http断点续传简单实现（java)

/* BbXU|QtY  
**SiteFileFetch.java $d2kHT  
*/ yxG:\y b  
package NetFox; 8_<&f%
/  
import java.io.*; esh$*)1  
import java.net.*; u 5Eo  
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public class SiteFileFetch extends Thread { ovQS ET18b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N /sEec  
long[] nStartPos; //开始位置 O>SuZ>g+7  
long[] nEndPos; //结束位置 k(-Z@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CQBT::  
long nFileLength; //文件长度 $^vp'^uW>  
boolean bFirst = true; //是否第一次取文件 `i t+D  
boolean bStop = false; //停止标志 Z:UgozdC  
File tmpFile; //文件下载的临时信息 5?3Isw`v2  
DataOutputStream output; //输出到文件的输出流 @)OnIQN~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Tsm1C#6 Y*  
public SiteFileFetch(SiteInfoBean bean) throws IOException JNxW6 cK  
{ 2AXF$YjY
 
siteInfoBean = bean; QIij
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <TLGfA1bC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8S.')<-f  
if(tmpFile.exists ()) ~A[YnJYA#  
{ 8/Et&TJ`  
bFirst = false; 9Qt)m fqM  
read_nPos(); uQ
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} VD9 q5tt7  
else q)K-vt)98  
{ OH$F >wO  
nStartPos = new long[bean.getNSplitter()]; eW%L$I  
nEndPos = new long[bean.getNSplitter()]; bK$/,,0=X/  
} JHvFIo   
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} }.fL$,7a  
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public void run() <S\;k@f  
{ wUru1_zjO  
//获得文件长度 Ud>`@2  
//分割文件 ee&nU(pK  
//实例FileSplitterFetch $xRo<,OV+  
//启动FileSplitterFetch线程 ov\Ct%]  
//等待子线程返回 F-$Z,Q]S  
try{ 0M#N=%31  
if(bFirst) dr|| !{\  
{ YH<$ +U  
nFileLength = getFileSize(); 7XUhJN3n  
if(nFileLength == -1) VFilF<jvu  
{ f![xn2T  
System.err.println("File Length is not known!"); y!7B,  
} ?-pxte8  
else if(nFileLength == -2) Nl~Z,hT$*  
{ U/.w;DI
 
System.err.println("File is not access!"); !: m`9o8  
} "t5 +*  
else "2ZIoa!^  
{ qxf+#  
for(int i=0;i<nStartPos.length;i++) Q<RT12|`  
{ 8s QQK.N(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); **T:eI+  
} /Qr
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for(int i=0;i<nEndPos.length-1;i++) 'fS?xDs-v  
{ Rz`@N`U  
nEndPos = nStartPos[i+1]; v\fzO#vj  
} gXq!a|eH  
nEndPos[nEndPos.length-1] = nFileLength; /lf\ E=  
} "%:7j!#X|I  
} g/OI|1a  
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Z -pyFK\  
//启动子线程 :6 Uk)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !(B_EM  
for(int i=0;i<nStartPos.length;i++) 536^PcJlN  
{ S8*^ss>?^R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5+y@ ]5&g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8BHL  
nStartPos,nEndPos,i); F`fGz)Mk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,"@w>WL<9  
fileSplitterFetch.start(); Vn)%C_-]A  
} i%xI9BO9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MPjr_yc]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IgLVn<5n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nped  
nEndPos = " + nFileLength); lN);~|IOv7  
// fileSplitterFetch[nPos.length-1].start(); ?$<SCN=  
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jVX._bEGX  
//等待子线程结束 s0gJ f[  
//int count = 0; n)tU9@4Np  
//是否结束while循环 B:e.gtM5  
boolean breakWhile = false; vAi"$e  
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86
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while(!bStop) ''_,S,.a20  
{ lx
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write_nPos(); "=9-i-K9B  
Utility.sleep(500); nARxn#<+  
breakWhile = true; XQK^$Iq]V  
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for(int i=0;i<nStartPos.length;i++) 9Kc0&?q@D  
{ +VwV5iy[`  
if(!fileSplitterFetch.bDownOver) h{\t*U54'  
