http断点续传简单实现（java)

/* ^Pu:&:ki  
**SiteFileFetch.java .5s^a.e'O  
*/ 3c(mZ  
package NetFox; Br42Qo2"T>  
import java.io.*; VN\VTSZh?\  
import java.net.*; V\e1NS  
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public class SiteFileFetch extends Thread { ue@W@pj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oR,zr  
long[] nStartPos; //开始位置 5ug|crX  
long[] nEndPos; //结束位置 ;volBfv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FUJ<gqL  
long nFileLength; //文件长度 :=5X)10
 
boolean bFirst = true; //是否第一次取文件 $/@  L  
boolean bStop = false; //停止标志 !y>up+cRjl  
File tmpFile; //文件下载的临时信息 4i}nk T  
DataOutputStream output; //输出到文件的输出流 B*Om\I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W,H=K##6<  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'Nuy/\[{\  
{ v&d'ABeT  
siteInfoBean = bean; 2mMi=pv9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,=c(P9}^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q>9bKP  
if(tmpFile.exists ()) ]\oT({$6B  
{ 1;i|GXY:h  
bFirst = false; 4GG>n  
read_nPos(); ^;9l3P{  
} =n_z`I  
else mW+5I-~  
{ XzqB=iX  
nStartPos = new long[bean.getNSplitter()]; JP5en  
nEndPos = new long[bean.getNSplitter()]; UIg?3J}R  
} C]l)Pz$  
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} V[]Pya|s+  
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public void run() oSf`F1;)HQ  
{ *PB/I4>{  
//获得文件长度 BS,EW  
//分割文件 -1NR]#P'  
//实例FileSplitterFetch @g+v2(f2v  
//启动FileSplitterFetch线程 0
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//等待子线程返回 }~ N\A  
try{ Ea'jAIFPpO  
if(bFirst) \/gf_R_GN  
{ 5K682+^5  
nFileLength = getFileSize(); v&7<f
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if(nFileLength == -1) 84reyA  
{ *:"60fkoU  
System.err.println("File Length is not known!"); 7ncR2-{g  
} A{k1MA<F6  
else if(nFileLength == -2) =h +SZXe<r  
{ }Qe(6'l_  
System.err.println("File is not access!"); K ;]dZ8  
} + @|u8+  
else W/WP }QM  
{ !Fxn1Z,  
for(int i=0;i<nStartPos.length;i++) +]NpcE'  
{ W&D{0i`y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f7!48
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} % WXl*  
for(int i=0;i<nEndPos.length-1;i++) S1@r.z2L  
{ wgolgof  
nEndPos = nStartPos[i+1]; gd#?rc*f<3  
} M8\/[R\  
nEndPos[nEndPos.length-1] = nFileLength; &m[}%e%~0  
} !g}@xwWax  
} -aE,KQ  
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//启动子线程 jq8TfJ|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8fBhX,1  
for(int i=0;i<nStartPos.length;i++) *P]]7DR  
{ .d$Q5Qae  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '@w'(}3!3R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |8[!`T*s  
nStartPos,nEndPos,i); 2J$vX(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BhbfPQ  
fileSplitterFetch.start(); tlg}"lY  
} w^ofH-R/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aaN
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ePIN<F;
I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ydY 7 :D  
nEndPos = " + nFileLength); $UK m[:7  
// fileSplitterFetch[nPos.length-1].start(); ?$tD  
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//等待子线程结束 ^;( dF<?'r  
//int count = 0; 4b`Fi@J\  
//是否结束while循环 "AKr;|m  
boolean breakWhile = false; \v<S:cTf  
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while(!bStop) uV@'898%5  
{ >=:mtcph  
write_nPos(); M6qNh`+HO
 
