http断点续传简单实现（java)

/* @)>D)
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**SiteFileFetch.java zf.-I  
*/ H{?9CxY
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package NetFox; j}F-Xs+  
import java.io.*; xq%{}  
import java.net.*; BR v+.(S  
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public class SiteFileFetch extends Thread { =H %-.m'f2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^*&X~8@)  
long[] nStartPos; //开始位置 :s-o0$PlJ  
long[] nEndPos; //结束位置 EQIUSh)M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `p0ypi3hn  
long nFileLength; //文件长度 2$ !D* <  
boolean bFirst = true; //是否第一次取文件 wNNB;n`l  
boolean bStop = false; //停止标志 2b=)6H1  
File tmpFile; //文件下载的临时信息 B
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DataOutputStream output; //输出到文件的输出流 U{~SXk'2+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,&7Wa-vf  
public SiteFileFetch(SiteInfoBean bean) throws IOException G\/"}B:(  
{ mmEp'E  
siteInfoBean = bean; 1/ZR*fa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]DvO:tM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |2`"1gt  
if(tmpFile.exists ()) 4KI
[D{  
{ sM\lO  
bFirst = false; dQgk.
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read_nPos(); Ogg#jx(4  
} .mL#6P!d3^  
else U@TjB  
{ I\Glc=T*  
nStartPos = new long[bean.getNSplitter()]; ?0<w  
nEndPos = new long[bean.getNSplitter()]; 8BXqZVm.  
} ogeL[7  
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} V%CUMH =U  
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public void run() *Q}[ ]g  
{ (LJ@SeM;  
//获得文件长度 E-ZRG!)[v  
//分割文件 #\4 b:dv  
//实例FileSplitterFetch fT Y/4(  
//启动FileSplitterFetch线程 $R^AEa7  
//等待子线程返回 {hqAnZ@]vr  
try{ !:fv>FEI9  
if(bFirst) ,smF^l   
{ Psa@@'w  
nFileLength = getFileSize(); znZ7*S >6\  
if(nFileLength == -1) ~# 7wdP  
{ beZ(o?uK  
System.err.println("File Length is not known!"); UQd6/mD`e  
} noNm^hFL  
else if(nFileLength == -2) q]<xMg#nu  
{ , fb( WY  
System.err.println("File is not access!"); N dR ]  
} %85Icg  
else W7UtA.2LT  
{ L>Jd7;=  
for(int i=0;i<nStartPos.length;i++) r
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{ u/AT-er;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |V`S>m
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} SFjU0*B$  
for(int i=0;i<nEndPos.length-1;i++) =^h~!ovj:  
{ <%bw
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nEndPos = nStartPos[i+1]; 
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} 3@5p"X  
nEndPos[nEndPos.length-1] = nFileLength; j%& IL0  
} V`fL%du,3  
} &K:' #[3V  
#iis/6"  
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//启动子线程 A
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *,#q'!Hq  
for(int i=0;i<nStartPos.length;i++) S2=%x.  
{ 0^_MN~s(X  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3;$bS<>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), PDw{R]V+  
nStartPos,nEndPos,i); BSXdvI1y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +lp{#1q0  
fileSplitterFetch.start(); ~v:#zU  
} ValS8V*N1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  pbB2wt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \~"#ld(x7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :d'65KMi  
nEndPos = " + nFileLength); [}""@?  
// fileSplitterFetch[nPos.length-1].start(); ,5-Zb3\  
}.%s xw  
;;LuU<,$  
//等待子线程结束 B.-A $/  
//int count = 0; 2mJ:c  
//是否结束while循环 c
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boolean breakWhile = false; IUhp;iH  
/)1v9<vM"  
]
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while(!bStop) 6$B'Q30}r  
{ Uu2N9.5  
write_nPos(); ha'qIT3&  
Utility.sleep(500); 2uu[52H8d%  
breakWhile = true; k
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for(int i=0;i<nStartPos.length;i++) ]Ti$ztJ  
{ sX'U|)/pD  
if(!fileSplitterFetch.bDownOver) 1*R_"#  
{ \j:gr>4  
breakWhile = false; E\e]K !  
break; d)*(KhYie@  
} _'*DT=H'U  
} wr@GN8e`  
if(breakWhile) u 2lXd'  
break; +#v4B?
