http断点续传简单实现（java)

/* sgO'wXcoP  
**SiteFileFetch.java t 0-(U\  
*/ de>v  
package NetFox; 2At
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import java.io.*; qQ0cJIISb\  
import java.net.*; [-)r5Dsdq  
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' 4ER00  
public class SiteFileFetch extends Thread { Q4*fc^?u  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kdn'6>\  
long[] nStartPos; //开始位置 ZKXo-~=>  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;\[(- )f!=  
long nFileLength; //文件长度 !vk|<P1  
boolean bFirst = true; //是否第一次取文件 kWNV%RlSx  
boolean bStop = false; //停止标志 !YP@m~  
File tmpFile; //文件下载的临时信息 0 s70r  
DataOutputStream output; //输出到文件的输出流 |QMhMGjV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l983vKr  
public SiteFileFetch(SiteInfoBean bean) throws IOException fPrLM'  
{ JR@.R ,rII  
siteInfoBean = bean; 8Th` ]tI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3LfC{ER  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @c~)W8  
if(tmpFile.exists ()) m~dC3}e8/?  
{ ^1wA:?uN}  
bFirst = false; l27\diKPJ  
read_nPos(); V~ TWKuR  
} CEC nq3  
else ) /v6l  
{ Nr0 (E   
nStartPos = new long[bean.getNSplitter()]; CT\;xt,S  
nEndPos = new long[bean.getNSplitter()]; Raw)9tUt  
} /l{&iLz[  
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} *A~ G_0B  
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public void run() m] W5+  
{ k64."*X  
//获得文件长度 dVQ-
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//分割文件 &*s0\ 8  
//实例FileSplitterFetch kEO7PK/  
//启动FileSplitterFetch线程 5'Q|EIL  
//等待子线程返回 @m?QR(LJ  
try{ zh$}~RG[  
if(bFirst) 4HAp{
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{ a"av#Y  
nFileLength = getFileSize(); >I<r)w]  
if(nFileLength == -1) U;n*j3wT  
{ )9S>ZZF  
System.err.println("File Length is not known!"); jAh2N3)  
} &w
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else if(nFileLength == -2) fA=#Fzk2  
{ BI:k
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System.err.println("File is not access!"); xcJ`1*1N  
} 7?v#'Ies  
else [Px'\nVf  
{ SSBg?H'T  
for(int i=0;i<nStartPos.length;i++) zd]D(qeX  
{ cV-1?h63  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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}  h C=:q  
for(int i=0;i<nEndPos.length-1;i++) 3@n>*7/E  
{ }YOL"<,:o  
nEndPos = nStartPos[i+1]; <}jPXEB"  
} |+U<S~  
nEndPos[nEndPos.length-1] = nFileLength; ICB~_O5  
} Kd3?I5t  
} =V97;kq+v  
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//启动子线程 #,(sAj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =N);v\ Q$!  
for(int i=0;i<nStartPos.length;i++) !'=15&5@  
{ GFk1
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -;;Z 'NM;8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U Q@7n1  
nStartPos,nEndPos,i); l$*=<tV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ( #Z`  
fileSplitterFetch.start(); O;HY%  
} qP!P +'B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Cc.cce5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c~<1':  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +]:2\TTGI  
nEndPos = " + nFileLength); ~^)^q8  
// fileSplitterFetch[nPos.length-1].start(); utlpY1#q/  
/cFzotr"9  
#k
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//等待子线程结束 Wk4.%tpeO7  
//int count = 0; E3/:.t  
//是否结束while循环 %m{U& -(l@  
boolean breakWhile = false; 2WvN2"f3  
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while(!bStop) P ,eH5w"  
{ {}>n{_  
write_nPos(); qu6DQ@ ~YC  
Utility.sleep(500); o**yZ2  
breakWhile = true; w-N1.^  
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for(int i=0;i<nStartPos.length;i++) h7_)%U<J2  
{ (3,.3)%`  
if(!fileSplitterFetch.bDownOver) ,je`YEC  
{ IF k  
breakWhile = false; 1D([@)^  
break; (9fdljl],:  
} mjnUs-`W|  
} @=]8^?$t 0  
if(breakWhile) |E/L.gdP7  
break; nw'-`*'rj  
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SjcL#S($&Y  
//count++; q<=: >?  
