http断点续传简单实现（java)

/* Qb't*2c%  
**SiteFileFetch.java IPR tm!  
*/ >-@ U_p  
package NetFox; zMYd|2bc  
import java.io.*; km\ld&d]$  
import java.net.*; _=*tDa  
_|  
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public class SiteFileFetch extends Thread { iqednk%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean C9F+e  
long[] nStartPos; //开始位置 ZutB_uW  
long[] nEndPos; //结束位置 n1>,#|#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lkl|4L  
long nFileLength; //文件长度 8q?;Hg  
boolean bFirst = true; //是否第一次取文件 MFH"$t+  
boolean bStop = false; //停止标志 U7"BlT!V\  
File tmpFile; //文件下载的临时信息 /"Yx@n  
DataOutputStream output; //输出到文件的输出流 2yQ}Lxr(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mheU#&|  
public SiteFileFetch(SiteInfoBean bean) throws IOException R@<_Hb;Aeb  
{ =`1m-   
siteInfoBean = bean; <m>l-]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Itr7lv'5xx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fNqmTRu  
if(tmpFile.exists ()) .'S^&M/$  
{ ?cO8'4 bq  
bFirst = false; <4Q12:  
read_nPos(); [{@zb-h  
} 3u4*ofjE5  
else Jh\:X<q  
{ L-z;:Ztk  
nStartPos = new long[bean.getNSplitter()]; L%WME8PB  
nEndPos = new long[bean.getNSplitter()]; }
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} b4v(k(<  
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} U=kx`j>  
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public void run() Har~MO?A  
{ e"fN~`NhY  
//获得文件长度 rBD(2M  
//分割文件 jC%35bi  
//实例FileSplitterFetch PFS;/   
//启动FileSplitterFetch线程 2e9jo,i  
//等待子线程返回 yuHZ&e  
try{ `/O`OrZ1K  
if(bFirst) s.yq}Q  
{ i<T P:  
nFileLength = getFileSize(); }bf=Ntk  
if(nFileLength == -1) ]*N:;J  
{ :zdEq")v  
System.err.println("File Length is not known!"); 0n:?sFY>  
} #bT8QbJ(  
else if(nFileLength == -2) M{?.hq  
{ w66v\x~  
System.err.println("File is not access!"); ;gDMl57PQ.  
} "z^(dF|  
else mC i[Ps  
{ $Y6I_U  
for(int i=0;i<nStartPos.length;i++) U4>O\sU  
{ Ia629gi5s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q!6|lZB3  
} l~bKBz  
for(int i=0;i<nEndPos.length-1;i++) g(aZT#ii=  
{ c$0_R;4/  
nEndPos = nStartPos[i+1]; X8/Tl\c  
} R?cUy8?'S  
nEndPos[nEndPos.length-1] = nFileLength; cjuZBFl  
} VFv9Q2/.  
} s%~L4Wmcq  
B?LXI3sQZ  
\6sqyWI %  
//启动子线程 c=6ahX}d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %*lp< D  
for(int i=0;i<nStartPos.length;i++) #(C/Cx54  
{ 3{"byfO#%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [,=d7*b(l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $5,~JYcb  
nStartPos,nEndPos,i); F|9+ +)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -hWC_X:9jP  
fileSplitterFetch.start(); $>*Yhz `  
} n~tqO!q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B2 c@kru  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @F>F#-2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "O*x' XhN  
nEndPos = " + nFileLength); z}ElpT[(;  
// fileSplitterFetch[nPos.length-1].start(); ak;6z]f8[  
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3HZ~.  
//等待子线程结束 Yi(1^'Bi  
//int count = 0; Z!6UW:&~7  
//是否结束while循环 @%1IkvJV  
boolean breakWhile = false; ["y6b*;x  
ju|]Qlek  
2j&v;dmh<  
while(!bStop) whye)w  
{ BkawL,  
write_nPos(); Fj1NN  
Utility.sleep(500);
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breakWhile = true; prtK:eGe2  
