http断点续传简单实现（java)

/* {5D%<Te  
**SiteFileFetch.java {D^ )%{  
*/ lP)n$?u  
package NetFox; 5+!yXkE^e  
import java.io.*; w'A*EWO  
import java.net.*; V6](_w!  
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public class SiteFileFetch extends Thread { pfIK9>i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean EPLHw  
long[] nStartPos; //开始位置 {fDRVnI?  
long[] nEndPos; //结束位置 37:tu7e~c  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QxaMe
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long nFileLength; //文件长度 -zMvpe-am&  
boolean bFirst = true; //是否第一次取文件 ?Fa$lE4  
boolean bStop = false; //停止标志 &Ep$<kx8  
File tmpFile; //文件下载的临时信息 VyNF)$'T  
DataOutputStream output; //输出到文件的输出流 CQ<d  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t
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public SiteFileFetch(SiteInfoBean bean) throws IOException UMBeY[?  
{ xi.?@Lff
 
siteInfoBean = bean; x=a#|]ngG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y7CXE6Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9z{}DBA  
if(tmpFile.exists ()) [h-NX  
{ E#Ue9J  
bFirst = false;
.#Z'CZO|  
read_nPos(); fKFD>u0%  
} ^_3$f  
else 0YL*)=pD,  
{ yx&}bu\  
nStartPos = new long[bean.getNSplitter()]; 87
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nEndPos = new long[bean.getNSplitter()]; Q.7X3A8  
} z1,#ma}.  
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} g\/|7:yB]  
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public void run() GHLnwym  
{ 'Kkp!eZQ~  
//获得文件长度 I]5){Q"S  
//分割文件 h(}#s1Fzq  
//实例FileSplitterFetch <_pLmYI  
//启动FileSplitterFetch线程 @XL49D12c  
//等待子线程返回 Gdx%#@/  
try{ *L>usLh  
if(bFirst) |B$JX'_  
{ *gGw/jA/  
nFileLength = getFileSize(); ^/Yk*Ny  
if(nFileLength == -1) ^t<L  
{ rfQs 7S;G  
System.err.println("File Length is not known!"); K iXD1Zpz  
} s nxwe  
else if(nFileLength == -2) ]Hi1^Y<  
{ Q2]7|C  
System.err.println("File is not access!"); "30=!k  
} U v>^ Z2  
else !@Vj&>mH$  
{ J32{#\By  
for(int i=0;i<nStartPos.length;i++) `WC4:8  
{ ZJGIib  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S\sy^Kt~4:  
} -gC%*S5&  
for(int i=0;i<nEndPos.length-1;i++) ho~WD'i  
{ H3d|eO4+W  
nEndPos = nStartPos[i+1]; K)`R?CZ:s  
} x~8R.Sg  
nEndPos[nEndPos.length-1] = nFileLength; <?8cVLW}O  
} d/3&3>/  
} wod{C!  
~ W8 M3(^  
r z@%rOWV  
//启动子线程 v[x 5@$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Qd% (]L[N.  
for(int i=0;i<nStartPos.length;i++) cw~GH  
{ RN1KM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hhylsm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =8p[ (<F=  
nStartPos,nEndPos,i); W0U|XX!&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F/A)2 H_  
fileSplitterFetch.start(); CnY dj~  
} ?H!&4o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n Zx^ej\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lu.xv6+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U;.cXU{  
nEndPos = " + nFileLength); 2e ~RM2PQ  
// fileSplitterFetch[nPos.length-1].start(); (lYC2i_b#  
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{"|GV~  
//等待子线程结束 D,-L!P  
//int count = 0; ;tD?a7  
//是否结束while循环 EmP2r*"rb  
boolean breakWhile = false; }!s$ /Kn  
[ CU8%%7  
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while(!bStop) c No)LF  
{ Pff-eT+~m  
write_nPos(); .&^M Z8  
Utility.sleep(500); .fhfO @  
breakWhile = true; +`m0i1uI3  
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for(int i=0;i<nStartPos.length;i++) 5KYR"-jY  
{ u<j.XPK  
if(!fileSplitterFetch.bDownOver) }zeKf/?'  
{ Xa>c]j  
breakWhile = false; RhjU^,%  
break; S|@ Y !  
} 7#T@CKdUd  
} &.0wPyw  
if(breakWhile) Dp@m"_1`+  
break; a5@lWpQsV  
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//count++; }LZz"b<aw  
//if(count>4) ,Qe`(vU*s  
// siteStop();  :KRe==/  
} aO\@5i_r  
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System.err.println("文件下载结束！"); :J5CmU$  
} wLQM]$O  
catch(Exception e){e.printStackTrace ();} (%M:=zm  
} `5~<)  
/dVcNo3"  
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//获得文件长度 n^epC>a"b  
public long getFileSize() d k|X&)xTJ  
{ [vCZD8"Y8  
int nFileLength = -1; _j_c&  
try{ :Sk<0VVd7  
URL url = new URL(siteInfoBean.getSSiteURL()); 1;MUemnx`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qRZLv7X*j  
httpConnection.setRequestProperty("User-Agent","NetFox"); y=}a55:qE  
mO\=#Q>  
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int responseCode=httpConnection.getResponseCode(); r3Ih]|FK#  
if(responseCode>=400) D4GXZX8K  
{ D2#.qoP #  
processErrorCode(responseCode); :4238J8  
return -2; //-2 represent access is error ."v&?o Ck]  
} ou&7v<)x4  
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String sHeader; y {Mh ?H  
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for(int i=1;;i++) X@B,w
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{ @j4~`~8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !r0 z3^*N  