//if(count>4) \X}8q  
// siteStop(); iT)WR90  
} =)<3pGO  
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System.err.println("文件下载结束！"); 17UK1Jx,  
} (hZ:X)E>  
catch(Exception e){e.printStackTrace ();} q@#BPu"\l  
} ZKbDp~  
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//获得文件长度 aSnp/g  
public long getFileSize() *crw^e  
{ $G?(OWI}l`  
int nFileLength = -1; ]YD(`42x  
try{ {/M\Q@j  
URL url = new URL(siteInfoBean.getSSiteURL()); )BV=|,j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qJs[i>P[W  
httpConnection.setRequestProperty("User-Agent","NetFox"); KjR4=9MD  
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int responseCode=httpConnection.getResponseCode(); mA{#]Yvf1  
if(responseCode>=400) ;lfWuU%R  
{ b&t[S[P.V  
processErrorCode(responseCode); Q)6va}2ai  
return -2; //-2 represent access is error F,Fo}YQX  
} 3XVk#)lw  
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String sHeader; 1MQ/r*(  
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for(int i=1;;i++) Ee?;i<u  
{ &:vscOl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .ewZV9P)t  
//Utility.log(in.readLine()); (Pz8iz  
sHeader=httpConnection.getHeaderFieldKey(i); lBiovT  
if(sHeader!=null) XJFnih  
{ q+/l"&j.  
if(sHeader.equals("Content-Length")) %Dyh:h  
{ BMjfqX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9s $PrF  
break; o>u!CL<  
} GVObz?Z]SB  
} X%J%A-k]  
else 8eww7k^R  
break; a!u3HS-i  
} p":@>v?  
} #:W%,$9\P  
catch(IOException e){e.printStackTrace ();} \dNhzd#  
catch(Exception e){e.printStackTrace ();} +!$dO'0nt,  
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Utility.log(nFileLength); @W)/\AZ3  
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return nFileLength; QZ0R:TY  
} _S<?t9mS  
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//保存下载信息（文件指针位置） =+(Q.LmhC  
private void write_nPos() k!c7a\">{  
{ }z{wQ\  
try{ @ay|]w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UC#"=Xd4  
output.writeInt(nStartPos.length); [iXi\Ex  
for(int i=0;i<nStartPos.length;i++) E@]sq A  
{ LH.%\TMN$  
// output.writeLong(nPos); %%x0w^  
output.writeLong(fileSplitterFetch.nStartPos); Q %y,;N"ro  
output.writeLong(fileSplitterFetch.nEndPos); \d$Rd")w  
} 1O9$W?)Q  
output.close(); kraVL%72  
} #rq?
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catch(IOException e){e.printStackTrace ();} H CuK  
catch(Exception e){e.printStackTrace ();} @|]G0&gn&?  
} 2moIgJ   
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//读取保存的下载信息（文件指针位置） )?9\$^I  
private void read_nPos() ] EV`dIk  
{ i)8gCDc  
try{ 7>KQRLw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -UTV:^  
int nCount = input.readInt(); ?0m?7{  
nStartPos = new long[nCount]; x36NL^  
nEndPos = new long[nCount]; Bf+^O)Ns^  
for(int i=0;i<nStartPos.length;i++) _Z0\`kba+  
{ [Q=4P*G}X  
nStartPos = input.readLong(); uYY=~o[ Tw  
nEndPos = input.readLong();
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} h\2}875  
input.close(); IF^[^^v+H  
} "C& Jwm?  