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for(int i=0;i<nStartPos.length;i++) *6Q|}b[qcD  
{ <8!  Tq  
if(!fileSplitterFetch.bDownOver) mT@nn,  
{ yb2}_k.JG  
breakWhile = false; ]kD"&&HV  
break; 0K`[,
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} tIc 7:th  
} nirDMw[  
if(breakWhile) +bA%  
break; N\NyXh$  
;),"M{"v  
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//count++; ;f1qLI  
//if(count>4) f>2MI4nMG  
// siteStop(); *$,:m  
} >Lft9e   
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i
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System.err.println("文件下载结束！"); ALc`t(..}A  
} 3B0PGvCI1  
catch(Exception e){e.printStackTrace ();} |kJ%`j(7R  
} #wY0D_3@1  
;Hmp f0$  
.iG&Lw\,  
//获得文件长度 ICC%,$C~l  
public long getFileSize() 'n;OB4  
{ Y}s@WJ  
int nFileLength = -1; h6~$/`&]b  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); <\ `$Jx#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -' g*^  
httpConnection.setRequestProperty("User-Agent","NetFox"); FAsFjRS  
g[H',)A)  
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int responseCode=httpConnection.getResponseCode(); Wp)*Mbq@  
if(responseCode>=400) Q GZyL)Q  
{ EV pi^>M  
processErrorCode(responseCode); C;+h.;}<D  
return -2; //-2 represent access is error ?W>qUr
Z  
} 1rKy@9  
#Tw@wfaq)  
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String sHeader; J(DN!  
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for(int i=1;;i++) /!h;c$  
{ ;oZ)Wt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6AG`&'"  
//Utility.log(in.readLine()); #7ohQrP  
sHeader=httpConnection.getHeaderFieldKey(i); 3?2 FP|G8  
if(sHeader!=null) |L2SFB?d=  
{ g0R~&AN!g  
if(sHeader.equals("Content-Length")) yY?b.ty  
{ Xtt?]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7d LuX   
break; {9UEq0  
} YIw1  
} kuyjnSo9i  
else hGpv2>M  
break; %_!bRo  
} Cj~'Lhmv'T  
} 7}M2bH} \K  
catch(IOException e){e.printStackTrace ();} 9IX/wm"  
catch(Exception e){e.printStackTrace ();} /c uLc^(X  
i3rH'B-I.  
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Utility.log(nFileLength); D$t k<{)oB  
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return nFileLength; BNL;Biyt7  
} ty8v 6J#  
,^uEYT}j  
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//保存下载信息（文件指针位置） hCC<?5q  
private void write_nPos() : |>Gc39`t  
{ @`gk|W3  
try{ C.FI~Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zux{S;:?  
output.writeInt(nStartPos.length); nDHTV!]<  
for(int i=0;i<nStartPos.length;i++) 
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{ Z<vKQ4G  
// output.writeLong(nPos); 3\XU_Xs(]  
output.writeLong(fileSplitterFetch.nStartPos); 2nR[Xh?L  
output.writeLong(fileSplitterFetch.nEndPos); r,h%[JKM  
} Ft&]7dT{W  
output.close(); m6w].-D8  
} 9b9$GyI  
catch(IOException e){e.printStackTrace ();} Y\No4w ^|d  
catch(Exception e){e.printStackTrace ();} T\D}kQM  
} 7eAX*Kgt<_  
~vyf4TF<#  
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//读取保存的下载信息（文件指针位置） ]x(!&y:h  
private void read_nPos() i%0ur}p  
{ Sy0$z39  
try{ =w{Z@S(ukz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5fd]v<  
int nCount = input.readInt(); %-1O.Q|f  
nStartPos = new long[nCount]; 7t0er'VC  
nEndPos = new long[nCount]; kZmpu?P  
for(int i=0;i<nStartPos.length;i++) ZZzMO6US0  
{ |R/%D%_g  
nStartPos = input.readLong(); *^VRGfpb
 
