http断点续传简单实现（java)

/* G3KiU($V  
**SiteFileFetch.java pS51fF9  
*/  ~B/|#o2  
package NetFox; )5bhyzSZI  
import java.io.*; R\6#J0&Y-  
import java.net.*; .0Cpqn,[  
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public class SiteFileFetch extends Thread { Pf]L`haGN  
6=FF*"-6E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `$Q $l  
long[] nStartPos; //开始位置 {n{ j*+  
long[] nEndPos; //结束位置 Lk`0z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M7UVL&_z%  
long nFileLength; //文件长度 *pj&^W?  
boolean bFirst = true; //是否第一次取文件 @eR>?.:&  
boolean bStop = false; //停止标志 GN(PH/fO9  
File tmpFile; //文件下载的临时信息 )R,*>-OPJL  
DataOutputStream output; //输出到文件的输出流 H!HkXm"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4_)@Nq  
public SiteFileFetch(SiteInfoBean bean) throws IOException vcq
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{ ix,5-j  
siteInfoBean = bean; :QB Wy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c!E+&5|n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KK/~W  
if(tmpFile.exists ()) _epi[zf@  
{ -SZ^;t  
bFirst = false; ^?w6  
read_nPos(); F~z4T/TN%G  
} 9^>nZ6  
else `nn;E%n  
{ BIS5u4  
nStartPos = new long[bean.getNSplitter()]; q>f1V3  
nEndPos = new long[bean.getNSplitter()]; kx*=1AfU+Y  
} vxY7/_]  
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} p e |k}{  
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public void run() =l?5!f9  
{ 2Q0fgH2  
//获得文件长度 LeXuTd  
//分割文件 67%o83\  
//实例FileSplitterFetch +Z#lf  
//启动FileSplitterFetch线程 89?AcZ.D  
//等待子线程返回 ?HAWw'QW  
try{ |'Z6M];8t  
if(bFirst) ig)rK<@*[  
{ -"#;U`.oh7  
nFileLength = getFileSize(); _.yBX\tf[  
if(nFileLength == -1) =X]$J@j  
{ >@`D@_v  
System.err.println("File Length is not known!"); ]t(;bD hT  
} `pOiv&>  
else if(nFileLength == -2) =;`+^  
{ c5nl!0XX  
System.err.println("File is not access!"); [r<lAS{ .  
} ldO6W7G|h  
else vrLI`3n]  
{ 1s"6  
for(int i=0;i<nStartPos.length;i++) &FW|O(
]  
{ *C}vy`X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1-Sc@WXd  
} f@]4udc e  
for(int i=0;i<nEndPos.length-1;i++) h,LwC9  
{ ix [aS  
nEndPos = nStartPos[i+1]; %\Z{~(&-v  
} uF/l,[0v  
nEndPos[nEndPos.length-1] = nFileLength; #EgFB}>1  
} @OV\raUO&V  
} 9Qst5n\Z  
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//启动子线程 LhUrVydL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @Q 8E)k@  
for(int i=0;i<nStartPos.length;i++) ]Wa.k  
{ 5~5d%C^3k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t6W$t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g!,>.  
nStartPos,nEndPos,i); A|Up>`QH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KD11<&4_x  
fileSplitterFetch.start(); n3da@ClBt  
} 'P3CgpF<Z2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I&,gCZ#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); * _)xlpy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Tky\W%Ag  
nEndPos = " + nFileLength); /\q1,}M  
// fileSplitterFetch[nPos.length-1].start(); |kB1>$  
}uz*6Z(S  
/=).)<&|R  
//等待子线程结束 }lvD 5  
//int count = 0; G];5'd~C;d  
//是否结束while循环 1O"7%Pvw  
boolean breakWhile = false; dj3}Tjt  
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while(!bStop) IV]s!  
{ NifzZEX  
write_nPos(); -Jr6aai3+  
Utility.sleep(500); iaPrkMhd  
breakWhile = true; vN=e1\  
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for(int i=0;i<nStartPos.length;i++) ]@wee08  
{ '85@U`e.  
if(!fileSplitterFetch.bDownOver) =BzyI  
{ G}<%%U D  
breakWhile = false; -!zyit5B  
break; e@}zp  
} ~M7 J{hK  
} !#wd~: H  
if(breakWhile) x%Ivd  
break; yqi=9NB  
~<!b}Hv  
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//count++; >|1.Z'r/  
//if(count>4) mltG4R ?  
// siteStop(); 0n` 1GU)W  
} 2mg4*Y
s  
U>PF#@ C/  
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System.err.println("文件下载结束！"); u2%/</]h  
} MY1s  
catch(Exception e){e.printStackTrace ();} XaOq&7  
} l?F
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9)N/J\b  
//获得文件长度 .hd<,\nW  
public long getFileSize() s4h3mypw
 
