http断点续传简单实现（java)

/* ,D  [  
**SiteFileFetch.java pz:$n_XC}  
*/ 1x V~EX  
package NetFox;  /e!/  
import java.io.*; UFyGp>/06  
import java.net.*; R5H UgI  
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public class SiteFileFetch extends Thread {  ?MPM@9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean O (tcu@vfl  
long[] nStartPos; //开始位置 q(\$-Dk.Vv  
long[] nEndPos; //结束位置 k&n7_[]n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pW:U|m1dS  
long nFileLength; //文件长度 !,V8?3.aJn  
boolean bFirst = true; //是否第一次取文件 `i9WnPRt  
boolean bStop = false; //停止标志 2Qc&6-;`  
File tmpFile; //文件下载的临时信息 s^AQJ{X  
DataOutputStream output; //输出到文件的输出流 %$:js4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException 'N,x=1R5  
{ )tz8(S  
siteInfoBean = bean; i5(_.1X<#{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t8U)za  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TEE$1RxV(  
if(tmpFile.exists ()) RCND|X  
{ Njc3X@4=  
bFirst = false; YM1tP'4j@  
read_nPos(); jQ4Pv`  
} =3a`NO5!  
else F<Z"W}I+6  
{ o//N"S.)  
nStartPos = new long[bean.getNSplitter()]; kVe^g
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nEndPos = new long[bean.getNSplitter()]; *O$kF.3q  
} @>ONp|}@qI  
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} H-1@z$p  
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public void run() vJtQ&,zG  
{ YxGIv8O]  
//获得文件长度 !MTm4Ls  
//分割文件 3-hu'xSU  
//实例FileSplitterFetch G"O%u|7  
//启动FileSplitterFetch线程 $QNfy.6Tn  
//等待子线程返回 }]=b%CPJh+  
try{ f|m.v +7k  
if(bFirst) Lyt6DvAp"  
{ XFG]%y=/6  
nFileLength = getFileSize(); \%mR*J+  
if(nFileLength == -1) 8W[QV  
{ B5=L</Aj  
System.err.println("File Length is not known!"); v\n!Li H  
} ~ Y4H)r  
else if(nFileLength == -2) E@0wt^  
{ E{wV
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System.err.println("File is not access!"); FK }x*d  
} U%t:]6d&}  
else OAOG&6xu8  
{ D<5gdIw  
for(int i=0;i<nStartPos.length;i++) /UN%P2>^1  
{ *yiJw\DRN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sN5x\9U  
} NV36Q^Am[  
for(int i=0;i<nEndPos.length-1;i++) HTQ.kV  
{ eq(|%]a=  
nEndPos = nStartPos[i+1]; |>j=#2  
} rZKv:x}{6  
nEndPos[nEndPos.length-1] = nFileLength; No=f&GVg  
} O|4~$7  
} \^|ncu:T  
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//启动子线程 X'7 T"5!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cK@O)Ko}  
for(int i=0;i<nStartPos.length;i++) bsP:tFw>  
{ 0=t_a]+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AH`tkPd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O JvEq@  
nStartPos,nEndPos,i); uLe+1`Y5Ux  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dbB2/RI  
fileSplitterFetch.start(); *>$'aQ  
} sFC1PdSk4T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h&h]z[r R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }\JoE4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nITr
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nEndPos = " + nFileLength); va~:oA  
// fileSplitterFetch[nPos.length-1].start(); _~HGMC)  
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//等待子线程结束 h*_r=' E  
//int count = 0; ]r'b(R; S  
//是否结束while循环 D 67H56[  
boolean breakWhile = false; ?#,\,  
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while(!bStop) wUh'1D<(r  
{ qe`W~a9x  
write_nPos(); cvn,&G-`  
Utility.sleep(500); [MFV:Z  
breakWhile = true; P@k ;Lg"  
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for(int i=0;i<nStartPos.length;i++) */O6cF7  
{ 7QQ3IepP  
if(!fileSplitterFetch.bDownOver) m4>v S  
{ +&(sZFW5o  
breakWhile = false; '9{H(DA  
break; I/XVo2
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} pC_2_,6$  
} $Snwx  
if(breakWhile) ]2h~Db=  
break; H# 2'\0u  
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//count++; <0JW[m  
//if(count>4) <9\_b6  
// siteStop(); zh*NRN  
} <:q]t6]$  
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System.err.println("文件下载结束！"); \DeZY97p%  
} tnRq?  
