http断点续传简单实现（java)

/* Qn`Fq,uvL  
**SiteFileFetch.java 6.
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*/ DwIX\9  
package NetFox; KVp3pUO  
import java.io.*; c3C<P  
import java.net.*; MXrh[QCU)  
7 |Q;E|=-Y  
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public class SiteFileFetch extends Thread { R_B`dP<"~Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !c;BOCqa  
long[] nStartPos; //开始位置 M1J77LfS8  
long[] nEndPos; //结束位置 a$]i8AeG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jn+BH3e  
long nFileLength; //文件长度 Bb*P);#.K  
boolean bFirst = true; //是否第一次取文件 -}9>#<v  
boolean bStop = false; //停止标志 ~ }?*v}  
File tmpFile; //文件下载的临时信息 X^)vZL?  
DataOutputStream output; //输出到文件的输出流 Y1 *8&xT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^'Qe.DW[  
public SiteFileFetch(SiteInfoBean bean) throws IOException 52q<|MW%  
{ D0LoT?$N  
siteInfoBean = bean; tlcNGPa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5'S~PQka*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {!NXu  
if(tmpFile.exists ()) [6f(3|"  
{ {R}Kt;L:Ut  
bFirst = false; E[2xo/H  
read_nPos(); l G $s(
 
} #SqU>R  
else I3d!!L2ma  
{
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nStartPos = new long[bean.getNSplitter()]; `R,g_{Mj  
nEndPos = new long[bean.getNSplitter()]; #GOL%2X  
} !Hx[ `3  
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} @y(<4kLz  
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public void run() N~+e\K6  
{ < m/@_"  
//获得文件长度 10{zF_9yx  
//分割文件 )=%TIkeF  
//实例FileSplitterFetch ##BfI`FJ  
//启动FileSplitterFetch线程 _7b' i6-  
//等待子线程返回 \&b1%Asyz  
try{ P; 9{;  
if(bFirst) 1i/&t[  
{ Lb}$)AcC  
nFileLength = getFileSize(); GDY=^r  
if(nFileLength == -1)  $M|  
{ /<Yz;\:Jy  
System.err.println("File Length is not known!"); NM4b]>  
} +AYB0`X)  
else if(nFileLength == -2) bz|-x"qk  
{ dT'd C  
System.err.println("File is not access!"); ?XB[awTD~  
} R_2T"  
else J
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{ Qz`v0"'w  
for(int i=0;i<nStartPos.length;i++) 6D/K=-  
{ Q|(G -  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m#`1.5%  
} x@? Y
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for(int i=0;i<nEndPos.length-1;i++) =H;F{J"  
{ !pxOhO
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nEndPos = nStartPos[i+1]; LGq T$ O|  
} PDkg@#&y,k  
nEndPos[nEndPos.length-1] = nFileLength; >*Ctp +X@  
} [(*?  
} Y>Fh<"A|$  
2k M;7:  
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//启动子线程 4KB>O)YNg'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W[t0hbVw  
for(int i=0;i<nStartPos.length;i++) SSysOeD+  
{ 7~!F3WT{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5F$~ZDu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HUalD3 \  
nStartPos,nEndPos,i); 'g:.&4x_w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0bl8J5Ar5  
fileSplitterFetch.start(); D.*o^{w|  
} k nljc^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u{5+hZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hj,yl&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y+!z]S/x  
nEndPos = " + nFileLength); i)= \-C  
// fileSplitterFetch[nPos.length-1].start(); JVR,Py:%G  
|syvtS{  
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//等待子线程结束 /@Ec[4^=!.  
//int count = 0; JS^!XB'!  
//是否结束while循环 3GPGwzX |  
boolean breakWhile = false; k\Z7Dg$\D  
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while(!bStop) ~PyZh5x  
{ 7f>~P_  
write_nPos(); ne 8rF.D  
Utility.sleep(500); 6)yi^v  
breakWhile = true; T&^b~T(y  
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for(int i=0;i<nStartPos.length;i++) $7*@TMX  
{ R?HuDxHk  
if(!fileSplitterFetch.bDownOver) eXi}-~o  
{ 4
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breakWhile = false; "2Q*-  
break; #+L:V&QE  
} Z $Fm73  
} R\-
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if(breakWhile) YnlZyw!  
