http断点续传简单实现（java)

/* #g#[|c.  
**SiteFileFetch.java j4wsDtmAU  
*/ <5!)
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package NetFox; cv5+[;(b  
import java.io.*; 50e vWD  
import java.net.*; RF}R~m9]  
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public class SiteFileFetch extends Thread { |
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SiteInfoBean siteInfoBean = null; //文件信息Bean #AH gY.  
long[] nStartPos; //开始位置 Ca["tks  
long[] nEndPos; //结束位置 Mw`S.M. B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yu}T><Wst  
long nFileLength; //文件长度 [(; .D  
boolean bFirst = true; //是否第一次取文件 *+%$OH,  
boolean bStop = false; //停止标志 q{}U5(,{0  
File tmpFile; //文件下载的临时信息 KwY6pF*  
DataOutputStream output; //输出到文件的输出流 YF(bl1>YC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gm$<U9L\v  
public SiteFileFetch(SiteInfoBean bean) throws IOException \I7&F82e  
{ yujv^2/  
siteInfoBean = bean; p'kB1)~|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #Cb~-2:+7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]P2Wa   
if(tmpFile.exists ()) ~H4Tr[8a  
{ !jg< S>S5  
bFirst = false; nTE\EZ+=2  
read_nPos(); *|
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} fskc'%x  
else h^f?rWD:nz  
{ })?KpYk  
nStartPos = new long[bean.getNSplitter()]; |[@v+koq  
nEndPos = new long[bean.getNSplitter()]; xf;Tk   
} uyoV)  
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} RijFN.s  
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public void run() qhmA)AWG>  
{ ,IPryI   
//获得文件长度 {A\y4D@  
//分割文件 hdpA& OteR  
//实例FileSplitterFetch JD~]aoH  
//启动FileSplitterFetch线程 loD:4e1  
//等待子线程返回 q+)s  
try{ 36d6KS 7  
if(bFirst) p@3 <{kLm  
{ B7n1'?  
nFileLength = getFileSize(); }O:l]O`  
if(nFileLength == -1) Aj+0R?9tG  
{ DuRC1@e  
System.err.println("File Length is not known!"); qSQsY:]j0  
} bKQ-PM&I/t  
else if(nFileLength == -2) Zzv,p  
{ (X|lK.W y  
System.err.println("File is not access!"); A[Vhy;xz  
} u:>*~$f   
else N lB%Qu  
{ (Zu8WyT2  
for(int i=0;i<nStartPos.length;i++) `7_s@4:  
{ { pu .l4nk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B0!W=T\  
} -l$-\(,M`#  
for(int i=0;i<nEndPos.length-1;i++) ETaLE[T%1  
{  gX]'RBTb  
nEndPos = nStartPos[i+1]; z
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} W4=<hB  
nEndPos[nEndPos.length-1] = nFileLength; vUgo)C#<  
} CQ#%v%  
} Jek)`D  
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y_Nn%(j  
//启动子线程 oHx=Cg;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K[i|OZWu  
for(int i=0;i<nStartPos.length;i++) E#,n.U>#)  
{ D4ud|$s1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lISu[{b?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }'Yk#Q  
nStartPos,nEndPos,i); O\zGN/!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z#|IMmT;*=  
fileSplitterFetch.start(); 3,{tGNl|  
} n*i1QC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SK {ALe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;Z}V}B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uM9RlI5  
nEndPos = " + nFileLength); I)F3sS45}  
// fileSplitterFetch[nPos.length-1].start(); ( O/+.qb  
}_o!fV  
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//等待子线程结束 yX;v  
//int count = 0; #[ hJm'G  
//是否结束while循环 )qx,>PL  
boolean breakWhile = false; _sp/RU,J-3  
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while(!bStop) +BE_K_56  
{ ~85Pgb<  
write_nPos(); 3re|=_ Hy  
Utility.sleep(500); c`h/x>fa  
breakWhile = true; 7ezf.[{R  
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for(int i=0;i<nStartPos.length;i++) Xm}~u?$3  
{ VwV`tKit  
if(!fileSplitterFetch.bDownOver) fdRw:K8  
{ = A;B-_c  
breakWhile = false; 0 SeDBs  
break; $zuemjW3p  
} h_Cac@F0  
} pC'GKk 8  
if(breakWhile) vS|uN(a.P  
break; Q1?G7g]N  
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//count++; __,1;=  
//if(count>4) <H)I06];  
// siteStop(); xW;-=Q  
} BI,j/SRK  
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System.err.println("文件下载结束！"); n)
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} V_g9
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catch(Exception e){e.printStackTrace ();} e)~7pXYV)  
} P]@m0f  
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//获得文件长度 N+9`'n^x  
public long getFileSize() u8Au `  
{ 4#z@B1Jx  
int nFileLength = -1; q.OkZI0n  
try{ ^
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URL url = new URL(siteInfoBean.getSSiteURL()); =_`4HDr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xrK%3nA4s"  
httpConnection.setRequestProperty("User-Agent","NetFox");
4 }l,F  
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0.
