http断点续传简单实现（java)

/* 8b $7#  
**SiteFileFetch.java :v48y.Ij7s  
*/ r73Xh"SL  
package NetFox; t?Znil|o  
import java.io.*; ymqhI\>y#  
import java.net.*; s#sXr  
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public class SiteFileFetch extends Thread { IHfqW?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nV1
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long[] nStartPos; //开始位置 T[J_/DE@  
long[] nEndPos; //结束位置 yK;I<8+>_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 **[p{R]8o  
long nFileLength; //文件长度 $S/8T  
boolean bFirst = true; //是否第一次取文件 =="SW"vNi  
boolean bStop = false; //停止标志 uEY5&wX`  
File tmpFile; //文件下载的临时信息 ,;}RIcvQV  
DataOutputStream output; //输出到文件的输出流 "b;?2_w:E  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `WL*Jb  
public SiteFileFetch(SiteInfoBean bean) throws IOException a WC sLH  
{ ujBADDwOg)  
siteInfoBean = bean; lnUy?0(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =n&83MYX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P'';F}NwfX  
if(tmpFile.exists ()) V00zk`PH  
{ 4|UIyDt8  
bFirst = false; Pr"ESd>Y  
read_nPos(); (C|%@61S  
} zyE yZc?  
else v%w]Q B  
{ fk_i~K  
nStartPos = new long[bean.getNSplitter()]; .l!Z=n|  
nEndPos = new long[bean.getNSplitter()]; ^ TS\x/P  
} 9`{cX  
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} "
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public void run() uq_SF.a'v  
{ }K\_N]#6n  
//获得文件长度 u-$AFSt  
//分割文件 +iR;D$w  
//实例FileSplitterFetch aJts  
//启动FileSplitterFetch线程 >#Yq&@G  
//等待子线程返回 Bf.RYLsh6  
try{ xYq8\9Qb  
if(bFirst) :A[/;|&  
{ H#:Yw|t  
nFileLength = getFileSize(); im`^_zebj  
if(nFileLength == -1) ){Y2TWW&0  
{ {z7{ta  
System.err.println("File Length is not known!"); Y;WrfO$J  
} -K{ID$!p  
else if(nFileLength == -2) !~#31kL&  
{ q]aRJ`9f  
System.err.println("File is not access!"); [S%
 
} t+VPX2  
else n >^?BU  
{ S_atEmQ  
for(int i=0;i<nStartPos.length;i++)
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{ 3 ren1   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U7N<!6  
} HD>{UU?  
for(int i=0;i<nEndPos.length-1;i++) c}lgWu~  
{ >X]<s^  
nEndPos = nStartPos[i+1]; s
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} , /pE*Yk  
nEndPos[nEndPos.length-1] = nFileLength; ~Hq 2'  
} \]D;HR`vo  
} &*}S 0  
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//启动子线程 b({2|R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f55Ev<oOa  
for(int i=0;i<nStartPos.length;i++) oj/tim  
{ JmK+#o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *e R$
  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5"sF#Y&  
nStartPos,nEndPos,i); P%.5xYn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T"z!S0I  
fileSplitterFetch.start(); Mo/
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} !(]|!F[m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W^x[maz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]Vubz54  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CNwh
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nEndPos = " + nFileLength); C'Ymz`iQ  
// fileSplitterFetch[nPos.length-1].start(); 0Ec -/   
`>V.}K^4  
wNPZ[V:  
//等待子线程结束 k$hWR;U  
//int count = 0; I%ez_VG  
//是否结束while循环 3|A"CU/z@  
boolean breakWhile = false; UY==1\  
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while(!bStop) SSzOz-&GA  
{ BH}u\K  
write_nPos(); A4#m&o  
Utility.sleep(500); {3;4=R3  
breakWhile = true; `1P &  
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for(int i=0;i<nStartPos.length;i++) (<f[$ |%  
{ F2u{Wzr_@  
if(!fileSplitterFetch.bDownOver) KT8Fn+  
{ ;c'jBi5W  
breakWhile = false; 'd28YjtoX  
break; GUK/Xiu  
} JsH9IK:  
} eVy,7goh  
if(breakWhile) zRz3ot,|  
break; m1
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//count++; >FY`xl\m}<  
//if(count>4) fQv^=DI#  
// siteStop(); 9@!`,Co  
} O|8p #  
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System.err.println("文件下载结束！"); l9-(ofY*J  
} i |C'_gw`n  
catch(Exception e){e.printStackTrace ();} lc*<UZR  
} (_d^iZyf  
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//获得文件长度 #wt#-U;  
public long getFileSize() 7^ER?@:W  
{ oJ5V^.  
int nFileLength = -1; "_9Dau$  
try{ &u.t5m7(  
URL url = new URL(siteInfoBean.getSSiteURL()); kMUjSa~\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b,s T[!X[  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ru2kC} Dx!  
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int responseCode=httpConnection.getResponseCode(); Lg-Sxz}P!  
if(responseCode>=400) j134iVF%  
{ p*vEVo  
processErrorCode(responseCode); @'dtlY5;  
return -2; //-2 represent access is error ,zO!`|I  
} @<;0h|  
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String sHeader; SxH b76 ;  
8
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{ "=d7i  
for(int i=1;;i++) EE-jU<>|  
{ fsb_*sh&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kbiMqiPG  
//Utility.log(in.readLine()); j#zUO&Q@  
sHeader=httpConnection.getHeaderFieldKey(i); K8f;AK  
if(sHeader!=null) i#=s_v8  
{ {p-&8-  
if(sHeader.equals("Content-Length")) !3E33
 
