http断点续传简单实现（java)

/* xt40hZ$  
**SiteFileFetch.java *S{%+1F  
*/ RQ|!?\a=  
package NetFox; mJWl#3  
import java.io.*; ZmYp!B_~  
import java.net.*; 9h~>7VeZ)  
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public class SiteFileFetch extends Thread { VN;Sz,1Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tS`fG;  
long[] nStartPos; //开始位置 xB 4A"|  
long[] nEndPos; //结束位置 &.Yh_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ywCE2N<-V?  
long nFileLength; //文件长度 %:((S]vAi  
boolean bFirst = true; //是否第一次取文件 qb "H&)aHw  
boolean bStop = false; //停止标志 R+, tn,<<  
File tmpFile; //文件下载的临时信息 b~v  
DataOutputStream output; //输出到文件的输出流 Q{mls  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]y!|x_5c3  
public SiteFileFetch(SiteInfoBean bean) throws IOException _X;5ORH"  
{ W^al`lg+y  
siteInfoBean = bean; 1kTJMtZG~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e 0!a &w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tQ] R@i  
if(tmpFile.exists ()) 0$* z   
{ (~/D*<A  
bFirst = false; $NJi]g|<3  
read_nPos(); k,b(MAiQ0  
} O^oFH OpFh  
else m.S@ e8kS  
{ 7c<2oTN'  
nStartPos = new long[bean.getNSplitter()]; TvMY\e  
nEndPos = new long[bean.getNSplitter()]; }GQ8|fg`U  
} <[[DS%(M^  
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} b^^Cj(  
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public void run() PX(Gx%s|  
{ {"'W!WTb  
//获得文件长度 B2&fvv?  
//分割文件 \asF~P  
//实例FileSplitterFetch ].2q.7Yur  
//启动FileSplitterFetch线程 WihOGdUS6  
//等待子线程返回 U*v//@WbH  
try{ xdp{y=,[  
if(bFirst) w.J2pvyB  
{ c?b?x 6 2  
nFileLength = getFileSize(); 3(6i6 vV  
if(nFileLength == -1) [0F+t,`  
{ "YHe]R>3s  
System.err.println("File Length is not known!");
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} Yq<D(F#qx  
else if(nFileLength == -2) :]e:-JbT4z  
{ OFCkQEG=y>  
System.err.println("File is not access!"); ,GZ(>|  
} yq\)8Fe  
else %=\h=\wt  
{ hSr#/dw&  
for(int i=0;i<nStartPos.length;i++) p;BdzV>  
{ f{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); <}N0y*m  
} '-gk))u>)  
for(int i=0;i<nEndPos.length-1;i++) :3{@LOil^  
{ Xp
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nEndPos = nStartPos[i+1]; $fuFx8`2W  
} uoaF(F-  
nEndPos[nEndPos.length-1] = nFileLength; %|oY8;0|A>  
} )^g}'V=vIr  
} O)&xT2'J  
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//启动子线程 tCtR(mG=A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %NX  
for(int i=0;i<nStartPos.length;i++) `=b*g24z[N  
{ NZ9`8&93  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wky~hm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ANp4yy+  
nStartPos,nEndPos,i); W[j =!o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9j$ OU@N 8  
fileSplitterFetch.start(); H>;km$b +  
} u=#LY$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (= uwx#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?GB($D=Y'&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]n\WCU]0  
nEndPos = " + nFileLength); Fov/?:f$  
// fileSplitterFetch[nPos.length-1].start(); t*e+[  
+5?sYp\  
u#la+/   
//等待子线程结束 9%kY8#%SV  
//int count = 0; -!(3fO:  
//是否结束while循环 U|-4*l9Ed  
boolean breakWhile = false; {eqUEdC  
#B)/d?aa'  
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while(!bStop) VH,k EbJ  
{ DU]MMR  
write_nPos(); B2WPjhzD  
Utility.sleep(500); zZki9P   
breakWhile = true; *G>V`||RW  
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for(int i=0;i<nStartPos.length;i++) burEo
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{ q
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if(!fileSplitterFetch.bDownOver) REnRpp$  
{ 7b:oz3?PI  
breakWhile = false; |C7GI[P  
break; X
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} \qV5mD]"M  
} >xJt&jW-  
if(breakWhile) {B?%r[nW  
break; H:d{Sru  
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' OdZ[AN  
//count++; Q*(]&qr"E  
//if(count>4) $ 7O[|:Yv  
// siteStop();
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} ^X[Kr=:Jp  