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int responseCode=httpConnection.getResponseCode(); Mlp[xk|  
if(responseCode>=400) #`C;@#xr  
{ $^Dx4:k<2  
processErrorCode(responseCode); lbv9 kk[
 
return -2; //-2 represent access is error {@u;F2?  
} @L8(
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String sHeader; {ZH9W
 
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for(int i=1;;i++) J3fcnI  
{ T1pA <6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !aD/I%X  
//Utility.log(in.readLine()); }Lx?RU+@=  
sHeader=httpConnection.getHeaderFieldKey(i); )k0P' zGb  
if(sHeader!=null) Memz>uux  
{ Z@=1-l  
if(sHeader.equals("Content-Length")) *]fBd<(8  
{ c<j2wKz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hbh
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break; 3u7N/OQ(  
} aD,s
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} 8oG0tX3i  
else DD\:glo  
break; ]&1Kz 2/  
} BF2,E<^A  
} T^8t<S@`  
catch(IOException e){e.printStackTrace ();} 1Fn+nDnO6  
catch(Exception e){e.printStackTrace ();} D;
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Utility.log(nFileLength); LQ"56PP<  
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return nFileLength; 'D8WNZ8Q  
} !Ac<A.  
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//保存下载信息（文件指针位置） !
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private void write_nPos() HcA;'L?Dw  
{ &IM;Yl  
try{ Fd-PjW/E8  
output = new DataOutputStream(new FileOutputStream(tmpFile));  Q0'xn  
output.writeInt(nStartPos.length); v'7,(.E  
for(int i=0;i<nStartPos.length;i++) |BnjT*_9  
{ Y"~I(,nx!  
// output.writeLong(nPos); m5SJB]a/  
output.writeLong(fileSplitterFetch.nStartPos); 5BCXI8Ox9x  
output.writeLong(fileSplitterFetch.nEndPos); nVV>;e[  
} *{8Kb>D  
output.close(); >S3iP?V7  
} Z9mY*}:U~  
catch(IOException e){e.printStackTrace ();} f8kPbpV,  
catch(Exception e){e.printStackTrace ();} W}bed],l  
} 5\}A8Ng  
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//读取保存的下载信息（文件指针位置） 4G0Er?D   
private void read_nPos() wl #Bv,xf  
{ IlJ6&9  
try{ " m<]B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "S.5
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int nCount = input.readInt(); vO!p8r F  
nStartPos = new long[nCount]; c1M/:*?%  
nEndPos = new long[nCount]; 5mUHk]W  
for(int i=0;i<nStartPos.length;i++) hIu;\dfwk  
{ sL|*0,#K  
nStartPos = input.readLong(); ]#;;)K}>  
nEndPos = input.readLong(); FjqoO.  
} g-"@%ps  
input.close(); X&fM36o7  
} J3gJSRT@P  
catch(IOException e){e.printStackTrace ();} =#dW^?p  
catch(Exception e){e.printStackTrace ();} ;rYL\`6L  
} __M(dN(^  
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private void processErrorCode(int nErrorCode) 9`Bmop  
{ OAO|HH  
System.err.println("Error Code : " + nErrorCode); ,
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} 3:Q5dr+1_  
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//停止文件下载 -qaJ@T+J+7  
public void siteStop() b{J
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{ $Y* d ' >  
bStop = true; =aZgq99  
for(int i=0;i<nStartPos.length;i++) AL@8v=  
fileSplitterFetch.splitterStop(); K8M[xaI@  
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} [AkL6  
} /W\@
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//负责部分文件的抓取 .anXsjD%W  
**FileSplitterFetch.java I^S gWC  
*/ ?D?_D,"C  
package NetFox; hB/4.K]8  
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import java.io.*; >tc#Ofgzd  
import java.net.*; .kKU
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public class FileSplitterFetch extends Thread {  %f3qCN  
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String sURL; //File URL ZNWo:N8;  
long nStartPos; //File Snippet Start Position } )DE  
long nEndPos; //File Snippet End Position \%&BK.t  
int nThreadID; //Thread's ID xE>H:YPm  
boolean bDownOver = false; //Downing is over LFvO[&  
boolean bStop = false; //Stop identical %-9?rOr  
FileAccessI fileAccessI = null; //File Access interface J:W|2U="  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4mHR+SZy  
{ h&5b
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this.sURL = sURL; rdj_3Utv  
this.nStartPos = nStart; _A]8l52pt  
this.nEndPos = nEnd; G-7!|&  
nThreadID = id; arVu`pD*n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1f}YKT  
} /%&Kbd  
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public void run() Q)]C~Q  
{ #3VOC#.  