{ "'~55bG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >Ta|#]{  
break; 1ti+ Q0~  
} Dz3=k
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} Y?ouB  
else :>+}|
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break; fIWOo >)D  
} *#\da]"{  
} /-4rcC  
catch(IOException e){e.printStackTrace ();} Y`.FSs  
catch(Exception e){e.printStackTrace ();} Bs:INvhYW  
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Utility.log(nFileLength); ]rY:C "#  
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return nFileLength; VB=$D|Ll  
} Ti:PKpc  
*jE>
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//保存下载信息（文件指针位置） }RvinF:5  
private void write_nPos() -q'G]}  
{ X?kw=x{2P  
try{ KsVN<eR{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7.}V
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output.writeInt(nStartPos.length); s_:7dD  
for(int i=0;i<nStartPos.length;i++) yUd>EnQna  
{ 9 M>.9~  
// output.writeLong(nPos); &![3{G"+>l  
output.writeLong(fileSplitterFetch.nStartPos); ^V,?n@c!  
output.writeLong(fileSplitterFetch.nEndPos); JiH^N!  
} p^J=*jm)x  
output.close(); {B|)!_M#  
} u2\QhP 9  
catch(IOException e){e.printStackTrace ();} apy9B6%PJ+  
catch(Exception e){e.printStackTrace ();} jAXKp b  
} J;8M._  
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//读取保存的下载信息（文件指针位置） jTHgh>n  
private void read_nPos() wX/0.aZ|  
{ z'"e|)  
try{ Es]:-TR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !:BmDX[<n  
int nCount = input.readInt(); ?5VPV9EX  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; ^W#161&  
for(int i=0;i<nStartPos.length;i++) Z/G`8|A  
{ `|&#=hl~  
nStartPos = input.readLong(); 7F$G.LhMw  
nEndPos = input.readLong(); 2;2FyKF(  
} Iy[TEB  
input.close(); D[i?T3i  
} m-u3^\'  
catch(IOException e){e.printStackTrace ();} :LrB9Cf$n  
catch(Exception e){e.printStackTrace ();} {f1iys'Om  
} (Y!{ UNq5  
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private void processErrorCode(int nErrorCode)  4>R)2g  
{ a*2JLK  
System.err.println("Error Code : " + nErrorCode); ! mb<z^>5  
} 0Ba*"/U]t~  
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//停止文件下载 (pv6V2i  
public void siteStop() ,::f? Gc7j  
{ (baBi9<P=  
bStop = true; e|1.-P@  
for(int i=0;i<nStartPos.length;i++) Ah:d2*SR4  
fileSplitterFetch.splitterStop(); [ikW3 '99,  
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} -4Hf5!  
} ZVIlVuZ}  
//负责部分文件的抓取 y?P4EVknM3  
**FileSplitterFetch.java >S}^0vNZX  
*/ +d!"Zy2|B  
package NetFox; GtLnh~)  
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import java.io.*; O= 84ZP%  
import java.net.*; qbx}9pp}g  
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public class FileSplitterFetch extends Thread { wGLSei-s  
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String sURL; //File URL a8}!9kL  
long nStartPos; //File Snippet Start Position wNm1H[{  
long nEndPos; //File Snippet End Position e| Sw+fhy<  
int nThreadID; //Thread's ID :meq4!g{1  
boolean bDownOver = false; //Downing is over #Y<QEGb(  
boolean bStop = false; //Stop identical z
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FileAccessI fileAccessI = null; //File Access interface |V-)3#c  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %X -G(Z  
{ O>,Rsj!e  
this.sURL = sURL; FR^(1+lx&  
this.nStartPos = nStart; irooFR[L9  
this.nEndPos = nEnd; ,V &RpKek  
nThreadID = id; \Z8:^ct.P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _Gtq]`y  
} HDQH7Bs  
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public void run() |2!cPf^8  
{ *
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while(nStartPos < nEndPos && !bStop) $:IEpV{  
{ f#3!Q!C^  
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try{ St|B9V?eEB  
URL url = new URL(sURL); qr'P0+|~5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v=J[p;H^H  
httpConnection.setRequestProperty("User-Agent","NetFox"); eh /QFm 4  
String sProperty = "bytes="+nStartPos+"-"; M/evZ?uis  
httpConnection.setRequestProperty("RANGE",sProperty); "JpnmE[`  
Utility.log(sProperty); 9jf2b  
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InputStream input = httpConnection.getInputStream(); f9a_:]F   
//logResponseHead(httpConnection); chszP{-@X  
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byte[] b = new byte[1024]; F.$NYr/|y  
int nRead; cr>"LAi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R4AKp1Y  
{ Sp\ 7  
nStartPos += fileAccessI.write(b,0,nRead); {GhM,-%e  
//if(nThreadID == 1) d: LP8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NsF8`rg  
} eUEO~M2&U{  
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wq>0W4(  
Utility.log("Thread " + nThreadID + " is over!"); Z"5ew
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bDownOver = true; &Ef_p-e-P  
//nPos = fileAccessI.write (b,0,nRead); #G\;)pT  
} m!sMr^W  
catch(Exception e){e.printStackTrace ();} E3d# T  
} AfXlV-v  
} (0!U,8zz  
L
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//打印回应的头信息 IgNL1KRD  
public void logResponseHead(HttpURLConnection con) ]:n! \G  
{ tWa_-Un3  
for(int i=1;;i++) eG08Xt|lc  
{ $[M5Vv  
String header=con.getHeaderFieldKey(i); 57rH`UFXH  
if(header!=null) o 4cqLMu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >Ni<itze$i  
Utility.log(header+" : "+con.getHeaderField(header)); g/BlTi
 
