http断点续传简单实现（java)

/* {VBx;A3*I  
**SiteFileFetch.java zc&>RM  
*/ V
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package NetFox; l
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import java.io.*; $Hcp.J[O  
import java.net.*; E5D5  
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public class SiteFileFetch extends Thread { {&,9Zy]"S  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gUf-1#g4\`  
long[] nStartPos; //开始位置 tbHU(#~  
long[] nEndPos; //结束位置 \.+.VK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5)fEs.r0U  
long nFileLength; //文件长度 zPWX%1Qr  
boolean bFirst = true; //是否第一次取文件 =e'b*KTL,  
boolean bStop = false; //停止标志 #9aB3C  
File tmpFile; //文件下载的临时信息 8&g|iG  
DataOutputStream output; //输出到文件的输出流 H)&6I
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） iM;7V*u  
public SiteFileFetch(SiteInfoBean bean) throws IOException PjriAlxD  
{ (R)\  
siteInfoBean = bean; fC>3{@h}*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r|t;#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b0 ))->&2  
if(tmpFile.exists ()) >[TB8  
{ |_Vi8Ly  
bFirst = false; ]m}<0-0  
read_nPos(); 44T>Yp09  
} yi`Z(j;
 
else 8&FnXhZg4  
{ u^H:z0  
nStartPos = new long[bean.getNSplitter()]; ~Xi_bTAyAW  
nEndPos = new long[bean.getNSplitter()]; 2Qg.b-C  
} /Po't(-x  
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} rZ<n0w  
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public void run() M&P?/Zi=L  
{ r )8[LN-  
//获得文件长度 P_11N9C  
//分割文件 {KJ!rT  
//实例FileSplitterFetch (S/f!Dk&3  
//启动FileSplitterFetch线程 g.-{=kZ   
//等待子线程返回 28qTC?  
try{ Zcq'u jU  
if(bFirst) ^Glmg}>q  
{ 
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nFileLength = getFileSize(); pyA;%vJn  
if(nFileLength == -1) *Dx&}"  
{ f0rM 4"1  
System.err.println("File Length is not known!"); df_hmkyj  
} s=0z%~H  
else if(nFileLength == -2) A&%vog]O  
{ <SeK3@Gi  
System.err.println("File is not access!"); SV%;w>  
} aewVq@ngq!  
else Fd@n#DR `  
{ &DoYz[q  
for(int i=0;i<nStartPos.length;i++) aO:wedfl  
{ H_gY)m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J^tLKTB  
} &AR@5M u  
for(int i=0;i<nEndPos.length-1;i++) O_%X>Q9  
{ 'Fi\Qk'D@  
nEndPos = nStartPos[i+1]; }7p`8?  
} Pf`HF|NI  
nEndPos[nEndPos.length-1] = nFileLength; M*M,Z  
} -4du`dg  
} *?sdWRbu}l  
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//启动子线程 s~N WJ*i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bCWSh~  
for(int i=0;i<nStartPos.length;i++) X@l>mAk
  
{ qffVF|7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9FB k|g"U)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FbH 1yz  
nStartPos,nEndPos,i); V~nqPh!Jc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vjNP  
fileSplitterFetch.start(); U^aMh-  
} {D6lSj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ft |W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `h%(ZG~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D^]g`V*N  
nEndPos = " + nFileLength); dMn0nc+  
// fileSplitterFetch[nPos.length-1].start(); BO5\rRa0  
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//等待子线程结束 3a|I| NP  
//int count = 0; p./9^S  
//是否结束while循环 ]7+9>V  
boolean breakWhile = false; UNK}!>HD  
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while(!bStop) Fa]|Y  
{ H3Ws$vl9n  
write_nPos(); 5?] Dn k.o  
Utility.sleep(500); t4Q&^AC  
breakWhile = true; =}F}XSvXH  
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for(int i=0;i<nStartPos.length;i++) }\#u~k!l  
{ H\r- ;,&  
if(!fileSplitterFetch.bDownOver) OSu/!Iv\  
{ ;W~H|M  
breakWhile = false; A,PF#G(  
break; >6X$iBb0
 
} 8uh^%La8b.  
} h#:_GNu
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if(breakWhile) }Od=WQv+  
break; zWO!z=  
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uW 7Yem&  
//count++; p;xMudM  
//if(count>4) Y|X!da/  
// siteStop(); .DrGr:UW  
} O3/w@q Q
 
