http断点续传简单实现（java)

/* .(gT+5[  
**SiteFileFetch.java USHlb#*  
*/ _Ex*%Qf.  
package NetFox; Q]2sj:  
import java.io.*; hi4h0\L!}  
import java.net.*; *Bb|N--jI  
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public class SiteFileFetch extends Thread { b7>,-O  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YiY&;)w  
long[] nStartPos; //开始位置 l&e5_]+%  
long[] nEndPos; //结束位置 ? bUpK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]%WD} 4e  
long nFileLength; //文件长度 }]Gi@Nh|o  
boolean bFirst = true; //是否第一次取文件 76u/WC>B  
boolean bStop = false; //停止标志 Bsih<`KF^  
File tmpFile; //文件下载的临时信息 Mo?t[]L  
DataOutputStream output; //输出到文件的输出流 D-2v>l_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZmYSi$B  
public SiteFileFetch(SiteInfoBean bean) throws IOException e$FAhwpon  
{ :!Y?j{sGU  
siteInfoBean = bean; _taHf %\4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `K@df<}%*,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d-#u/{jG)  
if(tmpFile.exists ()) #*7/05)  
{ &?5{z
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bFirst = false; uZ=UBir  
read_nPos(); g~$GE},,  
} U||w6:W5  
else #sm_.?P  
{ Zh fD`@>&  
nStartPos = new long[bean.getNSplitter()]; ="'P=Xh!8  
nEndPos = new long[bean.getNSplitter()]; fa*H cz  
} ,:dEEL+>c  
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} N8MlT \+r  
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public void run() YKX>@)Dxv  
{ 4,*^QK  
//获得文件长度 bN7UO  
//分割文件 yBD2  
//实例FileSplitterFetch h3;o!FF  
//启动FileSplitterFetch线程 >b!X&JU  
//等待子线程返回 Jv4D^>yj[  
try{ +D
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if(bFirst) "o5gQTwb  
{ mC[U)` ey  
nFileLength = getFileSize(); *n|0\V<  
if(nFileLength == -1) tci%=3,)  
{ w?$u!X  
System.err.println("File Length is not known!"); @7[.>I(  
} /
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else if(nFileLength == -2) |au qj2  
{ E23 Yk?"  
System.err.println("File is not access!"); >fZ/09&3  
} \w0b"p  
else +GPT:\*q6  
{ ~b6<uRnM.  
for(int i=0;i<nStartPos.length;i++) kvgs $  
{ ,wb|?
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); fj t_9-.  
} $ DZQdhv  
for(int i=0;i<nEndPos.length-1;i++) 1N$gE  
{ ]Re~V{uh  
nEndPos = nStartPos[i+1]; b]g&rwXYt  
} t+4Y3*WeGF  
nEndPos[nEndPos.length-1] = nFileLength; (HrkUkw  
} f;tyoN0wHx  
} mTuB
*  
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//启动子线程 ID)gq_k[8,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Uh|__DUkh  
for(int i=0;i<nStartPos.length;i++) }MavI'  
{ w[$nO#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,M/#Q6P0}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), va/4q+1GfH  
nStartPos,nEndPos,i); L..X)-D2n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j_a~)o-p  
fileSplitterFetch.start(); 6 XOu~+7  
} iZq@W3GL C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _l{5'm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,I&0#+}n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 548[!p4  
nEndPos = " + nFileLength); EAd:`X,Y  
// fileSplitterFetch[nPos.length-1].start(); =Z>V}`n  
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L5k>;|SA  
//等待子线程结束 hte9l)  
//int count = 0; c>i*HN}Z|  
//是否结束while循环 ox=7N{+`J  
boolean breakWhile = false; F)5B[.ce  
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while(!bStop) ;`PkmA
g  
{ PSQ:'  
write_nPos(); `jQ}^wEgu  
Utility.sleep(500); &<P^Tvqq&  
breakWhile = true; 4bFVyv  
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for(int i=0;i<nStartPos.length;i++) ]zq_gV8k  
{ Nj-rZ%&  
if(!fileSplitterFetch.bDownOver) c.{&~  
{ Nb!6YY=Ez-  
breakWhile = false; eZod}~J8  
break; ocuVDC  
} |o=\9:wV  
} v4>"p!_C  
if(breakWhile) x^O2Lj,w\  
break; 7fTg97eF  
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^'I5]cRa  
//count++; ^YJ^+:D(  
//if(count>4) -b>O4_N  
// siteStop(); n`T[eb~  
} %FWfiFV|<  
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System.err.println("文件下载结束！"); )>M@hIV5>  
} Y7V&zF{  
catch(Exception e){e.printStackTrace ();} 1gy}E=noP  
} cYwC,\uF  
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//获得文件长度 JX0_
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public long getFileSize() y3[)zv  
{ ;6 qdOD6  
int nFileLength = -1; *;yMD-=  
try{ = 4WZr  
URL url = new URL(siteInfoBean.getSSiteURL()); 2d;xAX]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "X(=  
httpConnection.setRequestProperty("User-Agent","NetFox"); !@Vp Bl  
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int responseCode=httpConnection.getResponseCode(); 6ym)F!t8l  
if(responseCode>=400) s&`XK$p  
{ hG;=ci3EE  
processErrorCode(responseCode); ^RAFmM#F  
return -2; //-2 represent access is error >;r05,mc  
} dlzamoS@AR  
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Ru')X{]25  
String sHeader; )zt4'b\)v  
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for(int i=1;;i++) j"sO<Q{6%  
{ 5YH mp7c-z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wVJFA1  
//Utility.log(in.readLine()); A^@<+?  
