http断点续传简单实现（java)

/* |'WaBy1  
**SiteFileFetch.java |e@9YDZ  
*/ GUJ[2/V~A  
package NetFox; sZ #Ck"n  
import java.io.*; *joy%F  
import java.net.*; uBI?nv,  
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public class SiteFileFetch extends Thread { i|PQNhUe  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YHN@?}T()  
long[] nStartPos; //开始位置 a<l(zJptG  
long[] nEndPos; //结束位置 qt5CoxeJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O7|0t\)  
long nFileLength; //文件长度 Kl<qp7o0  
boolean bFirst = true; //是否第一次取文件 :9N~wd  
boolean bStop = false; //停止标志 {7&(2Z]z  
File tmpFile; //文件下载的临时信息 v]|^.x:  
DataOutputStream output; //输出到文件的输出流 m`!C|?hu  
bj4cW\b(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _y&m4Vuu  
public SiteFileFetch(SiteInfoBean bean) throws IOException !4cR&@[  
{ E\Hhi.-  
siteInfoBean = bean; {"l_x]q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z.+-MNWV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZzPlIl}\  
if(tmpFile.exists ()) 9\RSJGx6  
{ Mw2?U>h1  
bFirst = false; hM^#X,7  
read_nPos(); ;:Q 5?zM  
} Uj&2'>MJ$  
else E+Z//)1Z  
{ v# ab2  
nStartPos = new long[bean.getNSplitter()]; l`8S1~j
 
nEndPos = new long[bean.getNSplitter()]; 1a4HThDXP  
} PVvN
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} &gxRw l  
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public void run() (yWU9q)5  
{ mh;<lW\K/Z  
//获得文件长度 b[,J-/;JNL  
//分割文件 y&Sl#IQ L  
//实例FileSplitterFetch )O~LXK=b  
//启动FileSplitterFetch线程 Iih~W&  
//等待子线程返回 v'0A$`w`  
try{ Ovh  
if(bFirst)

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{ mY?^]3-_  
nFileLength = getFileSize();
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if(nFileLength == -1) MjCD;I:C.  
{ $A\fm`  
System.err.println("File Length is not known!"); /,dcr*  
} x'_I{$C&  
else if(nFileLength == -2) %[0V>  
{ WCT}OiLsL  
System.err.println("File is not access!"); /n;-f%dL  
} bI.LE/yk  
else K5gh7  
{ r4/G&m[V  
for(int i=0;i<nStartPos.length;i++) p x1y#Q  
{ 3/V&PDC*'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .w3.zZ0[  
} vc
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for(int i=0;i<nEndPos.length-1;i++) lR[[]Yn  
{ j|"#S4IX)F  
nEndPos = nStartPos[i+1]; |Fz/9+I  
} fH?e9E4l  
nEndPos[nEndPos.length-1] = nFileLength; 5BnO-[3  
} (@*[^@ipV  
} tcyami6D4  
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//启动子线程 P F#+G;q;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4E]w4BG)  
for(int i=0;i<nStartPos.length;i++) _MQ)  
{ x? 3U3\W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W1S7%6y_1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C o v,#j j  
nStartPos,nEndPos,i); [sJ f)<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P3X;&iT  
fileSplitterFetch.start(); '<_nL8A^  
} %LeG.~?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $,$bZV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gV@FT|j!i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", - &u]B$  
nEndPos = " + nFileLength); Jm&7&si7  
// fileSplitterFetch[nPos.length-1].start(); Qa@b-v'by  
/.r|ron:e  
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//等待子线程结束 !_CBf#0  
//int count = 0; 3Ob"R%Yo  
//是否结束while循环 vI3L <[W  
boolean breakWhile = false; RGFanP  
"L^]a$&  
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while(!bStop) vw VeHjR  
{ Q qGf*  
write_nPos(); .%;`:dtj  
Utility.sleep(500); 1y@d`k`t:  
breakWhile = true; pEgQ) 9\  
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for(int i=0;i<nStartPos.length;i++) ApHs`0=(  
{ [4L[.N@  
if(!fileSplitterFetch.bDownOver) A\p'\@f  
{ ]OIB;h;3  
breakWhile = false; Hx[YHu KL^  
break; ax$ashFO/!  
