http断点续传简单实现（java)

/* ^\mN<z(  
**SiteFileFetch.java ][b
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*/ N1(}3O  
package NetFox; SJ7>*Sa(u$  
import java.io.*; j&Ayk*  
import java.net.*; i4!n O
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public class SiteFileFetch extends Thread { a@,tf'Sr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YKl!M/  
long[] nStartPos; //开始位置 ,^o^@SI)
 
long[] nEndPos; //结束位置 ,lA J{5\#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aM.l+D
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long nFileLength; //文件长度 foE2rV/Y  
boolean bFirst = true; //是否第一次取文件 O,JthlAV4  
boolean bStop = false; //停止标志 =OO_TPEZ  
File tmpFile; //文件下载的临时信息 uD:O[H-x  
DataOutputStream output; //输出到文件的输出流 r:Cad0xj;^  
Q:VD2<2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `U`Z9q5-  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9LJ/m\bi  
{ nhXa&Nro  
siteInfoBean = bean; rmQGzQnun  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4b3p,$BWS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <k^9l6@  
if(tmpFile.exists ()) WM=kr$/3  
{ x'JfRz  
bFirst = false; -07(#>  
read_nPos(); B{1+0k  
} TJsT .DWW~  
else 9f,HjR
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{ <)n
  
nStartPos = new long[bean.getNSplitter()]; #^#)OQq]  
nEndPos = new long[bean.getNSplitter()];  |Be.r{l  
} s9`T%pg  
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} u{p\8v%7  
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public void run() vW)GUAF[  
{ p6}
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//获得文件长度 *%)L?*  
//分割文件 ,}FYY66K  
//实例FileSplitterFetch NKd@Kp`,  
//启动FileSplitterFetch线程 7 cIVK}&  
//等待子线程返回 )s=z i"  
try{ tfv]AC7x  
if(bFirst) B4|%E$1+  
{ & bw1  
nFileLength = getFileSize(); s:]rL&|  
if(nFileLength == -1) H#Og0gEE}5  
{ V">Uh@[J_  
System.err.println("File Length is not known!"); `XWxC:j3%  
} bh7 1Zu  
else if(nFileLength == -2) 4a2&kIn  
{ KP<J~+_ik  
System.err.println("File is not access!"); @Qc['V)  
} ^jmnE.8R  
else / V{w<  
{ B|GJboQ  
for(int i=0;i<nStartPos.length;i++) Fsq S)  
{ IG9Q~7@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]-PF?8  
} h0^V!.-5  
for(int i=0;i<nEndPos.length-1;i++) nM0nQ{6  
{ G0]n4"~+?  
nEndPos = nStartPos[i+1]; 10}Zoq|)n  
} *!s4#|h  
nEndPos[nEndPos.length-1] = nFileLength; z~VA#8>  
} f1~3y}7^Jq  
} [#9ij3vxd  
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#JLDj(a?  
//启动子线程 GO?-z0V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~l}TlRqL  
for(int i=0;i<nStartPos.length;i++) %r
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{ BklB3*n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xd .I5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O5=ggG  
nStartPos,nEndPos,i); Y\%}VD2k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); f`IgfJN  
} "rKIXy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $&e(
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xY~ DMcO?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BO9Z"|"  
nEndPos = " + nFileLength); f$Ap\(.  
// fileSplitterFetch[nPos.length-1].start(); mJsYY,b8  
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1I@4xC #X  
//等待子线程结束 ]nQ$:%HP  
//int count = 0; c~tSt.^WX  
//是否结束while循环 YwF6/JA0^  
boolean breakWhile = false; =6W:O  
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while(!bStop) ~.@fk}'R  
{ pJv?  
write_nPos(); ~F(+uJbO  
Utility.sleep(500); 5~44R@`  
breakWhile = true; )Xh_q3=  
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for(int i=0;i<nStartPos.length;i++) -pD&@Wlwak  
{ `?D_=Gw  
if(!fileSplitterFetch.bDownOver) V!opnLatYS  
{ @"/
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breakWhile = false; KqSa"76R  
break; P5d@-l%}  
} $@Ay0GEI"  
} `-/l$A} U  
if(breakWhile) qA~D*=  
break; 1tr>D:c\  
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//count++; v|/3Mi9mz  
//if(count>4) !:n),sFv45  
// siteStop(); EIYM0vls(  
} U.)G#B  
7IHD?pnZ  
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System.err.println("文件下载结束！"); Zn/9BO5  
} t!T}Pg(Bo  
catch(Exception e){e.printStackTrace ();} Qr<%rU^{.  
