http断点续传简单实现（java)

/*
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**SiteFileFetch.java u|i.6:/=  
*/ ]Z6==+mCP  
package NetFox; RP!X5  
import java.io.*; %i$]S`A}  
import java.net.*; 'f]\@&Np  
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public class SiteFileFetch extends Thread { WF`y j%0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i#=s_v8  
long[] nStartPos; //开始位置 O6 bB CF;  
long[] nEndPos; //结束位置 %,1bh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =UT*1-yhR  
long nFileLength; //文件长度 d%8hWlffz  
boolean bFirst = true; //是否第一次取文件 0escp~\Z  
boolean bStop = false; //停止标志 !-)Hog5\  
File tmpFile; //文件下载的临时信息 9+_SG/@  
DataOutputStream output; //输出到文件的输出流 -ich N/U]s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $0=f9+@5  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z2!O)
8  
{ wgp{P>oBX  
siteInfoBean = bean; 9Eu.Y
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5Ay\s:hb[u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =*_T;;E  
if(tmpFile.exists ()) GB&<+5t2  
{ aOIE9wO  
bFirst = false; ^U)xQD"  
read_nPos(); wak_^8x  
} Pm*FA8a7  
else s8Bbet  
{ h0_od/D1r  
nStartPos = new long[bean.getNSplitter()]; oF7o"NHaWa  
nEndPos = new long[bean.getNSplitter()]; ,*!HN &  
} S&^i*R4]  
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} 86y)+h`  
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public void run() 8A}cxk  
{ @|BaZq,g  
//获得文件长度 Te_%r9P|2  
//分割文件 > yk2  
//实例FileSplitterFetch ?%K7IJ%  
//启动FileSplitterFetch线程 }]V
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//等待子线程返回 dTcrJ|/Y  
try{ C+tB$yahO  
if(bFirst) RE6d&#N  
{ ]6#bp,  
nFileLength = getFileSize(); ]jQj/`v1  
if(nFileLength == -1) r~N:|ip=  
{ mqUn3F3  
System.err.println("File Length is not known!"); !g=4\C`mY  
} Jvac|rN  
else if(nFileLength == -2) X"lPXoCN  
{ 0&wbGbg(W  
System.err.println("File is not access!"); ,sF49CD  
} l=4lhFG,Mk  
else qJN!L))  
{ Ps<;DE\$f4  
for(int i=0;i<nStartPos.length;i++) =cz^g^
7  
{ <MdIQ;I8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _ x8gEK8  
} g4z*6L,u  
for(int i=0;i<nEndPos.length-1;i++) >JVdL\3  
{ 0;6
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nEndPos = nStartPos[i+1]; l4:B(  
} tr?U/YG  
nEndPos[nEndPos.length-1] = nFileLength; e,V @t%  
} ;xqN#mqq  
} N5K\h}'%  
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//启动子线程 (+aU,E
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P]cC2L@Vbi  
for(int i=0;i<nStartPos.length;i++) bSJ@ 5qS  
{ ,#?iu?i/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [0>I6Jl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Tew?e&eO  
nStartPos,nEndPos,i); r8%"#<]/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V)<Jj  
fileSplitterFetch.start(); p#;I4d G  
} :}0>IPW-V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3mP251"dIW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2J;_9 g&M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s
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nEndPos = " + nFileLength); r{g8CIwGQ  
// fileSplitterFetch[nPos.length-1].start(); C!X"0]@FA  
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//等待子线程结束 P z< \q
;  
//int count = 0; "WF@T  
//是否结束while循环 T@H<Fm_  
boolean breakWhile = false; 0)Nu  
+%sMd]$,n  
/
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while(!bStop) nY M2Vxi0+  
{ ){}1u ?  
write_nPos(); lD9QS ;  
Utility.sleep(500); 0Ba*"/U]t~  
breakWhile = true; SB x<-^  
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for(int i=0;i<nStartPos.length;i++) y <] x  
{ qe[P'\]L  
if(!fileSplitterFetch.bDownOver) H3#rFO"C*  
{
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breakWhile = false; o$q})!  
break; Gg TrIF  
} 7ILb&JQ!%{  
} [Fk|%;B/~  
if(breakWhile) r}nz )=\Cj  
break; ~8 S2BV3@  
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8*&|Q1`K:  
//count++; )`5=6i  
//if(count>4) Bcl6n@{2f  
// siteStop(); ,hSTR)  
} SX1w5+p$C  
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System.err.println("文件下载结束！"); .o(S60iH!(  
} vw2yOLRX  
catch(Exception e){e.printStackTrace ();} O&g$dK!Rad  
} 2%_UOEayU  
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//获得文件长度 HRg< f= oz  
public long getFileSize() XMlcY;W  
{ b|Sjh;  
int nFileLength = -1; Mwtd<7<!A  
try{ lvp8{]I<  
URL url = new URL(siteInfoBean.getSSiteURL()); >Q#\X=a>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zvOSQxGQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); IeT1Jwe  
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int responseCode=httpConnection.getResponseCode(); kO}QOL4  
if(responseCode>=400) |%$mN{  
{ jI!WE$dt  
processErrorCode(responseCode); }AGdWt@  
return -2; //-2 represent access is error Q@ghQGn#  
} -izZ D  