3=T<c?[  
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System.err.println("文件下载结束！"); i*W8_C:S  
} #
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catch(Exception e){e.printStackTrace ();} "g>uNtt~  
} ( F0.lDZ  
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//获得文件长度 qSkt }F%'  
public long getFileSize() xm/v:hl=  
{ }@SZ!-t%rD  
int nFileLength = -1; ~k|~Q\  
try{ dH#S69>  
URL url = new URL(siteInfoBean.getSSiteURL()); =qCVy:RL4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (U/6~r'.L  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;9=9D{-4+  
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int responseCode=httpConnection.getResponseCode(); uC 5mxZ  
if(responseCode>=400) s-k~_C>Fw  
{ 6jPaS!E  
processErrorCode(responseCode); (gl CTF9v  
return -2; //-2 represent access is error C.%iQx`
 
} W(~G^Xu  
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String sHeader; E I)Pfx"0  
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for(int i=1;;i++) A6q,"BS^d  
{ f.V0uBDN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qaG%PH}a  
//Utility.log(in.readLine()); P,_GTs3/G  
sHeader=httpConnection.getHeaderFieldKey(i); *)L%pH>`  
if(sHeader!=null) D@>P%k$$s>  
{ j%]i#iqF  
if(sHeader.equals("Content-Length")) s:jr/ j!  
{ !i.`m-J*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7bQ#M )}  
break; #9#N+  
} PrDvRW
M  
} ZKAIG=l&!  
else F!c%&Z  
break; x>&1;g2r  
} TnPdpynP  
} W{=>c/  
catch(IOException e){e.printStackTrace ();} 5p U(A6RtS  
catch(Exception e){e.printStackTrace ();} E88_15'3D  
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{LR?#.  
Utility.log(nFileLength); rQj.W6w=  
7I(Sa?D:  
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return nFileLength; bveNd0hN  
} N%_-5Q)so  
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7 82NiVed  
//保存下载信息（文件指针位置） 7{."Y@  
private void write_nPos() Z;7f D  
{ W*`2lf  
try{ P[#V{%f*5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]Ny.  gu  
output.writeInt(nStartPos.length); x4.-7%VV%  
for(int i=0;i<nStartPos.length;i++) nDui9C  
{ /_o1b_1U  
// output.writeLong(nPos); vRRi"bo  
output.writeLong(fileSplitterFetch.nStartPos); 8'Z9Z*^h#x  
output.writeLong(fileSplitterFetch.nEndPos); x8b w#  
} /bfsC& 3  
output.close(); KB*[b  
} d[-w&[iy  
catch(IOException e){e.printStackTrace ();} 1wE~dpnx  
catch(Exception e){e.printStackTrace ();} @~QW~{y  
} uH65DI<  
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//读取保存的下载信息（文件指针位置） JS!rZi  
private void read_nPos() 7!Ym~M=  
{ o LuGW5wzj  
try{ *1Nz VV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @xSS`&b  
int nCount = input.readInt(); kTc'k  
nStartPos = new long[nCount]; n8iejdA'  
nEndPos = new long[nCount]; Kn=P~,FaG3  
for(int i=0;i<nStartPos.length;i++) ;gK+AU  
{ J--9VlC'  
nStartPos = input.readLong(); 224I%x.,  
nEndPos = input.readLong(); {j ${i  
} t}_qtO7>  
input.close(); `)1_^# k  
} ZfL\3Mn  
catch(IOException e){e.printStackTrace ();} <CzH'!FJN  
catch(Exception e){e.printStackTrace ();} RfEmkb<9Z  
} Tx`;y|  
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private void processErrorCode(int nErrorCode) Tj<W4+p{  
{ }`h)+Im=  
System.err.println("Error Code : " + nErrorCode); ^3*/x%A,g  
} #f\U
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//停止文件下载 M=`F $  
public void siteStop() /DQoM@X  
{ 9_KUUA  
bStop = true; 1;]cYIq  
for(int i=0;i<nStartPos.length;i++) >9uDY+70I3  
fileSplitterFetch.splitterStop(); hi`\3B  
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} zRL[.O9  
} ! Hdg $,  
//负责部分文件的抓取 H2E!A2\m  
**FileSplitterFetch.java \_De( p  
*/ #wk'&XsC#z  
package NetFox; Z+(V'e;  
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import java.io.*; 8`U5/!6fu  
import java.net.*; `GqS.O}C  
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public class FileSplitterFetch extends Thread { u6awcn  
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String sURL; //File URL e~i ?E  