} E~vM$$O$  
} 3V~871:-~  
if(breakWhile) wSoIU,I  
break; ssaEAm:  
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//count++; xUl=N   
//if(count>4) ?WPuTPw{
 
// siteStop(); EH{m~x[Ei  
} ~L\KMB/9e=  
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System.err.println("文件下载结束！"); hG~4i:p <  
} d-/{@   
catch(Exception e){e.printStackTrace ();} s2=rj?g&(X  
} "(bnr0  
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//获得文件长度 3!E*h0$}  
public long getFileSize() ZL/iX~}a'  
{ o 4G%m>$  
int nFileLength = -1; -]yM<dP  
try{  v?Dc3  
URL url = new URL(siteInfoBean.getSSiteURL()); FYPv:k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dr3j<D-Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); cmG*"  
v2=Iqo  
}j<:hDQP  
int responseCode=httpConnection.getResponseCode(); @qj4rt"  
if(responseCode>=400) nE.w  
{ 32h}+fd  
processErrorCode(responseCode); 1;_tu  
return -2; //-2 represent access is error %N5gQXg  
} :/YHU3~Y  
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String sHeader; 4 mj\wBp  
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for(int i=1;;i++) c;siMWw;  
{ 6ub-NtVu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NGQBOV  
//Utility.log(in.readLine()); UuXq+HYR  
sHeader=httpConnection.getHeaderFieldKey(i); P?|F+RoX$  
if(sHeader!=null) l~ 3H
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{ )~W 35  
if(sHeader.equals("Content-Length")) Hq<Sg4nz  
{ SURbH;[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ogD 8qrZ6J  
break; dH]0(aJ  
} Z;M}.'BE  
} 581Jp'cje  
else
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break; r~f*aD  
} /QuuBtp  
} z~Zu>Q1u[  
catch(IOException e){e.printStackTrace ();} NTq#'O) f  
catch(Exception e){e.printStackTrace ();} ,Dh+-}  
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Utility.log(nFileLength); Qm9r>m6p@N  
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return nFileLength; /G[2   
} \ a}6NIo  
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//保存下载信息（文件指针位置） }ACWSkWK  
private void write_nPos() (!'=?B "  
{ m@(8-_  
try{ |#OMrP+oi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zNTcy1Sthk  
output.writeInt(nStartPos.length); iakqCjV  
for(int i=0;i<nStartPos.length;i++) dU4 h  
{ 9gWR djK:  
// output.writeLong(nPos); Ltk'`  
output.writeLong(fileSplitterFetch.nStartPos); {B;<R1  
output.writeLong(fileSplitterFetch.nEndPos); tjONN(K`  
} h\qQ%|X  
output.close(); Cu2eMUGt  
} d}d1]@Y\  
catch(IOException e){e.printStackTrace ();} jVW .=FK  
catch(Exception e){e.printStackTrace ();} C1V:_-  
} (i3V  
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//读取保存的下载信息（文件指针位置） ;Gf,I1d}{  
private void read_nPos() <V`1?9c7D1  
{ I`e$U  
try{ aC!e#(q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @^q|C&j  
int nCount = input.readInt(); ;i;2c
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nStartPos = new long[nCount]; YgiLfz iT  
nEndPos = new long[nCount]; &\n<pXQ  
for(int i=0;i<nStartPos.length;i++) tr[(,kX  
{ (w1M\yodV  
nStartPos = input.readLong(); .~3s~y*s  
nEndPos = input.readLong(); "pZvV0'  
} dSdP]50M  
input.close(); x6n
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} G`;YB  
catch(IOException e){e.printStackTrace ();} Pn?,56SD=  
catch(Exception e){e.printStackTrace ();} ]t2zwHo#  
} OEZ`5"j  
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private void processErrorCode(int nErrorCode) kU75  
{ rnOg;|u8  
System.err.println("Error Code : " + nErrorCode); ejFGeR  
} NE~R&ym9  
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Xl/SDm_p  
//停止文件下载 /Jcf
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public void siteStop() |qOoL*z  
{ E*B6k!:  
bStop = true; }q$6^y  
for(int i=0;i<nStartPos.length;i++) OuZPgN  
fileSplitterFetch.splitterStop(); \]:}lVtxS  
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} H\>0jr`  
} "r+v^  
//负责部分文件的抓取 R5"5Z?'  