Utility.sleep(500); F1B/
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breakWhile = true; Q*1'k%7  
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for(int i=0;i<nStartPos.length;i++) Ygkf}n  
{ ?1Vx)j>|  
if(!fileSplitterFetch.bDownOver) $FX$nY  
{ gGBRfq>  
breakWhile = false; aK|  
break; 5!$sQ@#}D  
} +opym!\  
} O7LJ-M  
if(breakWhile) -b8SaLak  
break; VYh/URU>  
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//count++; s"w^E\>6  
//if(count>4) GE=S.P;  
// siteStop(); @"/H er  
} I?%q`GyP5  
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System.err.println("文件下载结束！"); )dEcKH<#  
} aUc#,t;Qd  
catch(Exception e){e.printStackTrace ();} *3@8,~_t
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} O\Z!7UQ$  
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//获得文件长度 Lyn{Uag  
public long getFileSize() P_8!Gp  
{ Z02EE-
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int nFileLength = -1; )8}k.t>'s  
try{ WJa7  
URL url = new URL(siteInfoBean.getSSiteURL());  Z,O-P9jC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wTZ(vX*mK  
httpConnection.setRequestProperty("User-Agent","NetFox"); %Ny1H/@Q1+  
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int responseCode=httpConnection.getResponseCode(); c~OPH 0,  
if(responseCode>=400) /kRCCs8t}  
{  n6Uf>5  
processErrorCode(responseCode); < ]+Mdy  
return -2; //-2 represent access is error wmXI8'~F&  
} xt"-Jmox  
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String sHeader; c>3? T^=  
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for(int i=1;;i++) #6[F&  
{ l7VTuVGUJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q{b-2k  
//Utility.log(in.readLine()); bT T>  
sHeader=httpConnection.getHeaderFieldKey(i); 6biR5&Y5U&  
if(sHeader!=null) 2$!,$J-<Y  
{ $9X?LGUz  
if(sHeader.equals("Content-Length")) vJVh%l+  
{ .v'`TD).6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NYG!\u\Rm  
break; e 6>j gy  
} ^*B@=  
} 3K/tB1  
else P(Zj}tGN  
break; KQ81Oxu*C  
} d=uGB"  
} C|w<mryx  
catch(IOException e){e.printStackTrace ();} H`URJ8k$Q  
catch(Exception e){e.printStackTrace ();} 9h)8Mq+M  
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Utility.log(nFileLength); Vmh$c*TE  
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return nFileLength; RF'nwzM3  
} (RG "2I3  
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//保存下载信息（文件指针位置） " Qyi/r41  
private void write_nPos() i^A=nsD`  
{ P7bb2"_9  
try{ W
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ,2 W=/,5A  
output.writeInt(nStartPos.length); hmG8 {h/  
for(int i=0;i<nStartPos.length;i++) 9Hb|$/FD  
{ |42;171  
// output.writeLong(nPos); _29wQn@]  
output.writeLong(fileSplitterFetch.nStartPos); "XLtrAu{  
output.writeLong(fileSplitterFetch.nEndPos); Yl"CIgt  
} "zQ<)Q]U  
output.close(); S-~)|7d.  
} y^n
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catch(IOException e){e.printStackTrace ();} 1=,2i)  
catch(Exception e){e.printStackTrace ();} m}oR*<.  
} f/IQ2yT-:D  
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//读取保存的下载信息（文件指针位置） xaoR\H  
private void read_nPos() (&r` l&0  
{ [UC_  
try{ W(4$.uZ)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g.%} +5  
int nCount = input.readInt(); s3Zt)xQ3  
nStartPos = new long[nCount]; v#<
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nEndPos = new long[nCount]; xVX:kDX  
for(int i=0;i<nStartPos.length;i++) 7I&o  
{ 7l=Tl[n  
nStartPos = input.readLong(); ~OvbMWu  
nEndPos = input.readLong(); H<<t^,E^.t  
} mTUoFXX[  
input.close(); &=n/h5e0t&  
} 7ZyP  
catch(IOException e){e.printStackTrace ();} r7R.dD/.  
catch(Exception e){e.printStackTrace ();} =_m3~=Z  
} }B
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private void processErrorCode(int nErrorCode) Qo^(r$BD  
{ I_Gz~qk6  
System.err.println("Error Code : " + nErrorCode); mD&I6F[s  
} %eIaH!x:  
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//停止文件下载 3"v>y]$U  