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System.err.println("文件下载结束！"); i;l0)q  
} RKb{QAK!v  
catch(Exception e){e.printStackTrace ();} X$A[~v  
} NG+%H1!$_  
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^ }kqAmr  
//获得文件长度 +~n"@ /  
public long getFileSize() n_9Wrx328  
{ 1sNZl&  
int nFileLength = -1;  =v!'?
 
try{ P[K42mm  
URL url = new URL(siteInfoBean.getSSiteURL()); M`D`-vv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,>3b|-C-  
httpConnection.setRequestProperty("User-Agent","NetFox"); yc7"tptfF  
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],|
;  
int responseCode=httpConnection.getResponseCode(); FT;I|+H*P  
if(responseCode>=400) [M#I Nm}  
{ 3gQ2wP*K  
processErrorCode(responseCode); u OB`A-K  
return -2; //-2 represent access is error BJP^?FUd=,  
} GLiD,QX<  
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String sHeader; $wm8N.I3I  
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for(int i=1;;i++) i Qa=4'9;  
{ fX/k;0l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y{9<>28  
//Utility.log(in.readLine()); 2PViY,V|  
sHeader=httpConnection.getHeaderFieldKey(i); #XeEpdE  
if(sHeader!=null) |IZ
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{ 4<A+Tf  
if(sHeader.equals("Content-Length")) t-Zk)*d/0  
{ tD+K4 ^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nC@UK{tVa  
break; ."h>I @MH  
} J%1 2Ey@6  
} qlg?'l$03)  
else f}:W1&LhI?  
break; PbIir=  
} UEH+E&BCC  
} ;|D8"D6]  
catch(IOException e){e.printStackTrace ();} `y*o-St3  
catch(Exception e){e.printStackTrace ();} TIVrbO\!o  
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Utility.log(nFileLength); ;hkzL_' E)  
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return nFileLength; !^IAn  
} m:C|R-IL  
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//保存下载信息（文件指针位置） Na>?1F"KHk  
private void write_nPos() \Z/#s;c,4  
{ jbs)]fqC;  
try{ >-4kO7.V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]7 2wv#-  
output.writeInt(nStartPos.length); wKj0vMW  
for(int i=0;i<nStartPos.length;i++) iNEE2BPp  
{ UO8./%'  
// output.writeLong(nPos); .Eg[[K_iD  
output.writeLong(fileSplitterFetch.nStartPos); {"@E_{\  
output.writeLong(fileSplitterFetch.nEndPos); 0|OmQ\SQ  
} |emZZj  
output.close(); 8\9s,W:5  
} |<w Z;d  
catch(IOException e){e.printStackTrace ();} 5}he)2*uD  
catch(Exception e){e.printStackTrace ();} A"no!AN  
} D",~?  
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//读取保存的下载信息（文件指针位置） .h@HAnmE  
private void read_nPos() FX:'38-fk  
{ MP%pEUomev  
try{ jjU("b=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #hP&;HZ2>"  
int nCount = input.readInt(); 4KT-U6zNx  
nStartPos = new long[nCount]; @DK;i_i  
nEndPos = new long[nCount]; M$+2f.(>k)  
for(int i=0;i<nStartPos.length;i++) s5D<c'-  
{ 8[mj*^P  
nStartPos = input.readLong(); zx=AT
 
nEndPos = input.readLong();  4xnM7t\  
} O*y@4AR"S  
input.close(); sN9 SuQ  
} F]7$Y  
catch(IOException e){e.printStackTrace ();} 0 |Y'@&  
catch(Exception e){e.printStackTrace ();} e+7x &-+  
} ^.; x  
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private void processErrorCode(int nErrorCode) P},d`4Ty@  
{ T!pjv8y@R  
System.err.println("Error Code : " + nErrorCode); a~"<lzu|$  
} 4.}J'3 .  
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//停止文件下载 "8YXF
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public void siteStop() EABy<i  
{ |m /XGr  
bStop = true; Vs~!\<?
 