catch(Exception e){e.printStackTrace ();} T(J&v|FK  
} eHPGzNXb  
lq.AQ  
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//获得文件长度 D
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public long getFileSize() @@SG0YxZ  
{ j><.tA~i  
int nFileLength = -1; li/IKS)e$  
try{ J*a`qU   
URL url = new URL(siteInfoBean.getSSiteURL()); `=q)-y_C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <:RU,  
httpConnection.setRequestProperty("User-Agent","NetFox"); NFmB ^@k  
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int responseCode=httpConnection.getResponseCode(); c9r2kc3cy{  
if(responseCode>=400) jUW{Z@{U  
{ (Pvch!  
processErrorCode(responseCode); %8S!l;\H5  
return -2; //-2 represent access is error n+Fl|4  
} -bZ^A~<O,  
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String sHeader; Bk?MF6  
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for(int i=1;;i++) oVc_(NH-  
{ =]Qu"nRB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r
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//Utility.log(in.readLine()); ``>WFLWTn  
sHeader=httpConnection.getHeaderFieldKey(i); "b-6kM  
if(sHeader!=null) m(*CuM[E  
{ (doFYF~w  
if(sHeader.equals("Content-Length")) G>*s+  
{ ywi Shvi8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6`X#<#_&  
break; ugUV`5w   
} j&Z:|WniK  
} i>b^n+74>  
else BR"*-$u0;  
break; /F/`?=1<$  
} i&"I/!3Q@  
} 3YA !2  
catch(IOException e){e.printStackTrace ();} urXM}^  
catch(Exception e){e.printStackTrace ();} iwrdZLE  
l ^\5Jr03  
- Nplx  
Utility.log(nFileLength); T'fE4}rY  
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return nFileLength; S`"IM?  
} 0~an\4nh  
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N @]*E  
//保存下载信息（文件指针位置） 
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private void write_nPos() 1)%9h>F7  
{ s{<rc>  
try{ MEq ()}7P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1wGd5>GDA  
output.writeInt(nStartPos.length); NZdQz  
for(int i=0;i<nStartPos.length;i++) i aP+Vab  
{ %<I0-o  
// output.writeLong(nPos); ?A,gDk/#  
output.writeLong(fileSplitterFetch.nStartPos); 8.]dThaq  
output.writeLong(fileSplitterFetch.nEndPos); nCXIWLw  
} o?/N4$&5l  
output.close(); @f{)]I +f  
} [4t_ 83  
catch(IOException e){e.printStackTrace ();} f[h=>O  
catch(Exception e){e.printStackTrace ();} ke)3*.Y%C  
} "o=h /q5&  
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//读取保存的下载信息（文件指针位置） }JrM!'  
private void read_nPos() BD,~M*%z  
{ F}i rCi47c  
try{ !Y`nKC(=z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 36&7J{MU  
int nCount = input.readInt(); _3hCu/BV  
nStartPos = new long[nCount]; kTs)u\r.  
nEndPos = new long[nCount]; iK=H9j  
for(int i=0;i<nStartPos.length;i++) .:_dS=ut  
{ 3vVhE,
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nStartPos = input.readLong(); F N(&3Ull  
nEndPos = input.readLong();  ,u
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} DRf~l9f  
input.close(); B3XVhU
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} 4?72TBl]  
catch(IOException e){e.printStackTrace ();} fN8A'p[  
catch(Exception e){e.printStackTrace ();} h/eKVRGs"  
} kwZC3p\\  
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private void processErrorCode(int nErrorCode) HTkce,dQ  
{ 6q6&N'We  
System.err.println("Error Code : " + nErrorCode); Dzc 4
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} ~''qd\.f$  
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VaSw}q/o:/  
//停止文件下载 o"QpV >x  
public void siteStop() ^ /:]HG  
{ 8>Ervi`  
bStop = true; v%86JUlK.  
