http断点续传简单实现（java)

/* 9u B?-.  
**SiteFileFetch.java 0#,a#P  
*/ xY^sC56Z  
package NetFox; `ONjEl  
import java.io.*; Gm=qn]c  
import java.net.*; )dXa:h0RZ  
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public class SiteFileFetch extends Thread { h)KHc/S  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {ZJO5*  
long[] nStartPos; //开始位置 bz4Gzp'6k  
long[] nEndPos; //结束位置 6K/RO)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 zC?'Qiuh*  
long nFileLength; //文件长度 "s2_X+4oY  
boolean bFirst = true; //是否第一次取文件 L$ZjMJ  
boolean bStop = false; //停止标志 CWj_K2=d  
File tmpFile; //文件下载的临时信息 ~6[?=mOi'  
DataOutputStream output; //输出到文件的输出流 S$6|KY u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?YhDjQs  
public SiteFileFetch(SiteInfoBean bean) throws IOException *FS8]!Qg  
{ [);oj<  
siteInfoBean = bean; [GwAm>k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wj)LOA0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &qv~)ZM$  
if(tmpFile.exists ()) %pC<T*f  
{ #NS|9jW  
bFirst = false; \Z-th,t  
read_nPos(); E C?}iP  
} qt"D!S
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else -t`kb*O3`  
{ E)"19l|}B  
nStartPos = new long[bean.getNSplitter()]; YagfCi ?  
nEndPos = new long[bean.getNSplitter()]; <Xf6?nyZ(  
} e~r/!B5X  
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} ( }-*irSsj  
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public void run() wQ_4_W  
{ #M,&g{  
//获得文件长度 Y },E3<  
//分割文件 8-Abg:)  
//实例FileSplitterFetch 2d)Dhxzxk  
//启动FileSplitterFetch线程 eYOY   
//等待子线程返回 144Y.  
try{ ZU4=&K  
if(bFirst) 4T
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{ ^y+k6bE  
nFileLength = getFileSize(); coP->&(@U#  
if(nFileLength == -1) Q(|@&83].  
{ f56yI]*N=<  
System.err.println("File Length is not known!"); 7?P'f3)fG  
} %hB-$nE  
else if(nFileLength == -2) I _nQTWcm  
{ |9*Rnm_  
System.err.println("File is not access!"); E`HoJhB  
} fSo8O  
else i~@gI5[k+  
{ ]RVu[k8  
for(int i=0;i<nStartPos.length;i++) N$fP\h^AR  
{ 5100fX}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bz*@[NQ  
} kmQ:wf:  
for(int i=0;i<nEndPos.length-1;i++) L&\W+k  
{ xIdb9hm<  
nEndPos = nStartPos[i+1]; Ly=.  
} 6pt,]FlU  
nEndPos[nEndPos.length-1] = nFileLength; ;jPsS^X  
} eI8o#4nT  
} /s?%ft#-9o  
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*5'8jC"2g  
//启动子线程 1k[_DQ=^l1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gtKih  
for(int i=0;i<nStartPos.length;i++) 9z,sn#-t  
{ ZCCCuB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xo PJ?63  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x{H+fq,M  
nStartPos,nEndPos,i); 3u@,OE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '}cSBbl&/n  
fileSplitterFetch.start(); +17!v_4^  
} rO87V!Cj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 01(U)F\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '5}hm1,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #X(2  
nEndPos = " + nFileLength); Fe8X@63  
// fileSplitterFetch[nPos.length-1].start(); VL#:oyWA  
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#}Qe{4L  
//等待子线程结束 yQJ0",w3o.  
