http断点续传简单实现（java)

/* 0OGCilOb*  
**SiteFileFetch.java 8Jz:
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*/ #A]-ax?Qc}  
package NetFox; k}~O}~-  
import java.io.*; 1b
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import java.net.*; %#$EP7"J  
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public class SiteFileFetch extends Thread { 2)j0Ai%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Q X%&~  
long[] nStartPos; //开始位置 ,m,)
I  
long[] nEndPos; //结束位置 [TNj;o5J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s: 3z'4oX  
long nFileLength; //文件长度  6m6zA/  
boolean bFirst = true; //是否第一次取文件 r-h#{==*c  
boolean bStop = false; //停止标志 I*VCpaA  
File tmpFile; //文件下载的临时信息 a')|1DnR  
DataOutputStream output; //输出到文件的输出流 cV`E>w=D0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） JMTvSXr  
public SiteFileFetch(SiteInfoBean bean) throws IOException n8.kE)?  
{ ['ksP-=  
siteInfoBean = bean; w9|w2UK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5+fLeC;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s`#(   
if(tmpFile.exists ()) Q[#vTB$f  
{ 7w3CXY  
bFirst = false; }2ZsHM^]%  
read_nPos(); Ko^c|}mh*!  
} `c'W-O/  
else Yq/.-4y  
{  TT-h;'nJ  
nStartPos = new long[bean.getNSplitter()]; zq%D/H6J,  
nEndPos = new long[bean.getNSplitter()]; I2H6y"pN  
} BATG FS&  
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} hS9;k9w  
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public void run() N~F RM& x  
{ Zk[&IBE_  
//获得文件长度 JH8zF{?  
//分割文件 2}W0 F2*  
//实例FileSplitterFetch YZ+RWu9K  
//启动FileSplitterFetch线程 8#Q$zLK42N  
//等待子线程返回 Oez>X=Xf  
try{ D0BI5q  
if(bFirst) 5y?-fT]X  
{ Q3"}Hl2  
nFileLength = getFileSize(); CA +uKM^"6  
if(nFileLength == -1) rm} R>4  
{ $U/YR&vcw  
System.err.println("File Length is not known!"); kHqztg  
} %e@#uxm  
else if(nFileLength == -2) It75R}B  
{ !\g
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System.err.println("File is not access!"); Zc?ppO  
} ox ;  
else 3 zn W=  
{ E#F/88(  
for(int i=0;i<nStartPos.length;i++) )Jv[xY~  
{ kkK kf'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {?`al5Sz  
}  -@ZiS^l  
for(int i=0;i<nEndPos.length-1;i++) B7z -7&TE  
{ ^H6<Km l/V  
nEndPos = nStartPos[i+1]; V=1Bo~  
} r0m*5rd1  
nEndPos[nEndPos.length-1] = nFileLength; @}:uu$OH  
} ]@Sj`J[fd  
} bz| D-.  
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//启动子线程 x\Y $+A,P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5xOvY  
for(int i=0;i<nStartPos.length;i++) $t/x;<.H  
{ #h@J=Ki  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V"!G2&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =H|6GJ  
nStartPos,nEndPos,i); nF5qw>t#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c_" ~n|  
fileSplitterFetch.start(); Ig5L$bAM~  
} P<K){V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B*gdgM*`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O=9-Qv|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %K]euEqs  
nEndPos = " + nFileLength); CpQN,-4  
// fileSplitterFetch[nPos.length-1].start(); $mCarFV-T  
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//等待子线程结束 <ioO,oS'  
//int count = 0; F H1Z2  
//是否结束while循环 ko^\HSXl  
boolean breakWhile = false; 46k?b|Q  
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while(!bStop) f}D1|\7  
{ F"N60>>  
write_nPos(); N&[D>
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Utility.sleep(500); 7w1wr)qSB  
breakWhile = true; nW|w
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8 B**8yg.  
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for(int i=0;i<nStartPos.length;i++) L_w+y  
{ 7+hK~  
if(!fileSplitterFetch.bDownOver) ^3hn0DVQ  
{ e]Zngt?b  
breakWhile = false; |!F5.%PY  
break; [NFNzwUB  
} &)oOeRwi].  