for(int i=0;i<nStartPos.length;i++) &AOw(?2  
fileSplitterFetch.splitterStop(); P%B1dRa  
s( 2=E|  
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} j!:U*}f  
} #@lr$^M  
//负责部分文件的抓取 -v>BeVF  
**FileSplitterFetch.java iT9cw`A^%  
*/ YN"102CK  
package NetFox; ?aO%\<b  
_lyP7$[: c  
%aL>n=$  
import java.io.*; .yg"!X  
import java.net.*; ,MOB+i(3*u  
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public class FileSplitterFetch extends Thread { ukq9Cjs  
( 9dV%#G\  
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String sURL; //File URL EX8]i,s|E  
long nStartPos; //File Snippet Start Position Mk,8v],-Tj  
long nEndPos; //File Snippet End Position kDO6:sjR7  
int nThreadID; //Thread's ID .B#L
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boolean bDownOver = false; //Downing is over C'7W50b  
boolean bStop = false; //Stop identical :qgdn,Me  
FileAccessI fileAccessI = null; //File Access interface wrGd40  
?R"5 .3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /x-Ja[kL  
{ :Q$3P+6a  
this.sURL = sURL; f_.1)O'83  
this.nStartPos = nStart; |(XV '-~  
this.nEndPos = nEnd; fa5($jJ&  
nThreadID = id; hO{@!H$l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xH3SVn(I  
} jCKRoao  
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public void run() ecf<(Vl}  
{ >[ 72]<6  
while(nStartPos < nEndPos && !bStop) 3^1)W!n/  
{ HzH_5kVW  
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try{ { H9pF2C  
URL url = new URL(sURL); 0Xk;X1Xl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w[4SuD  
httpConnection.setRequestProperty("User-Agent","NetFox"); R&PQ[Xc  
String sProperty = "bytes="+nStartPos+"-"; a
7#Eyw^H{  
httpConnection.setRequestProperty("RANGE",sProperty); Hvor{o5|tB  
Utility.log(sProperty); ,u~\$Az6  
Wc`Vcn1  
+".&A#wU  
InputStream input = httpConnection.getInputStream(); mn0QVkb}lc  
//logResponseHead(httpConnection); 4_r8ynq{z  
7^|3TTK  
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byte[] b = new byte[1024]; hw~cS7  
int nRead; nwcT8b87J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B#EF/\5  
{ r<C^hs&]  
nStartPos += fileAccessI.write(b,0,nRead); o~es>
;  
//if(nThreadID == 1) z{!wQ~ j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  tEP^w  
} Kau*e8  
{6/%w,{,  
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Utility.log("Thread " + nThreadID + " is over!"); a[9;Okm#  
bDownOver = true; Wuc,Cjm9(!  
//nPos = fileAccessI.write (b,0,nRead); ]*zF#Voc  
} NG5H?hVN=  
catch(Exception e){e.printStackTrace ();} 5bZ`Y
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} >(%im:_  
} K<+AJ(C  
* k=L  
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//打印回应的头信息 j#!J hi  
public void logResponseHead(HttpURLConnection con) _DJ0MR~3  
{ 5l(;+#3y/  
for(int i=1;;i++) OtQKDpJq  
{ UK&E#i  
String header=con.getHeaderFieldKey(i); G ROl9xp2  
if(header!=null) b[RBp0]x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ch :428  
Utility.log(header+" : "+con.getHeaderField(header)); %@pTEhpF  
else g08=D$P  
break; k"Sw,"e>+  
} #"7:NR^H^  
} Y71b Lg  
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public void splitterStop() rt~X(S  
{ pF"z)E|^  
bStop = true; by8d18:it  
} xYwb
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} ?pQ, 5+8
 
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/* tbOe,-U-@  
**FileAccess.java R9=,T0Y p  
*//文件访问(定位，写) jv_sRV  
package NetFox; xR1g  
import java.io.*; 09x
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) mv}u~  
public class FileAccessI implements Serializable{ % )|/s%W  
[;I.aT}R!;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~r=TVHjqi  
RandomAccessFile oSavedFile; |: nuT$(  
long nPos; :;??!V  
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public FileAccessI() throws IOException m+uh6IqN./  
{ F ^E(AE  
this("",0); u)Y#&qA  
} fylaH(LER  
\t!+]v8f8  
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public FileAccessI(String sName,long nPos) throws IOException ^i:%;oeG  
{ &ul9N)A  
oSavedFile = new RandomAccessFile(sName,"rw"); Wm3H6o*  
this.nPos = nPos; {z.}u5N
 
oSavedFile.seek(nPos); MuO>O97  
} q2/Vt0aYx  
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public synchronized int write(byte[] b,int nStart,int nLen) *><] [|Y@H  
{ PK+][.6H  
int n = -1; .3HC*E.e  
try{ PfuYT_p4s  
oSavedFile.write(b,nStart,nLen); 0tsll1  
n = nLen; W}.4$f>  
} _fa]2I  
catch(IOException e) CZ&TUE|:DA  
