http断点续传简单实现（java)

/* viJP
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**SiteFileFetch.java >I',%v\?@  
*/ ZZ T 9t#~  
package NetFox; &Mz]y?k'  
import java.io.*; AY;[v.Ff4  
import java.net.*; R:rols"QM  
@<&u;8y-Cn  
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public class SiteFileFetch extends Thread { .@ZrmO o]]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1vS-m
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long[] nStartPos; //开始位置 {vT9I4d8  
long[] nEndPos; //结束位置 'dqecmB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W0}FOfL9  
long nFileLength; //文件长度 Rd<K.7&A}  
boolean bFirst = true; //是否第一次取文件 >s )L(DHa"  
boolean bStop = false; //停止标志 5hh6;)  
File tmpFile; //文件下载的临时信息 LnM$@  
DataOutputStream output; //输出到文件的输出流 ;%k C?Vzi  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~z,
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public SiteFileFetch(SiteInfoBean bean) throws IOException q,> C^p|2b  
{ Hv2[=elc  
siteInfoBean = bean; cc
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4aW[`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $/$Hi U`.  
if(tmpFile.exists ()) 6J">@+  
{ F%.UpV,  
bFirst = false; 64vj6 &L  
read_nPos(); Ktu~%)k%  
} nPDoK!r'  
else -<sW`HpD'  
{ yYP>3]z  
nStartPos = new long[bean.getNSplitter()]; % [~0<uO  
nEndPos = new long[bean.getNSplitter()]; dn:\V?9  
} K=r~+4F  
9m\Yi  
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} Q- w_@~  
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public void run() RS#C4NG  
{ .*X=[" F  
//获得文件长度 c]i;0j? Dl  
//分割文件 IkG;j+=  
//实例FileSplitterFetch Vol}wc  
//启动FileSplitterFetch线程 ,`YIcr
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//等待子线程返回 Z$B%V t  
try{ Ypxp4B  
if(bFirst) =LgMG^@mu  
{ uy<<m"cA;  
nFileLength = getFileSize(); @%YbptT}  
if(nFileLength == -1) {;6a_L@q;|  
{ ;}M&fXFp"|  
System.err.println("File Length is not known!"); LOr(HgyC  
} BR_fOIDc  
else if(nFileLength == -2) TQPrOs?  
{ %;|dEY
 
System.err.println("File is not access!"); Qc=-M'9  
} $~VIx% h  
else TuaP  
{ &0H_W xKeB  
for(int i=0;i<nStartPos.length;i++) ;*ni%|K
 
{ Wyow MFp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7#Uzz"^  
} Mvp|S.  
for(int i=0;i<nEndPos.length-1;i++) jc\y{I\  
{ /5Vv5d/Z4!  
nEndPos = nStartPos[i+1]; Z@%A(nZ_  
} 1=C<aRZ b^  
nEndPos[nEndPos.length-1] = nFileLength; b`%!\I  
} O1wo KkfV  
} k+J63+obd  
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//启动子线程 vp9wRGd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tR2%oT>h  
for(int i=0;i<nStartPos.length;i++) }`!-WY  
{ ruyQ}b:zS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mNEh\4ai  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O%
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nStartPos,nEndPos,i); u} +?'B)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FvO,* r9  
fileSplitterFetch.start(); Oi]B%Uxy=  
} Jr= fc*f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [LUqF?K&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T LF'7ufq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Le{.B@2-"  
nEndPos = " + nFileLength); .:GOKyr(~  
// fileSplitterFetch[nPos.length-1].start(); wp5H|ctl  
dV16'  
.p?SPR  
//等待子线程结束 qQ6@43TC  
//int count = 0; -yTIv*y  
//是否结束while循环 ,oPxt  
boolean breakWhile = false; ledr[)  
|`s:&<W+kp  
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while(!bStop) Aon.Y Z  
{ CS5[E-%}T=  
write_nPos(); -WR<tkK  
Utility.sleep(500); 2;J\Z=7  
breakWhile = true; 6V}xgfB  
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for(int i=0;i<nStartPos.length;i++) +_u~Np  
{ ^4'!B +}F  
if(!fileSplitterFetch.bDownOver) Fs(S!;  