//Utility.log(in.readLine()); /lvH p  
sHeader=httpConnection.getHeaderFieldKey(i); TUd=qnu  
if(sHeader!=null) W}oAgUd  
{ SRk-3:  
if(sHeader.equals("Content-Length")) X_I.
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{ akA C^:F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *:,7 A9LY  
break; zhde1JE  
} r\{; ~V  
} -Ar 3>d  
else K<Y-/t  
break; 7Rom#Kl:  
} Lec%kC  
} }
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catch(IOException e){e.printStackTrace ();} gCS%J40r  
catch(Exception e){e.printStackTrace ();} F(:]lM|  
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Utility.log(nFileLength); i+.bR.WO  
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return nFileLength; KY;E.D`  
} N+ R/ti  
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//保存下载信息（文件指针位置） @AkD-}^[  
private void write_nPos() W*|U  
{ s|&2QG0'7  
try{ !ly]{DTmm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #9Dixsl*Q  
output.writeInt(nStartPos.length); }vdhk0  
for(int i=0;i<nStartPos.length;i++) =u`^QE  
{ rru `%~'O  
// output.writeLong(nPos); Nb;Yti@Y.  
output.writeLong(fileSplitterFetch.nStartPos); 1Q$Z'E}SK@  
output.writeLong(fileSplitterFetch.nEndPos); o%A
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} ;H8A"$%n~  
output.close(); J;BG/VI1  
} e c`3
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catch(IOException e){e.printStackTrace ();} :ITz\m  
catch(Exception e){e.printStackTrace ();} <)(STo  
} xlaBOKa%  
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//读取保存的下载信息（文件指针位置） P/FO,S-V  
private void read_nPos() #fYz367>  
{ $ p{Q]|ww  
try{ _nj?au(@`Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fKAG+t  
int nCount = input.readInt(); Iih~rWJ  
nStartPos = new long[nCount]; ~8EG0F;t  
nEndPos = new long[nCount]; C'}8  
for(int i=0;i<nStartPos.length;i++) '4qi^$|\  
{ ~?{@0,$  
nStartPos = input.readLong(); )f0t"l
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nEndPos = input.readLong(); !Hr +|HKQ?  
} v 1O*
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input.close(); 5fBW#6N/  
} hU `H\LE  
catch(IOException e){e.printStackTrace ();} R3$
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catch(Exception e){e.printStackTrace ();} 2$? )
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} +x0-hRD  
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private void processErrorCode(int nErrorCode) ;wz YZ5=Di  
{ l$Y7CIH  
System.err.println("Error Code : " + nErrorCode); %-:6#bz  
} l>M&S^/s j  
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//停止文件下载 T{j&w%(z  
public void siteStop() _>*$%R  
{ A_@#V)D2  
bStop = true; LE!3'^Zq  
for(int i=0;i<nStartPos.length;i++) E-irB/0  
fileSplitterFetch.splitterStop(); @hWt.qO3s  
{j E}mzi  
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} ^YKEc0"w(  
} h^bbU.  
//负责部分文件的抓取 Ydu=Jg5u7  
**FileSplitterFetch.java *,o)`  
*/ J%_ :A"  
package NetFox; ]#[R^t  
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import java.io.*; d7tH~9GX8  
import java.net.*; H6*d#!  
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public class FileSplitterFetch extends Thread { Zl.}
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String sURL; //File URL O&irgc!  
long nStartPos; //File Snippet Start Position V5RfxWtm:  
long nEndPos; //File Snippet End Position ,y?0Iwf  
int nThreadID; //Thread's ID y:Qo:Z~  
boolean bDownOver = false; //Downing is over (3"V5r`*;  
boolean bStop = false; //Stop identical #G^?4Za  
FileAccessI fileAccessI = null; //File Access interface r/fLm8+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (6fh[eK86  
{ -pc*$oe  
this.sURL = sURL; BxO8oKe  
this.nStartPos = nStart; 7WW@%4(  
this.nEndPos = nEnd; ~FM5]<X)  
nThreadID = id; K9gfS V>]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #tdI;x3  
} H
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public void run() }0|,*BkI m  
{ 5B@+$D[0?3  
while(nStartPos < nEndPos && !bStop) 4?,N;Q  
{ +=^10D  
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3
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try{ ' Ky5|4  
URL url = new URL(sURL); _bn*B$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4r5?C;g  
httpConnection.setRequestProperty("User-Agent","NetFox"); zN {'@B  
String sProperty = "bytes="+nStartPos+"-"; gz-}nCSi  
httpConnection.setRequestProperty("RANGE",sProperty); Y+sycdq  
Utility.log(sProperty); >c?Z.of  
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InputStream input = httpConnection.getInputStream(); kl_JJX6jPP  
//logResponseHead(httpConnection); DnP>ed"M!  
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byte[] b = new byte[1024]; 5EIh5Y EU>  
int nRead; <MI>>$seiJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \L(~50{(  
{ 3Qfj=; 4  
nStartPos += fileAccessI.write(b,0,nRead); 4WZ:zr N
 
