http断点续传简单实现（java)

/* N$Gx$u3Cd  
**SiteFileFetch.java 1{o CMq/v  
*/ H=X>o.iVqi  
package NetFox; VmBLNM?  
import java.io.*; Uj k``;  
import java.net.*; 51x^gX|  
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public class SiteFileFetch extends Thread { #l;Ekjfz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 _nx|ZJ  
long[] nEndPos; //结束位置 L@a-"(TN+
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CdZ;ZR  
long nFileLength; //文件长度 _rs#h)  
boolean bFirst = true; //是否第一次取文件 ACyQsmqm:  
boolean bStop = false; //停止标志 GrM~%ng  
File tmpFile; //文件下载的临时信息 2vWkAC;   
DataOutputStream output; //输出到文件的输出流 r`<evwIe  
}ZYK3F  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ni%^w(J3Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException t9K.Jc0  
{ zLxWyPM0;  
siteInfoBean = bean; H>DJ-lG(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^f`#8G7(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -\NB*|9m|  
if(tmpFile.exists ()) ^<% w'*gR  
{ ?: meix  
bFirst = false; DdSUB  
read_nPos(); B=Zo0p^  
} l^Lg"m2  
else 1H[lf B  
{ /`s^.Xh  
nStartPos = new long[bean.getNSplitter()]; p:4vjh=1h  
nEndPos = new long[bean.getNSplitter()]; zkd#vAY(A  
} RMi 2Ip  
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} -%t0'cKn,  
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public void run() Z].>U!7W  
{ 2l!"OiB.P  
//获得文件长度 sztnRX_  
//分割文件 N%?o-IY  
//实例FileSplitterFetch t]@Zd*  
//启动FileSplitterFetch线程 R]V`t^1  
//等待子线程返回 A?7%q^;E  
try{ d&ZwVF!  
if(bFirst) VJ$C)0xQA  
{ $PTedJ}*Y  
nFileLength = getFileSize(); /=3g-$o{`  
if(nFileLength == -1) O]PfQ  
{ _ssHRbE  
System.err.println("File Length is not known!"); <wSmfg,yF  
} .K7A!;  
else if(nFileLength == -2) h)<42Y  
{ Vm.u3KE  
System.err.println("File is not access!"); W
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} BF_k~  
else _*;cwMne-  
{ UwM}!K7)G  
for(int i=0;i<nStartPos.length;i++) z)]EB6uRg  
{ Q3/q%#q>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tL
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} GqAedz;.  
for(int i=0;i<nEndPos.length-1;i++) yNT2kB'  
{ (dT!u8Oe  
nEndPos = nStartPos[i+1]; i;tA<-$-  
} pIrAGA;  
nEndPos[nEndPos.length-1] = nFileLength; *K98z ?  
} 8bysg9H0  
} QO?ha'Sl  
>3kR~:;  
L.Lt9W2fi  
//启动子线程 @t2 Q5c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d,
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for(int i=0;i<nStartPos.length;i++) y$&a(S]  
{ y-@!, @e
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E:o:)h?$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A,og9<+j-  
nStartPos,nEndPos,i); I/>IB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nb8<8O ^  
fileSplitterFetch.start(); f|G7L5-  
} mQvKreo~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YH[_0!JY^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2(rZ@Wl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `MwQ6%lf  
nEndPos = " + nFileLength); =%u|8Ea*`  
// fileSplitterFetch[nPos.length-1].start(); hHg gH4T  
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b mm@oi  
//等待子线程结束 FezW/+D  
//int count = 0; qN0#=X  
//是否结束while循环 |)4$\<d  
boolean breakWhile = false; 8k1r|s@d  
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while(!bStop) t?
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{ _%2Umy|  
write_nPos(); ^sOm7S{  
Utility.sleep(500); 0V#t ;`Q3  
breakWhile = true; mc+wRx  
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for(int i=0;i<nStartPos.length;i++) }>w  
{ 5Hm!
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if(!fileSplitterFetch.bDownOver) D+)=bPMe  
{ |Hm'.-   
breakWhile = false; UjDF  
break; u#M)i30j  
} s4gNS eA  
} r^E]GDz  
if(breakWhile) 9sCk\`n  
break; Qkib;\2  
;F""}wzn  
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//count++; 9f^PR|F  
//if(count>4) BR^J y<^F'  
// siteStop(); 6XAr8mw9  
} 9xQ8`7  
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hcgc =$^  
System.err.println("文件下载结束！"); @,4%8E5  
} IOkC[([  
catch(Exception e){e.printStackTrace ();} ^CPfo/!  
