http断点续传简单实现（java)

/* .7 j#F  
**SiteFileFetch.java i;~.kgtq4  
*/ &&$*MHJ  
package NetFox; !lg_zAV  
import java.io.*; l@w\ Vxr  
import java.net.*; Tr>_R%bK  
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public class SiteFileFetch extends Thread { j@nK6`d+1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q}jh>`d  
long[] nStartPos; //开始位置 Edc3YSg%;  
long[] nEndPos; //结束位置 hyPS 6Y'1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H;a) `R3  
long nFileLength; //文件长度 ;xh.95BP`  
boolean bFirst = true; //是否第一次取文件 B:i$  
boolean bStop = false; //停止标志 n=DmdQ}  
File tmpFile; //文件下载的临时信息 Ot=nKdP}D  
DataOutputStream output; //输出到文件的输出流 {gEz;:!):  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q>X1 :Zn3  
public SiteFileFetch(SiteInfoBean bean) throws IOException AWFq5YMSI  
{ I^LU*A=  
siteInfoBean = bean; V`/c#y||  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D)4#AI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n|.eL8lX.<  
if(tmpFile.exists ()) :Id8N~g  
{ [KGj70|~  
bFirst = false; \{*`-Pv  
read_nPos(); g|^U?|;p  
} TRgj`FG  
else lM
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{ XpKeN2=p  
nStartPos = new long[bean.getNSplitter()]; 3^H-,b0^  
nEndPos = new long[bean.getNSplitter()]; qOD^P  
} w=nS*Qy2  
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} xG4 C 6s  
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public void run() [70 _uq  
{ 5<KBMCn  
//获得文件长度 b H5lLcdf  
//分割文件 B|^=2 >8s  
//实例FileSplitterFetch P"Q6wdm  
//启动FileSplitterFetch线程 dZkKAK:v  
//等待子线程返回 1'&HmBfcb  
try{ B&!>& Rbx  
if(bFirst) ~t*_  
{ _Nz?fJ:$@  
nFileLength = getFileSize(); Z~w?Qm:/  
if(nFileLength == -1) b,ZBol|X  
{ %dd B$(  
System.err.println("File Length is not known!"); 1,P2}mYv  
} UBnHtsM  
else if(nFileLength == -2) \,nhGh  
{ iH)vLD  
System.err.println("File is not access!"); >Wd=+$!I  
} *g'%5i1ed  
else (L1O;~$  
{ /_(l:q^  
for(int i=0;i<nStartPos.length;i++) =td(}3|D Y  
{ BG-nf1K(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !_>/ r  
} }*P;kV  
for(int i=0;i<nEndPos.length-1;i++) ucLh|}jJ5  
{ h=au`o&CG  
nEndPos = nStartPos[i+1]; SrdCLT8  
} "5sUE!)f  
nEndPos[nEndPos.length-1] = nFileLength; 44B9JA7u  
} [--] ?Dr  
} @[$q1Nm  
n#P?JyGm1g  
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//启动子线程 ZQ\O| n8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) G
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{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )q{e L$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v~!_DD au  
nStartPos,nEndPos,i); CfOhk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <HW2W"Go\  
fileSplitterFetch.start(); 8f&#WIZ  
} uF*tlaV6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :G<~x8]k0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TDR#'i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D0gz ((  
nEndPos = " + nFileLength); do< N+iK  
// fileSplitterFetch[nPos.length-1].start(); Jj1lAg0  
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&
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//等待子线程结束 6se[>'5  
//int count = 0; G>2: WQ/  
//是否结束while循环 'Hq#9?<2M  
boolean breakWhile = false; tF!C']  
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while(!bStop) C !
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{ w^ 8^0i-  
write_nPos(); f1Gyl  
Utility.sleep(500); gEq";B%?  