NR  
7t4v~'h;5e  
Z% Z"VoxH  
//count++; ggCr-  
//if(count>4) *98Ti|  
// siteStop(); di_gWE  
} RV]a%mVlM  
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System.err.println("文件下载结束！"); %<S7  
} 5`UJouHi  
catch(Exception e){e.printStackTrace ();} ;qVG \wQq  
} T5{T[YdX<  
R"Y?iZed3  
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//获得文件长度 ||gEs/6-  
public long getFileSize() vU9~[I`^p  
{ }
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int nFileLength = -1; -,@bA @&  
try{ (1y='L2rj  
URL url = new URL(siteInfoBean.getSSiteURL()); p5qx=p~c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z[FI2jl  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9d] tjT  
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int responseCode=httpConnection.getResponseCode(); xc*!W*04  
if(responseCode>=400) u S(@?m$  
{ b.6ZfB,+G  
processErrorCode(responseCode); T:@7S  
return -2; //-2 represent access is error Bb_}YU2#  
} hOSf'mi  
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String sHeader; X o_] v  
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for(int i=1;;i++) 6#?NL]A  
{ !Pe1o-O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ix4jof6(  
//Utility.log(in.readLine()); sVlZNj9i"  
sHeader=httpConnection.getHeaderFieldKey(i); )1BiEK`v  
if(sHeader!=null) As p8qHS  
{ J{^n=X9M0J  
if(sHeader.equals("Content-Length")) /\TlO.B=  
{ rN'.&;Y5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7zi"caY  
break; |Pj9ZG#  
} ]#M/$?!]g2  
} |#:=\gugh  
else B{N=0 cSi  
break; haik  
} w+3>DEfz  
} ^VC7C~NZ!M  
catch(IOException e){e.printStackTrace ();} Flne=ij6g  
catch(Exception e){e.printStackTrace ();} uJm#{[  
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,?;sT`Mh)  
Utility.log(nFileLength); 6HB]T)n  
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return nFileLength; 9DY|Sa]#=  
} 0\ZaMu #  
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//保存下载信息（文件指针位置） `Q+i-y  
private void write_nPos() >9(7h&[Y  
{  =05iW  
try{ KWtu,~O_u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Sn+FV+D  
output.writeInt(nStartPos.length); u% r!?-z  
for(int i=0;i<nStartPos.length;i++) f>?^uSpWH  
{ L F8Pb;I  
// output.writeLong(nPos); .O;!W<Ef$  
output.writeLong(fileSplitterFetch.nStartPos); X!2.IsIS8  
output.writeLong(fileSplitterFetch.nEndPos); QId"Cl)3  
} li1v 4  
output.close(); e2qpJ4i  
} .<0=a|IAz  
catch(IOException e){e.printStackTrace ();} d"LoK,p#  
catch(Exception e){e.printStackTrace ();} tru;;.lj8K  
} DXt]b,  
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[}jj<!9A_;  
//读取保存的下载信息（文件指针位置） @'@s*9Nr  
private void read_nPos() 3^j~~"2,w  
{ 3"f)*w7d  
try{ V^9$t/c&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 'MSEki67  
int nCount = input.readInt(); ze*&
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nStartPos = new long[nCount]; RCoeJ|  
nEndPos = new long[nCount]; d?Ia#K93G  
for(int i=0;i<nStartPos.length;i++) s+(l7xH$  
{ %_]=i@Y~  
nStartPos = input.readLong(); 0zlM.rjEZ  
nEndPos = input.readLong(); r.Y*{!t  
} e~tr^$/(  
input.close(); iLjuE)6-$  
} xI-=tib  
catch(IOException e){e.printStackTrace ();} )PsN_ 42~  
catch(Exception e){e.printStackTrace ();} XKpL4]{&q4  
} u-8X$aJ  
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private void processErrorCode(int nErrorCode) W\nHX I  
{ lNq:JVJ#\r  
System.err.println("Error Code : " + nErrorCode); 16a_GwfM  
} E\ K  
" whO}  
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//停止文件下载 RPz!UMQSD  
public void siteStop() ;"d?_{>7  
{ oV%( 37W9=  
bStop = true; =)mXCA^  
for(int i=0;i<nStartPos.length;i++) ?Ry%c6(}  
fileSplitterFetch.splitterStop(); ?ZSXoy-kr  
</K%i;l  
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} a7XXhsZ  
} Xtu:  
//负责部分文件的抓取 /%N31  
**FileSplitterFetch.java ws*~$x?7  
*/ Z/XM`Cy  
package NetFox; (#fm (@T  
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import java.io.*; ?Zc/upd:$N  
import java.net.*; >reaIBT  
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public class FileSplitterFetch extends Thread { *"|VNnB  
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String sURL; //File URL W+F<P@[u<$  
long nStartPos; //File Snippet Start Position &cv@Kihq(  
long nEndPos; //File Snippet End Position 8`L#1ybMO  
int nThreadID; //Thread's ID )OW(T^>_'I  
boolean bDownOver = false; //Downing is over C8bGae(  
boolean bStop = false; //Stop identical u7<qaOzs?  