//int count = 0; P@y)K!{Nk  
//是否结束while循环 ~-"CU:$
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boolean breakWhile = false; Z~:)hwF  
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while(!bStop) b+Q{Z*  
{ 3MQHoxX  
write_nPos(); U|wST&rU|  
Utility.sleep(500); =CzGI|pb  
breakWhile = true; F=\ REq  
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for(int i=0;i<nStartPos.length;i++) ^"Bhp:o2  
{ 4m~y%> &  
if(!fileSplitterFetch.bDownOver) 4 95Y<x}=  
{ u<j;+-]8h  
breakWhile = false; 4(8c L?J`0  
break; KKwM\  
} <gPM/4$G  
} vhZXgp0X  
if(breakWhile) CG uuadNI  
break; +B{u,xgg  
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//count++; zE;|MU@|  
//if(count>4) WOPIF~1v  
// siteStop(); Q 1i5"'][  
} 7<LuL  
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System.err.println("文件下载结束！"); >QDyG8*  
} H2iIBGu|L  
catch(Exception e){e.printStackTrace ();} f0eQq;D$K  
} ,b^Y8_ltoT  
} ew{WD  
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//获得文件长度 7!qeIz  
public long getFileSize() ;nlJD#  
{ 5NkF_&S_1  
int nFileLength = -1; e!=7VEB  
try{ \[!{tbK`2  
URL url = new URL(siteInfoBean.getSSiteURL()); YdV.+v(30  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G%Lt>5*!nE  
httpConnection.setRequestProperty("User-Agent","NetFox"); kM-8%a2i  
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int responseCode=httpConnection.getResponseCode(); 4~Q
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if(responseCode>=400) 5xT, O  
{ xqdkc^b  
processErrorCode(responseCode); ,or;8aYc#  
return -2; //-2 represent access is error @Y,t]  
} ,1~B7Zd  
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String sHeader; ;7[DFlS\P  
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for(int i=1;;i++) "z6p=B"?3  
{ o^5UHFxTCB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {Mo[C%  
//Utility.log(in.readLine()); r:rPzq1  
sHeader=httpConnection.getHeaderFieldKey(i); f:nXE&X[  
if(sHeader!=null) ;"f9"  
{ 1A93ol=  
if(sHeader.equals("Content-Length")) ys)
  
{ 7aRy])x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ']Czn._  
break; |-v/  
} vWW Q/^  
} /:-ig .YY  
else U e-AF#  
break; eVj 8u  
} gjiS+N[  
} 8\)4waz$  
catch(IOException e){e.printStackTrace ();} -0'<7FSQ  
catch(Exception e){e.printStackTrace ();} H[R6 ?H@$F  
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Utility.log(nFileLength); amQiH!}8R  
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return nFileLength; pcd?6jh8  
} t&yuo E  
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//保存下载信息（文件指针位置） / H GPy  
private void write_nPos() ](+u'8  
{ AHa]=ka>  
try{ Sw{rNzh%$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FIJ]`  
output.writeInt(nStartPos.length); OK@yMGz1I  
for(int i=0;i<nStartPos.length;i++) fTy{`}>  
{ x {Rj2~KC  
// output.writeLong(nPos); W$}2 $}r0U  
output.writeLong(fileSplitterFetch.nStartPos); Kk\
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output.writeLong(fileSplitterFetch.nEndPos); `)i4ZmE|  
} 3!KyO)8  
output.close(); !(_qM  
} >'3nsR  
catch(IOException e){e.printStackTrace ();} /Zz[vf
 
catch(Exception e){e.printStackTrace ();} h-03]M#8=  
} kCZ'p  
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//读取保存的下载信息（文件指针位置） tB0f+ wC  
private void read_nPos()
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{ 4f213h  
try{ s_!F`[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R|\kk?,u  
int nCount = input.readInt(); q) e*eN  
nStartPos = new long[nCount]; 3|Y.+W  
nEndPos = new long[nCount]; 7%|HtBXv^  
for(int i=0;i<nStartPos.length;i++) Jk`0yJi$q  
{ U@".XIDQ  
nStartPos = input.readLong(); cS",Bw\  
nEndPos = input.readLong(); 4g+o/+6!4  
} [WR*u\FF  
input.close(); Jb!s#g   
} o3:h!(#G  
catch(IOException e){e.printStackTrace ();} wA";N=i=  
catch(Exception e){e.printStackTrace ();} 2 o5u02x  
} UotLJa  
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private void processErrorCode(int nErrorCode) p+F>+OQ*  
{ X$<CIZ  
System.err.println("Error Code : " + nErrorCode); IP#qT `=}  
} 3Q#3S  
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//停止文件下载 KhNE_. Z  
public void siteStop() z|m-nIM  
{ 5Noy~
;  
bStop = true; ^B'N\[  
for(int i=0;i<nStartPos.length;i++) t|59/R  
fileSplitterFetch.splitterStop(); N}\3UHtO  
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} MJcWX|(y  
} M
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//负责部分文件的抓取 oazy%n(KZ  
**FileSplitterFetch.java q}p (p( N  
*/ Y-P?t
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package NetFox; kXZG<?  