} I|j
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//获得文件长度 ,|#>X>^FQQ  
public long getFileSize() 2 Lamvf  
{ &S3W/lQs  
int nFileLength = -1; |O)deiJRy  
try{ %'t~e?
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URL url = new URL(siteInfoBean.getSSiteURL()); XF7W'^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :HE]P)wz-  
httpConnection.setRequestProperty("User-Agent","NetFox"); `
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int responseCode=httpConnection.getResponseCode(); 9kF#*  
if(responseCode>=400) eb/V}%  
{ fD~!t 8J  
processErrorCode(responseCode); 38m%if
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return -2; //-2 represent access is error K8UAz"  
} jzj{{D[^  
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String sHeader; ,Mhe:^3  
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for(int i=1;;i++) ii;WmE&  
{ |tg?b&QR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {a3kn\6H0  
//Utility.log(in.readLine()); ZmULy;{<)  
sHeader=httpConnection.getHeaderFieldKey(i); `Q&]dE=  
if(sHeader!=null) &1p8#i  
{ bNROXiX  
if(sHeader.equals("Content-Length")) ,OKM\N,  
{ yo*iv+l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; nFfCw%T?  
} }91mQ`3  
} Qsntf.fT  
else P*PL6UQ  
break; f^)uK+:.  
} +2zuIW.  
} Ib2@Wi   
catch(IOException e){e.printStackTrace ();} KCk?)Qv  
catch(Exception e){e.printStackTrace ();} S(J\<)b  
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Utility.log(nFileLength); A&P1M6Of  
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return nFileLength; M?B(<j1Ri  
} IMGqJc,7  
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//保存下载信息（文件指针位置） uit-Q5@~  
private void write_nPos() UNQRtR/  
{ w`}9/s;$  
try{ s1vrzze  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v\Y}(fD  
output.writeInt(nStartPos.length); TJXraQK-=  
for(int i=0;i<nStartPos.length;i++) <KwK tgzs  
{ Uk:.2%S2  
// output.writeLong(nPos); cU*lB!  
output.writeLong(fileSplitterFetch.nStartPos); H\I!J@6g  
output.writeLong(fileSplitterFetch.nEndPos); <8)s  
} F36ViN\b  
output.close(); $a^isd4  
} ,Us2UEWNv  
catch(IOException e){e.printStackTrace ();} >J}n@MZ  
catch(Exception e){e.printStackTrace ();} 5!ubY 6Ph  
} zw:C*sY  
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//读取保存的下载信息（文件指针位置） JYd7@Msfc  
private void read_nPos() b;L>%;  
{ v1r_Z($  
try{ )_v\{N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s$Zq/l$1x  
int nCount = input.readInt(); .NkAD-k`  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; y5/6nvH_6  
for(int i=0;i<nStartPos.length;i++) qijcS2E6S  
{ (
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nStartPos = input.readLong(); tQ~<i %;  
nEndPos = input.readLong(); ~g1, !Wl  
} u5Ny=Xm  
input.close(); 5w3ZUmjO  
} `<J#l;y  
catch(IOException e){e.printStackTrace ();} v (ka,Dk3  
catch(Exception e){e.printStackTrace ();} irsfJUr[V  
} 3%R{"Q"  
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private void processErrorCode(int nErrorCode)  Wu!t C  
{ s^>
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System.err.println("Error Code : " + nErrorCode); N\q)LM !M  
} ]iDJ*!I  
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//停止文件下载 5!AV!A_Jp  
public void siteStop() f>r3$WKj  
{ rer|k<k;]G  
bStop = true; %X9b=%'+  
for(int i=0;i<nStartPos.length;i++) \V^*44+ <!  
