http断点续传简单实现（java)

/* r8`ffH  
**SiteFileFetch.java W=~~5jFX  
*/ .]8ZwAs=&  
package NetFox; c[0}AGJ  
import java.io.*; E>6MeO  
import java.net.*; KjD/o?JUr  
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public class SiteFileFetch extends Thread { j\eI0b @*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ju8>:y8  
long[] nStartPos; //开始位置 9)l$ aBa  
long[] nEndPos; //结束位置 k R?qb6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .yoH/2h  
long nFileLength; //文件长度 3(>B Ke  
boolean bFirst = true; //是否第一次取文件 tj'\tW+s'  
boolean bStop = false; //停止标志 %Hu5K>ZNYp  
File tmpFile; //文件下载的临时信息 t*p71U
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DataOutputStream output; //输出到文件的输出流 s n8Qk=K  
sU=H&D99  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &sl0W-;0  
public SiteFileFetch(SiteInfoBean bean) throws IOException bTI|F]^!  
{ .#EFLXs  
siteInfoBean = bean;  {y)=eX9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,V7nzhA2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z3Og=XHR  
if(tmpFile.exists ()) x[cL Bc<  
{ N:^n('U&j  
bFirst = false; lqy Qf$t  
read_nPos(); :a!^
  
} _5w]a 2  
else Q3 ea{!r  
{ %:i7s-0w  
nStartPos = new long[bean.getNSplitter()]; Jx:Y-$  
nEndPos = new long[bean.getNSplitter()]; \<bx[,?  
} n3WlZ!$  
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} [z:
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public void run() ;[ZEDF5H  
{ juJklSD  
//获得文件长度 GblA
9F7  
//分割文件 nkPh,X\N0  
//实例FileSplitterFetch 9+|$$)  
//启动FileSplitterFetch线程 
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//等待子线程返回 jRa43ck  
try{ RbB.q p  
if(bFirst) p%ki>p )E|  
{ @FAA2d  
nFileLength = getFileSize(); x>K Or,f  
if(nFileLength == -1) yxPazz  
{ /|}EL%a  
System.err.println("File Length is not known!"); l$KA)xbI  
} v&\Q8!r_  
else if(nFileLength == -2) hPB9@hT$  
{ +
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System.err.println("File is not access!"); : $1?i)  
} ,)cM3nu  
else #
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{ gT.sjd  
for(int i=0;i<nStartPos.length;i++) As&Sq-NWf  
{ %@b0[ZC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :U|1xgB  
} LENq_@$  
for(int i=0;i<nEndPos.length-1;i++) dFxIF;C>/  
{ M)Z7k/=<P  
nEndPos = nStartPos[i+1]; K8|r&`X0  
} bW427B0
 