else _28vf Bl?  
break; >*e,+ok  
} @DniYt/  
} m8NKuhu  
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public void splitterStop() {3){f;b  
{ eG\`SKx_  
bStop = true; 9xM7X?  
} ofHe8a8  
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} 5/C#*%EH'  
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/* Oq4J$/%  
**FileAccess.java nEbJ,#>Z  
*//文件访问(定位，写) a_amO<!   
package NetFox; p}9bZKyf  
import java.io.*; Ai5|N
 
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" twq#Alx  
public class FileAccessI implements Serializable{ Hribk[99  
s2;
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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 _S3qPPo3l]  
RandomAccessFile oSavedFile; tp?< e  
long nPos; ;nZN}&m   
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public FileAccessI() throws IOException 0pl |  
{ sEm064  
this("",0); i2Cw#x0s  
} ;.|).y1/`  
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public FileAccessI(String sName,long nPos) throws IOException VmTPE5d  
{ 61=D&lb  
oSavedFile = new RandomAccessFile(sName,"rw"); -1<*mbb0  
this.nPos = nPos; 6y}|IhX?z  
oSavedFile.seek(nPos); 7<7 /NZ<I  
} 3PgiV%]  
zD%@3NA4
1  
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public synchronized int write(byte[] b,int nStart,int nLen) 8}<4f|?  
{ {v~.zRW%]r  
int n = -1; 5&N55?G6  
try{ a^QyYX}\qR  
oSavedFile.write(b,nStart,nLen); GMJ</xG
  
n = nLen; p7eRAQ\'  
} e9@7GaL`"S  
catch(IOException e) P/;d|M(  
{ y;1l].L  
e.printStackTrace (); 8e*1L:oB!  
} h4lrt  
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return n; A0`#n|(Ad!  
} Fg<rz&MR  
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} 3r]N\c  
- }2AXP2q  
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/* `/\Z{j0_  
**SiteInfoBean.java DU=rsePWE  
*/ <Zn-P  
package NetFox; Qkq9
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public class SiteInfoBean { +?[,{WtV  
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private String sSiteURL; //Site's URL q#!]5
 
