http断点续传简单实现（java)

/* }&sF \b  
**SiteFileFetch.java Lo _5r T"  
*/ w]X~I/6g  
package NetFox; TV\21  
import java.io.*; W4Rs9NA}  
import java.net.*; ; S7 %  
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public class SiteFileFetch extends Thread { = zW}vm }  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8X!^ 2B}J  
long[] nStartPos; //开始位置 'hfQ4EN  
long[] nEndPos; //结束位置 Q4\EI=4P]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QyQ&xgS  
long nFileLength; //文件长度 <
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boolean bFirst = true; //是否第一次取文件 fiqeXE?E  
boolean bStop = false; //停止标志 U1G"T(;s:  
File tmpFile; //文件下载的临时信息 u!?cKZw  
DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $
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public SiteFileFetch(SiteInfoBean bean) throws IOException &+;z`A'|8  
{ vggyQf%  
siteInfoBean = bean; <gRv7 ?V[z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^55#!/9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }/q]:3M|  
if(tmpFile.exists ()) ~c~N _b  
{ W- 5Z"m1I  
bFirst = false; O`1_eK~1<  
read_nPos(); pe$" nUy|  
} \)'s6>58|  
else ts/rV#s~  
{ 1^^<6e  
nStartPos = new long[bean.getNSplitter()]; V`qHNM/t  
nEndPos = new long[bean.getNSplitter()]; iV;X``S  
} 8gWifx #N  
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} &Iv3_T<
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public void run() |LA@guN  
{ D_er(  
//获得文件长度 rKg~H=4x2  
//分割文件 k"X<gA  
//实例FileSplitterFetch T {Q]  
//启动FileSplitterFetch线程 ew -5VL   
//等待子线程返回 Y1?wf.  
try{ NF+^  
if(bFirst) ?CIMez(h  
{ vpu20?E>5z  
nFileLength = getFileSize(); _1_CYrUc  
if(nFileLength == -1) U;f~Q6iu  
{ 0V6gNEAUg  
System.err.println("File Length is not known!"); \nT, NV11  
} >KXSb@  
else if(nFileLength == -2) MebLY $&8  
{ F_0vh;Jo  
System.err.println("File is not access!"); &6 .r=,BO  
} uz-O%R-  
else jxB  
{ :H($|$\h  
for(int i=0;i<nStartPos.length;i++) 7(c7-  
{  V9\g?w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z9TmX A@  
} NT+%u-  
for(int i=0;i<nEndPos.length-1;i++) |35"V3bs  
{ aoj6/  
nEndPos = nStartPos[i+1]; w/+e  
} 1}nrVn[B9  
nEndPos[nEndPos.length-1] = nFileLength; Ca}T)]//  
}
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} OSACH0h  
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//启动子线程  1t7vP;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l]tda(  
for(int i=0;i<nStartPos.length;i++) i i&kfy  
{ 06pEA.ro  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b#\i]2b:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #+dF3]X(&  
nStartPos,nEndPos,i); AmYqrmJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A/pp
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fileSplitterFetch.start(); RMJq9a  
} 0 _4p>v:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u.W}{-+kp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d +0(H   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qQ\&]  
nEndPos = " + nFileLength); V`:iun^f  
// fileSplitterFetch[nPos.length-1].start(); J*HZ=6L  
JAPiR=  
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//等待子线程结束 nO-1^HUl  
//int count = 0; $&IF#uDf  
//是否结束while循环 ]6JI((  
boolean breakWhile = false; sXe=4`O  
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while(!bStop) xZ2^lsY  
{ fePt[U)2  
write_nPos(); U Px7u%Do  
Utility.sleep(500); .A 12Co  
breakWhile = true; }EFMJ,NQ  
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for(int i=0;i<nStartPos.length;i++) G.Z4h/1<  
{ Z*r;"WHB  
if(!fileSplitterFetch.bDownOver) qu>5 rg-  
{ EPO*{bN7O  
breakWhile = false; ~+_|J"\  
break; $'m&RzZ  
} vm,/?]P  
} _g{*;?mS  
if(breakWhile) VL6_in(  
break; lJZ-*"9V  
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//count++; ~\4`tc  
//if(count>4) kC :pa
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// siteStop(); #$/SM_X14C  
} P!uwhha/g  
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System.err.println("文件下载结束！"); 9hoTxWpmy  
} ?[Gj?D.Wc  
catch(Exception e){e.printStackTrace ();} r
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} 8&d
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//获得文件长度 #L,>)XkjS  
public long getFileSize() NR98I7  
{ a3i;r M2  
int nFileLength = -1; gie.K1@|  
try{ VE_%/Fs,  
URL url = new URL(siteInfoBean.getSSiteURL()); "XvM1G&s`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X0G Mly  
httpConnection.setRequestProperty("User-Agent","NetFox"); fK-tvP0}*  
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int responseCode=httpConnection.getResponseCode(); ^uG^XY&ItC  
if(responseCode>=400) Ed&;d+NM  
{  k2]Q~  
processErrorCode(responseCode); 3RYg-$NK[  
return -2; //-2 represent access is error (WoKrd.!  