{ D`V6&_.p  
breakWhile = false; +z+F-  
break; et@">D%;]  
} '^hsH1  
} :]EP@.(  
if(breakWhile) =\M)6"}y}  
break; 3b#L17D3_  
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aZP2
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//count++; kl| g  
//if(count>4) 3*G5F}7%=  
// siteStop(); jz|
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} Cm^Ylp  
HB%K|&!+  
7@JjjV  
System.err.println("文件下载结束！"); 6j_ 678  
} ol50d73B  
catch(Exception e){e.printStackTrace ();} aXC!t  
} B@d1xjp)']  
M/*Bh,M`  
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//获得文件长度 iM8sX B  
public long getFileSize() Hyf"iYv+  
{ {JXf*IJ  
int nFileLength = -1; kl=xu3j  
try{ D2{L=  
URL url = new URL(siteInfoBean.getSSiteURL()); 2v4
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :RHm*vt  
httpConnection.setRequestProperty("User-Agent","NetFox"); p*Xix%#6  
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int responseCode=httpConnection.getResponseCode(); en%J!<&W{K  
if(responseCode>=400) >#INEO  
{ 2bkJ /u`i  
processErrorCode(responseCode); ;r3}g"D@  
return -2; //-2 represent access is error )Q~C4C-j  
} xF&6e&nv  
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: g5(HH  
String sHeader; N=q#y@L  
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{ E^U6@  
for(int i=1;;i++) oI*d/*  
{ *u}'}jC1X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '|_/lz$h  
//Utility.log(in.readLine()); MBlBMUJk  
sHeader=httpConnection.getHeaderFieldKey(i); 2R\+}  
if(sHeader!=null) 7"#f!.E  
{ d)\2U{  
if(sHeader.equals("Content-Length")) ,'u*ZB;  
{ >[EBpYi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >G&^?5  
break; Vn^)  
} Zd$JW=KR]l  
} Z4#v~!  
else S.1(3j*  
break; 7H4L-J3  
} P:qz2Hw  
} nX)f'[ 7  
catch(IOException e){e.printStackTrace ();} g@Ld"5$^2  
catch(Exception e){e.printStackTrace ();} &Bm&i.r  
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Utility.log(nFileLength); qIz}$%!A  
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return nFileLength; H$Kw=kMw  
} C!5I?z&  
MF^_Z3GS'  
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//保存下载信息（文件指针位置） j|mv+O  
private void write_nPos() !3@{U@*Z]  
{ v$;@0t:;#  
try{ Je 31".  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lY8`5Uz  
output.writeInt(nStartPos.length); g>yry}>04%  
for(int i=0;i<nStartPos.length;i++) cv]BV>=E  
{ Ch t%uzb,  
// output.writeLong(nPos); b4)k&*dfR  
output.writeLong(fileSplitterFetch.nStartPos); O:._
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output.writeLong(fileSplitterFetch.nEndPos); )nOE8y/  
} ctHEEFWm  
output.close(); <<sE`>)  
} #jm@N7OZ  
catch(IOException e){e.printStackTrace ();} m<3w^mww  
catch(Exception e){e.printStackTrace ();} x)_r@l`$ix  
} []gRfM]$&  
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//读取保存的下载信息（文件指针位置） ' Rc#^U*n  
private void read_nPos() or!!s 5[d  
{ e}e6r3faz  
try{ p31oL{D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WFem#hq  
int nCount = input.readInt(); 6}#"qqnx  
nStartPos = new long[nCount]; 8
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nEndPos = new long[nCount]; uFo/s&6K  
for(int i=0;i<nStartPos.length;i++) n[P\*S  
{ `BjR.xMv  
nStartPos = input.readLong(); U<rI!!#9  
nEndPos = input.readLong(); Pj&A=  
} IJ_ m  
input.close(); m]P/if7  
} X$^JAZ09  
catch(IOException e){e.printStackTrace ();} 6OtVaT=}<O  
catch(Exception e){e.printStackTrace ();} {E~Xd  
} /tZ0 |B(  
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private void processErrorCode(int nErrorCode) ;{gT=,KQ`  
{ 3ev-Iqz  
System.err.println("Error Code : " + nErrorCode); (hN?:q?'  
