http断点续传简单实现（java)

/* ZG<!^tj  
**SiteFileFetch.java ~(/HgFLLu  
*/ b1]_e'jj  
package NetFox; yWtr,  
import java.io.*; Fd&!-`T?  
import java.net.*; E0]h|/A]  
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public class SiteFileFetch extends Thread { p\;)^O4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -z$2pXT ^  
long[] nStartPos; //开始位置 >?eTbtP  
long[] nEndPos; //结束位置 {dXBXC/Ju  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /t)c fFM  
long nFileLength; //文件长度 otD?J= B  
boolean bFirst = true; //是否第一次取文件 PZRn6Tc  
boolean bStop = false; //停止标志 S!W/K!wf  
File tmpFile; //文件下载的临时信息 @[lc0_b  
DataOutputStream output; //输出到文件的输出流 .4FcZJvy  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0DVZRB  
public SiteFileFetch(SiteInfoBean bean) throws IOException R 0HVLQI  
{ hUvuq,LH_  
siteInfoBean = bean; -Dxhq& }Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); poYAiq_3T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )z235}P  
if(tmpFile.exists ()) 'F"Y?y:!  
{ Ij}F<ZgZG  
bFirst = false; /:{_|P\  
read_nPos(); k+#l;<\2  
} x>,F*3d3  
else <!}l~Ln15  
{ 2, "q_d'V  
nStartPos = new long[bean.getNSplitter()]; oXlxPN39  
nEndPos = new long[bean.getNSplitter()]; 9_WPWFO  
} oA;Ty7s  
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R 4$Q3vcH  
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} tG2OVRx8u  
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public void run() _p J_V>l  
{ w-H%B`/  
//获得文件长度 SU%rWH  
//分割文件 q bZ,K@0  
//实例FileSplitterFetch l P$r   
//启动FileSplitterFetch线程 A?IZ( Zx(`  
//等待子线程返回 FfxX
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try{ 1 73<x){  
if(bFirst) :x""E5H  
{ vf'cx:m  
nFileLength = getFileSize(); -<51CDw,  
if(nFileLength == -1) )0U3w#,JQ  
{ w~$c= JO#  
System.err.println("File Length is not known!"); Uc&6=5~Ys\  
} d]7|v r]  
else if(nFileLength == -2) Dpdn%8+Z  
{ hk@`N;dn  
System.err.println("File is not access!"); ^s2m\Q(  
} JXL9Gge  
else X$-boe?  
{ t8AkdSU0  
for(int i=0;i<nStartPos.length;i++) ?{"XrQw
  
{ ^$=tcoQG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uS,p|}Q&  
} \7,MZt  
for(int i=0;i<nEndPos.length-1;i++) %wt2F-u  
{ :vYtMp  
nEndPos = nStartPos[i+1]; X`fhln9N  
} q}<.x8\  
nEndPos[nEndPos.length-1] = nFileLength; msc 1^2  
} \-Iny=$  
} NV}RRs  
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//启动子线程 "[jhaUAK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3:[!t%Yb  
for(int i=0;i<nStartPos.length;i++) *.m{jgi1X  
{ _{6,.TN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,8c dXt   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /~i.\^HX
 
nStartPos,nEndPos,i); FOCoiocPi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5-8]N>/b!  
fileSplitterFetch.start(); [8F \;  
} \npz.g^c_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4 ,p#:!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ";PG%_(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9?uqQ  
nEndPos = " + nFileLength); e7@li<3>d  
// fileSplitterFetch[nPos.length-1].start(); r0F_;  
V~OUE]]Q  
|EF>Y9   
//等待子线程结束 Y 3o^Euou  
//int count = 0; 94Xjz(  
//是否结束while循环 DpA\r_D  
boolean breakWhile = false; p QluGIX0V  
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while(!bStop) QTVa  
{ U?8i'5)  
write_nPos(); 3PfiQ|/b  
Utility.sleep(500); }%eD
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breakWhile = true; K<c2P
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for(int i=0;i<nStartPos.length;i++) YMi/uy  
{ 49o\^<4b  
if(!fileSplitterFetch.bDownOver) }A-{6Qe  
{ [!W5}=^H  
breakWhile = false; <z,+Eg  
break; nt7|f,_J  
} u[)_^kIE(n  
} O{~KR/  
if(breakWhile) ze&#i6S  
break; sr\cVv")  
)&>L !,z  
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//count++; G(3;;F7"  
//if(count>4) d [r-k 2  
// siteStop(); yx2z%E  
} ]a M-p@  
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System.err.println("文件下载结束！"); ^CUSlnB\(  
} K!p,x;YX  
catch(Exception e){e.printStackTrace ();} d,UCH  
} [P{a_(
 
