http断点续传简单实现（java)

/* V_]-`?S  
**SiteFileFetch.java h.b+r~u  
*/ {Gkn_h-^  
package NetFox; &7F&}7*c  
import java.io.*; \X opU"  
import java.net.*; z(UX't (q  
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public class SiteFileFetch extends Thread { m|dF30~A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w4}(Ab<Y  
long[] nStartPos; //开始位置 >@Khm"/T  
long[] nEndPos; //结束位置 JS2!)aqc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M,{<TpCx  
long nFileLength; //文件长度 YHh u^}|jQ  
boolean bFirst = true; //是否第一次取文件 yHw!#gWM  
boolean bStop = false; //停止标志 m/N(%oMWB=  
File tmpFile; //文件下载的临时信息 6SAQDE
 
DataOutputStream output; //输出到文件的输出流 L&HzN{K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~y%7w5%Un  
public SiteFileFetch(SiteInfoBean bean) throws IOException ST4(|K  
{ D4\(:kF\Hg  
siteInfoBean = bean; "GBUQ}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g{&PrE'e9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d.1Q~&`  
if(tmpFile.exists ()) A'v[SUW'm  
{ ndt8=6p  
bFirst = false; iy9VruT<x  
read_nPos(); | &\^n2`>  
} {8i}Ow  
else rN'k4V"K  
{ Cj=J;^vf  
nStartPos = new long[bean.getNSplitter()]; N>T=L0`  
nEndPos = new long[bean.getNSplitter()]; ,dq`EsHg`M  
} "p2u+ 8?  
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} /3;=xZq  
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public void run() -y<rM0"NE  
{ GY
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//获得文件长度 q .)^B@}_  
//分割文件 "N]WL5$i  
//实例FileSplitterFetch 6q!7i%fK?  
//启动FileSplitterFetch线程 }8X:?S %  
//等待子线程返回 +0)5H>h  
try{ {S# 5g2  
if(bFirst) ; vhnA$'a  
{ ob)D{4B'  
nFileLength = getFileSize(); <C2c"=b  
if(nFileLength == -1) Xek E#
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{ m.
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System.err.println("File Length is not known!"); X]>[Qz)K^  
} (rMTW+,  
else if(nFileLength == -2) R7y
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{ .|tQ=l@I  
System.err.println("File is not access!"); iNMLYYq]l  
} o<Ke3?J\  
else 8~rT  
{ .jy)>"h0  
for(int i=0;i<nStartPos.length;i++) $::51#^Wg  
{ y0lLFe~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SlM>";C\  
} aj+zmk~-  
for(int i=0;i<nEndPos.length-1;i++) I%C]>ZZh  
{ y;*My#  
nEndPos = nStartPos[i+1]; c lq <$-  
} 8VK
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nEndPos[nEndPos.length-1] = nFileLength; !G@V<'F  
} p` ^:Q*C"  
} :Fq2x_IUE  
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}qTv&Z3$  
//启动子线程 6!i( \Q*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) h6K!|-Gq.  
{ 6B4hSqjh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s$eK66H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D]3bwoFo&u  
nStartPos,nEndPos,i); NO%|c|B|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )I^)*(}  
fileSplitterFetch.start(); zV9 =  
} Ji)%Y5F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4"
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7 B4w.P,B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m3x!*9h  
nEndPos = " + nFileLength); ]M02>=1  
// fileSplitterFetch[nPos.length-1].start(); z0FR33-  
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//等待子线程结束 U!3uaz'  
//int count = 0; g#pIMA#/  
//是否结束while循环 +A;n*DF2  
boolean breakWhile = false; ) >-D={
 
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*
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while(!bStop) -sruxF  
{ _S[Rvb1e   
write_nPos(); j58Dki->.  