while(nStartPos < nEndPos && !bStop) sF.oZ>  
{ -d-vzri  
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try{ L i g7Ac,  
URL url = new URL(sURL); g2RrBK,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?Z^?A^; }$  
httpConnection.setRequestProperty("User-Agent","NetFox"); *sJT\J$D[  
String sProperty = "bytes="+nStartPos+"-"; Ow"e3]}Mt  
httpConnection.setRequestProperty("RANGE",sProperty); nj1T
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Utility.log(sProperty); ,r5'nDV=d  
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()}(3>O-  
InputStream input = httpConnection.getInputStream(); ~`Y!_'(x  
//logResponseHead(httpConnection); 7y?aw`Sw:  
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byte[] b = new byte[1024]; UWXl c  
int nRead; 0#G@F5; <  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tv[|^G9x  
{  g)Tr#  
nStartPos += fileAccessI.write(b,0,nRead); n2V $dF4m  
//if(nThreadID == 1) | V:9 ][\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C^IPddw>  
} \V(w=  
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Utility.log("Thread " + nThreadID + " is over!"); {{r.?m#{  
bDownOver = true; _|Uv7>}J^  
//nPos = fileAccessI.write (b,0,nRead); B7QRG0  
} ^?V9  
catch(Exception e){e.printStackTrace ();} ^7Rc\  
} 9oU1IT9   
} "Cz0r"N  
M!wa }  
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//打印回应的头信息 S[;d\Z]~  
public void logResponseHead(HttpURLConnection con) L`"j>),  
{ 'NNfzh  
for(int i=1;;i++) 3iIURSG@  
{ "
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String header=con.getHeaderFieldKey(i); ^~1Z"kAnT  
if(header!=null) it$w.v+W7V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q4T98s2J  
Utility.log(header+" : "+con.getHeaderField(header)); X \BxRgl},  
else i7b^b>B|e  
break; ElA(1o|9I  
} 7'!DK;=TD6  
} 5S*aZ1t18  
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public void splitterStop() iv ~<me0F  
{ 8AJ#].q0F  
bStop = true; QuIZpP=  
} f+lPQIB  
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} Mi}.  
] T<#bNK\1  
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/*
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**FileAccess.java 9>@Vk vpY  
*//文件访问(定位，写) #}HdylI\}  
package NetFox; ,1B`Ve  
import java.io.*; 6HZVBZhM  
P*]hXm85[K  
@A|#/]S1  
public class FileAccessI implements Serializable{ iS< ^MD  
w6h*dh$w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _C)\X(;  
RandomAccessFile oSavedFile; J|w%n5Y  
long nPos; @)C.IQ~  
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@*E=O|  
public FileAccessI() throws IOException ~RH)iI  
{ I+,CiJ|4  
this("",0); y'!"GrbZ  
} \mL]xE-  
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public FileAccessI(String sName,long nPos) throws IOException I_
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{ S!n?b|_  
oSavedFile = new RandomAccessFile(sName,"rw"); iuA_Jr  
this.nPos = nPos; phQ{<wzwp  
oSavedFile.seek(nPos); G^';9 UK  
} &WeN{  
~6K.5t7  
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public synchronized int write(byte[] b,int nStart,int nLen) e<qfM&*  
{ :5F(,
Z_  
int n = -1; gWL`J=DiU  
try{ fv@<  
oSavedFile.write(b,nStart,nLen); @j"6f|d  
n = nLen; |+KwyHE`9  
} =kf"%vFV  
catch(IOException e) {5fL!`6w  
{ pSI8"GwQ  
e.printStackTrace (); [RF
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} zkiwFEHA=  
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return n; #G_'5{V  
} Pf/8tXs}  
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} I~6 o<HO  
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+xgP&nw[-  
/* mYj)![  
**SiteInfoBean.java A2;6Vz=z  
*/ N!MDD?0  
package NetFox; I!Z"X&  
}-J0cV  
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public class SiteInfoBean { rlA/eQrS  
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5@-H8*  
