8>_,z^P)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iBPdCp%]`  
break; LzEE]i  
} ~3*ZG  
} .eDxIWW+ft  
else rt\<nwc  
break; 6"rFfdns  
} gl(6m`a>  
} !,-qn)b  
catch(IOException e){e.printStackTrace ();} n_!]B_Vd$  
catch(Exception e){e.printStackTrace ();}
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n  
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Utility.log(nFileLength); :+Z>nHe  
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return nFileLength; I;|5C=!  
} [u9S+:7"  
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//保存下载信息（文件指针位置） t6,M  
private void write_nPos() m;tY(kO  
{ 7Hr4yh[j&  
try{ Jz:W-o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gYH:EuY,  
output.writeInt(nStartPos.length); vI:bl~  
for(int i=0;i<nStartPos.length;i++) ,{mf+ 3&$,  
{ w3]0 !)t1  
// output.writeLong(nPos); ][>M<J  
output.writeLong(fileSplitterFetch.nStartPos); &|&YRHv  
output.writeLong(fileSplitterFetch.nEndPos); q%=7<( w  
} o`y*yucHI  
output.close(); 7$dc?K  
} LTls]@N  
catch(IOException e){e.printStackTrace ();} \ /X!tlwxh  
catch(Exception e){e.printStackTrace ();} WHD/s  
} :xUl+(+  
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//读取保存的下载信息（文件指针位置） `$x#_-Hn  
private void read_nPos() nD?M;XN  
{ $0`$
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try{ k~s>8N:&G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <K.C?M(9  
int nCount = input.readInt(); ZZ.0'   
nStartPos = new long[nCount]; krnk%
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nEndPos = new long[nCount]; dW=D]  
for(int i=0;i<nStartPos.length;i++) 2"{]A;@  
{ !A^w6Q;`V  
nStartPos = input.readLong(); 2O)Kn q
  
nEndPos = input.readLong(); RxDxLU2kt  
} yfw>y=/p  
input.close(); r@
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} 
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catch(IOException e){e.printStackTrace ();} }zfLm`vJ  
catch(Exception e){e.printStackTrace ();} BQfAen]  
} J/&*OC  
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private void processErrorCode(int nErrorCode) R7;rBEt8  
{ ,;ruH^  
System.err.println("Error Code : " + nErrorCode); uRq#pYn
@  
} Er+3S@sfq,  
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//停止文件下载 $q
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public void siteStop() )eGu4iEPM  
{ )b2E/G@X&  
bStop = true; yW=hnV{  
for(int i=0;i<nStartPos.length;i++) %IH|zSr)EM  
fileSplitterFetch.splitterStop(); 9oau_Q#  
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} +mQC:B7>  
} G`JwAy r'  
//负责部分文件的抓取  IOES3  
**FileSplitterFetch.java g#<?OFl  
*/ = ]HJa
 
package NetFox; &T/9yW[L  
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import java.io.*; LGgx.Z  
import java.net.*; Q_|S^hxQ  
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public class FileSplitterFetch extends Thread { `&Of82*w  
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String sURL; //File URL 7)It1i-  
long nStartPos; //File Snippet Start Position AeQ&V d|  
long nEndPos; //File Snippet End Position ,xM*hN3A  
int nThreadID; //Thread's ID 3'@jRK  
boolean bDownOver = false; //Downing is over >U Ich  
boolean bStop = false; //Stop identical ^0?cyv\>LA  
FileAccessI fileAccessI = null; //File Access interface )^2jsy -/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (IQ L`3f%  
{ XK9*,WA9r  
this.sURL = sURL; VqT[ca\  
this.nStartPos = nStart; 52R.L9Ai  
this.nEndPos = nEnd; RuEnr7gi  
nThreadID = id; *wZV*)}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %1d6j<7  
} hnLgsz  
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public void run() ]qG5Ne_  
{ n~cm?"
 