{ 9)4N2=  
e.printStackTrace (); ;'<K}h
 
} #lct"8  
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return n; Y[x ^59  
} :Z< 5iLq  
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} \XB71DUF  
::M/s#-@  
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/* o[cKh7&+  
**SiteInfoBean.java 2%@j<yS  
*/ 1":{$A?OB  
package NetFox; aa".d[*1  
XhIgzaGVu  
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public class SiteInfoBean { WVo%'DtF`  
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private String sSiteURL; //Site's URL 2"i<--Y  
private String sFilePath; //Saved File's Path a7d782~  
private String sFileName; //Saved File's Name }RoM N$r  
private int nSplitter; //Count of Splited Downloading File WQK#&r*  
`__CL )N|  
?Z14l0iZ%d  
public SiteInfoBean() ucA6s:!={  
{//nSplitter的缺省值为5 1C|j<w=i  
//default value of nSplitter is 5 ]1Q\wsB  
this("","","",5); <R!qOQI  
} Hh qx)u  
+ S%+Ku  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,,G0}N@
7s  
{ U2Ur N?T  
sSiteURL= sURL; )FHaJ*&d  
sFilePath = sPath; _6(zG.Fg  
sFileName = sName; Jl9T[QAJn1  
this.nSplitter = nSpiltter; zJx<]=]  
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} s!+?)bB  
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public String getSSiteURL() {{ wVM:1  
{ MK"Yt<e(o  
return sSiteURL; Y{J/Oib  
} }$UuYO/i  
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public void setSSiteURL(String value) ]T*{M  
{ TVjY8L9'h  
sSiteURL = value; [S<DdTY9hZ  
} i;\i4MT  
Z,d/FC#y(  
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public String getSFilePath() Lv_6Mf(  
{ 8XY4  
return sFilePath; Q% dpGI  
} RL&*.r&  
)v|a:'%K_  
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public void setSFilePath(String value) S>*T&K  
{ iYnw?4Y  
sFilePath = value; r^ "mPgY  
} yDyq. -Q  
V*)6!N[5  
{$s:N&5  
public String getSFileName() r]]Ke_s!  
{ ~ib#x~Db  
return sFileName; @L~
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} '17=1\Ss6;  
~pF'Qw"z|  

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public void setSFileName(String value) [@\f 0R  
{ OsK=% aDpj  
sFileName = value; h`vM+,I  
} NuP@eeF>,  
y'+^ ME$H  
jf%Ydr}`  
public int getNSplitter() k5ZwGJ#r  
{ =W4cWG?+  
return nSplitter; AOfQqGf
 
} da-3hM!u+  
k?";$C}#  
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public void setNSplitter(int nCount) j"NqNv  
{ ^|x{E20  
nSplitter = nCount; bqe;) A7  
} lLg23k{'  
} s@q54  
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/* T2Vj&EA@  
**Utility.java F_-yT[i  
*/ %r>vZ/>a  
package NetFox; @TH \hr]  
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public class Utility { W5x]bl#  
UGN. ]#"#  
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public Utility() iD]!PaFD`  
{ 'kC$R;#\7  
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} \u)(+t{  
V3m!dp]  
//线程睡眠 V~+Unn  
public static void sleep(int nSecond) kB8
l`| I  
{ hm5<_(F!  
try{ &=/.$i-w$  
Thread.sleep(nSecond); 5(F!*6i>  
} kPxEGuL'  
catch(Exception e) \e=@h!p  
{ P_?1Rwm-45  
e.printStackTrace (); [lnN~#(Y  
} PCU6E9~t2  
} *".7O*jjV  
59ivL6=3  
//日志 BPPhVE  
public static void log(String sMsg) %\^x3wP&o\  
{ I#,,h4C  
System.err.println(sMsg); <bid 6Q0|  
} QK@z##U  
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:N[2*
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public static void log(int sMsg) .O,gl$y}  
{ hrW.TwK  
System.err.println(sMsg); &3^40s/+  
} a{8GT2h`4  
} d5i/:  
:*8@MjZ4  
~k J#IA  
/* jt]+(sx  
**TestMethod.java vw!i)JO8M  
*/ XkNi'GJf  
package NetFox; z* `81  
,fNiZ  
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public class TestMethod { lz>5bR'  
+&t{IP(?  
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public TestMethod() ^]v}AEcmW  
{ ///xx/weblogic60b2_win.exe %] Bb;0G  
try{ l >O]Cpt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cvC;QRx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Npu;f>g0_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &zm5s*yNt  
fileFetch.start(); ?&1?uc  
} [OT@gp:  
catch(Exception e){e.printStackTrace ();} >!oN+8[~  
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9!R!H&  
} f{+8]VA  
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public static void main(String[] args) t,H,*2  
{ )8vcg{b{d  
new TestMethod(); s_kI\w4(x1  
} 3O]e  
} 6znm?s@
~  
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