} ,<:!NF9  
if(breakWhile) 3R&lqxhg  
break; ( 9]_ HW[  
&5L<i3BX  
cv/_r#vN  
//count++; ^V%rag  
//if(count>4) Wpc|`e<  
// siteStop(); "HYQqNj?Z  
} 2On_'^O  
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System.err.println("文件下载结束！"); Z;h<6[(  
} #Mg]GeDJ{  
catch(Exception e){e.printStackTrace ();} Ssk}e=]  
} V i&*&"q  
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//获得文件长度 }za[E>z  
public long getFileSize() '<0J@^vZ  
{ I=;+n-  
int nFileLength = -1; a {ab*tM  
try{ }^(}HBT  
URL url = new URL(siteInfoBean.getSSiteURL()); .IJ_jt-^d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <x\7L2#p  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^'jEnN(  
6; Y0a4Ax  
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int responseCode=httpConnection.getResponseCode(); >O5m5@GK3a  
if(responseCode>=400) \u&_sBLKV  
{ ;sch>2&ZWU  
processErrorCode(responseCode); xF8}:z0  
return -2; //-2 represent access is error r",]Voibd  
} c/5W4_J  
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Va$Pi19 O  
String sHeader; -8N|xQ378  
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for(int i=1;;i++) Uje|`<X  
{ CU7F5@+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^2wLxXO6  
//Utility.log(in.readLine()); %Qmk2  
sHeader=httpConnection.getHeaderFieldKey(i); YJ:3!B>Zo  
if(sHeader!=null) IHp_A  
{ A6oq.I0  
if(sHeader.equals("Content-Length")) G Xt4j  
{ 0R0{t=VJZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S60IPya  
break; pN\Vr8tJ  
} dSCzx .c  
} \Ofw8=N-2  
else >
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break; GjB]KA^  
} *z'yk*  
} V]S1X^
 
catch(IOException e){e.printStackTrace ();} -VZRujl  
catch(Exception e){e.printStackTrace ();} .q][? mW3  
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Utility.log(nFileLength); 7a=S  
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return nFileLength; RwVaZJe)l  
} )wVIb)`R>Y  
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//保存下载信息（文件指针位置）
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private void write_nPos() d`d0N5\  
{ A?Wk wf  
try{ umLb+GbI4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1qi@uYDug  
output.writeInt(nStartPos.length); .qob_dRA  
for(int i=0;i<nStartPos.length;i++) EVQ0l@K  
{ xmGk*W)P  
// output.writeLong(nPos); KS*oxZ  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); YwcPX`eg  
} 9%sM*[A  
output.close(); DF{OnF  
} !AJ]j|@VBd  
catch(IOException e){e.printStackTrace ();} iqW1#)3'R  
catch(Exception e){e.printStackTrace ();} $mGvJ*9  
} iK{T^vvk  
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//读取保存的下载信息（文件指针位置） ]S 7^ITn  
private void read_nPos() 0J~Qq]g  
{ iq*A("pU  
try{ UofTll)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (qwdQMj`  
int nCount = input.readInt(); 6b~28  
nStartPos = new long[nCount]; /HZumV?  
nEndPos = new long[nCount]; yg]2erR  
for(int i=0;i<nStartPos.length;i++) zdSh:  
{ F~U!1)  
nStartPos = input.readLong(); ]TstSF=  
nEndPos = input.readLong(); IF*&%pB  
} _y .]3JNm  
input.close(); woq)\;CK  
} 5.tvB  
catch(IOException e){e.printStackTrace ();} >5T_g2pkv  
catch(Exception e){e.printStackTrace ();}  8RwX=  
} t5 a7DD  
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private void processErrorCode(int nErrorCode) >6Lm9&}
 
{ Mp\<cE  
System.err.println("Error Code : " + nErrorCode); 6aOp[-Le  
} z1,tJH0  
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nws"RcP+Z  
//停止文件下载 FbACTeB  
public void siteStop() A<YsfDa_d  
{ jw6Tj;c  
bStop = true; O7aLlZdg~  
for(int i=0;i<nStartPos.length;i++) /)uM[ dnai  
fileSplitterFetch.splitterStop(); NE|[o0On  
0=v{RQ;W4  
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} )y7_qxwbV  
} ;LJ3c7$@lf  
//负责部分文件的抓取 5,b]V)4  
**FileSplitterFetch.java #G3N(wV3  
*/ !PUp>(  
package NetFox; ELa ja87  
A[UP"P~u/  
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import java.io.*; jJwkuh8R  
import java.net.*; N<z`yV  
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public class FileSplitterFetch extends Thread { @kD8^,(oH  
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String sURL; //File URL GO5~!g  
long nStartPos; //File Snippet Start Position _>bRv+RVR  
long nEndPos; //File Snippet End Position yZ}d+7T}  
int nThreadID; //Thread's ID +~2rW8  
boolean bDownOver = false; //Downing is over Hlj6$%.  