while(nStartPos < nEndPos && !bStop) <y
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{ IG@&l0ARL  
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.  
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try{ aZ0iwMK  
URL url = new URL(sURL); E6\~/=X=%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [?o vJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); {'bkU9+  
String sProperty = "bytes="+nStartPos+"-"; TZ_'nB~  
httpConnection.setRequestProperty("RANGE",sProperty); *1]k&#s  
Utility.log(sProperty); _[Wrd?Z  
6D]G*gwk[  
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InputStream input = httpConnection.getInputStream(); t-m,~IoW  
//logResponseHead(httpConnection); &zDFf9w2{  
}(IDPa
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byte[] b = new byte[1024]; oa|*-nw  
int nRead; weadY,-H8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |Dpfh  
{ p%tg->#L  
nStartPos += fileAccessI.write(b,0,nRead); 90k|u'ikOp  
//if(nThreadID == 1) rSCX$ @@F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `%:(IGxz  
} f3B8,>  
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Utility.log("Thread " + nThreadID + " is over!"); W
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bDownOver = true; jmVy4* P_  
//nPos = fileAccessI.write (b,0,nRead); \(t>(4s_~  
} ;AA7wK 4  
catch(Exception e){e.printStackTrace ();} #mx
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} ^moIMFl  
} Gl:T   
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//打印回应的头信息 T1[ZrY'0  
public void logResponseHead(HttpURLConnection con) "<R 2oo)^  
{ |W];v@b\y  
for(int i=1;;i++) eV}Tx;1|}  
{ RxG./GY  
String header=con.getHeaderFieldKey(i); @
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if(header!=null) YQs
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y|jesa {x  
Utility.log(header+" : "+con.getHeaderField(header)); `;GGuJb \  
else dR{ V,H7N  
break; 6MQ:C'8T&=  
} QP0X8%+p  
} HaUo+,=  
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public void splitterStop() glIIJ5d|,  
{ IcA~f@  
bStop = true; eZ$1|Sj]j  
} {-qTU6  
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} H43
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/* |:BYOxAYZ8  
**FileAccess.java wajhFBJ  
*//文件访问(定位，写) 1"PE@!
]  
package NetFox; )C6 7qY  
import java.io.*; 9F!&y-  
~[6|VpGc:  
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public class FileAccessI implements Serializable{ 6[7k}9`alz  
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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 -2d&Aq4m)  
RandomAccessFile oSavedFile; ;Nij*-U4~  
long nPos; I/|n ma/ $  
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public FileAccessI() throws IOException !-~(*tn  
{ 9x,+G['Zt  
this("",0); )5x?Qn(B
 