s'TY[  
[,rn3CA  
//获得文件长度 h(nj,X+  
public long getFileSize() J smB^  
{ L"^OdpOs  
int nFileLength = -1; wqP2Gw7jh6  
try{ ;,k=<]  
URL url = new URL(siteInfoBean.getSSiteURL()); Fwb5u!_,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6|5H=*)DH  
httpConnection.setRequestProperty("User-Agent","NetFox"); GV5qdD(  
.%IslLZ  
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int responseCode=httpConnection.getResponseCode(); [X<Pk  
if(responseCode>=400) ywOmQcZ  
{ *1$
 
processErrorCode(responseCode); 6T_K9  
return -2; //-2 represent access is error wG8 nw;  
} 2
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String sHeader; 'C
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for(int i=1;;i++) xzr<k S
p  
{ !zR)D|w&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 45<y{8  
//Utility.log(in.readLine()); cS(;Qs]Q  
sHeader=httpConnection.getHeaderFieldKey(i); :y1Bt+Fp  
if(sHeader!=null) |@wyC0k!  
{ @PX\{6&  
if(sHeader.equals("Content-Length")) wXbsS)#/  
{ o_$&XNC_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); to`mnp9Z  
break;  q=4Bny0  
} >g}G}=R~3  
} R/~,i;d>  
else R,,Qt TGB  
break; `*_CElpP"  
} )%F5t&lum  
} wd+K`I/v7h  
catch(IOException e){e.printStackTrace ();} :o8MUXH$  
catch(Exception e){e.printStackTrace ();} WbcS: !0  
"r$/  
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Utility.log(nFileLength); x)oRSsv!Tr  
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# yN*',I&  
return nFileLength; W5 ec  
} Zh'&-c_J  
{dzoEM[ 1s  
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//保存下载信息（文件指针位置） f<=Fe:1.  
private void write_nPos() tJU-<{8  
{ Bp_wnd  
try{ Ow/@Z7~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6gU{(H   
output.writeInt(nStartPos.length); -6C +LbV  
for(int i=0;i<nStartPos.length;i++)
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{ m4m<nnM  
// output.writeLong(nPos); *y]+dK&-  
output.writeLong(fileSplitterFetch.nStartPos); MbA\pG
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output.writeLong(fileSplitterFetch.nEndPos); AK@L32-S  
} OH'ea5xq  
output.close(); :]II-$/8  
} z]@6fM[  
catch(IOException e){e.printStackTrace ();} q.V-LXM  
catch(Exception e){e.printStackTrace ();} w/m:{cHk  
} [*4fwk^  
/,tAoa~FA  
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//读取保存的下载信息（文件指针位置） 5?u}#zO  
private void read_nPos() g0R[xOS|  
{ i.y)mcB4  
try{ EgM*d)X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `I;F$`\  
int nCount = input.readInt(); ] d?x$>  
nStartPos = new long[nCount]; zm#nV Y`  
nEndPos = new long[nCount]; 57I}RMT"  
for(int i=0;i<nStartPos.length;i++) TqAPAHg  
{ {/8
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nStartPos = input.readLong(); \R
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nEndPos = input.readLong(); nJFg^s1  
} V5mTu)tp5  
input.close(); =|U@  
} s8mr''  
catch(IOException e){e.printStackTrace ();} sen=0SB/  
catch(Exception e){e.printStackTrace ();} ccJM>9  
} Jjm|9|C,  
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#JW+~FU`  
private void processErrorCode(int nErrorCode) T)iW`vZg8  
{ |U'I/A  
System.err.println("Error Code : " + nErrorCode); svhI3"
r  
} j`>^1Q  
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[iS$JG-  
//停止文件下载 iCQ>@P]nE  
public void siteStop() 8|g<X1H{M  
{ 8y2+&#$  
bStop = true; dK9Zg,DZL  
for(int i=0;i<nStartPos.length;i++) ]uh3R{a/  
fileSplitterFetch.splitterStop(); LHYLC>J  
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3
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} $lwz-^1t.  
} YwDt.6(+,  
//负责部分文件的抓取 ^QXbJJ  
**FileSplitterFetch.java Bi%x`4Lf  
*/ 1NLg _UBOK  
package NetFox; `ldz`yu6++  
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import java.io.*; o>]`ac0b}Y  
import java.net.*; x!<yT?A  
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public class FileSplitterFetch extends Thread { hGTV;eU  
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String sURL; //File URL :l u5Uu~  
long nStartPos; //File Snippet Start Position O6s.<`\  
long nEndPos; //File Snippet End Position iJh!KEy~A5  
int nThreadID; //Thread's ID Sm{>rR  
boolean bDownOver = false; //Downing is over 2t#L:vY  
boolean bStop = false; //Stop identical 'DbMF?<.  
FileAccessI fileAccessI = null; //File Access interface OS-f(qXd+  
3`.P'Fh(k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException % ZU/x d  
{ 0#p/A^\#7M  
this.sURL = sURL; e]8,:Gd(  
this.nStartPos = nStart; Am4lEvb  
this.nEndPos = nEnd; 6sfwlT  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 }?8uH/+ZA  
} Fj p.T;  
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public void run() rSXzBi{  
{ (8a#
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while(nStartPos < nEndPos && !bStop) pbXi9|bI  
{ DvXHK  
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try{ |UnUG  
URL url = new URL(sURL); |bv,2uWz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bCv{1]RC2  
httpConnection.setRequestProperty("User-Agent","NetFox");
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String sProperty = "bytes="+nStartPos+"-"; n$L51#'  
httpConnection.setRequestProperty("RANGE",sProperty); ;t#]2<d*  
Utility.log(sProperty); LJlZ^kh  
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InputStream input = httpConnection.getInputStream(); rJyCw+N0  
//logResponseHead(httpConnection); >h~IfZU1  
"f.Z}AbP  
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byte[] b = new byte[1024]; :3h{ A`u  
int nRead; uRV<?y%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Av J4\  
{ +~zXDBS9  
nStartPos += fileAccessI.write(b,0,nRead); mB'3N;~  
//if(nThreadID == 1) jdA ]2]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =qVP] 9  
} ~#K@ADYr  
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22hSove.  
Utility.log("Thread " + nThreadID + " is over!"); V<Z'
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bDownOver = true; -T@`hk`  
//nPos = fileAccessI.write (b,0,nRead); ~EiH-z4U  
} n||A"
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catch(Exception e){e.printStackTrace ();} ?i\;:<e4  
} u
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} s54nF\3V  