}  ;Zq~w
 
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//获得文件长度 8}{o2r@  
public long getFileSize() yJ8}*Gj&  
{ 3> #mO}\  
int nFileLength = -1; P"x-7>c>Y  
try{ |NU0tct^  
URL url = new URL(siteInfoBean.getSSiteURL()); R5eB,FN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pRwGv  
httpConnection.setRequestProperty("User-Agent","NetFox"); q83~j`ZJ$  
kr(<Y|  
2-V)>98  
int responseCode=httpConnection.getResponseCode(); "q^#39i?  
if(responseCode>=400) f4k5R  
{ =/g$bZ  
processErrorCode(responseCode); Dw`m>'J0  
return -2; //-2 represent access is error uUz`=4%A  
} Ejms)JK+  
2d2@J{  
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String sHeader; F[kW:-ne@Z  
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for(int i=1;;i++) ZjZhz`  
{ H_?B{We  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "Ug/ ',jkV  
//Utility.log(in.readLine()); r)p2'+}pV  
sHeader=httpConnection.getHeaderFieldKey(i); DMQNr(w{!2  
if(sHeader!=null) N<06sRg#  
{ (.,'}+1  
if(sHeader.equals("Content-Length")) F@$RV_M  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ``$%L=_m  
break; xIQ/$[&v  
} 0TO_1 0D  
} nU&NopD+*G  
else \- =^]]b=  
break; S\9t4Ki_'  
} b0YiQjS6>  
} I f3{E  
catch(IOException e){e.printStackTrace ();} -XVEV  
catch(Exception e){e.printStackTrace ();} <!~1{`n%9J  
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Utility.log(nFileLength); d1V^2Hb?  
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return nFileLength; _ktK+8*6`  
} %j'G.*TD  
pw,O"6J*  

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//保存下载信息（文件指针位置） )sW6iR&_i  
private void write_nPos() [ WV@w  
{ l'*^$
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try{ Ot`LZ"H:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sI&i{D  
output.writeInt(nStartPos.length); 'tb(J3ZP  
for(int i=0;i<nStartPos.length;i++) -)1-~7 r  
{ 6a4'xq7  
// output.writeLong(nPos); A~Z6jK  
output.writeLong(fileSplitterFetch.nStartPos); ,3Wb4so  
output.writeLong(fileSplitterFetch.nEndPos); m'cz5mcD  
} JEWL)  
output.close(); 3CR@' qG-  
} (C daE!I4Q  
catch(IOException e){e.printStackTrace ();} D]IBB>F  
catch(Exception e){e.printStackTrace ();} sm 's-gD  
} #zON_[+s9  
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//读取保存的下载信息（文件指针位置） n*4lz^LR  
private void read_nPos() bIgh@= 2  
{ {5^K Xj$B  
try{ JD6aiI!Su  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iI5+P`sE&J  
int nCount = input.readInt(); IY=/`g  
nStartPos = new long[nCount]; &V'519vmoZ  
nEndPos = new long[nCount]; n(g)UNx  
for(int i=0;i<nStartPos.length;i++) ypx: )e"/  
{ )
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nStartPos = input.readLong(); GCDwWCxh  
nEndPos = input.readLong(); ^+ZgWS^
%  
} '77~{jy  
input.close(); ? ^M /[@  
} U@G"`RYl  
catch(IOException e){e.printStackTrace ();} .it#`Yz;  
catch(Exception e){e.printStackTrace ();} LL&ud_Y  
} ~9GOk;{~&  
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private void processErrorCode(int nErrorCode) HPg3`Ul  
{ Ck\7F?S  
System.err.println("Error Code : " + nErrorCode); :.kZR;  
} {~SaRB2<'  
{( #zcK  
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//停止文件下载 DAfyK?