FileAccessI fileAccessI = null; //File Access interface Sleu#]-  
*G2)@0 {  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kT Z?+hx  
{ Lo$Z>u4(c  
this.sURL = sURL; 3*X,{%  
this.nStartPos = nStart; fg>B  
this.nEndPos = nEnd; STFQ";z$  
nThreadID = id; 2A@Y&g(6T7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FqT,4SIR  
} =Do3#Xe2V  
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public void run() j#Ky0+@V  
{ z*NC?\  
while(nStartPos < nEndPos && !bStop) #Lhj0M;a  
{ hJC p0F9O  
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q 2_N90u  
try{ uFm(R/V  
URL url = new URL(sURL); QoT3;<r}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tdk2436=  
httpConnection.setRequestProperty("User-Agent","NetFox"); uI[-P}bSc&  
String sProperty = "bytes="+nStartPos+"-"; }rj C_q  
httpConnection.setRequestProperty("RANGE",sProperty); ^hl]
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Utility.log(sProperty);  &*>CPO  
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InputStream input = httpConnection.getInputStream(); *D09P%  
//logResponseHead(httpConnection); #TW>'lF  
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byte[] b = new byte[1024]; +s/N@]5nW  
int nRead; sw=JUfAhy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qmue!Fv#g  
{ ]@
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nStartPos += fileAccessI.write(b,0,nRead); 90y9~.v  
//if(nThreadID == 1) M0Kh>u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7q2"b?|h  
} 8f{}ce'E*  
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Utility.log("Thread " + nThreadID + " is over!"); aCYm$6LmA  
bDownOver = true; w ~L\Ebg  
//nPos = fileAccessI.write (b,0,nRead); JK:mQ_  
} >XXMIz:  
catch(Exception e){e.printStackTrace ();} q
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} lEYT{  
} ~J. Fl[  
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//打印回应的头信息 }{kTh%^  
public void logResponseHead(HttpURLConnection con) aG8D%i0  
{ q563,s  
for(int i=1;;i++) &JXHDpd$a^  
{ U>p
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String header=con.getHeaderFieldKey(i); xvx\H'  
if(header!=null) eMm~7\ R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Rbj+P;t&  
Utility.log(header+" : "+con.getHeaderField(header)); Kt4\&l-De  
else z:i X]df  
break; AHMV@o`V  
} fN"oa>X  
} -'H+lrmv  
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public void splitterStop() *a4b`HRT  
{ ?N!j.E4=  
bStop = true; }N#>q
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} ~0^,L3M  
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}
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/* _#YHc[Wz  
**FileAccess.java q5\LdI2  
*//文件访问(定位，写) yu?
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package NetFox; "<.  
import java.io.*; ?_Dnfa_  
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7 NB"oU^h%  
public class FileAccessI implements Serializable{ H;t8(-F@'  
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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 iq^L~RW5e  
RandomAccessFile oSavedFile; !^w\$cw&  
long nPos; 18/
@:u{  
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public FileAccessI() throws IOException \(>$mtS:  
{ Kf?{GNE7  
this("",0); F;Xq:e8  
} 
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public FileAccessI(String sName,long nPos) throws IOException mQA<t)1  
{ klC^xSx  
oSavedFile = new RandomAccessFile(sName,"rw"); h%w\O Z7  
this.nPos = nPos; '3u]-GU2_  
oSavedFile.seek(nPos); 1uge>o&  
}
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2  
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public synchronized int write(byte[] b,int nStart,int nLen) ~"rwP=<}  
{  ISnS;  
int n = -1; x&fCe{5  
try{ sBXk$  
oSavedFile.write(b,nStart,nLen); ~Ro:mH:w  
n = nLen; UH^wyKbM  
} wIR[2&b  
catch(IOException e) uF3p1by  
{ HToN+z%w3H  
e.printStackTrace (); zkMO3w>  
} qp_ `Fj:  
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return n; 8Y0<lfG  
} IV)W|/.  