} Fowh3go  
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public FileAccessI(String sName,long nPos) throws IOException ??Ac=K\  
{ 1^dWmxUZH  
oSavedFile = new RandomAccessFile(sName,"rw"); L,L7WObA  
this.nPos = nPos; @kymL8"2w  
oSavedFile.seek(nPos); v:;cTX=x`#  
} P2F>iK#U  
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Y.#+Yh[  
public synchronized int write(byte[] b,int nStart,int nLen) *h6i9V%'  
{ 1A`";E&  
int n = -1; nsk 6a  
try{ R0'EoX  
oSavedFile.write(b,nStart,nLen); ?>&Zm$5V  
n = nLen; s6uAF(4,  
} Cn '=_1p  
catch(IOException e) U7?ez  
{ pXa? Q@6  
e.printStackTrace (); N3) v,S-  
} k*^W lCZ3  
#w6CL  
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return n; v^'~
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} iSHl_/I<  
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} :DJ@HY  
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/* *E'K{?-K  
**SiteInfoBean.java wt;aO_l  
*/ x
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package NetFox; FeLP!oS>  
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public class SiteInfoBean { Y2EN!{YU  
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private String sSiteURL; //Site's URL Pa<X^&  
private String sFilePath; //Saved File's Path lH.2H  
private String sFileName; //Saved File's Name I"4B1g  
private int nSplitter; //Count of Splited Downloading File Ip0q&i<6  
.<dmdqk]  
4^&vRD,  
public SiteInfoBean() CgC wM=!r  
{//nSplitter的缺省值为5 4aC#Cv:0  
//default value of nSplitter is 5 ZD(gYNi  
this("","","",5); U,BBC  
} `>Cx!sYhV  
>^&+,*tsS4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l.$#IE  
{ T!bu}KO  
sSiteURL= sURL; se[};t:  
sFilePath = sPath; [eRMlSXA  
sFileName = sName; Ay]5GA!W+  
this.nSplitter = nSpiltter; "RLb wm~  
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} {QID@  
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public String getSSiteURL() yhaYlYv[_3  
{ oWmla*nCKL  
return sSiteURL; j
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} {Y Ymt!Ic  
@V)WJ{  
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public void setSSiteURL(String value) uc_ X;M;  
{ MXb(Z9)]kw  
sSiteURL = value; .+>}},  
} x<(h9tB  
JN_# [S$  
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public String getSFilePath() }kpkHq"`f  
{ &^.'g{\Y  
return sFilePath; g5)VV"  
} iweP3u##  
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#82B`y<<y/  
public void setSFilePath(String value) hlRE\YO&8R  
{ Y{KJk'xN5W  
sFilePath = value; -MjRFa  
} KVuv%?  
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public String getSFileName() ,v"A}g0"  
{ :Lx]`dSk  
return sFileName; Zu,f&smb  
} *D,T}N  
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public void setSFileName(String value) a;K:~R+@,  
{
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sFileName = value; 'g#GUSXfj  
} {% P;O ?  
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public int getNSplitter() D)5wGp  
{ VI?[8@*Z  
return nSplitter; "q$M\jK#V  
} {-xnBx  
zF PSk]  
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9 {  
public void setNSplitter(int nCount) {#vo^& B  
{ SZ_hGD0  
nSplitter = nCount; <\5{R
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} b{&@Lm0Tn  
} d1-QkW^0y  
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+"!IVHY  
/* =F9-,"EAI  
**Utility.java x-1[2K1"[  
*/ <x/&Ml+  
package NetFox; ,f$RE6  
@:63OLlrG  
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public class Utility { KvQ9R!V  
du !.j  

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public Utility() sd
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{ 7$'ja  
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} _/Hu'9432  
"ggq7cJ}_  
//线程睡眠 V|7 cdX#H  
public static void sleep(int nSecond) yxH[uJpb  
{ mU!c;O  
try{ FQ5# v{  
Thread.sleep(nSecond); %]-tA,
u  
} W/ERqVZR]  
catch(Exception e) R$q:Ct  
{ m*1=-"P  
e.printStackTrace (); R&?p^!`%  
} i[B%:q:&  
} 9I,Trk@&  
^#nAS2w7U  
//日志 j'Fni4;  
public static void log(String sMsg) ^dro*a,  
{ /#tOi[0[  
System.err.println(sMsg); U-@\V1;C  
} t4h* re+  
uB\A8zC  
o\N),;
LM  
public static void log(int sMsg) 2n\EZ  
{ |K]tJi4fz  
System.err.println(sMsg); dQ<EDtap  
} l{<@[foc  
} u!O)\m-  
+:b|I'S  
hGsYu)  
/* },l3N K  
**TestMethod.java }q^CR(h (R  
*/ |.YL2\  
package NetFox; NOvN8.K%  
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public class TestMethod { [,VD
^\  
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public TestMethod() zJPzI{-w|  
{ ///xx/weblogic60b2_win.exe \QVL%,.%M  
try{ 8{AzB8xp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'Ag?#vB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G=DRz F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8IO4>CMkv  
fileFetch.start(); O%OeYO69  
} T5ol2  
catch(Exception e){e.printStackTrace ();} WHL@]^E@m  
&T{+B:*v  
\j4TDCs_[  
} e7-U0rrE  
_di[P
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Au9Rr3n  
public static void main(String[] args) aPRF  
{ BV|LRB}G  
new TestMethod(); "
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} o]@?QAu  
} LqNsQu";  
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