nEndPos[nEndPos.length-1] = nFileLength; n`_{9R  
} >b
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} 6yG^p]zZ  
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B3`5O[6  
//启动子线程 'ZF{R3Xu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =ZznFVJ`={  
for(int i=0;i<nStartPos.length;i++) NG=-NxEcN  
{ bSlF=jT[S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /{J4:N'B>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t.y2ff<[U  
nStartPos,nEndPos,i); N
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /U*C\ xMm  
fileSplitterFetch.start(); X,% 0/6*]  
} M] %?>G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9rX&uP)j^#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e2Pcm_Ahv*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a5"D@E  
nEndPos = " + nFileLength); 5V~oIL  
// fileSplitterFetch[nPos.length-1].start();
&m7]v,&  
G_8RK,H.  
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//等待子线程结束 _.Nbt(mz  
//int count = 0; y14;%aQN  
//是否结束while循环 +)om^e@.  
boolean breakWhile = false; 76Cl\r
V  
K7B/s9/xs  
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while(!bStop) +o{R _  
{ r+i($jMs  
write_nPos(); NNR`!Pty  
Utility.sleep(500); | j`@eF/"  
breakWhile = true; P1 8hxXE3  
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for(int i=0;i<nStartPos.length;i++) [b%D3-}'  
{ SM#]H-3  
if(!fileSplitterFetch.bDownOver) 4he GnMD  
{ 65P0,b6"OT  
breakWhile = false; /t57!&  
break; aiUY>M#|  
} =:Fc;n>c<K  
} $9#H04.x  
if(breakWhile) x /S}Q8!"}  
break; \ZFGw&yN  
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//count++; ]@c+]{  
//if(count>4) #U4F0BdA  
// siteStop(); iN\4gQ!  
} LgU_LcoM*  
8 +/rlHp  
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System.err.println("文件下载结束！"); {SPq$B_VR  
} BLdvyVFx  
catch(Exception e){e.printStackTrace ();} &j`}vg  
} '~<m~UXvD#  
z&)A,ryW0  
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//获得文件长度 qPK*%Q<;  
public long getFileSize() \;3~a9q%  
{ YeL#jtC  
int nFileLength = -1; ~s*)f.l  
try{ *uf'zQ<9  
URL url = new URL(siteInfoBean.getSSiteURL()); =pO^7g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~O0 $Suv  
httpConnection.setRequestProperty("User-Agent","NetFox");  hoUD;3  
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H3^},.  
int responseCode=httpConnection.getResponseCode(); C*_C;6.~Y  
if(responseCode>=400) c /HHy,  
{
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processErrorCode(responseCode); g`' !HGY  
return -2; //-2 represent access is error 4N_R:B-Vu  
} uAJx.>$b  
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String sHeader; b9J_1Gl]  
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<I\/n<*  
for(int i=1;;i++) @ $ ;q;  
{ mbTEp*H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fI}to&qk  
//Utility.log(in.readLine()); v5#jZ$<F  
sHeader=httpConnection.getHeaderFieldKey(i); wedbx00o  
if(sHeader!=null) EoR}Af  
{ x.!V^HQSN  
if(sHeader.equals("Content-Length")) w!-gJmX>  
{ l'-Bu(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  5h=}j  
break; KE5kOU;  
} '4+ ur`  
} :Uzm  
else (l~AV9!m:  
break; 2^[`eg  
} XH4  
} S]e|"n~@  
catch(IOException e){e.printStackTrace ();} SumF 2  
catch(Exception e){e.printStackTrace ();} s 8jV(P(O  
#4Rx]zW^%  
Ar
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Utility.log(nFileLength); pHXm>gTd,J  
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return nFileLength; +ZaSM~   
} #C74z$  
m<
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n`?aC|P2s  
//保存下载信息（文件指针位置） / |;RV"  
private void write_nPos() Ct<udO  
{ Pe_W;q.  
try{ GbY7_N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y1W1=Uc uk  
output.writeInt(nStartPos.length); 36&e.3/#  
for(int i=0;i<nStartPos.length;i++) Eak$u>Fd8c  
{ rK6l8)o  
// output.writeLong(nPos); |/|5UiX7  
output.writeLong(fileSplitterFetch.nStartPos); T"}5}6rSG  
output.writeLong(fileSplitterFetch.nEndPos); *MFIV
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} T9E+\D  
output.close(); r,8 [O  
} bivuqKA  
catch(IOException e){e.printStackTrace ();} x*\Y)9Vgy  
catch(Exception e){e.printStackTrace ();} -e"H ^:  
} )5Q~I,dP  
kYP#SH/  
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//读取保存的下载信息（文件指针位置） lwxaMjaL4K  
private void read_nPos() "+R+6<"  
{ 1APe=tJ  
try{ hn7# L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U/66L+1  
int nCount = input.readInt(); ONB{_X?  
nStartPos = new long[nCount]; ,B*
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nEndPos = new long[nCount]; Jc&{`s^Nu  
for(int i=0;i<nStartPos.length;i++) ^,lIK+#Elz  
{ ]Grek<  
nStartPos = input.readLong(); T$)^gHS  
nEndPos = input.readLong(); kUL'1!j7  
} 8rAg\H3E  
input.close(); ?um;s-x)  
} Ke;E1S-~  
catch(IOException e){e.printStackTrace ();} Hp|kQJ[LE  
catch(Exception e){e.printStackTrace ();} m^!Z_]A![  
} 60^`JVGWH  
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private void processErrorCode(int nErrorCode) hIYNhZv  
{ /wGM#sFH
 