long nStartPos; //File Snippet Start Position g5; W6QX  
long nEndPos; //File Snippet End Position Ex&f}/F  
int nThreadID; //Thread's ID FC.y%P,  
boolean bDownOver = false; //Downing is over l`[*b_ Xt  
boolean bStop = false; //Stop identical B&O931E7  
FileAccessI fileAccessI = null; //File Access interface UStZ3A'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eH(
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{ C-@@`EP  
this.sURL = sURL; .NiPaUzc<  
this.nStartPos = nStart; UpN:F  
this.nEndPos = nEnd; (`<l" @:_*  
nThreadID = id; )o SFHf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Me`jh8(K\6  
} &t5pJ`$(Cy  
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public void run() s@jzu  
{ Fwm{oypg%  
while(nStartPos < nEndPos && !bStop) [8^jwnAYS  
{ Y9'Bdm/  
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*
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try{ L/"u,~[  
URL url = new URL(sURL); 8N'`kd~6[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DSM,dO'  
httpConnection.setRequestProperty("User-Agent","NetFox"); kK16+`\+  
String sProperty = "bytes="+nStartPos+"-"; cr27q6_  
httpConnection.setRequestProperty("RANGE",sProperty); vMRM/.  
Utility.log(sProperty); ALiA+k N  
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InputStream input = httpConnection.getInputStream(); AVZ-g/<  
//logResponseHead(httpConnection); _`+ !,kG[  
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byte[] b = new byte[1024]; ]RM
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int nRead; _o8il3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G!ty@ Fx  
{ ",B92[}Ar  
nStartPos += fileAccessI.write(b,0,nRead); xzyV|(  
//if(nThreadID == 1) 5dXC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EZ8Ih,j9  
} c}U&!R2p{  
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Utility.log("Thread " + nThreadID + " is over!"); Aq^1(-g  
bDownOver = true; DQ?'f@I&*  
//nPos = fileAccessI.write (b,0,nRead); QNLkj`PL/  
} vh"zYl`  
catch(Exception e){e.printStackTrace ();} >Yl?i&3n  
} b*no.eB  
} gLaFIeF<+  
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//打印回应的头信息 `9(T
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public void logResponseHead(HttpURLConnection con) +w?RW^:Q=  
{ 9F(<n  
for(int i=1;;i++) VuN= JX  
{ 
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String header=con.getHeaderFieldKey(i); 1ZJP.T`  
if(header!=null) exiCy1[+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ' &^:@V  
Utility.log(header+" : "+con.getHeaderField(header)); od"Oq?~/t  
else /VgA}[%y  
break; Sy6Y3 ~7  
} l`:M/z6"  
}
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public void splitterStop() ~gNa<t
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{ )V*Z|,#no  
bStop = true; ULIbVy7Y  
} frWw-<
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q~^Jd=cB\  
} s(w6Ldi  
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/* VC:.ya|Z  
**FileAccess.java u7=`u/  
*//文件访问(定位，写) QeuIAs*_  
package NetFox; ArDkJ`DE  
import java.io.*; x=pq-&9>B  
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public class FileAccessI implements Serializable{ >V2Tr$m j  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 UiqHUrx  
RandomAccessFile oSavedFile; oyZ}JTl(Q  
long nPos; <5?.s< y$"  
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public FileAccessI() throws IOException Kr3L~4>  
{ YDE;mIW  
this("",0); M.O3QKU4  
} l~kxt2&  
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public FileAccessI(String sName,long nPos) throws IOException 494"-F6  
{ d[;Sn:B  
oSavedFile = new RandomAccessFile(sName,"rw"); w[~O@:`]<o  
this.nPos = nPos; J+r\EN^9  
oSavedFile.seek(nPos); 3qR%Mf'  
} ;HtHN K(o  
jc)[5i0  
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public synchronized int write(byte[] b,int nStart,int nLen) -.~Dhk  
{ x9)^0Hbo  
int n = -1; $-H#M]Gq  
try{ P!q!+g  
oSavedFile.write(b,nStart,nLen); |j($2.  