**FileSplitterFetch.java :m&cm%W]ts  
*/ w4AA4
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package NetFox; AhyV  
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import java.io.*; s^&Oh*SP*  
import java.net.*; =/#+,  
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public class FileSplitterFetch extends Thread { /W|=Or2oR  
<<SUIY@X  
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String sURL; //File URL w7#9t  
long nStartPos; //File Snippet Start Position ,P>xpfdK  
long nEndPos; //File Snippet End Position xj!G9x<!  
int nThreadID; //Thread's ID 1(YEOZ  
boolean bDownOver = false; //Downing is over hvFXYq_[O  
boolean bStop = false; //Stop identical qN=l$_UD  
FileAccessI fileAccessI = null; //File Access interface Nn/f*GDvK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #$dEg  
{ m)1+D"z  
this.sURL = sURL; f{HjM? Mb3  
this.nStartPos = nStart; >N bb0T  
this.nEndPos = nEnd; o5(~nQ  
nThreadID = id; 8mc0(Z@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 id?B<OM  
} h>a/3a$g  
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public void run()  ob_*fP  
{ 1;E^3j$  
while(nStartPos < nEndPos && !bStop) .7K<9K+P  
{ L,/(^0;  
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try{ ^o8o  
URL url = new URL(sURL); l~C=yP(~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w=Yc(Y:h  
httpConnection.setRequestProperty("User-Agent","NetFox"); K2o\+t  
String sProperty = "bytes="+nStartPos+"-"; US'rhSV  
httpConnection.setRequestProperty("RANGE",sProperty); Chs#}=gzi  
Utility.log(sProperty); xX:N-  
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=jWjUkm2  
InputStream input = httpConnection.getInputStream(); 0|chRX  
//logResponseHead(httpConnection); dRGgiQO  
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byte[] b = new byte[1024]; /@O$jlX5I  
int nRead; 2FxrjA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -}G>{5.A  
{ 6>d0i S@R  
nStartPos += fileAccessI.write(b,0,nRead); ?l/+*/AR;  
//if(nThreadID == 1) /lb"g_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ve9*>6i&-4  
} \s@7pM=(  
Nu[0X  
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Utility.log("Thread " + nThreadID + " is over!"); 9`FPV`/  
bDownOver = true; t,IQ|B&0  
//nPos = fileAccessI.write (b,0,nRead); -L6V
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} Q13>z%Rge  
catch(Exception e){e.printStackTrace ();}
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} Ls2g#+  
} "/g\?Nce  
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//打印回应的头信息 '\wZKYVN  
public void logResponseHead(HttpURLConnection con) hhr!FQ.+/  
{ 2JR$  
for(int i=1;;i++) nl/~7({  
{ g5
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String header=con.getHeaderFieldKey(i); B(ZK\]  
if(header!=null) v2KK%Qy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lBZhg~{  
Utility.log(header+" : "+con.getHeaderField(header)); ><DXT nt'x  
else >0AVs6&;v  
break; +6;1.5Tc  
} @UwDsx&2(t  
} ++|vy~T  
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public void splitterStop() 9>!B .Z?!#  
{ )+dd  
bStop = true;
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} ,1ceNF#o
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} S7kZpD$  
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j= vlsW  
/* (!:+q$#BK  
**FileAccess.java ~fz9AhU8  
*//文件访问(定位，写) uD8,E!\  
package NetFox; %$ ^eY'-'  
import java.io.*; }pOJM&I  
qu+Zl1~$]  
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public class FileAccessI implements Serializable{ |S.;']t+  
jA,|.P>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %Q.|qyq  
RandomAccessFile oSavedFile; lr~c w#h*  
long nPos; ?Vo/mtbY5X  
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public FileAccessI() throws IOException )ad
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{ T(q/$p&q  
this("",0); w#w?Y!JXo  
} ){FXonVP  
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public FileAccessI(String sName,long nPos) throws IOException mNdEn<W  
{ MzpDvnI9  
oSavedFile = new RandomAccessFile(sName,"rw"); *<#$B}!{  
this.nPos = nPos; IRY/0v  
oSavedFile.seek(nPos); qt,;Yxx#^  
} p`T,VU&.  
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public synchronized int write(byte[] b,int nStart,int nLen) up )JU [  
{ @3W
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int n = -1; +I[Hxf~  
try{ 5K[MKfT  
oSavedFile.write(b,nStart,nLen); 1Farix1YDq  
n = nLen; "H3DmsB  
} hw)#TEt   
catch(IOException e) 'E_~>  
{ p)YI8nW  
e.printStackTrace (); .u^4vVz  
} V}po  
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return n; +H6cZ,  
} rpMjDjW  
/~}<[6ZGCY  
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} rw%1>]os  
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/* {-.ZFUZmT  
**SiteInfoBean.java &!0%"4  
*/ -;W`0k^  
package NetFox; {/Qg4pc!  