fileSplitterFetch.splitterStop(); jJVT_8J  
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} +~d1;0l|  
} (a `FS,M  
//负责部分文件的抓取 x=5P+_  
**FileSplitterFetch.java sz/*w7  
*/ L}W1*L$;<  
package NetFox; ku9@&W+  
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import java.io.*; \2Og>{"U  
import java.net.*; t<
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public class FileSplitterFetch extends Thread { JoCA{Fa}  
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String sURL; //File URL 't(}Rq@  
long nStartPos; //File Snippet Start Position {/d4PI7)tK  
long nEndPos; //File Snippet End Position {7?9jEj  
int nThreadID; //Thread's ID &$qF4B*  
boolean bDownOver = false; //Downing is over \Mb(6~nC  
boolean bStop = false; //Stop identical BWUt{,?KU  
FileAccessI fileAccessI = null; //File Access interface j1YH9T#|D  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x_==Ss  
{ )nwZ/&@  
this.sURL = sURL; H&X:!xa5  
this.nStartPos = nStart; AJyq>0p  
this.nEndPos = nEnd; F
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nThreadID = id; :N@U[Wx0A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %bP~wl~  
} MZ|\S/  
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public void run() \=!H2M  
{ fcRj  
while(nStartPos < nEndPos && !bStop) p jKt:R}  
{ mG)8U{L  
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try{ $!G`D=  
URL url = new URL(sURL); 9Ct_$.Q.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xb}!0k/{  
httpConnection.setRequestProperty("User-Agent","NetFox"); qy_%~c87  
String sProperty = "bytes="+nStartPos+"-"; '>3`rsu  
httpConnection.setRequestProperty("RANGE",sProperty); =}JBA>q(  
Utility.log(sProperty); <jeh`g  
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InputStream input = httpConnection.getInputStream(); Y@Y`gF6F  
//logResponseHead(httpConnection); n]+.  
;XG]Q<S\  
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byte[] b = new byte[1024]; {6'*Phw  
int nRead; <uZPqi||  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !@u&{"{`  
{ Sx8l<X  
nStartPos += fileAccessI.write(b,0,nRead); (ZV;$N-t  
//if(nThreadID == 1) HZ }6Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %>Bk
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} @(-yrU  
+?;j&p  
{h#6z>p"u2  
Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; flG=9~qcGQ  
//nPos = fileAccessI.write (b,0,nRead); {FWyu5.  
} t5paYw-b  
catch(Exception e){e.printStackTrace ();} R"*R99  
} 2"@Ft()]  
} K;x~&G0=  
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B{p4G`$i1  
//打印回应的头信息 yRC3 .[  
public void logResponseHead(HttpURLConnection con) 7JI:=yY!>:  
{ !z MDP/V  
for(int i=1;;i++) d$K=c1  
{ I"1CgKYK^+  
String header=con.getHeaderFieldKey(i); e*:}$u8a  
if(header!=null) {"m0)G,G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p1D()-  
Utility.log(header+" : "+con.getHeaderField(header)); LeSHRoD  
else 1Bg_FPu  
break; y"vX~LR  
} ,/&Z3e  
} @`wn<%o$  
OV[`|<C '  
> \3ah4"o  
public void splitterStop() h4(JUio  
{ *69c-`o  
bStop = true; R)+t]}  
} R&#tSL  
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} e.l!3xY2'  
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/* p
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**FileAccess.java o.Oq__>$H  
*//文件访问(定位，写) Nb;H`<JP  
package NetFox; tz4 ]hF  
import java.io.*;
, T\-;7  
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public class FileAccessI implements Serializable{ A59gIp*>  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Qz+sT6js-  
RandomAccessFile oSavedFile; jl}$HEI5m}  
long nPos; d(7NO;S8  
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public FileAccessI() throws IOException ^Kqf~yS%  
{ Au.:OeJm  
this("",0); .9h)bf+  
} *Qkc[XHqy  
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!msNEE@[  
public FileAccessI(String sName,long nPos) throws IOException ?NG=8.p  
{ +=eR%|!@  
oSavedFile = new RandomAccessFile(sName,"rw"); :#u}.G  
this.nPos = nPos; r_U>VT^E:  
oSavedFile.seek(nPos); uS<_4A;sD,  
} }`o?/!X   
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public synchronized int write(byte[] b,int nStart,int nLen) cp6WMHLj   
{ >72JV;W]  
int n = -1; 30Drrno7Io  
try{ dE5D3ze  
oSavedFile.write(b,nStart,nLen); m"d/b~q  
n = nLen; i]o"_=C  
} W7=V{}b+  
catch(IOException e) qX#MV>1  
{ 9+qOP>m  
e.printStackTrace (); >jx.R  
} |`O7nOM  
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return n; 2e1]}wlK  
} 27D!'S  
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} x/mp=   