{ "dE[X` }=  
breakWhile = false; )qOcx I  
break; H S
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} ,A)Z.OWOq  
} ET 0(/Zz  
if(breakWhile) -YmIRocx  
break; 2JcP4!RD  
3 `mtc@*  
>,I'S2_Zl  
//count++; #6
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//if(count>4) O6ugN-d>  
// siteStop();  M%W#0  
} 7s!rer>  
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;:+2.//  
System.err.println("文件下载结束！"); n}fV$qu  
} yy&L&v'  
catch(Exception e){e.printStackTrace ();} kHhku!CH  
} ^U96p0H"T  
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//获得文件长度 bR~5 :A^  
public long getFileSize() o;#8=q  
{ 3K/'K[~  
int nFileLength = -1; ,"{e$|iY  
try{ V<;_wO^  
URL url = new URL(siteInfoBean.getSSiteURL()); 0IA'5)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L/I ] NA!U  
httpConnection.setRequestProperty("User-Agent","NetFox"); DlAwB1Ak  
KaHe(  
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int responseCode=httpConnection.getResponseCode(); *K@O3n   
if(responseCode>=400) Y6v#0pT  
{ \Sv|yQUT  
processErrorCode(responseCode); %y*'bS  
return -2; //-2 represent access is error t)g%9 k^  
} `PvS+>q  
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String sHeader; z"QXPIXPk  
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for(int i=1;;i++) fwMYEj  
{ Ro<x#Uo  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [McqwU/Q  
//Utility.log(in.readLine()); a"T+CA  
sHeader=httpConnection.getHeaderFieldKey(i); &-JIXVd*R  
if(sHeader!=null) -S&9"=v  
{ a1u4v/Qu9  
if(sHeader.equals("Content-Length")) mH5>50H;  
{ Ggsts  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wg,@S*x(  
break; d6
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} Q2* 8c$  
} pSIXv%1J  
else Wa.!eAe}  
break; E|SmvIV-  
} p9mGiK4!  
} Q)qJ6-R|HD  
catch(IOException e){e.printStackTrace ();} nn$^iw`  
catch(Exception e){e.printStackTrace ();} EM!S ;i  
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Utility.log(nFileLength); 4mEJu  
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return nFileLength; ^P/OHuDL  
} w}t}Sh  
mqUDve(  
!dcvG9JZ  
//保存下载信息（文件指针位置） x2aG5@<3  
private void write_nPos() )1R[X!KQ7  
{ Tyb'p9  
try{ riaL
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output = new DataOutputStream(new FileOutputStream(tmpFile)); f~TkU\Rh  
output.writeInt(nStartPos.length); X*d!A >s  
for(int i=0;i<nStartPos.length;i++) dnXu(e%  
{ ,!g/1m  
// output.writeLong(nPos); /6yVbo"  
output.writeLong(fileSplitterFetch.nStartPos); b&1hj[`)  
output.writeLong(fileSplitterFetch.nEndPos); U2vb&Qu/  
} fb^R3wd$ff  
output.close(); nA.U'=`  
} 4e; le&  
catch(IOException e){e.printStackTrace ();} _%B,^0;C  
catch(Exception e){e.printStackTrace ();} 3DB= Xh  
} )hoVB  
W_Y56@7e  
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//读取保存的下载信息（文件指针位置） a>,_o(]cW  
private void read_nPos() yv>uzb`N  
{ {)!ua7GF0H  
try{ *8yC6|wL?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I3T;
|;P7  
int nCount = input.readInt();
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nStartPos = new long[nCount]; ^nOh8L;  
nEndPos = new long[nCount]; [z=!OFdE  
for(int i=0;i<nStartPos.length;i++) \VW":+  
{ CtD<%v3`  
nStartPos = input.readLong(); Qm"~XP  
nEndPos = input.readLong(); f(!cz,y^\*  
} OPqhdqo  
input.close(); v@s"*E/PF7  
} $kMe8F_  
catch(IOException e){e.printStackTrace ();} +ek6}f
#  
catch(Exception e){e.printStackTrace ();} p<l+js(5|  
} S==0/  
2_?VR~mA#  
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private void processErrorCode(int nErrorCode) U-f8D  
{ )qFqf<:yc  
System.err.println("Error Code : " + nErrorCode); `w@z Fc!"  