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String sHeader; 0eFvcH:qG  

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for(int i=1;;i++) FA$1&Fu3Y  
{ (5h+b_eB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W.m2`] &  
//Utility.log(in.readLine()); (W'3Zv'f  
sHeader=httpConnection.getHeaderFieldKey(i); l<-0@(x)  
if(sHeader!=null) ov|/=bzro  
{ WUK{st.z  
if(sHeader.equals("Content-Length")) aTFT'(O,  
{ ^
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oGKk2oP  
break; L(`Rf0smt  
} u.ub:  
} h(gpqSN  
else _ lE d8Cb  
break; VRA0p[  
} aX}:O  
} T{
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catch(IOException e){e.printStackTrace ();} ay>u``$R  
catch(Exception e){e.printStackTrace ();} ,}23  
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Utility.log(nFileLength); :<PwG]LO  
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return nFileLength; 0oPcZ""X]  
} ZUK'z  
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//保存下载信息（文件指针位置） Np2.X+  
private void write_nPos() E3d# T  
{ AfXlV-v  
try{ hngdeGa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8omk4 ;  
output.writeInt(nStartPos.length); &uLC{Ik}  
for(int i=0;i<nStartPos.length;i++) '[`pU>9  
{ {wCzm  
// output.writeLong(nPos); !~QmY,R  
output.writeLong(fileSplitterFetch.nStartPos); ";*Iwd*V  
output.writeLong(fileSplitterFetch.nEndPos); 't#E-+o  
} k*k 9hv?  
output.close(); TKrh3   
} D)GD9MJ  
catch(IOException e){e.printStackTrace ();} -iySU 6  
catch(Exception e){e.printStackTrace ();} vJfj1 f  
} pa2cM%48  
2>h.K/pC  
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//读取保存的下载信息（文件指针位置） DcX,o*ec!  
private void read_nPos() B`/p

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{ j7v?NY  
try{ ZE4xF8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f{ER]U  
int nCount = input.readInt(); a9niXy}a(  
nStartPos = new long[nCount]; <69Uq8GI  
nEndPos = new long[nCount]; by@}T@^\  
for(int i=0;i<nStartPos.length;i++) 3fhlMOm  
{ =plU3D2  
nStartPos = input.readLong(); v6*8C
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nEndPos = input.readLong(); m)"wd$O^w  
} Pj7n_&*/  
input.close(); "Oq>i9v;|$  
} gvy c(d  
catch(IOException e){e.printStackTrace ();} 6+ C
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catch(Exception e){e.printStackTrace ();} t`eUD>\  
} [fl^1!3{  
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private void processErrorCode(int nErrorCode) G !;
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{ +X4/l"|  
System.err.println("Error Code : " + nErrorCode); v|#}LQZ  
} Ika(ip#]=  
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//停止文件下载 IHStN,QD  
public void siteStop() \8iWcqJktN  
{ q&0I7OV  
bStop = true; 6U[bAp  
for(int i=0;i<nStartPos.length;i++) @`H47@e  
fileSplitterFetch.splitterStop(); /d-
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} Dfl%Knl@J  
} Ln@n6*%(/  
//负责部分文件的抓取  "?(N  
**FileSplitterFetch.java :vRUb>z  
*/ mIm.+U`a2  
package NetFox; hkoCbR0}8  
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:8jaW?~  
import java.io.*; <imIgt|`2  
import java.net.*; &0*IN nlc?  
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public class FileSplitterFetch extends Thread { mQqv{1  
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String sURL; //File URL 7<7 /NZ<I  
long nStartPos; //File Snippet Start Position 2SlOqH1  
long nEndPos; //File Snippet End Position zD%@3NA4
1  
int nThreadID; //Thread's ID 2m0laJ3p9  
boolean bDownOver = false; //Downing is over I'>r  
boolean bStop = false; //Stop identical $pGdGV\H  
FileAccessI fileAccessI = null; //File Access interface o<\9OQ0  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7qT>wCVT  
{ 1:VbbOu->V  
this.sURL = sURL; TaTs-]4  
this.nStartPos = nStart; kZJ.G  
this.nEndPos = nEnd; )ND%MYJSq  
nThreadID = id; g}Esj"7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P8=!/L2?  
} l4smAT  
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public void run() WC *e#QP  
{ '980.  
while(nStartPos < nEndPos && !bStop) NB[(O#  
{ L-QzC<[F/  
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try{ Cp[ NVmN  
URL url = new URL(sURL); bL"!z"NA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kb5 YA  
httpConnection.setRequestProperty("User-Agent","NetFox"); YH^h?s  
String sProperty = "bytes="+nStartPos+"-"; qt{{q  
httpConnection.setRequestProperty("RANGE",sProperty); 'mR9Uqq\  
Utility.log(sProperty); eV)'@8p
 