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public class SiteInfoBean { L3|~ i&k  
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private String sSiteURL; //Site's URL |N%#;7  
private String sFilePath; //Saved File's Path 1qN+AT  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File k:*(..!0z  
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 ie4BE'  
public SiteInfoBean() @78%6KZ`i  
{//nSplitter的缺省值为5 XTS%:S  
//default value of nSplitter is 5 Tt+E?C%Y  
this("","","",5); U%H6jVE  
} "e@?^J)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6o=Q;Mezl  
{ _n=,H  
sSiteURL= sURL; -E,p[Sp  
sFilePath = sPath; Jt|W%`X>D  
sFileName = sName; l#^weXSlk  
this.nSplitter = nSpiltter; "c*&~GSE4  
r"_SL!,^  
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} _}3N
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3JXKpk?   
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public String getSSiteURL() >A ?{cbJ  
{ P{%R*hb]  
return sSiteURL; )9s 6(Iu  
} kcio]@#  
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public void setSSiteURL(String value) i;I!Jc_b'  
{ hjx=?  
sSiteURL = value; D+('1E?  
} c!Wj^  
rLx'.:  
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public String getSFilePath() JLu>w:\  
{  j*#k%;c  
return sFilePath; cd:VFjT  
} ObEp0-^?  
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public void setSFilePath(String value) E-"b":@:  
{ x A"V!8C  
sFilePath = value; )Oix$B!-  
} D9;s%  
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public String getSFileName() 87q~ nk  
{ k.Q4oyei  
return sFileName; 6y   
} a n,$Z,G#K  
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public void setSFileName(String value) jrZH1dvE  
{ +hUz/G+3  
sFileName = value; 2'5
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} /Q\|u:oO,  
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public int getNSplitter() 4$MV]ldUI  
{ ,@r 0-gL  
return nSplitter; Wk
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} NW`L
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public void setNSplitter(int nCount) K}TSwY  
{ xF])NZy|  
nSplitter = nCount; qJYEsI2M  
} `z~L
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} 8;Eg>_cL:  
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y.+!+4Mg|  
/* ]Y
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**Utility.java BfdS3VrZ
/  
*/ Xn*>qm  
package NetFox; 8Y&_X0T|  
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public class Utility { uL9O_a;!  
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public Utility() ]D&\|,,(
 
{ bPUldkB:  
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}  #[yZP9  
=L&dV]'4P  
//线程睡眠 ;$/]6@bqB  
public static void sleep(int nSecond) mWX{I2  
{ qz&?zzz;  
try{ #55_hY#  
Thread.sleep(nSecond); hL}AgY@  
} z\+Ug9Of  
catch(Exception e) (;cvLop  
{ *TC#|5  
e.printStackTrace (); h$$2(!G4  
} H rI(uZ]  
} `<IaQY  
+ 3c (CTz  
//日志 'A)9h7k}  
public static void log(String sMsg) LQXMGgp  
{ yL"UBe}v  
System.err.println(sMsg); %1z`/B  
} _l{_n2D-  
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public static void log(int sMsg) p%ZAVd*|#V  
{ N.dcQQ_iS  
System.err.println(sMsg); ,FWsgqL{l  
} a&%v^r[  
} /f]'_t0\.  
@ w?,7i-S  
fO,m_ OR:)  
/* gaU1A"S}  
**TestMethod.java }
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*/ CC|=$(PgT  
package NetFox; IZOO>-g'f  
*:8,w?Nt  
 LXf*  
public class TestMethod { ~w"e 2a  
+r$M 9  
h_\OtoRa  
public TestMethod() mV#U=zqb!S  
{ ///xx/weblogic60b2_win.exe
\VHRI<$+5  
try{ L)9uBdF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ((T6z$:hA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *Z2#U?_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +XpQ9Cd  
fileFetch.start(); !MEA@^$#  
} cg_j.=M-  
catch(Exception e){e.printStackTrace ();} m e2$ R>@  
#y*p7~|@  
5m9;'SF  
} 3h**y %^  
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public static void main(String[] args) 'Oa(]Br[  
{ I;+>@Cn(g<  
new TestMethod(); *s$:"g-  
} ?9ScKN  
} oL -udH  
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