breakWhile = true; l2 #^}-
 
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for(int i=0;i<nStartPos.length;i++) c#[d7t8ONe  
{ a&n}pnEn)  
if(!fileSplitterFetch.bDownOver) hy
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{ `=W#owAF  
breakWhile = false; [k,FJ5X  
break; d6e]aO=g  
} LaIH3!M3  
} GmN~e*x>p  
if(breakWhile) n#5pd;!n  
break; "4QD\k5  
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//count++; kkV*
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//if(count>4) K./L'Me  
// siteStop(); J35[GZ';D  
} ;MKfssG  
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System.err.println("文件下载结束！"); ]K>x:vMKH  
} 4
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catch(Exception e){e.printStackTrace ();} u*!/J R  
} p( [FZ  
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R%%h=]  
//获得文件长度 n0@
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public long getFileSize() + gP 4MP  
{ @1peJJ{  
int nFileLength = -1; [JX=
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try{ mr#XN&e  
URL url = new URL(siteInfoBean.getSSiteURL()); zJtB?<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~VO?PfxZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); :eTzjW=  
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int responseCode=httpConnection.getResponseCode(); O(44Dy@2  
if(responseCode>=400) JclG*/Wjg4  
{ ]`n6H[6O  
processErrorCode(responseCode); 8` f=Eh  
return -2; //-2 represent access is error }?z_sNrDk  
} 2/G`ej!*  
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String sHeader; A/U,|  
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for(int i=1;;i++) L+$9 ,<'
[  
{ T! fF1cpF\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gJI(d6  
//Utility.log(in.readLine()); CXiSin  
sHeader=httpConnection.getHeaderFieldKey(i); 9^1.nE(R&  
if(sHeader!=null) j.y
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{ E6y ?DXWH  
if(sHeader.equals("Content-Length")) }Dc?Emb  
{ ;AK@Kb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }c0EGoU}?  
break; d+:pZ  
} n42XqR  
} "G @(AE(  
else ;b1*2-  
break; !8i[.EAT  
} Sg}]5Mn`  
} aJ}Cqk  
catch(IOException e){e.printStackTrace ();} h;8^vB y  
catch(Exception e){e.printStackTrace ();} )o@-h85";  
}CXL\,;  
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Utility.log(nFileLength); #i~2C@]  
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return nFileLength; !9JK95;  
} nd1%txIsr  
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//保存下载信息（文件指针位置） 8g CQ0w<  
private void write_nPos() P~"`Og+  
{ $s-HG[lX[  
try{ \+B+M 7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G_UxR9Qo  
output.writeInt(nStartPos.length); C 9:5c@G  
for(int i=0;i<nStartPos.length;i++) e^ygQ<6%  
{ s9-aPcA  
// output.writeLong(nPos); F)g.xQ  
output.writeLong(fileSplitterFetch.nStartPos); 4
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output.writeLong(fileSplitterFetch.nEndPos); AmmUoS\
 
} g` QbJ61a  
output.close(); K1K3s<y+  
} OCVF+D :  
catch(IOException e){e.printStackTrace ();} .U:DuyT  
catch(Exception e){e.printStackTrace ();} [J.-gN$X@  
} zS##YR  
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//读取保存的下载信息（文件指针位置） e+5]l>3)f  
private void read_nPos() K6Gri>Um  
{ fhZD#D  
try{ ;0f?-W?1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3Vj,O?(Z  
int nCount = input.readInt(); On{p(|l  
nStartPos = new long[nCount]; (X"WEp^Q{I  
nEndPos = new long[nCount]; hVAP )"5  
for(int i=0;i<nStartPos.length;i++) O1_dA%m  
{ Jj$N3UCg7  
nStartPos = input.readLong(); ch%-Cg~%  
nEndPos = input.readLong(); ~~_!&  
} DxLN{
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input.close(); pk
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} ?u9JRXj%  
catch(IOException e){e.printStackTrace ();} >=_Z\ wA  
catch(Exception e){e.printStackTrace ();} P|OjtI  
} ,^UNQO*{GI  
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private void processErrorCode(int nErrorCode) 8[|RsM  
{ )./%/
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System.err.println("Error Code : " + nErrorCode); i2EXE0;  
} 6(`Bl$M9  
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//停止文件下载 .WR+)^&zz  
public void siteStop() 5)MVkJ=R  
{ *y;(c)_w/%  
bStop = true; 3d2|vQx,K  
for(int i=0;i<nStartPos.length;i++) IwHYuOED]  
fileSplitterFetch.splitterStop(); Gn*vVZ@`x  
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} l 6;}nG  
} 4ISZyO=  
//负责部分文件的抓取 P%6-W5<  
**FileSplitterFetch.java + W ? /A]  
*/ fr1/9E;  
package NetFox; >~kSe=Hsb4  
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import java.io.*; xYJ|G=h&A  
import java.net.*; os]P6TFFX?  