Utility.sleep(500); PkZf(=-X  
breakWhile = true; [0( E>vm  
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for(int i=0;i<nStartPos.length;i++) S S7D1  
{ IX > j8z[  
if(!fileSplitterFetch.bDownOver) 96^1Ivd  
{ `*.r'k2R  
breakWhile = false; |^>L`6uo  
break; ^$g],PAY  
} A@fshWrl%  
} U/v"?pg[  
if(breakWhile) Lk$Je O  
break; S.?\>iH[  
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//count++; rVc zO+E  
//if(count>4) NG4eEnic!a  
// siteStop(); QqT6P`0u  
} 4rGO8R  
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System.err.println("文件下载结束！"); s0`]!7D<  
} Q*oA{eZY  
catch(Exception e){e.printStackTrace ();}
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} ]y$V/Ij=qK  
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//获得文件长度 .T N`p*  
public long getFileSize() bHlDm~5  
{ .jrR4@  
int nFileLength = -1; 9, sCJ5bb"  
try{ d[qEP6B  
URL url = new URL(siteInfoBean.getSSiteURL()); %s&E-*X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &,6y(-  
httpConnection.setRequestProperty("User-Agent","NetFox"); e{#a{`?Uez  
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int responseCode=httpConnection.getResponseCode(); ._F6-pl  
if(responseCode>=400) ft.}$8vIT  
{ GwU>o:g"  
processErrorCode(responseCode); {R6Zwjs  
return -2; //-2 represent access is error HnYFE@Nl:U  
} \M1M2(@pDJ  
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String sHeader; 6#lC(ko'  
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for(int i=1;;i++) (tz_D7c$F  
{ }tS6Z:fOY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WPh |~]by<  
//Utility.log(in.readLine()); m}'t'l4 c  
sHeader=httpConnection.getHeaderFieldKey(i); UHsrZgIRYT  
if(sHeader!=null) kxKnmB#m-  
{ 3T.M?UG>  
if(sHeader.equals("Content-Length")) olQ8s*  
{ AD4L`0D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^QL/m\zq@%  
break; OKLggim{  
} j@_) F^12  
} JWm^RQ  
else @{$Cv"6769  
break; \Z7([Gh  
} o\:f9JL  
} =-s20mdj  
catch(IOException e){e.printStackTrace ();} f 7QUZb\  
catch(Exception e){e.printStackTrace ();} M b /X@51  
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Utility.log(nFileLength); gPhw.e""  
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return nFileLength; { ves@p>?  
} |?t8M9[Z  
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//保存下载信息（文件指针位置） =='{[[J  
private void write_nPos() 1p"EE~v  
{ i2%m}S;D9  
try{ j*Wh;I+h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); '2qxcco  
output.writeInt(nStartPos.length); -aeo7C  
for(int i=0;i<nStartPos.length;i++) #SLxNAH  
{ S&)) 0d  
// output.writeLong(nPos); FsPDWy&x  
output.writeLong(fileSplitterFetch.nStartPos); 4+?ZTc(  
output.writeLong(fileSplitterFetch.nEndPos); meVVRFQ2+  
} QmkC~kK1.  
output.close(); mEc;-b f  
} V]PhXVJ  
catch(IOException e){e.printStackTrace ();} `J7L
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catch(Exception e){e.printStackTrace ();} f[I'
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} pNf9  
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//读取保存的下载信息（文件指针位置） /KvPiQ%  
private void read_nPos() m+8b2H:V  
{ xS\QKnG.  
try{ 0jZ{?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E["t Ccg  
int nCount = input.readInt(); { )GE
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nStartPos = new long[nCount]; eYSGxcx  
nEndPos = new long[nCount]; JW.&uV1Z  
for(int i=0;i<nStartPos.length;i++) 6UAxl3-\  
{ HtXBaIl\  
nStartPos = input.readLong(); 0<]!G|;|  
nEndPos = input.readLong(); Zow^bzy4  
} po
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input.close(); 4l!Yop0h  
} ![D,8]GD  
catch(IOException e){e.printStackTrace ();} LsD9hb7  
catch(Exception e){e.printStackTrace ();} ]!
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} EKS<s82hF&  
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private void processErrorCode(int nErrorCode) Nb9V/2c;V  
{ OVo  
System.err.println("Error Code : " + nErrorCode); ~aR='\<  
} ysT!^-&p  
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//停止文件下载 e2o9)=y  
public void siteStop() DW%K'+@M
 
{ ?9okjLp1n  
bStop = true; BG?
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for(int i=0;i<nStartPos.length;i++) h _7;UQH  
fileSplitterFetch.splitterStop(); w7?9e#>Z  
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} h|uP=0   
} T(Gf~0HYF  
//负责部分文件的抓取 .O-DVW Cm  
**FileSplitterFetch.java 9X&qdA/q  
*/ e`2R
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package NetFox; Ty|c@X  
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import java.io.*; H_f2:
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import java.net.*; <WKz,jh  
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public class FileSplitterFetch extends Thread { ^F0jI5j).  