System.err.println("Error Code : " + nErrorCode); K(e$esLs-  
} v ,i%Q$  
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//停止文件下载 //up5R_nx  
public void siteStop() W 8<&gh+  
{ p%up)]?0  
bStop = true; X~bX5b[P  
for(int i=0;i<nStartPos.length;i++) |"q5sym8Y_  
fileSplitterFetch.splitterStop(); Ko| d
+  
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} |MTnH/|  
} gi3F` m  
//负责部分文件的抓取 +)AG*  
**FileSplitterFetch.java q^@Q"J =v  
*/ c`)\Pb/O  
package NetFox;  C#.->\  
w0 M>[ 4  
: g7@PJND  
import java.io.*; wA ,6bj  
import java.net.*; R3f89  
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public class FileSplitterFetch extends Thread { J'6PmPzY|  
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String sURL; //File URL OU\~::  
long nStartPos; //File Snippet Start Position +%z>H"J.  
long nEndPos; //File Snippet End Position +yG~T  
int nThreadID; //Thread's ID EmWn%eMN  
boolean bDownOver = false; //Downing is over VcE:G#]5  
boolean bStop = false; //Stop identical P7bMIe  
FileAccessI fileAccessI = null; //File Access interface d UE,U=  
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k!
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [-1^-bb  
{ KJUH(]>F  
this.sURL = sURL; AEI>\Y  
this.nStartPos = nStart; FW;?s+Uyx  
this.nEndPos = nEnd; >{n,L6_t  
nThreadID = id; :1Xz4wkWS*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 XAKs0*J>  
} wYXQlxdy  
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public void run() |fJ};RLI"  
{ !<8W {LT  
while(nStartPos < nEndPos && !bStop)  #4NaL  
{ =+-UJo5  
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try{ St9?RD{4;  
URL url = new URL(sURL); ea2ayT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w$iX.2|9%u  
httpConnection.setRequestProperty("User-Agent","NetFox"); qbN =
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String sProperty = "bytes="+nStartPos+"-"; %)8}X>xq  
httpConnection.setRequestProperty("RANGE",sProperty); \~mT] '5  
Utility.log(sProperty); KhR81\  
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InputStream input = httpConnection.getInputStream(); qH>d  
//logResponseHead(httpConnection); _Kf%\xg  
|$Sedzj'  
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byte[] b = new byte[1024]; a$OE0zn`  
int nRead; `UyG_;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^98~U\ar  
{ 7hcYD!DS  
nStartPos += fileAccessI.write(b,0,nRead); ;(Or`u]Dr  
//if(nThreadID == 1) `cUl7 'j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g}{aZ$sta  
} dt]-,Y  
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Utility.log("Thread " + nThreadID + " is over!"); BhGu!Y6f  
bDownOver = true; '[:D$q;  
//nPos = fileAccessI.write (b,0,nRead); Cctu|^V  
} }@+0/W?\.  
catch(Exception e){e.printStackTrace ();} j{A y\n(  
} 8qTys8  
} i$G@R%  
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n
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//打印回应的头信息 zu{P#~21  
public void logResponseHead(HttpURLConnection con) *)T^ChD,  
{ S`0(*A[W*  
for(int i=1;;i++) AjMh,@  
{ KL57#gV  
String header=con.getHeaderFieldKey(i); & G4\2l9  
if(header!=null) Id .nu/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .j0$J\:i  
Utility.log(header+" : "+con.getHeaderField(header)); J @1!Oq>  
else b9HtR-iR;  
break; 7'V@+5
 
} ?mxMk6w  
} VU
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public void splitterStop() !ons]^km  
{ mnX2a  
bStop = true; {qJ1ko)$  
} jcf7n`L  
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} s8t;.^1}  
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/*
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**FileAccess.java _|I#{jK  
*//文件访问(定位，写) /%1ON9o>  
package NetFox; >tV{Pd1  
import java.io.*; +lcbi  
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public class FileAccessI implements Serializable{ p6Gy,C.  
2-EIE4
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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 I-(zaqp@  
RandomAccessFile oSavedFile; KRRdXx\~  
long nPos;
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public FileAccessI() throws IOException y??XIsF  
{ _Q4)X)F  
this("",0); 0~/_|?]`7  
} PKiy5D*8p  
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public FileAccessI(String sName,long nPos) throws IOException \Uq(Zga4)  
{ cR<fJ[*  
oSavedFile = new RandomAccessFile(sName,"rw"); `b7t4d*  
this.nPos = nPos; 7;wd(8  
oSavedFile.seek(nPos); B[?Ng}<g`  
} 7~.9=I'A  
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S;#'M![8  
public synchronized int write(byte[] b,int nStart,int nLen) TKmf+ZT*r  
{ c 3)jccWTc  
int n = -1; yl+gL?IES  
try{ R$[vm6T?  
oSavedFile.write(b,nStart,nLen); `Eo.v#<  
n = nLen; 6mxfLlZ  
} kUrkG80q|  
catch(IOException e) Y&Z.2>b
 