catch(IOException e){e.printStackTrace ();} }oV3EIH  
catch(Exception e){e.printStackTrace ();} "TUPYFK9  
} dUZ$wbV%h  
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private void processErrorCode(int nErrorCode) m
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{ we }#Ru*  
System.err.println("Error Code : " + nErrorCode); i{P%{hVb  
} (%Ng'~J\|  
` v>
/  
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//停止文件下载 0}6QO  
public void siteStop() >2nF"?"=  
{ :82?'aR  
bStop = true; q$3HvZP  
for(int i=0;i<nStartPos.length;i++) |^>u<E5  
fileSplitterFetch.splitterStop(); wXP_]-  
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} f>|9 l  
} |e~u!V\m  
//负责部分文件的抓取 #&}%70R)  
**FileSplitterFetch.java [2=^C=52  
*/ 8TUF w@H%  
package NetFox; CgN]dx*`  
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import java.io.*; tP&{ J^G  
import java.net.*; bb*c+XN0  
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public class FileSplitterFetch extends Thread { XSD"/_xD  
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String sURL; //File URL 2Y9y5[K,F)  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position Ar\IZ_Q  
int nThreadID; //Thread's ID J11dqj  
boolean bDownOver = false; //Downing is over ]}
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boolean bStop = false; //Stop identical @\#'oIc|  
FileAccessI fileAccessI = null; //File Access interface Rc$=+K#  
'2;Ny23  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mvUVy1-c  
{ \Sz4Gr0g3Z  
this.sURL = sURL; %Y#[%~|(  
this.nStartPos = nStart; aa%Yk"V@  
this.nEndPos = nEnd; T3=-UYx]  
nThreadID = id; Lr!L}
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 8:;u v7p  
} l|4xKBCV]  
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public void run() K8e4ax  
{ |;xfe"]  
while(nStartPos < nEndPos && !bStop) >FK)p   
{ 6)tB{:h&~0  
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try{ GQEIf$  
URL url = new URL(sURL); X3&SL~&>g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pf^Ly97  
httpConnection.setRequestProperty("User-Agent","NetFox"); \i&vO
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String sProperty = "bytes="+nStartPos+"-"; gPA>*;?E;@  
httpConnection.setRequestProperty("RANGE",sProperty); Z<$E.##  
Utility.log(sProperty); nN(D7wk  
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InputStream input = httpConnection.getInputStream(); X#f+m) S  
//logResponseHead(httpConnection); +73=2.C0  
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byte[] b = new byte[1024]; ;r0|_mnf  
int nRead; oF 1W
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .O@q5G  
{ 3.K{T  
nStartPos += fileAccessI.write(b,0,nRead); KV)Hywl`  
//if(nThreadID == 1) ? bUpK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nv*E .|G  
} E'Fv *UA  
X*c_^g{  
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Utility.log("Thread " + nThreadID + " is over!"); u+I r:k  
bDownOver = true; 5pKvNLy.t  
//nPos = fileAccessI.write (b,0,nRead); 5* o\z&*L  
} '!r+Tz  
catch(Exception e){e.printStackTrace ();} $jUS[.S_|I  
} K@$L~G
 
} Ok~W@sYST  
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//打印回应的头信息 a2klOX{  
public void logResponseHead(HttpURLConnection con) XYxm8ee"j  
{ Vm,f3~  
for(int i=1;;i++) %M0mwty]  
{ t}c}@i_c  
String header=con.getHeaderFieldKey(i); =|WV^0=S'%  
if(header!=null) %t5BB$y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DESViQM  
Utility.log(header+" : "+con.getHeaderField(header)); :+%h  
else 0:B^  
break; !>Qc2&ZV  
} l_j<aCY?|  
} ek;&<Z_ ]  
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public void splitterStop() X\$W'^np  
{
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bStop = true; a@_
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} Mn }Z
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} t+4Y3*WeGF  
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/* D`~{[cv)\  
**FileAccess.java }fZ=T4r  
*//文件访问(定位，写) -C'X4C+  
package NetFox; M6hvi(!X2  
import java.io.*; 4{pemqS*  
q V UUuyF  
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public class FileAccessI implements Serializable{ }jY[| >z  
 ZV q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3P^gP32  
RandomAccessFile oSavedFile; =u3@ Dhw  
long nPos; IL6f~!  
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public FileAccessI() throws IOException ;Y|~!%2~  
{ $@qs(Xwr  
this("",0); 6[h$r/GXh"  
} CpqSn/
 
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public FileAccessI(String sName,long nPos) throws IOException PD T\Q\J^X  
{ FqUt uN  
oSavedFile = new RandomAccessFile(sName,"rw"); ?^$4)Y>Kf  
this.nPos = nPos; CygV_q
  
oSavedFile.seek(nPos); nC!^,c  
} +l?ro[#6&.  
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public synchronized int write(byte[] b,int nStart,int nLen) )(!Z90@  
{ :0j`yo:w  
int n = -1; A{Htpm~  
try{ r=H\4%P4  
oSavedFile.write(b,nStart,nLen); (DMnwqr  
n = nLen; Fx99"3`3  
} l 75{JxZX  
catch(IOException e) Vv)E41  
{ U>-#('  
e.printStackTrace (); jKV?!~/F  
} `L*;58
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return n; 3pv1L~ ZI  
} @gjdyz  
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} /N{@g.edL  
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/* N5Mz=UgB  
**SiteInfoBean.java [gdPHXs  
*/ eL?si!ZL^  
package NetFox; OHnjI>/  
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public class SiteInfoBean { UYrzsUjg&  
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private String sSiteURL; //Site's URL <a[8;YQC  
private String sFilePath; //Saved File's Path xy3
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private String sFileName; //Saved File's Name de47O  
private int nSplitter; //Count of Splited Downloading File fO(S+}  
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public SiteInfoBean() *`.{K12T  
{//nSplitter的缺省值为5 TC{Qu;`H+U  
//default value of nSplitter is 5 E(LE*J  
this("","","",5); AHD%6 \$  
} @5G7bY7Nz  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M #&L@fg!  