} #kci=2q_  
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$w/E9EJ)3A  
//停止文件下载 mX;H((  
public void siteStop() R$d7\nBG  
{ |IN[uQ  
bStop = true; 1'fb @vO  
for(int i=0;i<nStartPos.length;i++) QD4:W"i  
fileSplitterFetch.splitterStop(); Du!._  
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} R5kH0{zM  
} n"Z |e tZ4  
//负责部分文件的抓取 Y{+3}drJE  
**FileSplitterFetch.java &a6,ln:P  
*/ ?Oc -aa  
package NetFox; RG1\=J$:E  
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import java.io.*; x*q35K^PE  
import java.net.*; V:Mk)8Gf|  
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public class FileSplitterFetch extends Thread { bLlH//ZRH  
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F 7LiG9H6`  
String sURL; //File URL t^U^Tr  
long nStartPos; //File Snippet Start Position SiTe
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long nEndPos; //File Snippet End Position R6P\T\~E  
int nThreadID; //Thread's ID BIj   
boolean bDownOver = false; //Downing is over c\K<sM{  
boolean bStop = false; //Stop identical 12OlrU  
FileAccessI fileAccessI = null; //File Access interface ShGp^xVj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4Jykos2  
{ QNg\4%  
this.sURL = sURL;  KGT3|)QN  
this.nStartPos = nStart; `eD1|Go9  
this.nEndPos = nEnd; !8/gL  
nThreadID = id; 6$RpV'xz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !y[3]8Xxv  
} u"Y]P*[k  
8,*3zVk-  
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public void run() -?fR|[\[U  
{ g~)3WfC$[  
while(nStartPos < nEndPos && !bStop) &*gbK6JB  
{ y-a|Lu*  
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try{ 5@f5S0
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URL url = new URL(sURL); I`^YAbnb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }-nU3{1  
httpConnection.setRequestProperty("User-Agent","NetFox"); @GeHWv  
String sProperty = "bytes="+nStartPos+"-"; Ep ">v>"  
httpConnection.setRequestProperty("RANGE",sProperty); bV6V02RF  
Utility.log(sProperty); {7X~!e|w  
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InputStream input = httpConnection.getInputStream(); _#pnjo  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; ~Z/7pP+  
int nRead; wS$46M<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >nM%p4E  
{ UA(;fZ@  
nStartPos += fileAccessI.write(b,0,nRead); 28UVDG1?  
//if(nThreadID == 1) mi^
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  S^j,f'2  
} (U9a@1  
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Utility.log("Thread " + nThreadID + " is over!"); iN)af5)[^  
bDownOver = true; ?,XC=}  
//nPos = fileAccessI.write (b,0,nRead); S#2[%o  
} P%)b+H{$h  
catch(Exception e){e.printStackTrace ();} yL&/m~{s  
} %?=)!;[  
} f#OQ (WTJE  
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{ERjeuDm]  
//打印回应的头信息 e{!vNJ0`  
public void logResponseHead(HttpURLConnection con) H(> M   
{  Zi4d]  
for(int i=1;;i++) R|Y~u*D  
{ U ~1SF  
String header=con.getHeaderFieldKey(i); 8&.-]{Z  
if(header!=null) 7>,rvW:]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1VLLo~L%  
Utility.log(header+" : "+con.getHeaderField(header)); .'lN4x  
else &HL{LnLP@/  
break; Ef,Cd[]b  
} ~ 5"J(  
} [hHG.  
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j-32S!  
public void splitterStop() 6?o>{e7n^  
{ Funj!x'uE  
bStop = true; 6K 4+0xXv  
} YoAg  
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} ;rHz;]si  
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/
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/* S
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**FileAccess.java H\+-cvl  
*//文件访问(定位，写) !01i%W'  
package NetFox; !<r8~A3!(  
import java.io.*; [H^ X"D  
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public class FileAccessI implements Serializable{ l%<c6;  
E}$V2ha0zu  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z,aGtJ.a'9  
RandomAccessFile oSavedFile; %U?)?iZdL  
long nPos; 7\%$>< K  
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public FileAccessI() throws IOException CZ tiWZ  
{ M/B/b<['  
this("",0); &+- e  
} v#Upw\!  
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public FileAccessI(String sName,long nPos) throws IOException kqf8=y  
{ $1e pf  
oSavedFile = new RandomAccessFile(sName,"rw"); 6~@5X}^<0  
this.nPos = nPos; os**hFPk;1  
oSavedFile.seek(nPos); O`(U
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} EfKntrom[  
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} 07r  
public synchronized int write(byte[] b,int nStart,int nLen) ? s4oDi|:  
{ (8x gn  
int n = -1; U>A6eWhH  
try{ ImHU:iR[J-  
oSavedFile.write(b,nStart,nLen); jL_5]pzJ  
n = nLen; a8QfkOe  
} VDn:SGj5  
catch(IOException e) )7AM3%z1?  
{ <kbnu7?a*  
e.printStackTrace (); q+%!<]7X  
} MYx88y  
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return n; 3:AU:  
} #Fzb8Yo  
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} ^ZVOql&  
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/* w4A#>;Qu*  
**SiteInfoBean.java rKIRNc#d  
*/ 7LdzZS0OM  
package NetFox; fTgbF{?xh  
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'!@A}&]  
public class SiteInfoBean { 8Fx]koP.  