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public class FileSplitterFetch extends Thread { 2U-F}Z  
{ L(Q|bB  
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String sURL; //File URL Dwq}O  
long nStartPos; //File Snippet Start Position RQZ|:SvV  
long nEndPos; //File Snippet End Position F;mK)Q-  
int nThreadID; //Thread's ID }?pY~f  
boolean bDownOver = false; //Downing is over HY,+;tf2r  
boolean bStop = false; //Stop identical Z2]ySyt]  
FileAccessI fileAccessI = null; //File Access interface S1<mO-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HrUQ X4  
{ e7<//~W7W  
this.sURL = sURL; =U6%Wdth  
this.nStartPos = nStart; f*VBSg[`  
this.nEndPos = nEnd; BTwLx-p9t  
nThreadID = id; m8q3Pp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7[wHNJ7)r  
} A d0dg2Gw  
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public void run() B*+3A!{s  
{ idLysxN  
while(nStartPos < nEndPos && !bStop) ic}M)S FD;  
{ K0#kW \4`  
asDq(J`sQ  
8#gS{  
try{ lD;="b  
URL url = new URL(sURL); S aCa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BTXS+mvl  
httpConnection.setRequestProperty("User-Agent","NetFox"); [/}y!;3iXM  
String sProperty = "bytes="+nStartPos+"-"; qV%t[>  
httpConnection.setRequestProperty("RANGE",sProperty); #OKzJ"g
 
Utility.log(sProperty); I<q=lK  
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InputStream input = httpConnection.getInputStream(); 7a@%^G @!  
//logResponseHead(httpConnection); 17Q1Xa  
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byte[] b = new byte[1024]; 
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int nRead; 1sL#XB$@N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L~yu  
{ %-y%Q.;k?  
nStartPos += fileAccessI.write(b,0,nRead); %ec9`0^4S  
//if(nThreadID == 1) (o/HLmr@Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gW
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} x~Egax  
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Th&* d;  
Utility.log("Thread " + nThreadID + " is over!"); '/^bO#G:  
bDownOver = true; l[EnFbD6  
//nPos = fileAccessI.write (b,0,nRead); =qY!<DB[L  
} P=:mn>  
catch(Exception e){e.printStackTrace ();} ?=:wIMV  
} =#N;ZG  
} VZ?"yUZ Id  
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3"O)"/"Q.  
//打印回应的头信息 CKShz]1  
public void logResponseHead(HttpURLConnection con) |sN>/89=/  
{ [E_eaez
7#  
for(int i=1;;i++) ~c>*3*  
{ -jc8ku3*  
String header=con.getHeaderFieldKey(i); (3YI>/#  
if(header!=null) ^`Tns6u>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~c~$2Xo  
Utility.log(header+" : "+con.getHeaderField(header)); PiD%PBmUl  
else HH>"J/;c,  
break; cTO\
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} rO]7g  
} ;-=Q6Ms8  
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public void splitterStop() lW^bn(_gQ  
{ \Kph?l9Ww  
bStop = true; gC81ICM  
} W\s ]qsLS  
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} i5  x[1  
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/* Y6T1_XG  
**FileAccess.java fk%yi[  
*//文件访问(定位，写) mX78Av.z!  
package NetFox; FgILQ"+  
import java.io.*; yoKl.U"&  
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public class FileAccessI implements Serializable{ T:ye2yg  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d'~sy>  
RandomAccessFile oSavedFile; 8}m bfuo1  
long nPos; :3k&[W*  
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public FileAccessI() throws IOException 0GR\iw$[J  
{ Mg H,"G  
this("",0); (?SK< 4!  
} !r:X`~\a  
o9)pOwk7;  
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public FileAccessI(String sName,long nPos) throws IOException ]C|Zs=5  
{ ]:CU.M1  
oSavedFile = new RandomAccessFile(sName,"rw"); 8(R%?>8  
this.nPos = nPos; ueO&%  
oSavedFile.seek(nPos); {C>.fg%t  
} N&`VMEB)k  
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Ue:'55  
public synchronized int write(byte[] b,int nStart,int nLen) 7^|oO~x6  
{ <3dmY=  
int n = -1; i6R2R8  
try{ e0O2>w  
oSavedFile.write(b,nStart,nLen); 2s,[DC  
n = nLen; Bl5*sfjG  
} J/3qJst
 
catch(IOException e) ZMmaM "9  
{ l[=7<F  
e.printStackTrace (); YQ}xr^VA  
} t^0^He$Ot  
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return n; NET?Ep  
} Mq-QWx"P  
)ndcBwQc"  
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} 0HUSN_3F  
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=[8EQdR  
/* `Tt}:9/3  
**SiteInfoBean.java :'aT4  
*/ .Ap-<FB  
package NetFox; 'P{0K?{H-4  
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public class SiteInfoBean { 70,V>=aJ  
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private String sSiteURL; //Site's URL y,&UST  
private String sFilePath; //Saved File's Path rQ|^H
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private String sFileName; //Saved File's Name uP<w rlW  
private int nSplitter; //Count of Splited Downloading File 5urM,1SQ@  
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public SiteInfoBean() ugexkdgM  
{//nSplitter的缺省值为5 Xg:w;#r,  
//default value of nSplitter is 5 *<k8H5z8]  
this("","","",5); ;K<e]RI;?  