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import java.io.*; #D Oui]  
import java.net.*; 4nD U-P#f  
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public class FileSplitterFetch extends Thread { cD9axlJ  
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String sURL; //File URL iR{*XE   
long nStartPos; //File Snippet Start Position R?J=5tO  
long nEndPos; //File Snippet End Position }
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int nThreadID; //Thread's ID L[}Ak1 A  
boolean bDownOver = false; //Downing is over I:o.%5)  
boolean bStop = false; //Stop identical @l@erCw@  
FileAccessI fileAccessI = null; //File Access interface w7Vl,pN,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <iznB8@  
{ ? VHOh9|AT  
this.sURL = sURL; 4w(#`'I>  
this.nStartPos = nStart; ~|=goHmm[  
this.nEndPos = nEnd; eGlPi|  
nThreadID = id; 5VK.Zs\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *ta?7uSiT  
} ;Km74!.e7  
= ^_4u%}  
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public void run() (b;*8  
{ 6%fF6  
while(nStartPos < nEndPos && !bStop) vFl06N2  
{ -gy@sSfvkv  
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try{ '(yjq<  
URL url = new URL(sURL); ]Qh0+!SdG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n8'#'^|  
httpConnection.setRequestProperty("User-Agent","NetFox"); %H8s_O  
String sProperty = "bytes="+nStartPos+"-"; Z-rHYfa4  
httpConnection.setRequestProperty("RANGE",sProperty); PuGc{kt  
Utility.log(sProperty); eaCh;IpIf  
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InputStream input = httpConnection.getInputStream(); _/@u[dWeL  
//logResponseHead(httpConnection); |Y]4PT#EE  
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byte[] b = new byte[1024]; pF
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int nRead; ><3!J+<?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v
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{ ZBl!7_[_  
nStartPos += fileAccessI.write(b,0,nRead); oeIza<:=R  
//if(nThreadID == 1) ~Rk~Zn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vOi4$I~CJ  
} g]E>e v{`  
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Utility.log("Thread " + nThreadID + " is over!"); iFkXt<_A  
bDownOver = true; X>4qL'b:z  
//nPos = fileAccessI.write (b,0,nRead); )HJ#|JpxC  
} Y]])Tq;h5  
catch(Exception e){e.printStackTrace ();} Xjs`iK=w  
} +jN%w{^=  
} b&\f 8xZ  
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8\B]!  
//打印回应的头信息 wC`+^>WFo  
public void logResponseHead(HttpURLConnection con) gvu1  
{ vj hh4$k  
for(int i=1;;i++) &$8YW]1M  
{ %8$ldNhV  
String header=con.getHeaderFieldKey(i); |cIv&\ x  
if(header!=null) g8L{xwx<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :oO ?A
 
Utility.log(header+" : "+con.getHeaderField(header)); ;?.w!|6  
else o#9Q   
break; Ge+T[  
}
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} TAp8x  
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public void splitterStop() :hFKmoy#  
{ RAB'%CY4  
bStop = true; G;Py%8  
} GvI8W)d3,R  
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} (Qf. S{;  
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/* "X,*VQl:  
**FileAccess.java P^[y~I#{  
*//文件访问(定位，写) V[2}  
package NetFox; e6gLYhf&  
import java.io.*; d3"QCl  
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public class FileAccessI implements Serializable{ U
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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
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RandomAccessFile oSavedFile; )=
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long nPos; ],s{%a5wC  
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public FileAccessI() throws IOException aUk]wiwIR9  
{ 7j8lhrM}^  
this("",0); 6uIgyO*;k  
} aM+Am,n`@  
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public FileAccessI(String sName,long nPos) throws IOException ,ygUy]  
{ 'P)c'uqd#  
oSavedFile = new RandomAccessFile(sName,"rw"); nh*6`5yj  
this.nPos = nPos; jss.j~
8  
oSavedFile.seek(nPos); L7]o^p{g}Q  
} "x3x$JQZy  
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public synchronized int write(byte[] b,int nStart,int nLen) [}!0PN?z~A  
{ +kN,OK~  
int n = -1; =0az5td  
try{ 5W0s9yD  
oSavedFile.write(b,nStart,nLen); Z/czAr@4  
n = nLen; u+^KP>rM(  
} +)LCYDRV7  
catch(IOException e) [*M':  
{ ,0c]/Sd*p  
e.printStackTrace (); k~F;G=
P  
} OG9 '[o`8  
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return n; 1'N<ITb  
} \SoT^PW  
@lWYc`>}  
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} D5!#c-Y-  
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--EDr>'D5P  
/* xS>vmnW  
**SiteInfoBean.java mfG m>U  
*/ 9c
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package NetFox; wX$|(Y}  
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public class SiteInfoBean { cUr!U\X[  
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private String sSiteURL; //Site's URL R$+p4@?S  
private String sFilePath; //Saved File's Path J.'%=q(Sb  
private String sFileName; //Saved File's Name *{P/3
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private int nSplitter; //Count of Splited Downloading File )ki Gk}2  
3H0B+F2XQ  
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public SiteInfoBean() K8Q3~bMf  
{//nSplitter的缺省值为5 XK\3"`kd  
//default value of nSplitter is 5 vK[%cA"  
this("","","",5); jFJ}sX9]  
} hO&_VCk  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PR]b]=  
{ reNf?7G+m  
sSiteURL= sURL; N#ZWW6  
sFilePath = sPath; zj(V\y&H  
sFileName = sName; -jy0Kl/p  
this.nSplitter = nSpiltter; KGcjZx04!  