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String sURL; //File URL Z q>.;>  
long nStartPos; //File Snippet Start Position QM=436fq  
long nEndPos; //File Snippet End Position kc']g:*]Y  
int nThreadID; //Thread's ID z>g& ?vo2  
boolean bDownOver = false; //Downing is over Ywk[VD+.  
boolean bStop = false; //Stop identical kJpHhAn4  
FileAccessI fileAccessI = null; //File Access interface c(g^*8Pb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hwc8i"{9y\  
{ QNa3S*  
this.sURL = sURL; g UAPjR  
this.nStartPos = nStart; #_sVB~sn@  
this.nEndPos = nEnd; "EkO>M/fr  
nThreadID = id; jy|xDQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ssbyvzQ  
} MW@b;=(  
$,#IPoi~X  
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public void run() 959jp85  
{ 0(f;am0y  
while(nStartPos < nEndPos && !bStop) s/0FSv x  
{ >:nJTr  
}'
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try{ N^`Efpvg  
URL url = new URL(sURL); ,lYU#Hx*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &L`p4AZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); y'wW2U/1-  
String sProperty = "bytes="+nStartPos+"-"; KCT"a:\  
httpConnection.setRequestProperty("RANGE",sProperty); DOU?e9I2  
Utility.log(sProperty); 7+r5?h|  
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InputStream input = httpConnection.getInputStream(); D5vtZu!"  
//logResponseHead(httpConnection); %d\+(:uu/  
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byte[] b = new byte[1024]; T5+b{qA  
int nRead; Ap9wH[H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hrt-<7U  
{ u#|Jl|aT  
nStartPos += fileAccessI.write(b,0,nRead); _Hj,;Z  
//if(nThreadID == 1) Oip..f0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %=eD)p7l-  
} 3iL&;D  
iiB$<b.((I  
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Utility.log("Thread " + nThreadID + " is over!"); M_I\:Q  
bDownOver = true; K%Ml2V   
//nPos = fileAccessI.write (b,0,nRead); g<3>7&^  
} 9DKB+K.1  
catch(Exception e){e.printStackTrace ();}
>;
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} <2A'   
} 7^X_tQf  
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//打印回应的头信息 " N4]e/.V  
public void logResponseHead(HttpURLConnection con) niBpbsO  
{ L]")TQ
 
for(int i=1;;i++) 4`]1W,t  
{ 1_]l|`Po  
String header=con.getHeaderFieldKey(i); e|y~q0Q$  
if(header!=null) w Vmy`OV/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nzDY!Y  
Utility.log(header+" : "+con.getHeaderField(header)); @S):a`J  
else <Ux;dekz}  
break; :gv#_[k  
} 8G<.5!f7`N  
} nJC}wh2d#  
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public void splitterStop() H;E{Fnarv  
{ hiuPvi}  
bStop = true; R5zV=N  
} 1tc9STYR}  
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} na)ceN2h  
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/* K2Zy6lGOZ  
**FileAccess.java I*"]!z1  
*//文件访问(定位，写) ;'}xD5]  
package NetFox; B;Vl+}R  
import java.io.*; )=@ XF0  
\ 3N#%  
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public class FileAccessI implements Serializable{ ]B||S7idq  
XF6=xD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?9A[;j|a0  
RandomAccessFile oSavedFile; y5}|Y{5  
long nPos; HDOaN  
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public FileAccessI() throws IOException xm5D$m3#  
{ \=~Ap#Mpc4  
this("",0); )9O{4PbU!  
} %e(,PL  
7 &Aakl  
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public FileAccessI(String sName,long nPos) throws IOException 3-D!ZS&  
{ =%p{"<  
oSavedFile = new RandomAccessFile(sName,"rw"); Ycwb1e#  
this.nPos = nPos; o hCPNm  
oSavedFile.seek(nPos); zO,sq%vQn'  
} /^"TMm   
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public synchronized int write(byte[] b,int nStart,int nLen) [A47OR  
{ s
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int n = -1; j06DP _9M  
try{ ?}.(k/  
oSavedFile.write(b,nStart,nLen); L~~aW0,  
n = nLen; zoU.\]#C  
} 57r)&8  
catch(IOException e) .IgQn|N  
{  jQhf)B  
e.printStackTrace (); 03PVbDq-  
} =Ao;[j)*!  
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F 7=-k/k  
return n; -uZ^UG!K  
} ~+F: QrXcI  
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} ~Y(M>u.+!  