for(int i=0;i<nStartPos.length;i++) ^lCQHz  
fileSplitterFetch.splitterStop(); )Y:9sd8g7  
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} ~76qFZe-  
} {9y
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//负责部分文件的抓取 ~[d|:]  
**FileSplitterFetch.java 35X4] t  
*/ 'AjDB:Mt$  
package NetFox; ~Q/G_^U:  
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import java.io.*; h,WF'X+  
import java.net.*; Lm}J&^>  
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public class FileSplitterFetch extends Thread { >84:1`  
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String sURL; //File URL _[_mmf1;:'  
long nStartPos; //File Snippet Start Position GI40Ztms  
long nEndPos; //File Snippet End Position si|DxDx  
int nThreadID; //Thread's ID +bv-!rf  
boolean bDownOver = false; //Downing is over x!@P|c1nKC  
boolean bStop = false; //Stop identical lImg+r T{  
FileAccessI fileAccessI = null; //File Access interface t@1bu$y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *U69rbYI  
{ Yo$ xz  
this.sURL = sURL; }co*%F{1  
this.nStartPos = nStart; PfKF!/c B  
this.nEndPos = nEnd; <#r/4a"V  
nThreadID = id; JM?X]l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]J%p&y+6  
} jQc.@^#+x  
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public void run() S`qa_yI)Ed  
{ z#!}4@_i3  
while(nStartPos < nEndPos && !bStop) '8|y^\  
{ .h;PMY+  
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try{ !PIpvx{aX  
URL url = new URL(sURL); 'l| e}eti>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A&:i$`m,  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,py:e>+^t  
String sProperty = "bytes="+nStartPos+"-"; 8 FqhSzw  
httpConnection.setRequestProperty("RANGE",sProperty); U0Y;*
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Utility.log(sProperty); U(jZf{`Mz  
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InputStream input = httpConnection.getInputStream(); nbGB84  
//logResponseHead(httpConnection); Q0\tK=Z/  
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byte[] b = new byte[1024]; ~baVS-v  
int nRead; y[W<vb+F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l-Q.@hG  
{ q*^F"D:?k  
nStartPos += fileAccessI.write(b,0,nRead); r[TTG0|  
//if(nThreadID == 1) I,:R~^qJ8v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (np %urx!  
} qXH\e|  
45u\v2,C3  
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Utility.log("Thread " + nThreadID + " is over!"); 5yHarC  
bDownOver = true; W
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//nPos = fileAccessI.write (b,0,nRead); @"\j]ZEnY  
} Dj~]]  
catch(Exception e){e.printStackTrace ();} 99\;jz7  
} JE<zQf(&  
} QBNnvg4v  
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//打印回应的头信息 4r&S&^  
public void logResponseHead(HttpURLConnection con) /%#LA  
{ oj6b33z  
for(int i=1;;i++) x tJ_azt  
{ RcASFBNpS  
String header=con.getHeaderFieldKey(i); nY#V~^|  
if(header!=null) lYS+EVcR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p;GT[Ds^  
Utility.log(header+" : "+con.getHeaderField(header)); J< E"ZoY  
else u]B15mT?  
break; 0u?{"xH{+}  
} yN0!uzdW*  
} C^o9::ER  
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public void splitterStop() #!m`A+!~!  
{ =?*6lS}gy  
bStop = true; D*>EWlZ   
} "funFvY  
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} d$3;o&VUNI  
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/* arCi$:-z@  
**FileAccess.java vZgV/?'z  
*//文件访问(定位，写) J3]W2m2Zw  
package NetFox;
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import java.io.*; !besMZ  
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public class FileAccessI implements Serializable{ y^rcUPLT  
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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 3'd(=hJ45$  
RandomAccessFile oSavedFile; *^BW[C/CTR  
long nPos; uhyw?#f  
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public FileAccessI() throws IOException K3jPTAw=#  
{ r'kUU]j9  
this("",0); Dq#/Uw#  
} e}x}
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public FileAccessI(String sName,long nPos) throws IOException TZ`@pDi  
{ y_^w|  
oSavedFile = new RandomAccessFile(sName,"rw"); E8TJ*ZU  
this.nPos = nPos; 1v)X]nW  
oSavedFile.seek(nPos); 6GxQ<  
} |-WoR u  
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public synchronized int write(byte[] b,int nStart,int nLen) b#**`Y  
{ jlmP1b9  
int n = -1; .k{omr&Dy5  
try{ x=+R0ny  
oSavedFile.write(b,nStart,nLen); k,EI+lCX  
n = nLen; ]r#YU0  
} 45Z"U<I,9  
catch(IOException e) XA cpLj]  
{ ~c e?xr|  
e.printStackTrace (); 4_CV.?  
} zeqP:goy  
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return n; 4$~]t:n  
} U'pm5Mc\q  
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} Km~\^(a '  
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/* dcFqK~  
**SiteInfoBean.java \
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*/ N4 O'{  
package NetFox; 9NH"Ik*  
8\Y/?$on  