//if(nThreadID == 1) me#
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KZ pqbI Z  
} Uoh!1_oV  
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Utility.log("Thread " + nThreadID + " is over!"); )VID ;l;4  
bDownOver = true; B_anO{3$4  
//nPos = fileAccessI.write (b,0,nRead); &%}6&PWi  
} iZB?5|*  
catch(Exception e){e.printStackTrace ();} S v$%-x^t  
} *f=H#  
} 1j "/}0fx  
I1S*=^Z_U  
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//打印回应的头信息 V.6h6B!vB  
public void logResponseHead(HttpURLConnection con) p@y?xZS  
{ 9H$#c_zrq  
for(int i=1;;i++) oEd+  
{ ?`,<l#sj  
String header=con.getHeaderFieldKey(i); >fPa>[_1  
if(header!=null) 9"
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); +ZEj(fd9  
Utility.log(header+" : "+con.getHeaderField(header)); #TM+Vd$  
else Lf{9=;  
break; /mX/ "~  
} _$]3&P  
} ] hGU.C"(  
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#!l\.:h%  
public void splitterStop() V<Q''%k  
{ LWuciHfd+  
bStop = true; V6B`q;lA  
} j]#qq]c  
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} Stq&^S\x69  
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/* GSIRZJl  
**FileAccess.java oW3j|V  
*//文件访问(定位，写) I{U7BZy  
package NetFox; gE]6]L  
import java.io.*; kHygif !I4  
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public class FileAccessI implements Serializable{ 9AO`Zk{/Ez  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /]zn8d  
RandomAccessFile oSavedFile; j\iE3:94$  
long nPos; bfcQ(m5  
+sq'\Tbp  
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public FileAccessI() throws IOException v% 6uU  
{ 3DRJl,v  
this("",0); AI0YK"c?  
} m r"b/oM{  
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public FileAccessI(String sName,long nPos) throws IOException ],#Xa.r  
{ Y S/x;  
oSavedFile = new RandomAccessFile(sName,"rw"); Hd]o?q\  
this.nPos = nPos; .\XFhOsa  
oSavedFile.seek(nPos); ^3"~
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} /k8Lu+OJ  
.}!"J`{W  
Z"j #kaXA  
public synchronized int write(byte[] b,int nStart,int nLen) yNCd} 4Ym5  
{ [qbZp1s|(  
int n = -1; 4&

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try{ '/8{Mx+  
oSavedFile.write(b,nStart,nLen); C{(&Yy"  
n = nLen; pURtk-Fr2  
} WxLbf+0o  
catch(IOException e) vZMb/}-o  
{ Q*4{2oQ  
e.printStackTrace (); )E9[=4+*C$  
} 'KvSI=$  
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return n; O|%03q(  
} |H-%F?<{  
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} !r\u,l^
  