nEndPos = input.readLong(); |l]XpWV  
} ;z$(nhJ  
input.close(); v0H@Eg_  
} W*),y:  
catch(IOException e){e.printStackTrace ();} ,)Znb=  
catch(Exception e){e.printStackTrace ();} `xqr{lhL  
} ',JinE95  
n'E(y)9|  
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private void processErrorCode(int nErrorCode) 4R1<nZ"e~  
{ 0dE@c./R i  
System.err.println("Error Code : " + nErrorCode); @1o/0y"  
} 8 Hg+H=?  
w"-Lc4t+  
,9zjFI  
//停止文件下载 K8GP@yD]M  
public void siteStop() +0nJ  
{ "K6&dk jY  
bStop = true; z[L8
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for(int i=0;i<nStartPos.length;i++) !>..Q)z  
fileSplitterFetch.splitterStop(); 7:plQ!7^  
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} X86O lP)eX  
} 0zmE>/O+
 
//负责部分文件的抓取 'YmIKIw  
**FileSplitterFetch.java I9_RlAd  
*/ Lt?lv2k=L  
package NetFox; m Bu  
iT3BF"ZqBO  
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import java.io.*; M?Y;a5{  
import java.net.*; [1g8*j~L  
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public class FileSplitterFetch extends Thread { le|~BG hL  
?+@n3]`0  
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String sURL; //File URL jS]ru-5.  
long nStartPos; //File Snippet Start Position >JHryS.j$4  
long nEndPos; //File Snippet End Position EN<F# Y3E  
int nThreadID; //Thread's ID {f3YsM;]C  
boolean bDownOver = false; //Downing is over fIn
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boolean bStop = false; //Stop identical Gw/Pk4R  
FileAccessI fileAccessI = null; //File Access interface s4X>.ToMC  
8]M;T>n[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~7*.6YnI  
{ ,1~"eGl!  
this.sURL = sURL; Y2N>HK0  
this.nStartPos = nStart; ! `  
this.nEndPos = nEnd; $v4.sl:x  
nThreadID = id; "jeb%k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dyz2.ZY~2  
} R1adWBD>  
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public void run() Z3"%`*Tmq-  
{ g/ T   
while(nStartPos < nEndPos && !bStop) ,k +IPkN+  
{ 'nzg6^I7g  
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b z`+k,*  
try{ \pa"%c)  
URL url = new URL(sURL); :%lTU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I&D5;8  
httpConnection.setRequestProperty("User-Agent","NetFox"); f%is~e~wc  
String sProperty = "bytes="+nStartPos+"-"; ity & v9  
httpConnection.setRequestProperty("RANGE",sProperty); e>} s;H,  
Utility.log(sProperty); b1(T4w6  
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InputStream input = httpConnection.getInputStream(); QyEnpZ8?a  
//logResponseHead(httpConnection); 5bRJS70M  
3
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byte[] b = new byte[1024]; FvaUsOy
"  
int nRead; JrJo|0Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
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{ u(z$fG:g  
nStartPos += fileAccessI.write(b,0,nRead); lEH
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//if(nThreadID == 1) Z+*9#!?J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kjTduZ/3"  
} {BP{C=p  
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52@C9Q,  
Utility.log("Thread " + nThreadID + " is over!"); &W|[r(  
bDownOver = true; M1k{t%M+S  
//nPos = fileAccessI.write (b,0,nRead); :NhO2L  
} y*4=c_Z  
catch(Exception e){e.printStackTrace ();} @CpfP;*{w`  
} z 9vInf@M  
} `LrHKb aP  
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4V{:uuI;f  
//打印回应的头信息 K?6jXJseb  
public void logResponseHead(HttpURLConnection con) / kF)  
{ j
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for(int i=1;;i++) 35h8
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{ AuvkecuIh  
String header=con.getHeaderFieldKey(i); FI)17i$  
if(header!=null) BOX{]EOj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hwPw]Ln/  
Utility.log(header+" : "+con.getHeaderField(header)); h){0rX@:&  
else .UQzPnK  
break; Jz\%%C  
} &yct!YOB2  
} #Vnkvvv  
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public void splitterStop() (9tX5$e6N  
{ oTEL?hw5  
bStop = true; .r|tSfm6  
} P9/q|>F  
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} 2Sle#nw3  
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/* kGH}[w  
**FileAccess.java 7!evm;A  
*//文件访问(定位，写) cb@?}(aFl  
package NetFox; d8DV[{^  
import java.io.*; eln)BW#  
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public class FileAccessI implements Serializable{ =
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({ +!`}GY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 To\QjP-  
RandomAccessFile oSavedFile; cF\;_0u  
long nPos; nB_?ckj,  
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public FileAccessI() throws IOException $6#CqWhI  
{ ;/bewivNJ  
this("",0); ,A9]CQ  
} 2\)xpOj  
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public FileAccessI(String sName,long nPos) throws IOException ):P?  
{ 'Y?"{HZ  
oSavedFile = new RandomAccessFile(sName,"rw"); ~]nRV *^  
this.nPos = nPos; a`wc\T^
 
oSavedFile.seek(nPos); Av$]|b  
} /~DI 6g  
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7( #:GD  
public synchronized int write(byte[] b,int nStart,int nLen) ]v?@g:iE  
{ ?#Ge.D~u  
int n = -1; G5{T5#  
try{ %3s1z<;R[S  
oSavedFile.write(b,nStart,nLen); .7O*pJ2(H  
n = nLen; 4M^=nae  
} We)xB  
catch(IOException e) q~rEq%tk  
{ !'Ak&j1:`  
e.printStackTrace (); [.K1iZyTi  
} %Wg'i!?cB  
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return n; ;$HftG>B  
} K:J3Z5"  
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} /pm]BC  
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/* y~(h>gi,x  
**SiteInfoBean.java =NpYFKmMhV  
*/ ht|z<XJ  
package NetFox; mD/9J5:  
Ltv]pH}YN  
 vx\r!]  
public class SiteInfoBean { w?3p';C  
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-N6f1>}pE  
private String sSiteURL; //Site's URL K'55O&2  
private String sFilePath; //Saved File's Path LI'6R=  
private String sFileName; //Saved File's Name H[m:0eF'5  
private int nSplitter; //Count of Splited Downloading File s:?