} z>n<+tso  
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String sHeader; [):&R1U  
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for(int i=1;;i++) M mihWD02  
{ 8vP
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,gdf7&r  
//Utility.log(in.readLine()); pxj}%LH  
sHeader=httpConnection.getHeaderFieldKey(i); BbCt_z'  
if(sHeader!=null) 7*{
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{ fDq`.ZW)s  
if(sHeader.equals("Content-Length")) c5KJ_Nfi  
{ Z:TW{:lrI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X?3?R\/  
break; C
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} A4C4xts]N  
} IdY\_@$ v  
else ,2*^G;J1  
break; A4kYEA  
} u<}PcI.  
} ux8:  
catch(IOException e){e.printStackTrace ();} [1Os.G2  
catch(Exception e){e.printStackTrace ();} ^M51@sXI7  
I $5*Puy#  
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Utility.log(nFileLength); 0u,
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W  
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return nFileLength; fi/[(RBG  
} @|7Ma/8v  
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//保存下载信息（文件指针位置） S7/0B4[  
private void write_nPos() WKHEU)'!  
{ ;JNI$DR  
try{ N s
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output = new DataOutputStream(new FileOutputStream(tmpFile)); w-[A"M]I  
output.writeInt(nStartPos.length); @(;zU~l/  
for(int i=0;i<nStartPos.length;i++) rSGt`#E-s.  
{ GQU9UXe  
// output.writeLong(nPos); /.?m9O^ F  
output.writeLong(fileSplitterFetch.nStartPos); ;p$KM-?2D  
output.writeLong(fileSplitterFetch.nEndPos); k@,&'imx  
} )_7OHV *3  
output.close(); z3 zN^ZT  
} WJB/X"J  
catch(IOException e){e.printStackTrace ();} >Ei-Spy>Xl  
catch(Exception e){e.printStackTrace ();} #7wOr78  
} 8Gw0;Uu8D  
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//读取保存的下载信息（文件指针位置） "CS{fyJ  
private void read_nPos() M*& tVG  
{ Iy2KOv@a5  
try{ %Pz'D6 /  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }!^/<|$=  
int nCount = input.readInt(); 9/La_:K  
nStartPos = new long[nCount]; 'Z<V(;W  
nEndPos = new long[nCount]; btQDG  
for(int i=0;i<nStartPos.length;i++)
 :RYh@.  
{ I eQF+Xz  
nStartPos = input.readLong(); {;iG}jK  
nEndPos = input.readLong(); Q%x |  
} 3A~53W$M  
input.close(); Cfz020u`g  
} `0]kRA8=  
catch(IOException e){e.printStackTrace ();} EQ;,b4k?&g  
catch(Exception e){e.printStackTrace ();} >:2Br(S  
} d=q&UCC  
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private void processErrorCode(int nErrorCode) Q t!X<.  