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InputStream input = httpConnection.getInputStream(); :$gR >.`  
//logResponseHead(httpConnection); Mpu8/i gX,  
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byte[] b = new byte[1024]; 5}"@$.{i  
int nRead; Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5y%-K=d  
{ Hd9vS"TN]  
nStartPos += fileAccessI.write(b,0,nRead); [9>h! khs  
//if(nThreadID == 1) Od5I:p]N  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /n&Y6@W  
} % XS2;V  
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Utility.log("Thread " + nThreadID + " is over!"); 'g7eN@Wh.z  
bDownOver = true; 1?j['~aE  
//nPos = fileAccessI.write (b,0,nRead); @x@*=  
} Fo@cz"%  
catch(Exception e){e.printStackTrace ();} 3sy|pa  
} Sp>v`{F  
} / Hg/)  
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//打印回应的头信息 V.U9Q{y
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public void logResponseHead(HttpURLConnection con) rjLPX  
{ wSwDhOX=  
for(int i=1;;i++) &)y$XsSMW  
{ 4UV<Q*B\F  
String header=con.getHeaderFieldKey(i); )%T<Mw2u  
if(header!=null) {Z^ G]@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kD
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Utility.log(header+" : "+con.getHeaderField(header));
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else sQac%.H;`U  
break; 5a$EXV  
} 849,1n^  
} :C(/yg  
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public void splitterStop() )N8b
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{ }b&lHr'Uw  
bStop = true; ?VmgM"'md  
} oV0T   
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} YnRO>`
  
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/* Z17b=xJw  
**FileAccess.java BZ1wE1t  
*//文件访问(定位，写) Y~85Z0l  
package NetFox; gS5MoW1  
import java.io.*; ~x\uZ^:  
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public class FileAccessI implements Serializable{ {tUe(  
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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 $R/@8qnP W  
RandomAccessFile oSavedFile; _&BK4?H@b  
long nPos; =g9n =spAn  
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public FileAccessI() throws IOException Z%]K,9K
 