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/* 6f)2F< 7  
**SiteInfoBean.java 0CAa^Q
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*/ qpp/8M  
package NetFox; M\D]ml~  
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public class SiteInfoBean { nFM@@oA  
Ne6}oQy(S`  
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private String sSiteURL; //Site's URL 9$1)k;ChP/  
private String sFilePath; //Saved File's Path 9em*r9
-  
private String sFileName; //Saved File's Name {1-V]h.<J  
private int nSplitter; //Count of Splited Downloading File }|wv]U~  
:c.JhE3D  
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public SiteInfoBean() oxz{ ejd{  
{//nSplitter的缺省值为5 kc$)^E7  
//default value of nSplitter is 5
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this("","","",5); zsXpA0~3s  
} ..W-76{  
s9)8b$t]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f{&bOF v  
{ ?KE$r
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sSiteURL= sURL; OMrc_)he\  
sFilePath = sPath; OJO!FH)  
sFileName = sName; SOf{Hx0C6  
this.nSplitter = nSpiltter; {~Tg7<\L  
, YW|n:X  
s!+ pL|  
} ?]O7Ao  
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Vw
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public String getSSiteURL() g);^NAA  
{ hJ;$A*Y  
return sSiteURL; B 0ee?VC  
} Wp0 Dq(  
}8K4-[\  
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public void setSSiteURL(String value) b=;nm#cAI  
{ 9~\kF5Q"  
sSiteURL = value; ^
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} C.Uju`3  
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b~m2tC=A
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public String getSFilePath() )c2_b  
{ 1bnBji  
return sFilePath; eU@Cr7@,|  
} iq$$+y,  
,m3e?j@;r  
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public void setSFilePath(String value) z+{,WHjo  
{ iBg3mc@OO  
sFilePath = value; uQ1@b-e`5  
} o{:xp r=(  
|*5
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public String getSFileName() u+m,b76  
{ NpP')m!`}  
return sFileName; <UP m=Hb  
} 7, } $u  
~&dyRtW
4  
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public void setSFileName(String value) ZP\M9Ja  
{ bm~W EX  
sFileName = value; C4$:mJ>y  
} Sl2iz?   
1T&Rc4$Sn7  
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public int getNSplitter() {Azn&|%.t  
{ 9pn>-1NJ  
return nSplitter; BaI $S>/Q  
} WsU)Y&  
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public void setNSplitter(int nCount) n.MRz WJpZ  
{ gmKGy@]
 
nSplitter = nCount; CqMhk  
} 82{&# Vc  
} 5|0,X<
&  
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/*
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**Utility.java \W5O&G-C  
*/ JCx WWre  
package NetFox; +j_;(Gw7  
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public class Utility { PX:'/{V  
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public Utility() ?lGG|9J\  
{ g,tjm(  
b \KL;H/  
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} LsEXM-  
mYN7kYR}<`  
//线程睡眠 <#=N m0S$  
public static void sleep(int nSecond) /@ !CKh`  
{ f),TO  
try{ Ei}/iBG@  
Thread.sleep(nSecond); |:[tNs*,O  
} +CH},@j  
catch(Exception e) K;?,FlH  
{ c .3ZXqpI;  
e.printStackTrace (); ,u }XWV  
} oBQ#eW aY  
} p^<yj0Y  
fqX"Lus `=  
//日志 y.5/?{GL  
public static void log(String sMsg) 00I}o%akO  
{ Ars687WB  
System.err.println(sMsg); E1dD7r\  
} ^'CPM6J  
n~"$^Vr  
<?-
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public static void log(int sMsg) `g8E1-]l  
{ f0<hE2  
System.err.println(sMsg); 2]GdD*  
} =ph&sn$;L  
} CTt vyr  
+;$oJJ  
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/* {2/LRPT  
**TestMethod.java iLP7!j  
*/ 9CA^B2u  
package NetFox; f.aSKQD  
q{s(.Uq$&  
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public class TestMethod { i|w8.}0  
!CXt*/~  
]2#  
public TestMethod() _J
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{ ///xx/weblogic60b2_win.exe NaVQ9ku7VW  
try{ S6}@I ,Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,fK3ZC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "|;:>{JC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V/cP4{L  
fileFetch.start(); bCref$|  
} ZX ?yL>4  
catch(Exception e){e.printStackTrace ();} D3|oOOoG  
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}  tz#gClo  
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public static void main(String[] args) o7mZzzP  
{ !d<"nx[2`  
new TestMethod(); k(zsm"<q  
} ?9l [y  
} O: @}lK+H  
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