n = nLen; }SIUsh'  
} h W\q  
catch(IOException e) @iWql*K;m  
{ 8Ux3,X=  
e.printStackTrace (); 'B ocMjRA  
} *Hx{eqC  
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return n; A0Pg|M  
} tu8n1W  
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} FvQ>Y')R7Z  
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/* c193Or'6Y  
**SiteInfoBean.java MO|aN,  
*/ [}Vne;V  
package NetFox; `./$hh  
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public class SiteInfoBean { b2]1Dfw  
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private String sSiteURL; //Site's URL f}
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private String sFilePath; //Saved File's Path ?*lpu  
private String sFileName; //Saved File's Name @(Q'J`  
private int nSplitter; //Count of Splited Downloading File ;K]6/Wt  
rvrv[^a(  
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public SiteInfoBean() w64/$  
{//nSplitter的缺省值为5 YTP6m9hA+  
//default value of nSplitter is 5 &o@IMbJ8  
this("","","",5); :%-xiv  
} *\ZK(/V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S?TyC";!  
{ 
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sSiteURL= sURL; Qz6Ry\u  
sFilePath = sPath; Ni"n_Yun  
sFileName = sName; Dg(882#_  
this.nSplitter = nSpiltter; =w&JDj  
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} Tv2d?y  
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&  
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public String getSSiteURL() O%feBe  
{ LA?h+)  
return sSiteURL; sswYwU  
} Bs7/<$9K/  
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public void setSSiteURL(String value)  zE$KU$  
{ VE3,k'^v  
sSiteURL = value; R)4L]ZF  
} B^Z %38o  
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public String getSFilePath() &)Y26*(`  
{ rZ}y'A   
return sFilePath; rm}OVL  
} Wc]L4
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public void setSFilePath(String value) =^  
{ c~j")o  
sFilePath = value; !\D[lh}rL  
} <i}lP/U  
8bl&-F`  
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public String getSFileName() .C$4jR.KC  
{ <*O~?=6p  
return sFileName; QAs$fi}f]s  
} wCT. (d_  
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public void setSFileName(String value) u!wR  
{ 9a4Xf%!F>z  
sFileName = value; w'uI~t4  
} =/_tQR~  
#|\w\MJamP  
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public int getNSplitter() )8ub1,C  
{ x""gZzJ$L  
return nSplitter; )qxZHV  
} i n}N[  
`` !BE"yN  
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public void setNSplitter(int nCount) #9=as Y  
{ Z.:g8Xl-6  
nSplitter = nCount; mRJX,  
} RE*;_DF  
} |"7F`M96I  
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/* j2\B(PA  
**Utility.java urM=l5Sx  
*/ 1D@'uApi.  
package NetFox; fcDiYJC*  
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public class Utility { _wvSLu<q  
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public Utility() a g=,oYn  
{ G.ag$KF
 
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} LI`L!6^l  
x}acxu 2H7  
//线程睡眠 }ZPO^4H;-  
public static void sleep(int nSecond) HfQZRDH  
{ /HlLfW  
try{ T~=r*4  
Thread.sleep(nSecond); ?_hKhn%K9  
} )83UF r4kP  
catch(Exception e) <m") 2dJ  
{ ?\_\pa/+  
e.printStackTrace (); }cl~Vo-mp  
} eN]AJ%Ig  
} 8 K7.; t1  

km%c0
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//日志 '*`25BiQ  
public static void log(String sMsg) w]<a$C8*y:  
{ OHEl.p]|  
System.err.println(sMsg); pi/Jto25z  
}
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ar+ j`QIe  
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public static void log(int sMsg) |:yWDZg[  
{ ;"d>lyL  
System.err.println(sMsg); O7]p `Xi8  
} |@Cx%aEKU  
} zk#NM"C+  
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|$hBY
w  
/* k/U1 :9  
**TestMethod.java WAd5,RZ?  
*/ Ib8*rL0p<L  
package NetFox; {=Z xF  
gL)l)}#  
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public class TestMethod { 8mrB_B5  
]g/:lS4  
ef !@|2  
public TestMethod() {>x6SVF  
{ ///xx/weblogic60b2_win.exe he/WqCZg  
try{ !xqy6%p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NVt612/'7y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >#9f{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8[PD`*w  
fileFetch.start(); Z%rMX}  
} -^R6U~  
catch(Exception e){e.printStackTrace ();} C'Gj\  

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} -k4w$0)  
R
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public static void main(String[] args) ,b b/ $   
{ N9SC\  
new TestMethod(); -[h2fqu1  
} HITw{RPrW  
} QsXy(w#F  
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