{ Hbc&.W;g7[  
sSiteURL= sURL; r+pjv_R  
sFilePath = sPath; J\D3fh97-  
sFileName = sName; xF|*N<9(</  
this.nSplitter = nSpiltter; \U>Kn_7m  

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} xG/qDc  
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public String getSSiteURL() A_|FsQ6$P  
{ 7e[\0:Z  
return sSiteURL; gSYX@'Q!  
} fGWK&nONyk  
Nb/%>3O@  
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public void setSSiteURL(String value) !T. @  
{ bR,Iq}p  
sSiteURL = value; D07u?  
} S\!E;p  
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public String getSFilePath() `_^=OO
n  
{ (C@@e'e  
return sFilePath; ,`@|C Z-4A  
} Uk\U*\.  
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{?hjx+v[  
public void setSFilePath(String value) kq0m^`  
{ ".D +# 2Kl  
sFilePath = value; 7*
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} Ntiz-qW  
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.p>8oOp  
public String getSFileName() 1hij4m$b  
{ )aSkUytg"  
return sFileName; ?s
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} j]&{ @Y  
+(%[fW  
{hz:[  
public void setSFileName(String value) hhhO+D1(  
{ {H2i+"cF  
sFileName = value; E76:}(  
} HXI}f\6x  
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public int getNSplitter() eVXbYv=gJ@  
{ sf0U(XYQ^  
return nSplitter; ^ BKr0~4A  
} 9<S-b |!@  
,RQ-w2j?  
q?&&:.H"?5  
public void setNSplitter(int nCount) ]U%Tm>s.  
{ KK</5Aw9p  
nSplitter = nCount; aDuanGC/V  
} mN02T@R-  
} 6! 'Xo:p  
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/* e{&gF1"[  
**Utility.java ;rgsPVbVf  
*/ sa*-B  
package NetFox; x}d\%*B  
*OiHrI9y  
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public class Utility { UB}mI0/w  
k1J}9HNYR  
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public Utility() M_K&x-H0  
{ 7[LC*nrr  
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} srL,9)OC  
k"J
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//线程睡眠 <FEO6YP  
public static void sleep(int nSecond) *?{)i~  
{ ]7;;uhn`  
try{ Dg`W{oj  
Thread.sleep(nSecond); 6F2}|c  
} 1a<~Rmcil  
catch(Exception e) F/8y p<_r  
{ Y2Bu,/9^  
e.printStackTrace (); GfDA5v[  
} a'BBp6  
} V6Y!0,w!a  
\T0`GpE  
//日志 _ 0-YsD  
public static void log(String sMsg) 4y'R
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{ eIJQ|p<v  
System.err.println(sMsg); =B 9U  
} /-T%yuU  
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public static void log(int sMsg) Jy9&=Qh   
{ AOpf
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System.err.println(sMsg); [{YV<kN  
} ]l`DR4 =  
} j2+&B9(  
; ?!sU  
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/* 3hkA`YSYt  
**TestMethod.java a`}-^;}SW  
*/ ,Fb#%r%  
package NetFox; @B+];lr/-  
>a,w8^7  
sB $!X@  
public class TestMethod { yDPek*#^"q  
{zw#My   
4R6X"T9-  
public TestMethod() 2l9_$evK~  
{ ///xx/weblogic60b2_win.exe k,2%%m  
try{ c8(.bmvF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); epQ7@9,Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }G]]0Oi2  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  M`
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fileFetch.start(); M:ttzsd  
} Q?~l=}2  
catch(Exception e){e.printStackTrace ();} bp }~{]:b  
!$j'F?2>  
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} s;>jy/o0 s  
t JJaIb6Xj  
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public static void main(String[] args) b(wiJ&t  
{ Zvc{o8^z  
new TestMethod(); .^/OL}/~<  
} <|v]
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} T3\Q<  
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