{ UlF=,0P  
int nFileLength = -1; }A
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try{ =iF}41a  
URL url = new URL(siteInfoBean.getSSiteURL()); |O =Fz3)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O{u^&V]  
httpConnection.setRequestProperty("User-Agent","NetFox"); vl+vzAd  
'Pyeb`AXE9  
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int responseCode=httpConnection.getResponseCode(); ug47JW  
if(responseCode>=400) 0].*eM  
{ lt%bGjk  
processErrorCode(responseCode); QhV!%}7  
return -2; //-2 represent access is error zfAHE{c  
} =I. b2e1z  
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String sHeader; B^`'2$3  
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for(int i=1;;i++) ?L.c~w;l  
{ XoI,m8A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CtItzp  
//Utility.log(in.readLine()); /4w"akB|P  
sHeader=httpConnection.getHeaderFieldKey(i); Ck
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if(sHeader!=null) 3N%%69JN)  
{ -OY[x|0  
if(sHeader.equals("Content-Length")) 0NKo)HT  
{ Rf7*Ut wVr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2pa: 3O  
break; tS!|#h-J  
} RDX".'`(=  
} m<]b]FQ  
else 2Hltgt,  
break; e]N?{s   
} G;r-f63N  
} 'Y`.0T[&  
catch(IOException e){e.printStackTrace ();} QI\&D)  
catch(Exception e){e.printStackTrace ();} Z[+H$=$%  
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Utility.log(nFileLength); ODE9@]a
  
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return nFileLength; Zr!he$8(2  
} eq>E<X#<  
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//保存下载信息（文件指针位置） X2ShxD|  
private void write_nPos() 7|=*z  
{ JUBihw4  
try{ i^hgs`hvU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eO<:X|9T  
output.writeInt(nStartPos.length); Ya$JX(aUe  
for(int i=0;i<nStartPos.length;i++) ;Kb]v\C:  
{ WR;"^<i9  
// output.writeLong(nPos); &gIDcZ  
output.writeLong(fileSplitterFetch.nStartPos); 7
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output.writeLong(fileSplitterFetch.nEndPos); \gd.Bl
 
} jU K0?S>  
output.close(); 'W0?XaEk-  
} RJMrSz$  
catch(IOException e){e.printStackTrace ();} ?R2`RvQ  
catch(Exception e){e.printStackTrace ();} ~4p@m>>  
} ba_T:;';0  
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)2c[]d/a4  
//读取保存的下载信息（文件指针位置） WgBV,{C  
private void read_nPos() ==d@0`  
{ z;x1p)(xt  
try{ Vj.5b0/(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y~jKytq^@  
int nCount = input.readInt(); ((BuBu>  
nStartPos = new long[nCount]; nx<q]Juv\  
nEndPos = new long[nCount]; Y)%CxaO`  
for(int i=0;i<nStartPos.length;i++) [[fhfV+H  
{ )KvQaC  
nStartPos = input.readLong(); (C;oot
,  
nEndPos = input.readLong(); FBfyW- 7  
} S&BJR!FQ  
input.close(); ]@@3]  
} v6{qKpU#  
catch(IOException e){e.printStackTrace ();} gHS;RF9  
catch(Exception e){e.printStackTrace ();} I<Vh Eo,  
} -QaS/WO_  
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private void processErrorCode(int nErrorCode) =\IcUY,4
 