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public void siteStop() bLzs?eos  
{ Z(j{F<\jS  
bStop = true; )VSwTx&  
for(int i=0;i<nStartPos.length;i++) (hIF]>,kl  
fileSplitterFetch.splitterStop(); ?38lHn`FyQ  
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} %Y]=1BRk}  
} @@@=}!<H=  
//负责部分文件的抓取 :_5/u|{  
**FileSplitterFetch.java y}FZD?"  
*/ ~e `Bq>  
package NetFox; $=B8qZ+  
oc7$H>ET1  
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import java.io.*; .f:n\eT):  
import java.net.*; V8WFQdXc  
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public class FileSplitterFetch extends Thread { "T2"]u<52  
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String sURL; //File URL Tlq-m2]  
long nStartPos; //File Snippet Start Position eg/<[ A:  
long nEndPos; //File Snippet End Position .B72C[' c  
int nThreadID; //Thread's ID b0v:12q  
boolean bDownOver = false; //Downing is over R!(ZMRMn  
boolean bStop = false; //Stop identical  foRD{Hx  
FileAccessI fileAccessI = null; //File Access interface R'}95S<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7y^%7U \  
{ lDc-W =X=  
this.sURL = sURL; fX~'Zk\u  
this.nStartPos = nStart; g7\,{Bw#E  
this.nEndPos = nEnd; oVvc?P  
nThreadID = id; dY7'OAUyVl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} G{Yz8]m  
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public void run() Cx<0 H  
{ /./"x
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while(nStartPos < nEndPos && !bStop) {q%Sx*k9[  
{ uo\ .7[1  
hRC
 
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try{ *N'K/36;  
URL url = new URL(sURL); P{
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A4C+5R  
httpConnection.setRequestProperty("User-Agent","NetFox"); : _e#  
String sProperty = "bytes="+nStartPos+"-"; :bu>],d-8'  
httpConnection.setRequestProperty("RANGE",sProperty); bmgncwlz  
Utility.log(sProperty); +mj*o(  
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InputStream input = httpConnection.getInputStream(); /1N6X.Zb  
//logResponseHead(httpConnection); (jjTK'0[  
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byte[] b = new byte[1024]; ~Q{QM:k  
int nRead; 1 `^Rdi0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5=Xy,hmnC  
{ "Z Htr<+  
nStartPos += fileAccessI.write(b,0,nRead); L`f^y;Y.  
//if(nThreadID == 1) >~%e$a7}+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *IgE
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} **9x?s  
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Utility.log("Thread " + nThreadID + " is over!"); f-DL:@crU  
bDownOver = true; oSiMpQu08  
//nPos = fileAccessI.write (b,0,nRead); {3;AwhN0H  
} :w}{$v}#D;  
catch(Exception e){e.printStackTrace ();} valtev0<  
} Xq'cA9v=$J  
} !cKz7?w  
? WJ> p  
|,9JNm$  
//打印回应的头信息 XE^)VLH:  
public void logResponseHead(HttpURLConnection con) !.2<| 24  
{ fYKOJ5f  
for(int i=1;;i++) SGb;!T*  
{ %ZHP2j %~  
String header=con.getHeaderFieldKey(i); (c0A.L)  
if(header!=null) z/i+EE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2,ECYie^  
Utility.log(header+" : "+con.getHeaderField(header)); YK|bXSA[  
else %%(R@kh9  
break; Y5fLmPza  
} DNGvpKY@  
} P[s8JDqu  
*~w[eH!!  
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public void splitterStop() 'SQG>F Uy  
{ EC
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bStop = true; y:v,j42%  
} UH3sH t  
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} k,euhA/&  
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/* Z7 E
  
**FileAccess.java @?h/B=56  
*//文件访问(定位，写) @&[T _l  
package NetFox; 1S@vGq}  
import java.io.*; l<M'=-Y  
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public class FileAccessI implements Serializable{ ~'R(2[L!;  
aZ\UrV4,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y8fsveX  
RandomAccessFile oSavedFile; 'M3">$N  
long nPos; qKJSj   
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public FileAccessI() throws IOException z0/} !  