break; S|r,RBeZ  
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+%R{j|8#  
//count++; t6Nkv;)>@  
//if(count>4) (?1
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// siteStop(); i-,_:z=J  
} yb) a  
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System.err.println("文件下载结束！"); ,j(S'Pw  
} T 3<2ds  
catch(Exception e){e.printStackTrace ();} ;s?,QvE{r#  
} tHV+#3h  
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,"5][RsOn  
//获得文件长度 RMlx[nsq  
public long getFileSize() LwcAF g|  
{ E|y   
int nFileLength = -1; h-6x! 6pm  
try{ v+C%t!dx  
URL url = new URL(siteInfoBean.getSSiteURL()); 0t%`jY~%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); upiYo(sN.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3;F up4!4}  
` >[Offhd  
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int responseCode=httpConnection.getResponseCode(); _ ($U\FW  
if(responseCode>=400) 7{p6&xXx  
{ ~p x2kHZ  
processErrorCode(responseCode); lBLL45%BIN  
return -2; //-2 represent access is error y.gjs<y  
} 10CRgrZ  
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String sHeader; 5%"sv+iO  
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for(int i=1;;i++) ~cSE 9ul  
{ )i<Qg.@MX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >[S\NAE>  
//Utility.log(in.readLine()); $:D\yZ,  
sHeader=httpConnection.getHeaderFieldKey(i); >,x``-  
if(sHeader!=null) lJt?0;gn  
{ WmuYHE
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if(sHeader.equals("Content-Length")) 4VhKV JX  
{ kOQ!]-;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nw0Tg=
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break; V W(+sSQ  
} 7 lu_E
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} 4wPP/`  
else {J-Ojw|Y b  
break; H^+Znmo  
} e17]{6y  
} NmTo/5s  
catch(IOException e){e.printStackTrace ();} ZQAiuea  
catch(Exception e){e.printStackTrace ();} yT
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Utility.log(nFileLength); x{S2   
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return nFileLength; *d:$vaL  
} d(C5i8d  
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//保存下载信息（文件指针位置） 5ljEh -  
private void write_nPos() V`}u:t7r  
{ @zT2!C?^L  
try{ }$#PIyz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H__'K/nH+  
output.writeInt(nStartPos.length); i4mP*RwC  
for(int i=0;i<nStartPos.length;i++) JtxitF2  
{ ucFfxar"  
// output.writeLong(nPos); =lL)g"xX  
output.writeLong(fileSplitterFetch.nStartPos); Tr, zV  
output.writeLong(fileSplitterFetch.nEndPos); 3[
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} pzb`M'Z?C  
output.close(); aVp-Ps|r  
} ZUS06#t}  
catch(IOException e){e.printStackTrace ();} m}'!W`<  
catch(Exception e){e.printStackTrace ();} ppnl bL^*  
} lS?#(}a1)  
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//读取保存的下载信息（文件指针位置） gdS@NUM  
private void read_nPos() ($t;Xab  
{ _gQ_ixu  
try{ ) .W0}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); UL" M?).5  
int nCount = input.readInt(); !e}4>!L,(^  
nStartPos = new long[nCount]; o_&Qb^W  
nEndPos = new long[nCount]; |k]fY*z(  
for(int i=0;i<nStartPos.length;i++) X?Or.  
{ .\8LL,zT  
nStartPos = input.readLong(); 1V-sibE  
nEndPos = input.readLong(); eE@7AM  
} j|LOg  
input.close(); 5:%`&B\  
} ~'N+O K  
catch(IOException e){e.printStackTrace ();} zZP&`#TAy  
catch(Exception e){e.printStackTrace ();}
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} R#!U
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private void processErrorCode(int nErrorCode) luJNdA:t&  
{ De<i 8/^=  
System.err.println("Error Code : " + nErrorCode); GjbOc   
} Kf
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//停止文件下载 PoD/i@  
public void siteStop() &;U F,  
{ p,14'HS%@  
bStop = true; I7W?}bR*6  
for(int i=0;i<nStartPos.length;i++) m,&2s-v  
fileSplitterFetch.splitterStop(); 1^2]~R9,9  
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} VP*B<u  
} kNX8y--  
//负责部分文件的抓取 YMj iJTl  
**FileSplitterFetch.java !\\OMAf7  
*/ *!yA'
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package NetFox; 3*-!0  
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import java.io.*; kb!W|l"PN  
import java.net.*; %DKC/%  
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public class FileSplitterFetch extends Thread { 3U*4E?g  
g\H~Y@'{  
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String sURL; //File URL $F6GCM3Cx  
long nStartPos; //File Snippet Start Position G`f|#-}  
long nEndPos; //File Snippet End Position cbW=kQc_  
int nThreadID; //Thread's ID qNUd "%S  
boolean bDownOver = false; //Downing is over VH] <o0  