{ G?'^"ae"Z  
this("",0); gV
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} ,3Q~X$f  
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public FileAccessI(String sName,long nPos) throws IOException m0TVi]v  
{ f7~dn#<@  
oSavedFile = new RandomAccessFile(sName,"rw"); 'E3T fM  
this.nPos = nPos; 1vj@qw3  
oSavedFile.seek(nPos);  4d5c]%  
} aC\f;&P>  
z
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9 A ?{}c  
public synchronized int write(byte[] b,int nStart,int nLen) =wdh#{  
{ R+Hu?Dv&F  
int n = -1; |p&EP2?T  
try{ BZ?3=S1*  
oSavedFile.write(b,nStart,nLen); CF{b Yf^%  
n = nLen; &/]en|f"  
} vS>'LX  
catch(IOException e) >X$JeME3  
{ 'NhQBk  
e.printStackTrace (); E(4c&  
} P\7*ql`  
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return n; z/1
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} =#Sw.N  
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} 0w3c8s.  
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MF4(  
/* B@&sG 5ES  
**SiteInfoBean.java Bdw33z*m  
*/ djOjd,  
package NetFox; 3y}E*QE  
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public class SiteInfoBean { OB(oOPH  
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private String sSiteURL; //Site's URL kWXLncE  
private String sFilePath; //Saved File's Path Kd5'2"DI  
private String sFileName; //Saved File's Name wc;n= %  
private int nSplitter; //Count of Splited Downloading File qg oB}n%  
z3+@[I$  
.d1ff];  
public SiteInfoBean() 9;e!r DW,#  
{//nSplitter的缺省值为5 .C% 28fH  
//default value of nSplitter is 5 )y,^M3$?C  
this("","","",5); 5)!g.8-!  
} :snO*Zg  
\0b}Z#'0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P }sr  
{ *H QcI-  
sSiteURL= sURL; z$%twBg}#  
sFilePath = sPath; ukSv70Ev  
sFileName = sName; Jp=fLo 9  
this.nSplitter = nSpiltter; 7Bp7d/R-  
y!#-[K:  
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} N y'\Q"Y]  
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public String getSSiteURL() k7CKl;Fck  
{ ' P?h?w^T  
return sSiteURL; faQmkO  
} t%lat./yT  
rm[C{Pn  
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public void setSSiteURL(String value) $d?W1D<A  
{ G\@pg;0|y  
sSiteURL = value; ljKIxSvCFp  
} +X=*>^G(-  
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public String getSFilePath() WoEK #,I;  
{
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return sFilePath; yq%5h[M  
} u.GnXuax  
1r;zA<<%R  
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public void setSFilePath(String value) w 9dkJo  
{ N[e,){v  
sFilePath = value; yajdRU  
} >pv.,cj  
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public String getSFileName() 3kn-tM  
{ G4)~p!TSQ  
return sFileName; ;g|Vt}a&4  
} <Y]LY_(  
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public void setSFileName(String value) X94a
  
{ mJSfn"b}K  
sFileName = value; c#n 2
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} }s~c(sL?;  
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public int getNSplitter() ORExI.<`W  
{ }t H$:Z  
return nSplitter; r]3-}:vU  
} ]@{Lx>Oh"  
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public void setNSplitter(int nCount) 23}` e  
{ jf9+H!?^N  
nSplitter = nCount; bv+u7B6,  
} ){;XI2
 
} b,xZY1a  
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/* n:5M E*  
**Utility.java [X(4
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*/ aFnel8  
package NetFox; pXk^EV0  
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public class Utility { s4|\cY`b-  
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public Utility() 5J5?cs-!  
{
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#Bd]M#J17a  
} bZnOX*y]  
5hrI#fpOR  
//线程睡眠 H"A%mrb  
public static void sleep(int nSecond) >e;-$$e  
{ qRt!kWW  
try{ +?_!8N8  
Thread.sleep(nSecond); hOj{y2sc  
} @62T:Vl  
catch(Exception e) '}.
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{ /R#zu_i  
e.printStackTrace (); ">H
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} gaF6j!p  
} o<G 9t6~  
}9fa]D-a?  
//日志 /_C2O"h  
public static void log(String sMsg) =nEP:7~{  
{ 98[uRywI  
System.err.println(sMsg); B~Sj#(WEa  
} &uq.k{<p\  
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public static void log(int sMsg) Sc<dxY@w7-  
{ }icCp)b>v  
System.err.println(sMsg); {;yO3];Hqw  
} *;<fh,wOk  
} KWJVc `  
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yaUtDC.|  
/* \v2!5z8|  
**TestMethod.java E>~R P^?Uz  
*/ n$iX6Cd  
package NetFox; =?i?-6M  
&W<7!U:2m  
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public class TestMethod { 6h:QSVfx  
n Bu!2c  
?@64gdlwq  
public TestMethod() =2R4Z8
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{ ///xx/weblogic60b2_win.exe ":
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try{ g3^s_*A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8g#$Y2P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [&lK.?V)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); il0K^i  
fileFetch.start(); ^z?b6kTC  
} !cW rB9  
catch(Exception e){e.printStackTrace ();} vrs  
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} h]4xS?6O  
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public static void main(String[] args) ]2AOW}=  
{ @Z5q2Q  
new TestMethod(); k/K)nH@)  
} MB]E[&Q!  
} 8lyIL^
 
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