".%d{z}vz  
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} k|\M(Z*(P  
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public String getSSiteURL() pu+Q3NfR  
{ f*B
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return sSiteURL; w]yVNB  
} R^$|D)(  
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public void setSSiteURL(String value) kaXq.  
{ -YAtM-VL  
sSiteURL = value; rv(?%h`  
} g27'il  
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public String getSFilePath() $\Y&2&
1s  
{ <JH,B91  
return sFilePath; uBa<5YDF  
} 4$[o;t>  
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public void setSFilePath(String value) M@{#yEP  
{ 5N;'CAk  
sFilePath = value; n)98NSVDbT  
} T"W<l4i-  
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public String getSFileName() P+}~6}wJE  
{ jh)@3c  
return sFileName; xF8n=Lc  
} DJL
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1wKXOy=v0  
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public void setSFileName(String value) o#e8 Piw  
{ 0DmA3  
sFileName = value; hj9TiH/+  
} At
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public int getNSplitter() G/<zd)  
{ QMsq4yJ)%  
return nSplitter; () _RLA  
} Giv,%3'  
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public void setNSplitter(int nCount) OL
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{ LJGpa)(  
nSplitter = nCount; 6M*z`B{hV  
} 1+;bd'Ie  
} nc k/Dw  
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/* UhDQl%&He  
**Utility.java 'K?h6?#  
*/ +Y sGH~jX  
package NetFox; 9efDM  
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public class Utility { SH{@yS[c!  
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public Utility() Q"XDxa'7"  
{ /:4J  
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} D$}8GYq  
rFg$7  
//线程睡眠 "[_j8,t`  
public static void sleep(int nSecond) *(OG+OkC  
{ ;'n%\*+fHH  
try{ \Ggh 95y  
Thread.sleep(nSecond); 2LtDS?)@  
} U
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catch(Exception e) eJ?o
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{ !<p,G`r  
e.printStackTrace (); ccag8LC  
} = j1Jl^[  
} k:Pn.<  
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//日志 Qo#]Lo> \g  
public static void log(String sMsg) 7S a9  
{ 
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System.err.println(sMsg); Jl~ *@0(  
} TJ"-cWpO1  
6m:$mhA5  
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public static void log(int sMsg) hC\ l \y  
{ z\]Z/Bz:6  
System.err.println(sMsg); k H.dtg_  
} ~7PD/dre  
} B)JMughq_  
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/* o}rG:rhIh  
**TestMethod.java LiG$M{0  
*/ |R}=HsYey  
package NetFox; d_!Z /M,  
(P|[<Sd  
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public class TestMethod { pe?)AiTZ:  
4?R979  
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public TestMethod() ix!xLm9\  
{ ///xx/weblogic60b2_win.exe dQ`Tt- n  
try{ +RooU?Aq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U^dfNi@q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]fM|cN8(zM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E5ce=$o  
fileFetch.start(); l 
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} xo[o^go  
catch(Exception e){e.printStackTrace ();} b84
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} &hYgu3O  
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 !VGG2N8  
public static void main(String[] args) 1/}H 0\9'  
{ ,2FK$:M\  
new TestMethod(); Z8SwW<{ $  
} | b'Ut)E  
} 6<lo0PQ"Z  
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