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public class SiteInfoBean { l2
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private String sSiteURL; //Site's URL L  lP  
private String sFilePath; //Saved File's Path 8:Yha4<Bv7  
private String sFileName; //Saved File's Name C
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private int nSplitter; //Count of Splited Downloading File b8V]/  
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public SiteInfoBean() 9N9dQ}[:g  
{//nSplitter的缺省值为5 ]w _
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//default value of nSplitter is 5 Q AJX7  
this("","","",5); 1a#oJU  
} yVThbL_YJ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o0-7#2  
{ zcrLd={  
sSiteURL= sURL; K\ww,S  
sFilePath = sPath; !XjvvX"j  
sFileName = sName; ({3hX"C@Q  
this.nSplitter = nSpiltter; +"Pt?k  
-b>"2B?  
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} Jtj_R
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public String getSSiteURL() .p%p_  
{ $|v_ pjUu]  
return sSiteURL; GS|sx  
} q#W|*kL3  

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public void setSSiteURL(String value) ?3!"js B  
{ +zxj-diM  
sSiteURL = value; ![WX -"lW  
} DG8LoWZ  
!Gu,X'#Ab  
**rA
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public String getSFilePath() 3Oy-\09  
{ "|CzQ&e  
return sFilePath; %dTkw+J  
} 96aA2s
1  
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public void setSFilePath(String value) ]trVlmZXH}  
{ ODK$G [-  
sFilePath = value; jw$3cwddH  
}
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public String getSFileName() ;bVC7D~~4w  
{ 'v^CA}  
return sFileName; U0'>(FP~2  
} i(9=` A}  
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2"lDKjj  
public void setSFileName(String value) TEl:;4  
{ D<$~bUkxR  
sFileName = value; zyTP|SXk  
} |R:gu\gG  
cZKK\h
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public int getNSplitter() h5WS<P  
{ b:/;  
return nSplitter; AOQim
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} \o9-[V#Gm  
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public void setNSplitter(int nCount) obRR))  
{ V|b9zHh  
nSplitter = nCount; !7!xJ&/V  
} X-9>;Mb~y  
} T6JN@:8  
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8RWfv}:X  
/* AEx I!  
**Utility.java r H;@N  
*/ |n=m{JX\m  
package NetFox; <qN0Q7  
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public class Utility { $u_0"sUV  
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public Utility() RvKP&  
{ s42M[BW]  
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} 1o)@{x/pd  
c^vPd]Ed  
//线程睡眠 km2('t7?  
public static void sleep(int nSecond) py.lGywb_  
{ ia 1Sf3  
try{  S[!K  
Thread.sleep(nSecond); fyPpzA0  
} lP& 7
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catch(Exception e) o&P}GcEIw  
{ M*FUtu  
e.printStackTrace (); 3ny>5A!;2  
} 0 3fCn"  
} [G2@[CtY1  
/!;oO_U:#  
//日志 dfY(5Wc+f  
public static void log(String sMsg) RY'f%c  
{ Y$hYW  
System.err.println(sMsg); =!T@'P?  
} y\Kr@;q0w  
I Y%M5
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public static void log(int sMsg) 7S$Am84%  
{ 0fwmQ'lW(  
System.err.println(sMsg); k#Qav1_  
} koOkm:(,  
} nVkx Q?2  
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/* K ;\~otR^  
**TestMethod.java pgbm2mT9  
*/ YoyJnl.?u  
package NetFox; ,5oe8\uz  
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public class TestMethod { &_Kb;UVRj  
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public TestMethod() Aq'yr,  
{ ///xx/weblogic60b2_win.exe MU6|>{  
try{ m>yb}+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eewhT^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); np2oXg%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Fp'qn'){:#  
fileFetch.start(); !5,>[^y3  
} zVN/|[KP4  
catch(Exception e){e.printStackTrace ();} ]0v;;PfVl6  
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} A!EmJ  
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public static void main(String[] args) 5ncjv@Aa  
{ :5)Dn87  
new TestMethod(); \H<gKZquR  
} >tF3|:\  
} &Tz@lvOv%  
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