{ VU>s{_|{  
System.err.println("Error Code : " + nErrorCode); MYqxkhcLH1  
} *.ffyBI*~  
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//停止文件下载 8'+XR`g:ax  
public void siteStop() >j]*=&,7  
{ Q7PqN1jTE  
bStop = true; IyE9G:fY  
for(int i=0;i<nStartPos.length;i++) E|2klA^+*  
fileSplitterFetch.splitterStop(); l\l\T<wa,  
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} xe)< )y  
} qcxq-HS2'  
//负责部分文件的抓取 |q$br-0+  
**FileSplitterFetch.java _"`wUMee  
*/ 54 8w v  
package NetFox; 1KxtHLLU  
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import java.io.*; b2;Weu3WN  
import java.net.*; Q$iGpTL  
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public class FileSplitterFetch extends Thread { i,
/|H]Mzr  
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String sURL; //File URL "HR &Rf k  
long nStartPos; //File Snippet Start Position 8;3T65KY  
long nEndPos; //File Snippet End Position ~Ra1Zc$o:  
int nThreadID; //Thread's ID ilv6A9/  
boolean bDownOver = false; //Downing is over Vxif0Bx&/d  
boolean bStop = false; //Stop identical :SSlUl4sU$  
FileAccessI fileAccessI = null; //File Access interface 1{+Ni{  
$UlA_l29  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WU1I>i  
{ 2S^xqvh  
this.sURL = sURL; fU~>A-P  
this.nStartPos = nStart; 1'EMYQ  
this.nEndPos = nEnd; n?@o:c5,r  
nThreadID = id; LV=!nF0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d87pQ3e:&  
} st36xS  
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,)+O.Lf7&.  
public void run() j#%*@]>Tg  
{ ->vfQwBFd  
while(nStartPos < nEndPos && !bStop) &G55<tRE  
{ &Qghm o  
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lfR"22t  
try{ /B!"\0G/,  
URL url = new URL(sURL); GpF,=:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >fo &H_a  
httpConnection.setRequestProperty("User-Agent","NetFox"); {Z;W|w1t  
String sProperty = "bytes="+nStartPos+"-"; eU7RO  
httpConnection.setRequestProperty("RANGE",sProperty); +7+ VbsFG  
Utility.log(sProperty); "/hs@4{u9  
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InputStream input = httpConnection.getInputStream(); X%,;IW]a  
//logResponseHead(httpConnection); 'rf='Y  
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byte[] b = new byte[1024]; ?MeP<5\A  
int nRead; K1z"..(2J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f7OfN#I  
{ fx.FHhVu  
nStartPos += fileAccessI.write(b,0,nRead); UeE& 8{=d  
//if(nThreadID == 1) l)VMF44  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]@ETQ8QN  
} D]b5*_CT  
0*:]eM};P  
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Utility.log("Thread " + nThreadID + " is over!"); :KX/GN!n  
bDownOver = true; I?-9%4 8iM  
//nPos = fileAccessI.write (b,0,nRead); Ltcr]T(Ic  
} C bG"8F|4  
catch(Exception e){e.printStackTrace ();} [.z1  
} 4)9X) Qx  
} SVXey?A;CJ  
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V6wYJ$]
 