boolean bStop = false; //Stop identical O6ltGtF  
FileAccessI fileAccessI = null; //File Access interface +pe\9F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s\(@f4p  
{ -c#vWuLl  
this.sURL = sURL; c_Iq!MH  
this.nStartPos = nStart;  ~;uU{TT  
this.nEndPos = nEnd; %&eBkN!T  
nThreadID = id; d"S\j@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &UAYYH  
} HcpAp]L)  
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public void run() 9{%/I   
{ [-^xw1:  
while(nStartPos < nEndPos && !bStop) =-avzuy#  
{ WfQZ7e  
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try{ 
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URL url = new URL(sURL); zL3I!& z2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TRr%]qd{Hr  
httpConnection.setRequestProperty("User-Agent","NetFox"); e@PY(#ru  
String sProperty = "bytes="+nStartPos+"-"; u ^M'[<{  
httpConnection.setRequestProperty("RANGE",sProperty); 7gREcL2  
Utility.log(sProperty); @B!gxW\C  
>^g\s]c[  
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InputStream input = httpConnection.getInputStream(); 4}0Ry\ 6  
//logResponseHead(httpConnection); %
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byte[] b = new byte[1024]; 3!8u
 
int nRead; $5DlCN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M2nU
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{ w`atk=K  
nStartPos += fileAccessI.write(b,0,nRead); *P?Rucg  
//if(nThreadID == 1) c`oW-K{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +y\o^w4sT  
} C%#u2C2  
}4?z<.V  
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Utility.log("Thread " + nThreadID + " is over!"); hb1eEn  
bDownOver = true; !1l~'/r  
//nPos = fileAccessI.write (b,0,nRead); I(b]V!mj:  
} NzS`s,N4/0  
catch(Exception e){e.printStackTrace ();} k{bC3)'$#R  
} {gzVbZ#  
} CW FE{  
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8_M"lU0[  
//打印回应的头信息 Q~`{^fo1  
public void logResponseHead(HttpURLConnection con) Dn`  
{ z~ua#(z1S  
for(int i=1;;i++) V14+?L  
{ GQ sE5Vb  
String header=con.getHeaderFieldKey(i); SQ<{X/5  
if(header!=null) B[d%?L_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F:AVik  
Utility.log(header+" : "+con.getHeaderField(header)); |<%v`*  
else D#[<N  
break; lkJe7 +s  
} 5=1Ml50  
} V?~!Dp  
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public void splitterStop() p[}~Z|(  
{ Ao\Im(?  
bStop = true; 8EU/}Ym  
} ,x?Jrcx~'C  
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} {:=]J4]  
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+K,T^<F;  
/* 7tne/Yz  
**FileAccess.java szD9z{9"y  
*//文件访问(定位，写) Az/B/BLB  
package NetFox; g*!1S  
import java.io.*; w8zr0z  
}|wC7*^)  
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public class FileAccessI implements Serializable{ EXR6Vb,  
u(8dsgR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6#ktw)e  
RandomAccessFile oSavedFile; MjK<n[.  
long nPos; 4~2 9,  
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public FileAccessI() throws IOException &AVX03P  
{ i?,\>LTG  
this("",0); .R^ R|<x  
} |W}D_2  
0 c]]  

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public FileAccessI(String sName,long nPos) throws IOException YD0j&@.  
{ EAz>`~  
oSavedFile = new RandomAccessFile(sName,"rw"); 6q,CEm  
this.nPos = nPos; (px3o'lsh  
oSavedFile.seek(nPos); ^2i$AM1t  
} 7cO1(yE#vr  
@.,'A[D!K  
+wZ|g6vMct  
public synchronized int write(byte[] b,int nStart,int nLen) =&~ K;=:  
{ { T<[-"h  
int n = -1; {U4{v=,!I  
try{ @~FJlG(n  
oSavedFile.write(b,nStart,nLen); R_"6E8N  
n = nLen; #}Bv/`t  
} X.ZG-TC  
catch(IOException e) iO$ ?No  
{ [7 t  
e.printStackTrace (); C8=rsh  
} /l8wb~vl  
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return n; tH:?aP*2  
} EJNHZ<  
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} O2xqNQ`d  
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/* _qH]OSo  
**SiteInfoBean.java @c}Gw;e  
*/ }N:QB}7'_  
package NetFox; YoZd,} i  
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public class SiteInfoBean { #%{  
%}unlSTPP  
}H/94]~tH  
private String sSiteURL; //Site's URL "2 D{X  
private String sFilePath; //Saved File's Path h;mOfF  
private String sFileName; //Saved File's Name '-#gQxIpD  
private int nSplitter; //Count of Splited Downloading File Iz&d S?p_  
?"kU+tCxg  
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public SiteInfoBean() G0Z$p6z  
{//nSplitter的缺省值为5 s !II}'Je  
//default value of nSplitter is 5 s"~,Zzy@j  
this("","","",5); 4C3i  
} Z=l2Po n  
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?P}) Qa  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X>Z83qV5d!  