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/* 'Ur1I"  
**SiteInfoBean.java [$\KS_,Mn  
*/ #+CH0Z  
package NetFox; sgYPR  
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public class SiteInfoBean { `1Ui  
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private String sSiteURL; //Site's URL Wo)$*?  
private String sFilePath; //Saved File's Path Qa`+-Wu8  
private String sFileName; //Saved File's Name U{1%ldOJ%  
private int nSplitter; //Count of Splited Downloading File xB5qX7*.  
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public SiteInfoBean() F8xz^UQO  
{//nSplitter的缺省值为5 B&fH FyK1n  
//default value of nSplitter is 5 HSwC4y}  
this("","","",5); 2|`7_*\  
} l4Au{%j\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,
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{ P^(uS'j)+  
sSiteURL= sURL; ,GeW_!Q[  
sFilePath = sPath; _oz1'}=  
sFileName = sName; d1
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this.nSplitter = nSpiltter; ql/K$#u  
)6U6~!k  
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} zv.#9^/y  
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public String getSSiteURL() M

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{ *@;bWUJ  
return sSiteURL; GG
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} L"8Z5VHA&&  
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public void setSSiteURL(String value) mzO5&h7  
{ CwjKz*
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sSiteURL = value; J]W? Vvv  
} xe"A;6H  
!LR9}Xon  
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public String getSFilePath() dzk1!yy  
{ /07iQcT(  
return sFilePath; mX2X.ww(4  
} jXPf}{^  
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public void setSFilePath(String value) ^O.` P  
{ 4V<.:.k  
sFilePath = value; 9y'To
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} _|r/*(hh  
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public String getSFileName()  sWyx_  
{ F4NMq&_  
return sFileName; B
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} 7Y?59 [  
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public void setSFileName(String value) xLdkeuL[%  
{ (}RTHpD  
sFileName = value; lLur.f  
} f4O}WU}l{s  
g-pEt#  
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public int getNSplitter() !_q=r[D\  
{ &E]<KbVx  
return nSplitter; r}:Dg fn  
} %0p9\I  
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public void setNSplitter(int nCount) sFPh?  
{ v}5||s!=  
nSplitter = nCount; U:AB%gr[  
} v4]#Nc$~T  
} /hur6yI8  
}ssP%c]  
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/* 00LL&
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**Utility.java tUksIUYD\  
*/ ba tXj]:  
package NetFox; >u\'k+=  
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public class Utility { !
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n5 <B*  
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public Utility() qgs:9V xF  
{ W!+eJ!Da  
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} '=H3Y_{oO  
8%`h:f
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//线程睡眠 %J+ w9Z  
public static void sleep(int nSecond) F0wW3+G  
{ 9!PM1<p  
try{ "yK)9F[9Mo  
Thread.sleep(nSecond); I^)_rOgM  
} Rzyaicj^
c  
catch(Exception e) bZ#KfR  
{ th{ie2$  
e.printStackTrace (); E9w"?_A)  
} IrIW>r} -  
} (Z0.H3  
Vp1Q^`a{G  
//日志 9.:&u/e  
public static void log(String sMsg) FzOlM-)m   
{ v8 II=9  
System.err.println(sMsg); </B:Zjn  
} %EYh*g{G  
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public static void log(int sMsg) o4^#W;%w  
{ pJ x H
  
System.err.println(sMsg); q&&uX-ez5W  
} ,g1~4,hqQ  
} N3V4Mpf  
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#<@_mbQ@|K  
/* UhXVeGO  
**TestMethod.java S"fqE%  
*/ R2qz>kyyB  
package NetFox; uF{l`|b'  
<vzU}JA\  

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public class TestMethod { A9WOu*G1O  
&?I3xzvK  
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public TestMethod() -^*8D(j*  
{ ///xx/weblogic60b2_win.exe ]vuxeu[cu,  
try{ djn<Oc`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t Kjk<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Va4AE)[/*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -j^G4J  
fileFetch.start(); Oiw!d6"Ovq  
} V0bKtg1f?-  
catch(Exception e){e.printStackTrace ();} !-7<x"avm  
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} fG<[zt\e  
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public static void main(String[] args) CX7eCo  
{ =T$2Qo8  
new TestMethod(); BOl*. t  
} P#/s5D
8  
} sDwE,f0h  
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