public void siteStop() ']I!1>v$[  
{ o~\.jQQxa  
bStop = true; _-543B}  
for(int i=0;i<nStartPos.length;i++) p[].4_B;  
fileSplitterFetch.splitterStop(); }mIN)o  
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} aBG^Xhx  
} hAc|a9 o  
//负责部分文件的抓取
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**FileSplitterFetch.java xLi3|^q  
*/ X/vy
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package NetFox; $\/^O94-l  
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import java.io.*; |mHf7gCX  
import java.net.*; oD\t4]?E  
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public class FileSplitterFetch extends Thread { cqJXZ.XC  
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String sURL; //File URL i '*!c  
long nStartPos; //File Snippet Start Position n^hkH1vY  
long nEndPos; //File Snippet End Position >1Hv c7DP  
int nThreadID; //Thread's ID 8zlvzp  
boolean bDownOver = false; //Downing is over G7v<Q,s  
boolean bStop = false; //Stop identical iDl#foXa`  
FileAccessI fileAccessI = null; //File Access interface oPni4^g i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WSxoGly  
{ srAWet  
this.sURL = sURL; ~TS!5Wiv  
this.nStartPos = nStart; 8]b;l; W5  
this.nEndPos = nEnd; \9` ~9#P  
nThreadID = id; Sa[lYMuB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y?O-h1"3,  
} D
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public void run() \~+b&  
{ 8OV=;aM?{  
while(nStartPos < nEndPos && !bStop) G6W|l2P!  
{ PLz+%L;{  
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try{ ")vtS}Ekt  
URL url = new URL(sURL); /!?Tv8TPp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U5~aG!E  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6S3D#SY  
String sProperty = "bytes="+nStartPos+"-"; AzZhIhWl">  
httpConnection.setRequestProperty("RANGE",sProperty); 5Ww,vSCV)  
Utility.log(sProperty); :A @f[Y'9  
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InputStream input = httpConnection.getInputStream(); }[UH1+`L  
//logResponseHead(httpConnection); ZX`x9/0&  
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byte[] b = new byte[1024]; $|J+  
int nRead; 7 L,`7k|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7#G!es  
{ Et(H6O8  
nStartPos += fileAccessI.write(b,0,nRead); j nSZ@u  
//if(nThreadID == 1) V?"U)Y@Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [f lK  
} $/g`{OI]K  
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Utility.log("Thread " + nThreadID + " is over!"); >]gB@tn[  
bDownOver = true; JU5,\3Lz#  
//nPos = fileAccessI.write (b,0,nRead); \ctzv``/n  
} YlG#sBzl  
catch(Exception e){e.printStackTrace ();} >yP>]r+  
} p"~@q}3  
} Vq`/]&  
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//打印回应的头信息 O{\<Izm`D  
public void logResponseHead(HttpURLConnection con) VBDb K|  
{ <D)@;A  
for(int i=1;;i++) W% Lrp{  
{ =EA @  
String header=con.getHeaderFieldKey(i); {Ke IYjE  
if(header!=null) +$(y2F7|u-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kv2o.q  
Utility.log(header+" : "+con.getHeaderField(header)); {fl[BX]kZ  
else LK*9`dzv=G  
break; `fX\pOk~e  
} y_q1Y70i2r  
} ;R2A>f~  
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public void splitterStop() .6 0yQ[aE  
{ NopfL  
bStop = true; {cLWum[SY  
} Viw,YkC  
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} -X%twy=  
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8,vP']4r%  
/* fSVM[  
**FileAccess.java hslT49m>  
*//文件访问(定位，写) lV4TFt,  
package NetFox; 7SYe:^Dx  
import java.io.*; E)jd>"  
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public class FileAccessI implements Serializable{ O_th/hl  
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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 fB]2"(  
RandomAccessFile oSavedFile; OiZ-y7;k^  
long nPos; '@#(jY0_  
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public FileAccessI() throws IOException '" &*7)+g*  
{ "oZ_1qi<  
this("",0); <^{(?*  
} Nr,I`x\N
 