{ :u2tu60&MJ  
sSiteURL= sURL; [a.(0YLr'w  
sFilePath = sPath; YVk +zt~S  
sFileName = sName;
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this.nSplitter = nSpiltter; .!'rI7Kz'i  
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} fT=ZiHJ3Gu  
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7,Q7`}gBf  
public String getSSiteURL() `.wgRUhFH;  
{
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return sSiteURL; }I
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} [geT u  
|
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public void setSSiteURL(String value) bNoZ{ 7  
{ gL1r"&^L  
sSiteURL = value; @[1,i~H  
} 9
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*48LQzc  
1+l[P9?R[  
public String getSFilePath() ,S?:lQuK5  
{ $H6ngL  
return sFilePath; uL^X$8K;(  
} \\ZhM  
r%LG>c
`^  
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public void setSFilePath(String value) y }h2
  
{ YL[y3&K  
sFilePath = value; <4^y7]]F  
} u%Z4 8wr  
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{q&A/  
public String getSFileName() p4K 8L'nZ  
{ }@53*h i(  
return sFileName; rWBgYh  
} $<f+CtD4  
7K!n'dAi6  
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public void setSFileName(String value) 7/\SN04l  
{ / $'M  
sFileName = value; ])WIw'L!  
} RC!T1o~L  
6X$\:>  
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public int getNSplitter() sZokiFJ  
{ -Q1~lN m:  
return nSplitter; b+BX >$  
} 0%3T'N%  
WhV>]B2+"  
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public void setNSplitter(int nCount) k7z{q/]M  
{ 4Q\~l(  
nSplitter = nCount; n>%TIoY  
} eT8h:+k  
} S7CD#Y[s  
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/ZSdY_%s  
/* u#Uc6? E  
**Utility.java \BSPv]d  
*/ ~s[Yu!(  
package NetFox; ET3+07  
KpO%)M!/Z#  
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public class Utility { $U%N$_k?  
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public Utility() GU)NZ[e  
{ Q\$cBSJC1  
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dr4m}v.  
} E+eC #!&w  
_?>f
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//线程睡眠 J-Fqw-<aFJ  
public static void sleep(int nSecond) M]e _@:!  
{ l,Ixz1S3e  
try{ p*=9Ea:  
Thread.sleep(nSecond); a#,lf9M  
} Js!Zk\O  
catch(Exception e) Pu!%sGjD  
{ ;'|t>'0_  
e.printStackTrace (); glWa?#1  
} /A`Lyp#  
} *\[GfTL  
OH~I+=}.  
//日志 m*TJ@gI*t  
public static void log(String sMsg) k12mxR/  
{ =v=H{*dWA  
System.err.println(sMsg); [0n&?<<  
} fOO[`"'Pq  
\"A~ks~  
'
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public static void log(int sMsg) +'?axv6e  
{ %MN>b[z  
System.err.println(sMsg); fehM{)x2:  
} 2lBu"R6}  
} rjT!S1Hs  
4_?*@L1  
j'FBt8P'  
/* TM$`J  
**TestMethod.java 6.GIUM%D  
*/ !rgdOlTR^  
package NetFox; m2Q#ATLW  
,vUMy&AV  
n!\&X9%[8  
public class TestMethod { i52:<< 8a  
*AN2&>Y  
jo
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public TestMethod() {2%@I~US  
{ ///xx/weblogic60b2_win.exe _{'HY+M  
try{ G(y@Tor+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xBMhk9b^0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \9dC z;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9#niMv9  
fileFetch.start(); }!RFX)T  
} ,LJX  
catch(Exception e){e.printStackTrace ();} c-^\YSDMN  
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_&6&sp<n  
} d[I}+%{[  
BM]sW:-v  
m.N/g,  
public static void main(String[] args) 0sKY;(  
{ Ot_xeg;7  
new TestMethod(); P(za8l
>  
} 20H$9M=}  
} kVe_2oQ_>  
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