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/* = N#Ww
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**SiteInfoBean.java zV]0S o  
*/ pP#?|  
package NetFox; C+Z"0\{o  
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public class SiteInfoBean { SO%5ts  
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private String sSiteURL; //Site's URL fjb2-K  
private String sFilePath; //Saved File's Path )UeG2dXx7  
private String sFileName; //Saved File's Name {D@y-K5  
private int nSplitter; //Count of Splited Downloading File R[(,wY_1  
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public SiteInfoBean() ATU@5,9  
{//nSplitter的缺省值为5 1\2 m'o  
//default value of nSplitter is 5 ]kPco4  
this("","","",5); Dj|S  
} I4hr5M3  
:/3`+&T^/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M3''xrpC  
{ |lv4X}H  
sSiteURL= sURL; >@X=E3  
sFilePath = sPath; 1;h>^NOq  
sFileName = sName; l@Ki`if  
this.nSplitter = nSpiltter; YW5E |z  
/X?Nv^Hy  
-H \nFJ6+  
} H`
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public String getSSiteURL() -'nx7wnj2  
{ )D^P~2  
return sSiteURL; zR4huo  
} p#&6Ed*V  
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^~0r+w
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public void setSSiteURL(String value) .cb mCFXL  
{ Zj JD@,j  
sSiteURL = value; %F7aFvl*  
} ^ey\ c1K  
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public String getSFilePath() Ub"\LUu  
{ 8c~H![2u  
return sFilePath; @EQ{lGpU3  
} 23>?3-q
 
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public void setSFilePath(String value) D"hiEz  
{ ck}y-,>,[O  
sFilePath = value; b9U2afd  
} ql4T@r3l}3  
Ut%ie=c  
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public String getSFileName() _w26
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{ _k}b  
return sFileName; ("aYjKk  
} sqy5r
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`XD$1>  
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public void setSFileName(String value) D,7! /u'  
{ ] =D+a&  
sFileName = value; V;z?m)ur  
} e0qa~5  
X[|>r@Aa!  
D&'".N,}  
public int getNSplitter() N&n{R8=^"  
{ s)C.e# xl  
return nSplitter; +,%x&L&I  
} eY-$hnUe  
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public void setNSplitter(int nCount) [;2v[&
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{ u66w('2  
nSplitter = nCount; Cr&ua|%F  
} h m"B kOA  
} G0^PnE0-  
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n_!&Wr^CX  
/* UKzmR
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**Utility.java &@RU}DnvM&  
*/ # WxH  
package NetFox; c(~M<nL0  
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public class Utility { l/`Z+];  
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public Utility() Ywni2-)<  
{ 3w-0v"j U  
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} -H]svOX  
$Fn# b|e  
//线程睡眠 8xNKVj)@  
public static void sleep(int nSecond) mr;WxxO5  
{ A[b'MNsv  
try{ x&f?c=\F  
Thread.sleep(nSecond); >1r>cZn  
} ZF`ckWT:-N  
catch(Exception e) -AbA6_j  
{ 6q5V*sJ&  
e.printStackTrace (); AXJC&O}`  
} \UiuJ+  
} a{HvrWs?Q  
u_uC78`p  
//日志 )I*V('R6|  
public static void log(String sMsg) 86I".R$d  
{ > 4^U=T#  
System.err.println(sMsg); xv)7-jlx  
} gKPV*  
4b(iGLrt0  
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public static void log(int sMsg) zgO
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{ ^{bP#f  
System.err.println(sMsg); \'p)kDf  
} =\q3;5[  
} rsIjpPa  
^RY_j>i  
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/* jW6@U%[!b  
**TestMethod.java osnDW aN  
*/ f>RPh bq|  
package NetFox; *d%m.:)N  
D6 M:pIN*  
f[X>?{q  
public class TestMethod { EswM#D9(4  
[6c{t  
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public TestMethod() ){6;o&CC:  
{ ///xx/weblogic60b2_win.exe T$+}Srb  
try{ Z,
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {yJ{DU?%Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); upX/fLc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Sd{>(YWx~  
fileFetch.start(); SQEXC*08  
} Q.5a"(d@  
catch(Exception e){e.printStackTrace ();} ov|s5yH8e  
}g`A*y;t  
\tQRyj\|  
} 'vh:(-  
v!W,h2:J  
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public static void main(String[] args) =n;ileGm+^  
{ ((H}d?^AJ  
new TestMethod(); /at#[Pw~01  
} }U8H4B~UtY  
} +pDuRr  
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