boolean bStop = false; //Stop identical qX>Q
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FileAccessI fileAccessI = null; //File Access interface Tvf~P w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lj&>cScC  
{ & 7QH^  
this.sURL = sURL; 8V4V3^_xs  
this.nStartPos = nStart; \+qOO65/+  
this.nEndPos = nEnd; ;7
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nThreadID = id; i+M*J#'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -.vDF?@G  
} 4f1D*id*`#  
1(`M~vFDK  
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public void run() >R,?hWT  
{ jOtX 60;  
while(nStartPos < nEndPos && !bStop) e-D4'lu  
{ F!KV\?eM$  
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try{ #GqTqHNE<  
URL url = new URL(sURL); XKLF8~y8A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DOm-)zl{|x  
httpConnection.setRequestProperty("User-Agent","NetFox"); T<jfAE  
String sProperty = "bytes="+nStartPos+"-"; wFlV=!>,  
httpConnection.setRequestProperty("RANGE",sProperty); DOL%'k?B  
Utility.log(sProperty); P6?0r_Y  
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InputStream input = httpConnection.getInputStream(); $T dC/#7  
//logResponseHead(httpConnection); T'rjh"C&|  
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byte[] b = new byte[1024]; V;9 }7mw  
int nRead; Ht=$] Px  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Qd8b-hg  
{ 1 ycc5=.  
nStartPos += fileAccessI.write(b,0,nRead); Z}cIA87U  
//if(nThreadID == 1) "xwM+AC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lg/sMF>z\f  
}
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Utility.log("Thread " + nThreadID + " is over!"); sj9D  
bDownOver = true; Da,&+fZI!  
//nPos = fileAccessI.write (b,0,nRead); y' tRANxQ  
} LC
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catch(Exception e){e.printStackTrace ();} \K`jCsT  
} -ID!pTvW  
}  Q
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//打印回应的头信息 m<fA|9 F#  
public void logResponseHead(HttpURLConnection con) ZzL@[g  
{ -Z?Ck!00  
for(int i=1;;i++) |>sv8/!  
{ 44C+h    
String header=con.getHeaderFieldKey(i); Fd!iQ  
if(header!=null) >rR
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); H%.zXQ4}n  
Utility.log(header+" : "+con.getHeaderField(header)); |[w^eg  
else ul}'{|4  
break; q,,j',8kq/  
} (UW6F4:$  
} ( Yi=v'd  
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public void splitterStop() ;nf&c;D  
{ Iu6W=A  
bStop = true; +L6" vkz  
} rdI]\UH  
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} MuSaK %  

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/* 1jOKcm'#  
**FileAccess.java Qk7J[4  
*//文件访问(定位，写) v!!;js^  
package NetFox; "8t\MKt(  
import java.io.*; J8h7e}n?  
B "n`|;r5  
oWrE2U;  
public class FileAccessI implements Serializable{ 83?1<v0%  
X<K9L7/*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^n71'MW  
RandomAccessFile oSavedFile; <UAP~RH{  
long nPos; QE6E
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public FileAccessI() throws IOException r9;`  
{ UG=I~{L  
this("",0); #L1>dHhat  
} FAd``9kRT  
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public FileAccessI(String sName,long nPos) throws IOException !Ud:?U  
{ >e_%M50  
oSavedFile = new RandomAccessFile(sName,"rw"); q4k`)?k9  
this.nPos = nPos; k1wr/G'H[  
oSavedFile.seek(nPos); 9i[4"&K  
} x,-S1[#X;  
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public synchronized int write(byte[] b,int nStart,int nLen) u !.DnKu  
{ ULTNhq R*n  
int n = -1;
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try{ \A
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oSavedFile.write(b,nStart,nLen); eRVY.E<  
n = nLen; |=,83,a  
} #jgqkMOd,j  
catch(IOException e) 4[(?L{  
{ Lv3XYZ
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e.printStackTrace (); :B+Rg cqi  
} Q4CJ]J`  
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return n; yI:r7=KO  
} 6mAB
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}
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/* 'FqEB]gu  
**SiteInfoBean.java km}MqBQl  
*/ A~XOK;sB  
package NetFox; >.LgsMRIKi  
RCQAtBd  
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public class SiteInfoBean { >.n;mk  
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private String sSiteURL; //Site's URL V 1*Ad  
private String sFilePath; //Saved File's Path 44Q9*."  