private String sFilePath; //Saved File's Path JOvRUDZ  
private String sFileName; //Saved File's Name <C6*-j1oz  
private int nSplitter; //Count of Splited Downloading File I|oS`iLl$  
l1MVC@'pvP  
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public SiteInfoBean() Vp~c$y+  
{//nSplitter的缺省值为5 OPP^n-iPr  
//default value of nSplitter is 5 ">D7wX,.>  
this("","","",5); ERQc1G]3Dd  
} j!;y!g  
:^[HDI-[2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z<^TO1xs9B  
{ 67{>x[  
sSiteURL= sURL;  ]H_|E  
sFilePath = sPath; jt?.g'  
sFileName = sName; ? j8S.d~  
this.nSplitter = nSpiltter; H@%Y"iIUP  
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1QPS=;|)  
} 4UV<Q*B\F  
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public String getSSiteURL() isiehKkD
 
{ g!*5@k|C  
return sSiteURL; okv`+VeA  
} aF (L_  
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public void setSSiteURL(String value) 4`M7 3k0  
{ 8\H*Z2yF+  
sSiteURL = value; X@j.$0eK  
} ccPTJ/%$  
!/;/ X\d  
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public String getSFilePath() `z)q/;}fC  
{ k(bDj[0q^  
return sFilePath; ^KRe(  
} XHER[8
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public void setSFilePath(String value) [)wLj
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{ -\dcs?  
sFilePath = value; g;n6hXq4  
} A$=h'!$  
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public String getSFileName() R|u2ga~  
{ &Fg|52  
return sFileName; Ua2waA  
} ZCC T  
, R;k>'.  
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public void setSFileName(String value) 3Ud{W$Ym  
{ km,I75o.  
sFileName = value; !-cK@>.pE  
} GVKc4HGt  
1&.q#,EMn(  
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public int getNSplitter() f]C`]qg  
{ 3"O&IY<  
return nSplitter; 49iqrP'  
} dMlJ2\]u  
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r>;(\_@  
public void setNSplitter(int nCount) /Y#Q<=X  
{ 3o^~6A  
nSplitter = nCount; ;#XF.l,u  
} bHK[Z5  
} mTU[khEmL=  
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/* 3\2^LILLO  
**Utility.java K3.z>.F'h  
*/ k@ So l6  
package NetFox; `P/87=h  
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public class Utility { nJ2
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public Utility() Ov~vK\  
{ 8JojKH  
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} E|"QYsi.Ck  
9 Eqv^0u  
//线程睡眠 <El!,UBq<  
public static void sleep(int nSecond) a^eR~efdu@  
{ "BA&  
try{ 9WT{~PGj  
Thread.sleep(nSecond); E4N"|u|  
} SNrX(V::z  
catch(Exception e) Aj{G=AT  
{ :qvA'.L/;z  
e.printStackTrace (); R+5yyk\  
} pebNE3`#  
} IO{iQ-Mg  
v`\CzT  
//日志 Mt*eC)~Yx  
public static void log(String sMsg) CuFlI?~8 z  
{ B,4 3b O  
System.err.println(sMsg); ,E&W{b  
} PnJA'@x  
!N74y%=M  

#SR )tU  
public static void log(int sMsg) l<UA0*t  
{ "\O{!Hj8  
System.err.println(sMsg); J?/NJ-F  
} nkkUby9  
} c?}{>ig/)  
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1Gw_S?$7  
/* M!Ywjvw*)3  
**TestMethod.java \=j|ju3  
*/ #&Fd16ov  
package NetFox; T~naAP  
Z|BOuB^  
9Idgib&  
public class TestMethod { 5|g#>sx>`q  
hY/i)T{  
!|-:"hE1h  
public TestMethod() @N6KZn|R  
{ ///xx/weblogic60b2_win.exe nnuJY$O;M  
try{ |k<5yj4?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (AT)w/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vpP8'f.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :auq#$B  
fileFetch.start(); -ze@~Z@  
} NC%)
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catch(Exception e){e.printStackTrace ();} OyATb{`'  
yJ2A!id  
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} s@K #M  
oRHWb_$"  
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public static void main(String[] args) Tl S904'  
{ N#8$pE  
new TestMethod(); +K61-Div  
} /'L/O;H20  
} X({R+  
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