} ymqn1ja1  
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//停止文件下载 > #9 a&O  
public void siteStop() Ep')@7^n  
{ n%~r^C_  
bStop = true; qxZf!NX5  
for(int i=0;i<nStartPos.length;i++) rfSEL 57'  
fileSplitterFetch.splitterStop(); 9Q\B1Q  
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} tO"AeZe%|  
} 4U'sBaY!K  
//负责部分文件的抓取 ATmyoN2@>  
**FileSplitterFetch.java ,5 
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*/ j0Os]a  
package NetFox; 19oyoi"  
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import java.io.*; k{ZQM  
import java.net.*; [W<j  
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public class FileSplitterFetch extends Thread { A L|,\s  
w^3S6lK  
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String sURL; //File URL !Ow M-t  
long nStartPos; //File Snippet Start Position X;vUz  
long nEndPos; //File Snippet End Position 8hyXHe  
int nThreadID; //Thread's ID 6KN6SN$  
boolean bDownOver = false; //Downing is over +9<:z
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boolean bStop = false; //Stop identical />>KCmc  
FileAccessI fileAccessI = null; //File Access interface Y[>`#RhP  
X~\O]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException evVxzU&  
{ lC d\nE8G  
this.sURL = sURL; , BZ(-M  
this.nStartPos = nStart; X?`mYoe  
this.nEndPos = nEnd; qpa}6JVQ+j  
nThreadID = id; Q!7mN?l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2) 2:KX  
} ,t'"3<^Jg  
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public void run() $!\L6;:  
{ ;2sP3!*  
while(nStartPos < nEndPos && !bStop) ~1
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{ ~)ysEZl  
`\=~ $&vjC  
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try{ "tA.`*  
URL url = new URL(sURL); 6&2{V? W3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2xB
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httpConnection.setRequestProperty("User-Agent","NetFox"); '68#
7Hs.  
String sProperty = "bytes="+nStartPos+"-"; ^ $N3.O.  
httpConnection.setRequestProperty("RANGE",sProperty); MY(
51)*  
Utility.log(sProperty); #wh[F"zX  
,E+\SBQS_  
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InputStream input = httpConnection.getInputStream(); rDc$#  
//logResponseHead(httpConnection); 2B_+5  
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byte[] b = new byte[1024]; =~21.p  
int nRead; +.m:-^9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DKl\N~{F  
{ y'^b{q@  
nStartPos += fileAccessI.write(b,0,nRead); /<o?T{z<-  
//if(nThreadID == 1) FJW,G20L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i&)OJy  
} Kzwe36O;?  
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Utility.log("Thread " + nThreadID + " is over!"); B? XK;*])  
bDownOver = true; oS_YQOoD  
//nPos = fileAccessI.write (b,0,nRead); @?t+O'&  
} K>-01AGHL  
catch(Exception e){e.printStackTrace ();} 0rAuK7  
} Jl$ X3wE  
} U1|{7.R  
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3i9~'j;F3  
//打印回应的头信息 jgfr_"@A  
public void logResponseHead(HttpURLConnection con) e&Z ?I2J  
{ vOtILL6  
for(int i=1;;i++) aZo>3z;
  
{ QS-X_  
String header=con.getHeaderFieldKey(i); /In=u6D O  
if(header!=null) e :@PI(P!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YH{n   
Utility.log(header+" : "+con.getHeaderField(header)); ?rdWhF]  
else %+C6#cj  
break; pM*( kN  
} ~!/agLwY  
} ?H8dyQ5"  
]tmMk7  
veS) j?4  
public void splitterStop() "R% RI( y{  
{ OM@z5UP  
bStop = true; $ao7pvU6  
} f{{J_""?&  
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} Z[1|('   
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/* Y&$puiH-j  
**FileAccess.java
mRC   
*//文件访问(定位，写) TT&%[A+  
package NetFox; iaRCV6cl  
import java.io.*; /2$d'e  
/!*=*  
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public class FileAccessI implements Serializable{ s Dsq:z  
7{NH;U t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C879eeJ  
RandomAccessFile oSavedFile; @r\{iSg&g.  