{ ]#UyY
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System.err.println("Error Code : " + nErrorCode); wEMh !jAbv  
} *1Q~/<W  
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//停止文件下载 c[/h7
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public void siteStop() qac4GZ  
{ ";I|\ T  
bStop = true; RV*7?y%3  
for(int i=0;i<nStartPos.length;i++) JZCRu_M>|  
fileSplitterFetch.splitterStop(); 71nI`.Z  
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} p6qza @  
} 5<?O S &B  
//负责部分文件的抓取 ciq'fy
 
**FileSplitterFetch.java %:^|Q;xe  
*/ T8ga)BA  
package NetFox; **zh>Y}6  
(c{<JYEC  
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import java.io.*; 4 Ar\`{c>  
import java.net.*; $LS$:%i4  
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public class FileSplitterFetch extends Thread { dkz79G}e  
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String sURL; //File URL kW'xuZ&  
long nStartPos; //File Snippet Start Position kfod[*3  
long nEndPos; //File Snippet End Position 2{<5?Op  
int nThreadID; //Thread's ID ?A[q/n:K  
boolean bDownOver = false; //Downing is over  X,zqI  
boolean bStop = false; //Stop identical 8x`?Yc  
FileAccessI fileAccessI = null; //File Access interface 2>E.Q@c  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5`$.GV  
{ H#/}FoBiS  
this.sURL = sURL; +1K9R\  
this.nStartPos = nStart; $"+ahS<?tC  
this.nEndPos = nEnd; '?q \mi  
nThreadID = id; XJ3 5Z+M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _L?`C  
} i7qG5U  
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public void run() m=Z1DJG  
{ <
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while(nStartPos < nEndPos && !bStop) DPrFBy  
{ |<,!K;@  
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@"`J~uK  
try{ %;SOe9  
URL url = new URL(sURL); G~oGBq6Gz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MroJ!.9  
httpConnection.setRequestProperty("User-Agent","NetFox"); z|VQp,ra  
String sProperty = "bytes="+nStartPos+"-"; ryd*Ha">I  
httpConnection.setRequestProperty("RANGE",sProperty); {x3"/sF  
Utility.log(sProperty); vJX3fE}F  
67Z.aaXD1  
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InputStream input = httpConnection.getInputStream(); mk)F3[ke  
//logResponseHead(httpConnection); %Uq
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byte[] b = new byte[1024]; 82w='~y  
int nRead; 99'e)[\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 29]T:I1d[  
{ #d+bld\  
nStartPos += fileAccessI.write(b,0,nRead); "=7y6bM  
//if(nThreadID == 1) xLfx/&2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n'<FH<x  
} vT*z3  
MuzlUW]  
[m>kOv6>
^  
Utility.log("Thread " + nThreadID + " is over!"); eq0&8/=  
bDownOver = true; .xRJ )9q  
//nPos = fileAccessI.write (b,0,nRead); 6 ufF34tA  
} aP}kl[W  
catch(Exception e){e.printStackTrace ();} f'hrS}e  
} }i32  
} Pt/dH+r`%  
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//打印回应的头信息 :i
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public void logResponseHead(HttpURLConnection con) PgNg1  
{ Ae&470  
for(int i=1;;i++) l_K=7\N  
{ 58x=CN\QU  
String header=con.getHeaderFieldKey(i); HZp}<7NR(7  
if(header!=null) ,KXS6:1%5Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )aW;w|#n  
Utility.log(header+" : "+con.getHeaderField(header)); wS*An
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else t'msgC6=>u  
break; ),#%jc2_^  
} <ID/\Qx`q  
} MfJ;":]O!  
&5]&6TD6  
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public void splitterStop() jB+K)NXHL  
{ !Cq2<[K#  
bStop = true; !f 7CN<  
} -;/;dz;  
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} =Q#} ,T  
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/* `)sC".b7  
**FileAccess.java ZPrL)']  
*//文件访问(定位，写) /U |@sw4  
package NetFox; cG)i:  
import java.io.*; I9xQ1WJc`  
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public class FileAccessI implements Serializable{ {Kn:>l$*7  
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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 11%<bmJ]Q3  
RandomAccessFile oSavedFile; g_<^kg"  
long nPos; vM_UF{a$=  
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public FileAccessI() throws IOException xcBV,[E{  
{ c&!EsMsU  
this("",0); H7&>cM  
} \k?Fu=@  
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public FileAccessI(String sName,long nPos) throws IOException }.j<kmd  
{ b
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oSavedFile = new RandomAccessFile(sName,"rw"); oMM+af  
this.nPos = nPos; +;Yd<~!c Z  
oSavedFile.seek(nPos); <g/Z(<{wor  
} y~,mIM$[@  
>LvQ&fAo  
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public synchronized int write(byte[] b,int nStart,int nLen) Q-scL>IkCb  
{ $ {Y?jJ  
int n = -1; tOQ29
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try{ d
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oSavedFile.write(b,nStart,nLen); A .]o&S}  
n = nLen; : ,0F_["3  
} _!vxX]  
catch(IOException e) }/dGC;p"  
{ r]GG9si  
e.printStackTrace (); ]r]=Q"/5  
}  t0$}  
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return n; %9bf^LyD  
} 6V[ce4a%  
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} T7F)'Mx<  
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/* :Nry |  
**SiteInfoBean.java N*Is_V\R  
*/ hFLD2<   
package NetFox; 7iI6._"!w  
jv8diQ.  