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2!1.E5.I  
//打印回应的头信息 Rfb?f}j  
public void logResponseHead(HttpURLConnection con) kh$_!BT  
{ g\fhp{gWB  
for(int i=1;;i++) ;!>Wz9  
{ Qq& W3  
String header=con.getHeaderFieldKey(i); w0m^ &,;#  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); oih5B<&f#  
Utility.log(header+" : "+con.getHeaderField(header)); \/`?  
else 6c4&VW
  
break; 'fV%Z  
} xg`h40c  
} e0,'+;*=g  
h+~P"i}&\  
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public void splitterStop() cV K7  
{ 0rSIfYZa  
bStop = true; \`.F\Z  
} E8\XNG)V4  
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} %hS|68pN6  
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Y qdWctUY  
/* jjs&`Fy,  
**FileAccess.java G`h+l<  
*//文件访问(定位，写) yGBQ0o7E  
package NetFox; x+5p1sv6  
import java.io.*; o?Nu:&yE  
+Lm4kA+aE5  
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public class FileAccessI implements Serializable{ rnFM/GAy  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y7\"[<E`(V  
RandomAccessFile oSavedFile; .Ce8L&cU  
long nPos; OWjJxORB  
. v)mZp  
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public FileAccessI() throws IOException I
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{ `g''rfk}  
this("",0); Wl"0m1G  
} t G.(flW,  
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public FileAccessI(String sName,long nPos) throws IOException v5ur&egVs  
{ []W;t\h  
oSavedFile = new RandomAccessFile(sName,"rw"); ?8@>6IXn  
this.nPos = nPos; Ds8 EMtS  
oSavedFile.seek(nPos); sRHA."A!8  
} n| O [a6G  
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public synchronized int write(byte[] b,int nStart,int nLen)
l]!9$  
{ '(+<UpG_Q}  
int n = -1; 8y';\(;  
try{ v`[Eb27W.  
oSavedFile.write(b,nStart,nLen); gYAF'?  
n = nLen; \,UZX&ip  
} ;;s* Ohh  
catch(IOException e) ,8G{]X)  
{ Y(
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e.printStackTrace (); x|64l`Vp(:  
} vEe NW  
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return n; :c[n\)U[aa  
} >-<8N-@"n  
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} KLQTKMNv  
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/* Fig&&b a  
**SiteInfoBean.java `D5HC  
*/ I3S9Us-\  
package NetFox; ?NNn:tiD  
9a$56GnW1  
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public class SiteInfoBean { )QiQn=Ce  
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private String sSiteURL; //Site's URL W1aa:hEf  
private String sFilePath; //Saved File's Path C.MoKa3  
private String sFileName; //Saved File's Name C&\5'[*  
private int nSplitter; //Count of Splited Downloading File >XW
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$K~LM8_CKy  
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public SiteInfoBean() \[2lvft!  
{//nSplitter的缺省值为5 'fwU]Hm  
//default value of nSplitter is 5 &sVvWNO#2  
this("","","",5); {Z;t ^:s#  
} F9q8SA#"  
SU_SU".  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a@d=>CT$  
{ 9~IQw#<  
sSiteURL= sURL; 0"k|H&  
sFilePath = sPath; donw(_=  
sFileName = sName; nx":"LFI  
this.nSplitter = nSpiltter; v0*N)eqDGd  
%!Q`e79g8  
N@o?b  
} xom<P+M!|  
{1J&xoV"  
a)-FGP^  
public String getSSiteURL() w>?Un,K  
{ _cDF{E+;  
return sSiteURL; _+f+`]iM  