//打印回应的头信息 iG!MIt*  
public void logResponseHead(HttpURLConnection con) 7+T\  
{ r~nrP=-%  
for(int i=1;;i++) $.
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{ }9P)<
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String header=con.getHeaderFieldKey(i); U$VT
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if(header!=null) ;?inf`t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |c8p{)  
Utility.log(header+" : "+con.getHeaderField(header)); jopC\Z  
else \/K>Iv'$  
break; BY,%+>bc)  
} 
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} vR1%&(f{  
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public void splitterStop() 9'//_ A,  
{ ZWf{!L,@Z  
bStop = true; .(9IAAwKn  
} 4KybN  
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} !;CY @=  
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/* mq'q@@:c  
**FileAccess.java 6t]oSxN  
*//文件访问(定位，写) P'ZWAxd  
package NetFox; aKCCFHq t!  
import java.io.*; WlZ
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public class FileAccessI implements Serializable{ NX)7g}S  
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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 qLYv=h$,  
RandomAccessFile oSavedFile; d2X#_(+d  
long nPos; V=(4 c  
 ]g?G0m  
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public FileAccessI() throws IOException (2qo9j"j/Y  
{ D"1ciO8^I]  
this("",0); ]]%C\Ryy}  
} 0TA/ExJ-LT  
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public FileAccessI(String sName,long nPos) throws IOException s?%1/&.~  
{ YVW!u6W'[6  
oSavedFile = new RandomAccessFile(sName,"rw"); T/S-}|fhQ  
this.nPos = nPos; :^iR&`2~  
oSavedFile.seek(nPos); sOJ"~p  
} } A#C  
2~]c`/M3  
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public synchronized int write(byte[] b,int nStart,int nLen) 3Q`'C7Pi  
{ /.WD'*H  
int n = -1; gn(n</\/O  
try{ 3v0
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oSavedFile.write(b,nStart,nLen); Nt/*VYUn  
n = nLen; HM[BFF[;/  
} kFk+TXLDIt  
catch(IOException e) QG9 2^  
{ RI*Q-n{  
e.printStackTrace (); 2! wz#EC  
} 2N)vEUyDV  
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return n; g>f(5  
} ;utjW1y  
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} PS=crU@"H  
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/* A0[flIl  
**SiteInfoBean.java yobi$mnsy!  
*/ 2EE#60  
package NetFox; iwmXgsRa9}  
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public class SiteInfoBean { EKoCm)}d  
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private String sSiteURL; //Site's URL N+}yw4lb  
private String sFilePath; //Saved File's Path 3rR(>}:[V  
private String sFileName; //Saved File's Name 2,_BO6 !d  
private int nSplitter; //Count of Splited Downloading File n!tCz<v  
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public SiteInfoBean() ruE.0VI@  
{//nSplitter的缺省值为5 )O7Mfr  
//default value of nSplitter is 5 y5R6/*;N.  
this("","","",5); uNx3us-  
} ^Y'>3o21f  
((?^B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O9>/WmLe  
{ CF>NyY:_  
sSiteURL= sURL; iWtWT1n8n  
sFilePath = sPath; (iS9
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sFileName = sName; z-,U(0 .  
this.nSplitter = nSpiltter; _N<qrH^;  
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2+?M(=4  
} X$st{@}ZB  
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public String getSSiteURL() 0q62{p7  
{ WnIh( 0  
return sSiteURL; E26ZVFg  
} 1[}VyP6 e  
@7BH`b$)!  
~^3B(feQ]  
public void setSSiteURL(String value) f8uVk|a  
{ ^R2:Z&Iv%  
sSiteURL = value; 4QDF%#~q^  
} dB1bf2'b#  
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y  
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public String getSFilePath() e1'_]   
{ rP>5OLP  
return sFilePath; ^Nc\D7( l  
} xwz2N5  
&t6L8[#yd  
^,`yt^^A  
public void setSFilePath(String value) `#l_`j=r$  
{ WRo#ZVt9$  
sFilePath = value; fd)}I23Q'  
} R a9/L  
(2a~gQGD  
"2Ye\#BU6  
public String getSFileName() D%BV83S   
{ fC81(5  
return sFileName; 5SK.R;mn  
} -$mzzYH  
U:IQWlC  
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public void setSFileName(String value) < Gu s9^_  
{ \9 ^wM>U  
sFileName = value; UHxXa*HyI  
} GadD*psD2  
oFY'Ek;d  
0gnr@9,X  
public int getNSplitter() ousoG$Pc  
{ EW YpYMkm  
return nSplitter; YgVZq\AV"  
} Y%Saz+  
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,{]>U'-  
public void setNSplitter(int nCount) ThFI=K  
{ R2r0'Yx  
nSplitter = nCount; O*c+TiTb  
} 3lLO.  
} '5{gWV`  
/oh[Nu1D  
hL&z"_
`  
/* jg2>=}  
**Utility.java 8vchLl#  
*/ g.z/%LpK  
package NetFox; i5:fn@&  
"|&SC0*  
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public class Utility { 1vQ*Br  
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public Utility() HQ4o^WC  
{ l$z-'  
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} NO;+:0n  
B6|=kl2C  
//线程睡眠 bY]aADv\  
public static void sleep(int nSecond) A.(Z0,S-i  
{ m[%&KW(  
try{ X$J  
Thread.sleep(nSecond); d+z8^$z"  
} OCF=)#}qd  
catch(Exception e) a^|mF# z  
{ d)9=hp;,
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e.printStackTrace (); o
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} ,@(lYeD
"  
} ~kF^0-JZY  
\iO ,y:  
//日志 ql^n=+U  
public static void log(String sMsg) h\:"k_u#  
{ = q;ACW,z  
System.err.println(sMsg); qJrK?:O;  
} 'BtvT[KM  
j#.Aiy:,  
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public static void log(int sMsg) dd_n|x1  
{ i.6c;KU  
System.err.println(sMsg); Wc#4%kT  
} U%m,:b6V  
} 0<
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jIg]?4bW[  
/* @2Z{en?  
**TestMethod.java }eSaF@.  
*/ qN[U|3k  
package NetFox; 08cCrG  
ioz4kG!  
r m\]  
public class TestMethod { _KLKa/3  
8+^q9rLii  
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public TestMethod() =J<3B H^m  
{ ///xx/weblogic60b2_win.exe c7,p5[  
try{ Qne@Vf kA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bRfac/:}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xrf z-"n4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yIA-+# r[  
fileFetch.start(); 6||zfH  
} k_/*>lIZY  
catch(Exception e){e.printStackTrace ();} 'de&9\  
?sk{(
UN]  

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} }k~ih?E^s  
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public static void main(String[] args) jH({Qc,97  
{ fX2sjfk  
new TestMethod(); #Ipi3  
} F}wy7s2i  
} Z8%?ej`8  
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