{ .Vvx
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e.printStackTrace (); ~U&AI1t+J  
} P{lB50  
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return n; M&9+6e'-F  
} ')<hON44EX  
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} &Hs!:43E-<  
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/* ":QZy8f9%  
**SiteInfoBean.java DT&@^$?  
*/ 'c$+sp ?  
package NetFox; ~6LN6}~|.  
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s&3Vg7B  
public class SiteInfoBean { lA8`l>I  
f x+/C8GK  
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private String sSiteURL; //Site's URL YNsJZnGr8#  
private String sFilePath; //Saved File's Path d<P\&!R(  
private String sFileName; //Saved File's Name +A?U{q  
private int nSplitter; //Count of Splited Downloading File >(t6.=  
=fFP5e ['  
OYn}5RN  
public SiteInfoBean() *VxgARIL  
{//nSplitter的缺省值为5 3AN/ H  
//default value of nSplitter is 5 n,WqyNt*  
this("","","",5); ^.QzQ1=D  
} ge8ZsaiU  
4 "'~NvO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?m"( Soh  
{ Q>Yjy!.<^  
sSiteURL= sURL; Wg]Qlw`\|  
sFilePath = sPath; -PR N:'T  
sFileName = sName; z!9-
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this.nSplitter = nSpiltter; /f;~X"!  
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} ##"HF  
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public String getSSiteURL() +TDw+  
{ +ksVtG,  
return sSiteURL; C e$w8z  
} ;u)I\3`*!  
1yu4emye4  
#S"nF@   
public void setSSiteURL(String value) ^k9I(f^c-_  
{ +QJ#2~pE  
sSiteURL = value; #QMz<P/Gl6  
} 9'bwWBf7  
8bld3p"^  
I b5rqU\  
public String getSFilePath() *J`O"a  
{ gRcQt:  
return sFilePath; TOQP'/   
} d7bS wL  
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public void setSFilePath(String value) IjnU?Bf  
{ Pe3o;mx  
sFilePath = value; &Au@S$ij  
} `VguQl_,gA  
1bwOmhkS  
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public String getSFileName() ey$&;1x#5  
{ GnJt0{  
return sFileName; p9-K_dw3X@  
} .(k|wX[Fu~  
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public void setSFileName(String value) ^} >w<'0  
{ +ami?#Sz*;  
sFileName = value;  _6vWF  
} sK?twg;D*|  
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public int getNSplitter() &mS^ZyG  
{ mj7#&r,1l  
return nSplitter; 19%imf  
}  _;\_l  
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vKAN@HSYr  
public void setNSplitter(int nCount) &s>Jb?_5Mx  
{ G7/ +ogV  
nSplitter = nCount; tw)mepwB  
} XC#oB~K'  
} ]JQULE)  
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/* +D*Z_Yh6  
**Utility.java Bdpy:'fJn  
*/ ]7c=PC  
package NetFox; -M#Wt`6A  
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public class Utility { {R{=+2K!|k  
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public Utility() gbD KE{  
{ H3oFORh  
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} cPQiUU~W@  
\a3+rNdj  
//线程睡眠 Y8t8!{ytg  
public static void sleep(int nSecond) es0hm2HT3  
{ *|HY>U.  
try{ E _|<jy$`  
Thread.sleep(nSecond); 3Tm+g2w2V8  
} ~pky@O#b  
catch(Exception e) .*Qx\,  
{ z\4.Gm-  
e.printStackTrace (); e&>2 n  
} tfWS)y7  
} p5*jz
Q  
@>7%qS  
//日志 GTxk%   
public static void log(String sMsg) &uVnZ@o42  
{ uhq8  
System.err.println(sMsg); 9W);rL|5  
} ?Q;=v~-Q  
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:Llb< MY2  
public static void log(int sMsg) tpx2IE  
{ ]eV8b*d6  
System.err.println(sMsg); %@Jsal'  
} b#o|6HkW  
} /g.U&oI]D  
\GU<43J2uo  
iN.n8MN=I  
/* 8RHUeRX  
**TestMethod.java )O6>*wq  
*/ !dT4  
package NetFox; 0tJZ4(0  
3__-nV  
*yGGBqd  
public class TestMethod { wdoR
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bhs _9ivw  
c[
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public TestMethod() GKeU%x
 
{ ///xx/weblogic60b2_win.exe A?0Nm{O;3v  
try{ FC4wwzb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0IWf!Sk ]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MUwMb!Z.s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $Z>'Jp  
fileFetch.start(); fTX;.M/%   
} fd9k?,zM  
catch(Exception e){e.printStackTrace ();} TJ*T:?>e  
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} *n"{J(Jt`  
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public static void main(String[] args) +W+|%qM,\  
{ 9Gz=lc[!7  
new TestMethod(); HLi%%"'  
} %N_%J
K\{@  
} 9MqGIOQ${j  
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