sHeader=httpConnection.getHeaderFieldKey(i); L.:QI<n  
if(sHeader!=null) ]bE?n.NwZ  
{ Hpg;?xAT  
if(sHeader.equals("Content-Length")) b-zX3R;  
{ gG;W:vR}l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); to|9)\  
break; M*6@1.n  
} LbbQ3$@WD  
} {bW3%iU  
else ~
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break; _";pk _  
} xy3
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} vl~   
catch(IOException e){e.printStackTrace ();} }Q^a.`h  
catch(Exception e){e.printStackTrace ();} *>$)#?t  
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Utility.log(nFileLength); GiwA$^Hg\  
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return nFileLength; gbf=H8]  
} LhRe?U\  
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//保存下载信息（文件指针位置） V(uRKu x  
private void write_nPos() Z2jb>%  
{ `80Hxp@  
try{ 5@%-=87S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y+afUJT  
output.writeInt(nStartPos.length); /(pChY>  
for(int i=0;i<nStartPos.length;i++) Ht^2)~e~:  
{ M #&L@fg!  
// output.writeLong(nPos); c!^}!32j)  
output.writeLong(fileSplitterFetch.nStartPos); V>92/w.fe  
output.writeLong(fileSplitterFetch.nEndPos); Fh$&puF2  
} 9?$!=4  
output.close(); RAbq_^Q  
} %<|KJb4?  
catch(IOException e){e.printStackTrace ();} X2?_lZ[\  
catch(Exception e){e.printStackTrace ();} a`iAA1HJ  
} 1ZFSz{  
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//读取保存的下载信息（文件指针位置） 8~#Q *  
private void read_nPos() /-4B)mL  
{ %\&
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try{ t+J
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wj=ex3K3u.  
int nCount = input.readInt(); + qqN  
nStartPos = new long[nCount]; $i>VI  
nEndPos = new long[nCount]; M?zAkHNS$  
for(int i=0;i<nStartPos.length;i++) {=7i}xY]T  
{ 1^^D :tt  
nStartPos = input.readLong(); S Tk#hhx  
nEndPos = input.readLong(); >D62l*VC)  
} r!,V_a4n  
input.close(); zL8A?G)=M  
} @2*6+w_Ae  
catch(IOException e){e.printStackTrace ();} Kp8T;&<Iay  
catch(Exception e){e.printStackTrace ();} s2=X>,kz?  
} &ru0i@?)  
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private void processErrorCode(int nErrorCode) vGT.(:\-,  
{ }*R6p?L5  
System.err.println("Error Code : " + nErrorCode); 7"i*J6y*  
} eJp-s" %  
9'h^59  
M6#(F7hB  
//停止文件下载 ~'=4K/39  
public void siteStop() p,Hk"DSs%  
{ M[_I16s  
bStop = true; BmXGk  
for(int i=0;i<nStartPos.length;i++) AB\4+ CLV  
fileSplitterFetch.splitterStop(); L]<4{8H.  