private String sSiteURL; //Site's URL 6Ol9P56j  
private String sFilePath; //Saved File's Path 7(oA(l1V  
private String sFileName; //Saved File's Name @g4o8nH}  
private int nSplitter; //Count of Splited Downloading File 5&h">_j  
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qTN%9!0@9  
public SiteInfoBean() y4LUC;[n  
{//nSplitter的缺省值为5 #r]Z2Y]  
//default value of nSplitter is 5 .c~z^6x  
this("","","",5); cJv/)hRaz  
} i;U*Y *f  
beC%Tnb7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qT!lq  
{ u '/)l}  
sSiteURL= sURL; (3lA0e`Y  
sFilePath = sPath; =JgR c7  
sFileName = sName; C}pm>(F~  
this.nSplitter = nSpiltter; \~z$'3H`  
,z>-_HOnw  
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} zfv@<'  
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public String getSSiteURL() H$C*&p  
{ 5cinI^x)f  
return sSiteURL; @$n $f  
} !cYID \}S,  
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public void setSSiteURL(String value) 8K
?}!$fz  
{ 8K-P]]  
sSiteURL = value; Ycspdl+(S$  
} ){w{#  
#gO[di0WhC  
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public String getSFilePath() oJr+RO  
{ XLCqB|8`V  
return sFilePath; Yq6 @R|u  
} *c[
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r8:"\%"f>  
public void setSFilePath(String value) v$Fz^<Na  
{ K+!e1 '  
sFilePath = value; \f? K74  
} .=J- !{z  
W1X3ArP]m8  
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public String getSFileName() sV,Yz3E<u$  
{ # euG$(  
return sFileName; 1g{}O^ul  
} UHvA43  
'LPyh ;!f  
m\XsU?SuX  
public void setSFileName(String value) +5*bU
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{ L<@*6QH  
sFileName = value; 9X4[Zk  
} AZc=Bbh  
}k-8PG =  
:G@z?ZJ[  
public int getNSplitter() 8Lx/ZGy  
{ c86KDEF  
return nSplitter; j AOy3c  
} $Bz};@  
6R<+_e+v  
~:7y!=8#  
public void setNSplitter(int nCount) S._2..%G  
{ er7(Wph  
nSplitter = nCount; "[?DS  
} }6-olVg  
} &Jj|+P-lY  
02t({>`  
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/* ]#f%Dku.m  
**Utility.java B;(U?gC  
*/ '[liZCg  
package NetFox; gjG SI'M0B  
aq_K,li#w  
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public class Utility { GD.Ss9_h1  
u
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public Utility() 3JQ7Cc>  
{ s,#We} bv  
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} !xck ~EAS  
o!+%|V8Y  
//线程睡眠 (J5}1Q<K  
public static void sleep(int nSecond) <<?32r~  
{ QyVAs;  
try{ */IiL%g4u  
Thread.sleep(nSecond); ;]grbqXVE  
} dX/7n=  
catch(Exception e) 7BU7sQjs  
{ $?W2'Xm!V  
e.printStackTrace (); xAd@.^  
} e&ysj:W5 "  
} f}2}Ta  
3A`]Rk   
//日志 LJ <pE;`d  
public static void log(String sMsg)
RN-gZ{AW  
{  :2nsi4  
System.err.println(sMsg); 3E;@
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} +U<YM94?  

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public static void log(int sMsg) /lUfxc4  
{ [(x<2MTj  
System.err.println(sMsg); Z}!'fX."  
} ].xSX0YQ%  
} -W^{)%4g
 
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03 gbcNo  
/* #d,)Qe[  
**TestMethod.java ZH\t0YhrVe  
*/ :lo5,B;k  
package NetFox; RBf#5VjOG!  
(K=0c6M3=  
' F.^ 8/>  
public class TestMethod { Ygk_gBRiC  
{Ia1H  
1+$F= M~  
public TestMethod() *:TwO=)  
{ ///xx/weblogic60b2_win.exe dlfjx  
try{ %"
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hOk
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $,by!w'e:l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9Zl4NV&B  
fileFetch.start(); UAXp;W`  
} *O'|NQhNx>  
catch(Exception e){e.printStackTrace ();} T2Z$*;,>T  
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} udUc&pX  
{2:baoG-  
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public static void main(String[] args) wnd #J `  
{ 3G4WKg.^  
new TestMethod(); +I5\`By=  
} `&c[s%0  
} v[uVAbfQ  
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