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GC<l#3+  
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public SiteInfoBean() B|Du@^$  
{//nSplitter的缺省值为5 i
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//default value of nSplitter is 5 Ac96 [  
this("","","",5); =MSr/O2  
} ?:pP8/y  
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t

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ICpAt~3[M  
{ 7z/|\D_{  
sSiteURL= sURL; 5:\},n+VE  
sFilePath = sPath; %]Fd[pzF  
sFileName = sName; >i_2OV  
this.nSplitter = nSpiltter; &[_g6OL  
Z.c'Hs+;  
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} yu;+o3WlK  
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public String getSSiteURL() pqk?|BvpK_  
{ pyH:#5  
return sSiteURL; vmi+_]  
} 5k!g%sZ  

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} bQ  
public void setSSiteURL(String value) ht7l- AK  
{ ATJWO1CtB  
sSiteURL = value; zxJ]"N  
} yaD~1"GA'O  
%9w::hav  
b+,';bW  
public String getSFilePath() rEv@YD   
{ VkvB<3  
return sFilePath; 9K
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} 
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public void setSFilePath(String value) 6
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{ 11TL~xFh  
sFilePath = value; ^]7}YF2|  
} ao%NK<Lt  
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ahuGq'  
public String getSFileName() S)lkz'tdk  
{ &atu
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return sFileName; esHg'8?U  
} !LggIk1  
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public void setSFileName(String value) G.rrv  
{ yXz*5W_0D  
sFileName = value; G]D+Sl4<7i  
} %{ABaeb]  
^X0P'l&D2  
4^TG>j?M  
public int getNSplitter() Ge2q%  
{ ozAS[B6  
return nSplitter; }x@2]juJ  
} i'4B3  
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vu|
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public void setNSplitter(int nCount) Px$/ _`H  
{ 8C[C{qOJ  
nSplitter = nCount; EKA#|^Q:NX  
} #OIcLEn%  
} `!XY]PI+e  
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>*]Hq.&8  
/* /s?r`'j[  
**Utility.java UF?H>Y&  
*/ C 'v+f=  
package NetFox; 9S-Z&2L  
=+ytTQc*ot  
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public class Utility { AmaT0tzJC  
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public Utility() WX=Jl<  
{ "5-^l.CKH  
e<
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} fIj|4a+  
4kG,*3&2  
//线程睡眠 86(I^=  
public static void sleep(int nSecond) n;(\5{a  
{ R#2t)y  
try{ F{EnOr`,m=  
Thread.sleep(nSecond); j:k[90  
} Kz>3 ic$I  
catch(Exception e) 6b+b/>G0  
{ 2ggdWg7
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e.printStackTrace (); E0u~i59Z  
} jgbLN/_{  
} CPP` qt%f  
-sw  .  
//日志 ANJ$'3tg  
public static void log(String sMsg) VCn{mp*h  
{ nX(+s*Y+w  
System.err.println(sMsg); )+}]+xRWGj  
} NXNY"r7~  
PIH*Rw*GKZ  
P^w
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public static void log(int sMsg) Q.]}]QE   
{ sYjpU  
System.err.println(sMsg); f2^r[kPX"  
} DTaN"{  
} D+]a.& {p  
VwOW=4`6  
3=Cc.a/3  
/* x9;gT&@H  
**TestMethod.java O)ME"@r@:  
*/ EX?MA6U  
package NetFox; |P -8HlOr  
]@uE#a:[  
NR -!VJQ  
public class TestMethod { 7N:Y?Hi\  
MxY/`9>E|+  
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public TestMethod() &4b&X0pU  
{ ///xx/weblogic60b2_win.exe \8<BLmf4U  
try{ 0KGY\,ae:;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4?-.ZUT-1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,Fi>p0bz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N5i+3&  
fileFetch.start(); P@,nA41,j  
} ``OD.aY^s  
catch(Exception e){e.printStackTrace ();} !<SA6m#  
'ow.=1N-
 
\ gLHi~  
} Zf'TJ`S  
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public static void main(String[] args) ;_^fk&+  
{ xfb]b2  
new TestMethod(); e46/{4F,  
} Nk
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} nS&3?lx9_  
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