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public class SiteInfoBean { !CJh6X!  
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private String sSiteURL; //Site's URL 75>)1H)Xm  
private String sFilePath; //Saved File's Path /' +GYS
  
private String sFileName; //Saved File's Name U|[+M@F_L  
private int nSplitter; //Count of Splited Downloading File &OK[n1M  
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public SiteInfoBean() 9E@}@ZV(  
{//nSplitter的缺省值为5 /w5~ O:  
//default value of nSplitter is 5 EbG`q!C  
this("","","",5); G@Jl4iHug"  
} [I XX#^F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wD*z >v$  
{ 8-f
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sSiteURL= sURL; nnw5 !q_  
sFilePath = sPath; Wciw6.@  
sFileName = sName; 2q4dCbJ!  
this.nSplitter = nSpiltter; erhxZ|."P  
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} J83{&N2u  
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public String getSSiteURL() HB/q v IzB  
{ XGs d"UW  
return sSiteURL; ZxvqLu  
} 4hymQ3 g  
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public void setSSiteURL(String value)
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{ F9N/_H*+  
sSiteURL = value; mN!5JZ'2  
} MfJs?N0  
@Czj] t`  
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public String getSFilePath() 4>JDo,AWy  
{ vt(A?$j|A  
return sFilePath; 1\hh,s  
} P&6hk6#  
Q&JnF`*  
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public void setSFilePath(String value) @c>a  
{ L`iC?<}  
sFilePath = value; dg(fD>+  
} Ke5fe#  
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public String getSFileName() #3+-vyZm  
{ z?b[ 6DLV;  
return sFileName; )bl'' yO  
} {6/Yu:;  
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public void setSFileName(String value) ``Yw-|&:Ae  
{ ]>:LHW  
sFileName = value; Za5bx,^  
} ~_;x o?@ba  
,(D:cRN  
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public int getNSplitter() \W;+@w|c  
{ ~9tPT0^+  
return nSplitter; P S$6`6G  
} p!XB\%sv'"  
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public void setNSplitter(int nCount) T#>1$0yv  
{ hYj!*P)uV  
nSplitter = nCount; )|d]0/<  
} c~bTK" u  
} =}8:zO 2'{  
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f{[]m(X;  
/* 5os(.  
**Utility.java Wej'AR\NX  
*/ 88]UA  
package NetFox; Zn-F!Lsv  
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public class Utility { '`+GC9VG  
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public Utility() A3;}C+K  
{ jTDaW8@L  
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} m\XgvpvrP  
['G@`e*\  
//线程睡眠  hxedQvW  
public static void sleep(int nSecond) l9zkx'xt.-  
{ 9:]w|lE:D  
try{ oX;D|8
f  
Thread.sleep(nSecond); App9um3:  
} Kgb3>r  
catch(Exception e) e*zt;SR  
{ O< \i{4}}  
e.printStackTrace (); `<3/k  
} @77%15_Jz  
} IPIas$  
[VsTyqV a  
//日志 4dd]Ju  
public static void log(String sMsg) ;QiSz=DyA  
{ FA+'E  
System.err.println(sMsg); {hE\ECT-  
} =/|2f
; Q  
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npJyVh47  
public static void log(int sMsg) 3Dm`8Xt  
{ 7M#irCX  
System.err.println(sMsg); $v6`5;#u  
} X=W.{?  
} U)3*7D  
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}kCaTI?
@#  
/* Oh|KbM*vS  
**TestMethod.java =:5o"g  
*/ Q`ALyp,9b  
package NetFox; p1O[QQ|  
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public class TestMethod { ?FRuuAS  
;:Yz7<>Y,  
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public TestMethod() (9_O||ee  
{ ///xx/weblogic60b2_win.exe ^1b/Y8&8A  
try{ ISbhC!59  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m7F"kD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bH7 lUS~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o~(/Twxam  
fileFetch.start(); \MY`R  
} Q.$|TbVfds  
catch(Exception e){e.printStackTrace ();} Cd"cU~HAB  
{ +$zgg  
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} lo!.%PP|  
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public static void main(String[] args) *Bse3%-v  
{ }1sFddGVt  
new TestMethod(); '&OJ hLE  
} rZK;=\Ot  
} uE]kv  
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