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} 2
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} :q1r2&ne  
//负责部分文件的抓取 MV\zwH  
**FileSplitterFetch.java U~t(YT  
*/ ]t;5kj/  
package NetFox; ]bweQw@i  
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import java.io.*; Mwc3@  
import java.net.*; D/U
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public class FileSplitterFetch extends Thread { c iX2G  
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,$-PC=Ti(  
String sURL; //File URL L9oZ7o  
long nStartPos; //File Snippet Start Position u`|fmVI  
long nEndPos; //File Snippet End Position \]%U?`A  
int nThreadID; //Thread's ID Y&:i^k  
boolean bDownOver = false; //Downing is over `Cxe`w4  
boolean bStop = false; //Stop identical >O
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FileAccessI fileAccessI = null; //File Access interface qr6jn14.c  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g"Bv!9*H  
{ !d(V7`8  
this.sURL = sURL; eVXbYv=gJ@  
this.nStartPos = nStart; idy:Jei}  
this.nEndPos = nEnd; .SN
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nThreadID = id; !&[4T#c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X2v'9 x  
} Z]BR
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public void run() e AjtWqg  
{ [dMxr9M  
while(nStartPos < nEndPos && !bStop) :^a$ve3(Jq  
{ (xL=X%6a  
i;Y^}2   
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try{ sSUd;BYf  
URL url = new URL(sURL); aDuanGC/V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W(YJz#]6_  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kq$1lPI  
String sProperty = "bytes="+nStartPos+"-"; 7ZZt|bl  
httpConnection.setRequestProperty("RANGE",sProperty); {wI0 =U  
Utility.log(sProperty); HrGX-6`  
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InputStream input = httpConnection.getInputStream(); \ua.%|  
//logResponseHead(httpConnection); :xCobMs_/  
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byte[] b = new byte[1024]; fF%r$`2  
int nRead; x}d\%*B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'oG'`ED"  
{ O5 SX"A  
nStartPos += fileAccessI.write(b,0,nRead); 1~
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//if(nThreadID == 1) M .,|cx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2uIAnbW]M  
} v
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Utility.log("Thread " + nThreadID + " is over!"); 5S LF1u;  
bDownOver = true; {Hu0  
//nPos = fileAccessI.write (b,0,nRead);  >pKI'  
} Gj=il-Po  
catch(Exception e){e.printStackTrace ();} Ry C7  
} bxs@_fH  
} A7H=#L+C  
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-|mABHjx*  
//打印回应的头信息 GF&"nW9A  
public void logResponseHead(HttpURLConnection con) 5 *_#"  
{ Wm61  
for(int i=1;;i++) s/V[tEC*z  
{ )1/O_N6C  
String header=con.getHeaderFieldKey(i); ^gG,}GTl  
if(header!=null) rQJoaP+\q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YC~+r8ME$j  
Utility.log(header+" : "+con.getHeaderField(header)); F/8y p<_r  
else 6]VTn-  
break; iYnt:C  
} x>cu<,e$d\  
} pN[i%\vh  
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public void splitterStop() *L=CJg  
{ v&Kw 3!X#E  
bStop = true; ^s5)FdF8  
} 2;/hF
wm  
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} 5zU$_M  
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g:HIiGN0Ic  
/* 2sngi@\  
**FileAccess.java A.n1|Q
#  
*//文件访问(定位，写) RW5T
}  
package NetFox; y}A-o_u@cD  
import java.io.*; Liof
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public class FileAccessI implements Serializable{ ~c4Y*]J  
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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 "'%x|nB  
RandomAccessFile oSavedFile; xfb%bkr  
long nPos;
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public FileAccessI() throws IOException I/'>Bn+  
{ rie1F,  
this("",0); \C#Vh7z"2&  
} ]BA8[2=m  
'2NeuK-KD  
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public FileAccessI(String sName,long nPos) throws IOException T"O!  
{ '?\Hm'8  
oSavedFile = new RandomAccessFile(sName,"rw"); "xWC49
  
this.nPos = nPos; 61wiXX"N  
oSavedFile.seek(nPos); [X|P(&\hQd  
} @uc%]V<:k  
m|!sY[!  