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public FileAccessI(String sName,long nPos) throws IOException u0oTqD?  
{ T>#~.4A0  
oSavedFile = new RandomAccessFile(sName,"rw"); BOM0QskLf  
this.nPos = nPos; ,d_rK\J  
oSavedFile.seek(nPos); N!dBF t"  
} $qZ6i  
|HY{Q1%
  
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public synchronized int write(byte[] b,int nStart,int nLen) ]K>bSK^TX  
{ Th\T$T`X$  
int n = -1; '4u/g  
try{ &X` lh P  
oSavedFile.write(b,nStart,nLen); tK*y/S  
n = nLen; lcReRcjm  
} ]=xX_  
catch(IOException e) &vN!>bR  
{ y,`0f|  
e.printStackTrace (); .T(vGiU  
} -:45Q{u/  

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return n; jHatUez4O  
} B]gyj  
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} FS @55mQ  
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/* if\`M'3Xx  
**SiteInfoBean.java ){,Mv:#+T  
*/ w}$;2g0=a<  
package NetFox; V7gL*,3>=  
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public class SiteInfoBean { 8$iHd  
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private String sSiteURL; //Site's URL &P35\q   
private String sFilePath; //Saved File's Path r#w7qEtD  
private String sFileName; //Saved File's Name Z]k@pR !  
private int nSplitter; //Count of Splited Downloading File 4JO16  

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public SiteInfoBean() pTTM(Hrx  
{//nSplitter的缺省值为5 $X\2h+ Os  
//default value of nSplitter is 5 zO$r   
this("","","",5);
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} Sz1J4$5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 017nhI  
{ j*f\Z!EeZ  
sSiteURL= sURL; uXUuA/O5-  
sFilePath = sPath; 7'{Vh{.  
sFileName = sName; wr,+9uK  
this.nSplitter = nSpiltter; y )<+?@sP  
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7,
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} 4,Uqcw?!F'  
{36N=A  
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public String getSSiteURL() H`q[!5~8  
{ W.D>$R2  
return sSiteURL; t pxk8Ys  
} @uQ *$  
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public void setSSiteURL(String value) i;|I;5tC  
{ a gL@A  
sSiteURL = value; \ZE=WvnhZ  
} $ZB`4!JxG  
W*v3B.  
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public String getSFilePath() N Mx:Jh-YN  
{ Y!Io @{f  
return sFilePath; m$pRA0s2`  
} [!uVo>Q4  
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public void setSFilePath(String value) ~>~qA0m"m  
{ f3>DmH#  
sFilePath = value; U.$Th_  
} Y5"HK
W^  
# M!1W5#  
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public String getSFileName() |}<Gz+E>  
{ AKk&  
return sFileName; HN5,MD[  
} qFq$a9w|@  
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public void setSFileName(String value) "o_'q@.}  
{ 6'<[QoW];  
sFileName = value; =1 S%E  
} Wa&!1' @  
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public int getNSplitter() jPZpJ:  
{ b8vZ^8tBV  
return nSplitter; 7~k=t!gTY  
} t&EY$'c  
Nqz6_!  
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public void setNSplitter(int nCount) N&Ho$,2s  
{ )t\aB_ =  
nSplitter = nCount; K"X"2c1o  
} M,
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} vEGI  
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/* WNQ<XBqAw  
**Utility.java ?`O^
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*/ S QGYH  
package NetFox; Un T\6u  
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public class Utility { %&V%=-O_7  
S)
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public Utility() _)~VKA]""  
{ ?~yJ7~3TS<  
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#5'
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} ``6-   
Nv6"c<(L=  
//线程睡眠 <dr2 bz  
public static void sleep(int nSecond) @';.$  
{ ha 2=O  
try{ %:;g|PC  
Thread.sleep(nSecond); P*VZ$bUe5@  
} zZ<
*  
catch(Exception e) -%^'x&e  
{ pv-c>8Wb6  
e.printStackTrace (); DL!%Np?`  
} 2' ^7G@%  
} K,%CE ].  
d2-oy5cEB  
//日志 lmL$0{Yr  
public static void log(String sMsg) Fqgs S  
{ BfVh\lkH  
System.err.println(sMsg); Ude?[6  
} p?4[nS-,  
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M'|p<SO]  
public static void log(int sMsg) 4i^WE;|s  
{ v_WQ<G?  
System.err.println(sMsg); )4c?BCgy  
} R:R<Xt N`5  
} 10OkrNQ  
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X;l/D}
,.  
/* kLU-4W5t  
**TestMethod.java DrC"M*$!  
*/ ['sNk[-C  
package NetFox; N0vECk  
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public class TestMethod { K:~tZ  
mZPvG  
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public TestMethod() a }*i [  
{ ///xx/weblogic60b2_win.exe rPGj+wL5-  
try{ /@
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iemp%~UZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $gD8[NAIx=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 57gt"f  
fileFetch.start(); 4K? \5(b  
} JPng !tvR  
catch(Exception e){e.printStackTrace ();} 8UqH"^9.Q7  
n\JI7A}  
2l^_OrE!  
} 7C,giCYU  
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[A"=!e$<  
public static void main(String[] args) GdVF;  
{ nhjT2Sl  
new TestMethod(); C])s'XTs  
} 9:-7.^`P  
} n_9Ex&?e  
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