long nPos; g)IW9q2  
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public FileAccessI() throws IOException [Y^h)k{-$  
{ }gd'pgN"t  
this("",0); KNOVb=#f_  
} 2M+*VO  
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public FileAccessI(String sName,long nPos) throws IOException wv Mp~  
{ +HG
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oSavedFile = new RandomAccessFile(sName,"rw"); P4 #j;k4P  
this.nPos = nPos; KD--w(4  
oSavedFile.seek(nPos); `A8ErfA  
} sR)jZpmC(  
?^`fPH=  
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public synchronized int write(byte[] b,int nStart,int nLen) r5NH*\Q  
{ }$(\,SzW  
int n = -1; Fj"/jdM  
try{ !mUO/6Q hq  
oSavedFile.write(b,nStart,nLen); 4AKPS&k;  
n = nLen; <@Y`RqV+  
} eAG)+b  
catch(IOException e) $\PU Y8  
{ \(r$f!`  
e.printStackTrace (); ;{v2s;  
}  #J  
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return n; bo@, B  
} z8xBq%97us  
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} eK}GBBdO  
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/* `Io#440;  
**SiteInfoBean.java h,,B"vPS  
*/ 4b6)+*[O  
package NetFox; ^@Z8_PZo  
^|2m&2  
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public class SiteInfoBean { ~Bi%8G  
2HF`}H)H  
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private String sSiteURL; //Site's URL !-ZY_  
private String sFilePath; //Saved File's Path 1X9J[5|ll  
private String sFileName; //Saved File's Name |f(*R_R  
private int nSplitter; //Count of Splited Downloading File "akAGa!V+  
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mmy/YP)  
public SiteInfoBean() v7%}ey[  
{//nSplitter的缺省值为5 J|<C;[du>  
//default value of nSplitter is 5 =r3g:j/>q  
this("","","",5); F_4Et  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DhD##5a  
{ <5}j(jxz}  
sSiteURL= sURL; : t
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sFilePath = sPath; >P//]nn  
sFileName = sName; jBl$r{L  
this.nSplitter = nSpiltter; gAf4wq  
!T 9CpIM%  
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} 6?[SlPPE1  
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public String getSSiteURL() /vu]ch  
{ q+cD  
return sSiteURL; X8A.ag0Uu  
} c c/nzB  
[70 5[  
1/K1e$r  
public void setSSiteURL(String value) 2<:dA >1  
{ fzvyR2 I  
sSiteURL = value; OXn-!J90P  
} O,S>6o)?  
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public String getSFilePath() #zBqj;p  
{ u7j,Vc'~  
return sFilePath; $\bVu2&I  
} VN'\c3;  
S(CVkCP  
'fCSP|  
public void setSFilePath(String value) LXPO@2QF  
{ 2A9crL$  
sFilePath = value; C%CgWO`Xj  
} q?@*  
v>N*f~n  
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public String getSFileName() yO,Jgn  
{ 1}+b4"7]  
return sFileName; n$9Xj@+  
} E&5S[n9{3  
owb+,Gk(  
^7Z;=]8J  
public void setSFileName(String value) S4-jFD)U  
{ t)rPXvx}!  
sFileName = value; 0WYu5|  
} '2|P-/jU  
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public int getNSplitter() bOp%  
{ D5f[:  
return nSplitter; (hg6<`  
} 8Op^6rX4  
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public void setNSplitter(int nCount) .yFO] r1aL  
{ KWAd~8,mk  
nSplitter = nCount; oe0YxSauL  
} Q]3]Z/i  
} =1'WZp}D5  
bf{_U%`  
9)o@d`*  
/* FK`:eP{  
**Utility.java zmL VFGnS  
*/ YMU""/(  
package NetFox; v~jm<{={g  
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public class Utility { z%
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p .P#S  
public Utility() &m  GU  
{ x'..j5  
x
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} g j]8/~lr  
 7Z<GlNv  
//线程睡眠 (n7{?`Yid  
public static void sleep(int nSecond) #g0N/  
{  Fq5u%S  
try{ ! Vlx  
Thread.sleep(nSecond); cMnN} '  
} " a,4E{7  
catch(Exception e) !$>b}w'  
{ 9!Jt}n?!g  
e.printStackTrace (); 4;r,U{uR  
} r>TOJVT&]  
} =&qH%S
6  
>5"e<mwD7d  
//日志 E)f9`][  
public static void log(String sMsg) gA}<Y  
{ kE
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System.err.println(sMsg); UK1)U)*+  
} -3azA7tzz  
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MI
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public static void log(int sMsg) "PO8Q  
{ AI#.+PrC{/  
System.err.println(sMsg);
H$ g*  
} w/rJj*  
} BHYguS^qz  
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/* (v|<" tv  
**TestMethod.java \_6  
*/ 75R#gQ]EV  
package NetFox; -)3+/4Q(  
bZ OCj1  
-1d*zySL  
public class TestMethod { o?t
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public TestMethod() r jxkgd  
{ ///xx/weblogic60b2_win.exe B8n[ E  
try{ N5ZOpRH{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1_v\G   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ->.9[|lIg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ",Vx.LV  
fileFetch.start(); !>80p~L  
} "`cPV){]  
catch(Exception e){e.printStackTrace ();} b=pk;'-  
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|YyNqwP`,  
} un -h%-e|  
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public static void main(String[] args) g\@.qKF  
{ S.1>bs2  
new TestMethod(); Ol+D"k~<C  
} ]?wz.  
} 3&AJN#c  
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