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} m',_kY3  
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/* :kx#];2i  
**SiteInfoBean.java bSmaE7  
*/ }NBJ T4R  
package NetFox; Jx9%8Ek  
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public class SiteInfoBean { hic$13KuP  
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private String sSiteURL; //Site's URL e/Oj T  
private String sFilePath; //Saved File's Path kt3#_d^El  
private String sFileName; //Saved File's Name <$ZT]pT  
private int nSplitter; //Count of Splited Downloading File G~tOCp="p  
i|,A1c"*  
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public SiteInfoBean() T\s#-f[x  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 geN%rD
  
this("","","",5); jp]geV54  
} pbvEIa-Y4  
5)v^ cR?&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xAz4ZXj=q  
{ Jo(}#_y?  
sSiteURL= sURL; l(
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sFilePath = sPath;
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sFileName = sName; }qdJ8K  
this.nSplitter = nSpiltter; LXF%~^^@d  
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} 446hrzW>@  
8=o(nFJw  
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public String getSSiteURL() h>%JG'DV  
{ # %y{mn  
return sSiteURL; x,c68Q)g  
} `6sQlCOnF  
%R"/`N9R,  
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public void setSSiteURL(String value) <T/L.>p4  
{ Kcdd=2 [T  
sSiteURL = value; S^VV^O5 ^  
} a[cH@7W.#  
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public String getSFilePath() 7CMgvH)O  
{ cH-
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return sFilePath; n4&j<zAV{  
} ']Xx#U N  
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public void setSFilePath(String value) 64>[pZF8  
{ w&cyGd D5  
sFilePath = value; uBkny;  
} xa0%;nFKe  
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public String getSFileName() 3&Rqz9W  
{ B[|/wHMsT}  
return sFileName; $K fk
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} !jq6cND  
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public void setSFileName(String value) _-\{k
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{
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sFileName = value; T2; 
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} q.F1
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public int getNSplitter() #7T={mh  
{ hD"~ ^  
return nSplitter; h5keYBA  
} 9d}ny
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'="){  
public void setNSplitter(int nCount) @}!$NI8  
{ w>Sz^_ h  
nSplitter = nCount; ( +hI
  
} 8N_rJ)f  
} cGp 6yf  
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/* ClZyQ=UAD  
**Utility.java ppP?1Il`kb  
*/ "TJ^Z!  
package NetFox; @il}0  
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public class Utility { v[3sg2.  
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public Utility() 1&"1pH  
{ 0^Cx`xdX:  
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} :+!b8[?Z  
;rL$z;}8  
//线程睡眠 L-$g& -  
public static void sleep(int nSecond) LXV6Ew5E  
{ =ApT#*D)o  
try{ *60)Vo.=  
Thread.sleep(nSecond);  y-#tU>P  
} gNQJ:!  
catch(Exception e) }!Lr!eALr  
{ !{lb#  
e.printStackTrace (); d6&t
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} ksp':2d}  
} 9<mj@bI$  
GqxK|G1  
//日志 b;l%1x9r  
public static void log(String sMsg) 1*jm9])#  
{ iL1so+di  
System.err.println(sMsg); ,[#f}|s_  
} s%|J(0  
`BD`pa7.%  
7SZs/wWh%  
public static void log(int sMsg) z\ pT+9&  
{ Y%@'a~  
System.err.println(sMsg); \YS\*'F  
} @CDRbXoFk  
} #JucOWxjY  
=^vUb  
@7'gr>_E  
/* B=|sLs`I  
**TestMethod.java 'WCTjTob/  
*/ GXVGU-br  
package NetFox; >.4Sx~VH2  
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public class TestMethod { |-D.  
0fU>L^P_?  
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public TestMethod() f}eVfAf
 
{ ///xx/weblogic60b2_win.exe 5GkM7Zu!{j  
try{ kGP?Jx\PkH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d*HAKXd&:j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JH#+E04#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kw'D2692  
fileFetch.start(); B,T.bgp\  
} `^vD4qD|  
catch(Exception e){e.printStackTrace ();} :Ej)AfS  
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} Cj9Tj'0@I+  
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public static void main(String[] args) ^5}3FvW  
{ =`H(`2  
new TestMethod(); jN0v<_PJED  
} I|H mbTXa  
} i,T{SV  
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