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private String sSiteURL; //Site's URL ?Cc :)  
private String sFilePath; //Saved File's Path }.t^D|  
private String sFileName; //Saved File's Name ^O \q3HA_4  
private int nSplitter; //Count of Splited Downloading File O{BW;Deo  
T 9MzUV&  
#JFYws  
public SiteInfoBean() DaCblX  
{//nSplitter的缺省值为5 0%H24N 9.  
//default value of nSplitter is 5 R8ZD#,;  
this("","","",5); U!NI_uk  
} kQ[Jo%YT?E  
2-7Z(7G{ F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N'a?wBBR  
{ tWX7dspx/  
sSiteURL= sURL; wPQ&Di*X}  
sFilePath = sPath; ^XNw$@&',  
sFileName = sName; -;ER`Jqs,  
this.nSplitter = nSpiltter; z L8J`W  
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e# <4/FR  
} B,MQ.|s[  
P eHW[\)  
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public String getSSiteURL() AoU_;B\b%  
{ q#m!/wod  
return sSiteURL; J@gm@ jLc  
} "u5KbJW  
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public void setSSiteURL(String value) AHWh}~Yi  
{ p9Z].5Pd"  
sSiteURL = value; BjB&[5?z  
} ,3k@L\$.x  
0}D-KvjyP  
HoL~j({  
public String getSFilePath() []=_<]{   
{ T;J7+0  
return sFilePath; $)f"K  
} l-
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3l$E8?[Zwi  
public void setSFilePath(String value) y,V6h*x2  
{ 9u?Eb~#$  
sFilePath = value; VZTmzIk.Y  
} R)Q/Ff@o0  
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fw:7U%MGv  
public String getSFileName() |SxMN%M
!  
{ },v&rkwR  
return sFileName; Enu!u~1]F  
} 'H!V54 \j  
v`
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public void setSFileName(String value) HmW=t}!  
{ brj[c>
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sFileName = value; aj?2jU~Pq  
} *|^,DGfQ6  
:q(D(mK  
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public int getNSplitter() 'OG{*TDPu  
{ JBvk)
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return nSplitter; &jt02+Hj'  
} 1*L^^%w  
3`xsK[  
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public void setNSplitter(int nCount) 3Fgz)*Gu]  
{ )U]:
9)  
nSplitter = nCount; %n4@[fG%K  
} &{BBxv)y  
} ?THa5%8f  
>n1h^AW  
[#IBYJ.6  
/* [;*\P\Xih  
**Utility.java 40R"^*  
*/ fjcr<&{:  
package NetFox; Bpm,mp4g\#  
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public class Utility { p?}f|mQS)  
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public Utility() )sRN
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{ (v]P<3%  
uW ) \,  
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} U7jhV,gO4  
eU`
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//线程睡眠 ]F !'M  
public static void sleep(int nSecond) 3xP~~j;7  
{ 
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o;  
try{ DQ%`v=  
Thread.sleep(nSecond); c!.=%QY
 
} K4_~ruhr  
catch(Exception e) N`f!D>b:dn  
{ c$.
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e.printStackTrace (); h|K\z{ A  
} *U:VM'a  
} NS h%t+XU]  
3T"2S[gT  
//日志 Pa3{Ds  
public static void log(String sMsg) I+*osk  
{ 0K&_D)  
System.err.println(sMsg); ejP,29  
} BHEs+e0  
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d
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public static void log(int sMsg) 3(aRs?/O  
{ MgHOj  
System.err.println(sMsg); D% oueW  
} bh{E&1sLh  
} <_=JMA5  
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/* #c6ui0E%;t  
**TestMethod.java lq~GcM  
*/ T@B"BoKU  
package NetFox; 7We?P,A\;  
f$Gr`d  
JtSuD>H`"  
public class TestMethod { c]GQU  
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public TestMethod() u wH)$Pl  
{ ///xx/weblogic60b2_win.exe c'"#q)  
try{ qsD?dHi7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !>CE(;E>z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V+Y|4Y&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R 4DM_u  
fileFetch.start(); d&/^34gn  
} )C'G2RV  
catch(Exception e){e.printStackTrace ();} ` 52%XI  
=9kj? u~  
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} OD{5m(JwL  
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public static void main(String[] args) ?lu_}t]  
{ ,lrYl!,  
new TestMethod(); kEp.0wL'  
} X(4s;i  
} <ED8"~_  
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