private String sFileName; //Saved File's Name U~CdU  
private int nSplitter; //Count of Splited Downloading File ki`8(u6l  
Q;Q%SI`yT  
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public SiteInfoBean() J2'W =r_#  
{//nSplitter的缺省值为5 ,y{0bq9*2  
//default value of nSplitter is 5 _o&94&  
this("","","",5); {&0mK"z_  
} =g >.X9lr  
RP(a,D|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B%2L1T=  
{ <_>.!9q  
sSiteURL= sURL; T G_bje  
sFilePath = sPath; CJv>/#$/F  
sFileName = sName; xM%`KP.8X  
this.nSplitter = nSpiltter; _HLC>pH~#  
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} </|)"OD9  
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public String getSSiteURL() 2+,5p  
{ |7]?>-  
return sSiteURL; Yg[ v/[]  
}
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public void setSSiteURL(String value) abL/Y23 "  
{ G5Je{N8W  
sSiteURL = value; 2YE7 23H=Z  
} 3IGCl w(  
:fRmUAK%  
Q js2hj-$  
public String getSFilePath() Sf=F cb  
{ O@nqHZ  
return sFilePath; QH4k!^  
} AfUZO^<  
qQL.c+%L  
5dqQws-,?1  
public void setSFilePath(String value) 8^8>qSD1  
{ A%h~Z a  
sFilePath = value; ]7v81G5E  
} sZ]'DH&_(  
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L{Q4=p,A  
public String getSFileName() pF|8OB%  
{ *wViH  
return sFileName; jYrym-  
} Z
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<njIXa{  
{d^Q7A:`  
public void setSFileName(String value) -xw98  
{ y!SF/i?Py  
sFileName = value; r@olC7&  
} T~s&)wD  
{a]pF.^kf  
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public int getNSplitter() =E&24  
{ "!xvpsy  
return nSplitter; $U~=.!_du  
} zpbcmQB*  
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public void setNSplitter(int nCount) ,>&?ty9o  
{ $[j-C9W  
nSplitter = nCount; 5LO4P>f
q  
} O|?Z~  
} ?E%U|(S)=L  
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/* KLG6QBkj  
**Utility.java TG4\%S$w  
*/   YfTd  
package NetFox; ~^^!"-  
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hK:#+hg,  
public class Utility { CFD*g\g<*  
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public Utility() :/>7$)+  
{ I%
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} \k|_&hG  
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//线程睡眠 _2]e1_=  
public static void sleep(int nSecond) F<h&3  
{ $eK8GMxZ#  
try{ J f\Qf  
Thread.sleep(nSecond); ?nB helW^  
} lO551Y^  
catch(Exception e) T
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{ ,@}W@GGP)  
e.printStackTrace (); :5r:I[FFy  
} -;l`hRW  
} T^KCB\\<  
2.^7?ok  
//日志  qJsQb  
public static void log(String sMsg) bs:C1j\&  
{ }UyzMy,  
System.err.println(sMsg); h{Oz*Bq  
} Sja"(sJ  
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public static void log(int sMsg) +<'uw  
{ NFdJb\  
System.err.println(sMsg); &z./4X  
} z2rQ$O-#  
} " 7l jc  
1i5 vW-'4  
D /,|pC  
/* 5Z^$`$/.v#  
**TestMethod.java 6&g!ZE'G  
*/ 38"8,k  
package NetFox; #B}BI8o (  
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M\:"~XW  
public class TestMethod { ?whRlh  
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d[~au=b  
public TestMethod() ^JYF1  
{ ///xx/weblogic60b2_win.exe #nU@hOfg  
try{ Wwn5LlJ^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0z#l0-NdQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k$9Gn9L%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2N6Pa(6  
fileFetch.start(); [{6&.v  
} vG'vgUo  
catch(Exception e){e.printStackTrace ();} &M!4]pow
 
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} 
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public static void main(String[] args) d+gk q\  
{ Ktg&G<%J0  
new TestMethod(); m _t(rn~f6  
} |_Naun=+~  
} }M"-5K}  
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