} F&US-ce:M  
fUQuEh5_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \F]X!#&+  
{ )(~s-x^\z@  
sSiteURL= sURL; oJC-?  
sFilePath = sPath; OgJd^  
sFileName = sName; su]CaHU  
this.nSplitter = nSpiltter; ( zQ)EHRD  
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v3|-eWet^  
} ;-p1z% u  
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public String getSSiteURL() 7'wt/9  
{ ~=hM y`Ml  
return sSiteURL; )i8Hdtn  
} ;AV[bjRE\  
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3`PPTG  
public void setSSiteURL(String value) $o rN>M42  
{ ^'EeJN  
sSiteURL = value; ,"?h_NbF  
} ?>b>LDpx?  
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cIqk=_]  
public String getSFilePath() aty"6~  
{ 4Q2=\-KFj  
return sFilePath; }7iWmXlI  
} PI{;3X}9$,  
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public void setSFilePath(String value) j^ L"l;m  
{ MhMY"bx8  
sFilePath = value; )cA#2mlS'1  
} Jy&O4g/'5  
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Q 6djfEN>  
public String getSFileName() gL%%2 }$  
{ zjVBMqdD  
return sFileName; *Ag</g@ h  
} AR9D;YfR~  
j)4:*R.Z]  
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public void setSFileName(String value) ,ra!O=d~0  
{ Sa5+_TW  
sFileName = value; -dXlGOD+C  
} ? b;_T,S[  
(_S`9Z8=  
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public int getNSplitter() u6o:~=WwM  
{ RlH|G  
return nSplitter; *?|LE C  
} V1Yab#  
:1h1+b@,  
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public void setNSplitter(int nCount) $OI 6^  
{ hdky:2^3  
nSplitter = nCount; nulCk33x'=  
} t)|*-=  
} wQR>S>p  
l ;"v&?  
@<]sW*s  
/* 9>gxJ7pY  
**Utility.java r{y&}gA  
*/ qYD$_a  
package NetFox; }Rujh4*  
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4.7YIM  
public class Utility { npsDy&  
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public Utility() E`#m0Q(8  
{ RLBeti>  
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} A*d Pw.  
}j=UO*|  
//线程睡眠 gDHgXDD_b  
public static void sleep(int nSecond) ? yL3XB>  
{ T(LqR?xOo  
try{ !|!k9~v!  
Thread.sleep(nSecond); ^PwZP;On  
} #_]/Mr1  
catch(Exception e) '@4Myg* b  
{ y|r+<  
e.printStackTrace (); R*Jnl\?>@  
} DK' ? '  
} JbT+w\o  
+Sz%2Q  
//日志 [ .]xy  
public static void log(String sMsg) =Uy;8et  
{ r6 k/QZT  
System.err.println(sMsg); ,4kly_$BH  
} G- _h 2  
yV{&x
 
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public static void log(int sMsg) M::  
{ Fjnp0:p9X  
System.err.println(sMsg); D~~
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} &j}08aK%  
} isU7nlc!  
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e}@VR<h  
/* !VLk|6mn  
**TestMethod.java '6^+|1  
*/ e"=/zZH3  
package NetFox; |3LD"!rEx  
p\;\hHai  
;_$Q~X  
public class TestMethod { @= E~`  
EY$Dtb+g8  
>(EC.ke  
public TestMethod() B#Q` !B4v  
{ ///xx/weblogic60b2_win.exe KU]co4]8^s  
try{ Za[
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e0s*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ! qVuhad.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pyHU+B  
fileFetch.start();  3o_)x  
} _\/KI /  
catch(Exception e){e.printStackTrace ();} mS$9D{  
ppm=o4`s[  
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} ;s*   
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public static void main(String[] args) X| !VjUH  
{ M&QzsVH  
new TestMethod(); ?xa70Pb{;  
} eeVDU$*e=  
} /"+CH\) E  
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