;kY=}=9  
public synchronized int write(byte[] b,int nStart,int nLen) 7{6wNc  
{ fy-(B;  
int n = -1; epQ7@9,Q  
try{ yt?#T#  
oSavedFile.write(b,nStart,nLen); X]N8'Yt  
n = nLen; Mf?4 `LM  
} -Jb I7Le  
catch(IOException e) #p^D([k \  
{ \o/oM,u  
e.printStackTrace (); PWTAy\  
} hSxf;>(d  
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m
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return n; Ba"Z^(:  
} &4DWLI  
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} y<)x`&pcD  
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/* /gxwp:&lY  
**SiteInfoBean.java [K^RC;}nV^  
*/ 'INdZ8j_  
package NetFox; tYnNOK*|  
xSw ^v6!2  
Ax&+UxQ0|  
public class SiteInfoBean { +?%huJYK,  
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private String sSiteURL; //Site's URL #U^@)g6  
private String sFilePath; //Saved File's Path Rt+s\MC^r  
private String sFileName; //Saved File's Name <=WQs2  
private int nSplitter; //Count of Splited Downloading File )AnX[:y  
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public SiteInfoBean() %0L9)-R  
{//nSplitter的缺省值为5 < d?O#(  
//default value of nSplitter is 5 UtzW5{  
this("","","",5); |@Bl?Bs+  
} (%tKGeb
  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u\50,N9Wp{  
{ YI|7a#*F  
sSiteURL= sURL; leiP/D6s  
sFilePath = sPath; jfk`%CEk=  
sFileName = sName; fF;-d2mF  
this.nSplitter = nSpiltter; fxjs"rD5  
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} A%pcPzG;  
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7Y:1ji0l  
public String getSSiteURL() QDs]{F#  
{ JBp^@j{_  
return sSiteURL; /.P*%'g  
} I U/gYFT  
Y7= *-  
"+p_{J/P  
public void setSSiteURL(String value) b3W@{je  
{ ;:f.a(~c  
sSiteURL = value; ;8H m#p7,  
} 7&E3d P  
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public String getSFilePath() @a+1Ri`)  
{ I6~.sTl  
return sFilePath; = 
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} y^?7de}  
h49|x&03  
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public void setSFilePath(String value) ) m[0,  
{ |X0h-kX4  
sFilePath = value; 5?{a=r9  
} NZ7g}+GTG  
xM'bb5  
eNR>W>;'  
public String getSFileName() `;L>[\Xi  
{ ihdN{Mx<2  
return sFileName; Y:XE4v/)@L  
} /0IvvD!7N  
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D:4Iex9$F"  
public void setSFileName(String value) (w}iEm\b  
{ )[i0~o[  
sFileName = value; LY(YgqL  
} B|zJrz0q3  
r>+\9q1  
r3*0`Rup  
public int getNSplitter() A}W)La\  
{ !RN(/ &%y  
return nSplitter; v'mRch)d  
} BagO0#  
a"@k11  
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public void setNSplitter(int nCount) jhl9  
{ /_rEI,[k  
nSplitter = nCount; ]c4?-Vq%u  
} gMS-mkZ  
} 3 -Nwg9U  
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/*
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**Utility.java MOi.bHCQJP  
*/ %ukFn &-2@  
package NetFox; n]S DpptM  
DryN}EMOKD  
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public class Utility { M{w[hV  
>+ZBQ]~  
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public Utility() [uqe|< :  
{ Q8OA{EUtq  
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} 9$U@h7|Q`  
TrD2:N}dI  
//线程睡眠 Er509zZ,[  
public static void sleep(int nSecond) 1j"_@?H[  
{ &3~lZa;D  
try{ B)>r~v]  
Thread.sleep(nSecond); cAnL,?_v  
} Q$u&/g3NvL  
catch(Exception e) qz[qjGdHg  
{ YW9r'{(D(I  
e.printStackTrace (); B8_)I.  
} WZ,}]D  
} <?yf<G'$  
dp;;20z  
//日志 F<H[-k*t/  
public static void log(String sMsg) Av6=q=D  
{ 4j+FDc`  
System.err.println(sMsg); ])Rs.Y{Q5  
} JWQd/   
5yBaxw`  
j=c=Pe"?u  
public static void log(int sMsg) 7m='-_w)?w  
{ r?Q`b2Q  
System.err.println(sMsg); xgeDfpF'  
} 4u0\|e@a  
} NEp )V'  
z 3((L  
d+DdDr  
/* +pMa-{  
**TestMethod.java Zfwhg4G~  
*/ vfBIQfH  
package NetFox; T .#cd1b  
*XN|ZGl/  
[=/Yo1:v  
public class TestMethod { 4PdJ  
Em6P6D>S>,  
vl}fC@%WRI  
public TestMethod() TEB<
ia3+  
{ ///xx/weblogic60b2_win.exe ,yPs4',d  
try{ Z!#n55|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zt,Tda4Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %*:X FB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Qk`ykTS!  
fileFetch.start(); iB-h3/  
} <;eXbO>Q  
catch(Exception e){e.printStackTrace ();} $
+'bRUo  
%PF:OB6[|  
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} %3SBs*?  
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M( euwy  
public static void main(String[] args) HgVPyo  
{ *aem5E`c  
new TestMethod(); skSs|slp  
} 3jeB\  
} Gz09#nFZk  
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