} D]! aT+  
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public void setSSiteURL(String value) uv{P,]lK  
{ Jc4L5*Xn/  
sSiteURL = value; cX!Pz.C  
} or ;f&![w  
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public String getSFilePath() v*hRz;  
{ .]4W!])9  
return sFilePath; em@EDMvI  
} jZfx Jm  
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public void setSFilePath(String value) Si}HX!s  
{ G)=HB7u[a  
sFilePath = value; I{0k  
} n;XW
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public String getSFileName() ZsP2>%"  
{ I XA>`D  
return sFileName; (n( fI f  
} y
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)(Iy<Y?#  
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public void setSFileName(String value) WUdKLx%F  
{ e=P  
sFileName = value; JYqSL)Ta*t  
} nCg66-3A  
EEy$w1ec  
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public int getNSplitter() Tq<2`*Qs  
{ ihL/n  
return nSplitter; 05\dl  
} @!=\R^#p  
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public void setNSplitter(int nCount) JM$.O;y -  
{ pz^<\  
nSplitter = nCount; XP[uF ;w  
} K5Wg"^AHY/  
} I lR\  #  
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yQS+P8x&|]  
/* yWPIIWHx!  
**Utility.java EER`?Sa(  
*/ S|AM9*k9  
package NetFox; _S0+;9fhY  
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public class Utility { H2gj=krK  
QA!_} N4n  
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public Utility() Lju7,/UD  
{ UQCo}vM  
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} R  
10Wz,vW,n  
//线程睡眠
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public static void sleep(int nSecond) FaT
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{ =%)+%[wv  
try{ !{,F~i9  
Thread.sleep(nSecond); aAvsb$  
} 4wzlJ19E(  
catch(Exception e) Qq-"Cg@-/  
{ SD\= m/W  
e.printStackTrace (); /
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} /h2b;"  
} bte~c  
{'+QH)w(  
//日志 1&=0Wg0ig  
public static void log(String sMsg) qr\!*\9  
{ I<b?vR
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System.err.println(sMsg); 0X2@CPIFf  
} ij5g^{_T;8  
8$N8}q%  
NMO-u3<6.  
public static void log(int sMsg) w JwX[\
 
{ 9ch#}/7B  
System.err.println(sMsg); Z[!d*O%R_  
} Ey{%XR+*;  
} 1iT\df  
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/* K[\'"HyQ,X  
**TestMethod.java -u!qrJ*Z  
*/ stl 1QO(h  
package NetFox; `?\tUO2_T  
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Dz=k7zRg"  
public class TestMethod { Rr(* aC2P  
m%+IPZ2m  
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public TestMethod() {MAQ/5  
{ ///xx/weblogic60b2_win.exe Vpfp}pL  
try{ ulHn#)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,''cNV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /e\{   
SiteFileFetch fileFetch = new SiteFileFetch(bean); z!Q
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fileFetch.start(); `+lHeLz':  
} 6< J #^ 6  
catch(Exception e){e.printStackTrace ();} ~d{.ng 4K  
f"#m=_Xm  
? ]sM8Bd}  
} 7fp(R&)1  
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public static void main(String[] args) <BWkUZz\P|  
{ kpwt]]e*  
new TestMethod(); hli|B+:m"  
} Oh.ZPG=  
} G |*(8r()  
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