{ WJ*n29^N^h  
this("",0); Qt|c1@J  
} ?McQr1  
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public FileAccessI(String sName,long nPos) throws IOException ([xo9FP;  
{ 4b:s<$TZ  
oSavedFile = new RandomAccessFile(sName,"rw"); /T.KbLx~q  
this.nPos = nPos; vVL@K,q  
oSavedFile.seek(nPos); ne^imht  
} ^{8Gt@  
6 PxW8pn  
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public synchronized int write(byte[] b,int nStart,int nLen) |{,KRO0P  
{ [d* ~@P  
int n = -1; %$TGzK1  
try{ 8/K!SpM*d  
oSavedFile.write(b,nStart,nLen); _D|^.)=U|  
n = nLen; 0q&'(-{s1  
}  YBnA+l*  
catch(IOException e) eAqz3#_My  
{ IJ/sX_k  
e.printStackTrace (); uPniLx\t:  
} (!:cen~|[  
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return n; MCdx?m3]  
} 8iekEG$H  
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} mg,j
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/* 57 #6yXQ  
**SiteInfoBean.java LzCw+@-umw  
*/ owPm/
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package NetFox; %e@#uxm  
+Y+Y6Ac[}  
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public class SiteInfoBean { Y \:0Ev  
'KPASfC  
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private String sSiteURL; //Site's URL (< =}]v  
private String sFilePath; //Saved File's Path B7z -7&TE  
private String sFileName; //Saved File's Name =V^.}WtO  
private int nSplitter; //Count of Splited Downloading File OaL\w D^  
RW P<B0)  
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public SiteInfoBean() !`7B^RZ  
{//nSplitter的缺省值为5 w/L `  
//default value of nSplitter is 5 VAXT{s&4>  
this("","","",5); yOvm`9  
} x=#VX\5k:  
J sEa23  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B*gdgM*`  
{ *x)8fAr  
sSiteURL= sURL; pc?>cs8  
sFilePath = sPath; z.rh]Zq  
sFileName = sName; ~l2aNVv;  
this.nSplitter = nSpiltter; $Q*<96M  
v|E"[P2e  
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} *~/OOH$"  
;Q+xKh%  
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public String getSSiteURL() " ZX3sfkh  
{ L_w+y  
return sSiteURL; WYc7aciJ  
} FCkf#  
wR{'y)$  
FaBqj1O1  
public void setSSiteURL(String value) A 8 vbQ  
{ >s`J5I!  
sSiteURL = value; ^`<w&I@  
} Wpc|`e<  
@JW@-9/  
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public String getSFilePath() G"T',~  
{ ~n/ $  
return sFilePath; +t
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} M4WiT<|]R  
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public void setSFilePath(String value) '<0J@^vZ  
{ !d&C>7nb  
sFilePath = value; 9 fMau  
}
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>Yt/]ta4+  
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public String getSFileName() Skz|*n|eY  
{ z]3 `*/B  
return sFileName; F]mgmYD%  
} xm6EKp:  
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?:Y#Tbi3  
public void setSFileName(String value) ^;c16  
{ *.&HD6Qr  
sFileName = value; v2,%K`pAU  
} %Qmk2  
Y4IGDY*  
>]%8Zx[  
public int getNSplitter() KgW:@X7wvM  
{  8L*GE  
return nSplitter; >E,U>@+  
} $F.kK%-*  
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public void setNSplitter(int nCount) |;A/|F0-e  
{ tDDy]==E  
nSplitter = nCount; Tg3!Rq55  
} i*eAdIi  
} RwVaZJe)l  
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/* I\|N  
**Utility.java 1
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*/ u>
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package NetFox; HMY@F_qY`u  
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public class Utility { oRp:B&  
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public Utility() Npn=cLC&  
{ [\R>Xcu>  
}`yiT<z  
B}d.#G+_$x  
} 0J~Qq]g  
I?Q+9Rmm`J  
//线程睡眠 _GqS&JHSf  
public static void sleep(int nSecond) V^Rkt%JY  
{ z<]bv7V  
try{ /XS&d%y  
Thread.sleep(nSecond); m=qOg>k  
} _y .]3JNm  
catch(Exception e) `P@- %T  
{ ?*r!{3T ,u  
e.printStackTrace (); l2
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} ) uP\>vRy  
} +CM7C%U   
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//日志 W4YE~  
public static void log(String sMsg) 7m5Co>NkuK  
{ g<\z=H  
System.err.println(sMsg); b]gY~cbI8  
} )R{UXk3q}  
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public static void log(int sMsg) w?csV8ot  
{ NBl __q  
System.err.println(sMsg); 6@4n'w{"  
} 6Gn4aso
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} #f'DEo<b  
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/* ?TEK=mD#u  
**TestMethod.java !d9AG|  
*/ \|Dei);k  
package NetFox; +
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public class TestMethod { B94 &elu  
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public TestMethod() DpL8'Dib  
{ ///xx/weblogic60b2_win.exe S-E++f9D~  
try{ heD,&OX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XKLF8~y8A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |LYKc.xo  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); Sw! j=`O  
} E;-qP)yU  
catch(Exception e){e.printStackTrace ();} T'rjh"C&|  
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} J^H=i)A  
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public static void main(String[] args) ^Qh-(u`  
{ v}il(w;O  
new TestMethod(); Sr y,@p)  
} h-'wV${b  
} \K`jCsT  
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