http断点续传简单实现（java)

/* [p_C?hHO  
**SiteFileFetch.java KHXnB  
*/ N DV_/BI  
package NetFox; S>p>$m, Q  
import java.io.*; DnPV Tp(>  
import java.net.*; cj/FqU"  
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public class SiteFileFetch extends Thread { cb~m==G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Yt;.Z$i ,  
long[] nStartPos; //开始位置 tI(co5 W  
long[] nEndPos; //结束位置 .{W)E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sWnU*Q  
long nFileLength; //文件长度 YEqWTB|w  
boolean bFirst = true; //是否第一次取文件 Bhrp"l +|  
boolean bStop = false; //停止标志 :!Tb/1  
File tmpFile; //文件下载的临时信息 v4Q8
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DataOutputStream output; //输出到文件的输出流 {z}OZHJN  
) 4'@=q  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /1lUFL2D  
public SiteFileFetch(SiteInfoBean bean) throws IOException CR$5'#11)  
{ =>6'{32W_  
siteInfoBean = bean; 89)rss  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y,@{1X`0@3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +P<LoI  
if(tmpFile.exists ()) +<H)DPG<  
{ etH%E aF[  
bFirst = false; dGz
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read_nPos(); *l^%7Wrk  
} 4<&`\<jZ  
else qcfLA~y  
{ _#+~#U%5n  
nStartPos = new long[bean.getNSplitter()]; Kq';[Yc  
nEndPos = new long[bean.getNSplitter()]; s0"1W"7vh  
} !(Y23w*  
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} X^H)2G>e  
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public void run() m.p{+_@M&  
{ 8+1tys  
//获得文件长度 7>J8\=  
//分割文件 ;[@< ,  
//实例FileSplitterFetch Ui7S8c#tH  
//启动FileSplitterFetch线程 u1&pJLK0[  
//等待子线程返回 Ij}RlYQz  
try{ ~$i36"  
if(bFirst) 70:a2m  
{ ?c^0%Op  
nFileLength = getFileSize(); 2@aVoqrq#  
if(nFileLength == -1) K/jC>4/c/  
{ {@oYMO~  
System.err.println("File Length is not known!"); kGMI ?  
} 7PZ0  
else if(nFileLength == -2) rr#&0`]  
{ Khxl'qj  
System.err.println("File is not access!"); ALiXT8q  
} fG5U' Vw  
else m$:o+IH/  
{ b{t'Doe  
for(int i=0;i<nStartPos.length;i++) }cG
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{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); n||/3-HDj  
} F%x8y  
for(int i=0;i<nEndPos.length-1;i++) g#1_`gK  
{ Cv|ya$}a  
nEndPos = nStartPos[i+1]; r"a0!]n  
} gYx|Na,+
 
nEndPos[nEndPos.length-1] = nFileLength; YzSUJ=0/  
} 8|w_PP1oE  
} iP;X8'< BC  
0zaE?dA]  
(<pc4#B@*  
//启动子线程 =$IjN v(?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 40oRO0p  
for(int i=0;i<nStartPos.length;i++) -Vk+zEht  
{ nqt;Ge M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &V[m{.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q7C>A`w  
nStartPos,nEndPos,i); XU .FLNe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WLEjRx  
fileSplitterFetch.start(); uHUicZf.  
} V7!x-E/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C9U~lcIS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o@r+Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eqQAst#~  
nEndPos = " + nFileLength); m#mM2Guxe  
// fileSplitterFetch[nPos.length-1].start(); !h{qO&ZH=  
2`Xy}9N/Y  
z)r)w?A  
//等待子线程结束 HP2]b?C  
//int count = 0; #m6 eG&a  
//是否结束while循环 _U)DL=a'  
boolean breakWhile = false; INsc!xOQ  
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while(!bStop) _pM&Ya  
{ C$x
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write_nPos(); _gjsAbM  
Utility.sleep(500); e7ixi^Q  
breakWhile = true; rE-Xv. |
 
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;Id%{1  
for(int i=0;i<nStartPos.length;i++) 6)kF!/J  
{ b/
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if(!fileSplitterFetch.bDownOver) :Q=Jn?Gjb  
{ 1GVJ3VXt  
breakWhile = false; 74rz~ZM 5  
break; e;R
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} B i?DmrH  
} /+ vl({vV  
if(breakWhile) 7$+n"Cfm  
break; (CS"s+y1  
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//count++; %lAJ]$m  
//if(count>4) ? r=cLC  
// siteStop(); )R+@vh#Q<$  
} W\o(f W  
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xXM`f0s@+]  
System.err.println("文件下载结束！"); ]QM6d(zDA  
} )Fk%,H-1  
catch(Exception e){e.printStackTrace ();} `9Zoq=/  
} 0Np}O=>  
9`+c<j4/B  
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//获得文件长度 I|,^a|\  
public long getFileSize() 2GA6@-u\  
{ V=BF"S;-'
 
int nFileLength = -1; ~S15tZ $  
try{ sXkWs2!  
URL url = new URL(siteInfoBean.getSSiteURL()); %p)6m2Sb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |j$&W;yC  
httpConnection.setRequestProperty("User-Agent","NetFox"); IY?[0S  
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int responseCode=httpConnection.getResponseCode(); 2c@R!*  
if(responseCode>=400) ~sshhuF  
{ /cUcfe#X  
processErrorCode(responseCode); (X@JlAfB  
return -2; //-2 represent access is error 0:R}  
} .@ZqCH  
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String sHeader; G0Smss=K  
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for(int i=1;;i++) 4:=']C  
{ snOd 3Bw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v-J*PB.0p  
//Utility.log(in.readLine()); So\(]S  
sHeader=httpConnection.getHeaderFieldKey(i); Q5b?- P  
if(sHeader!=null) h.ojj$f,  
{ *fso6j#%  
if(sHeader.equals("Content-Length")) (p'yya{(  
{ >_(Xb%w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "]Wrir?l  
break; +^YXqOXU  
} O E0w/{  
} T>e!DOW;  
else =0TnH<`  
break; mS5'q q;t  
} '+N!3r{G  
} 1w/1k6`0  
catch(IOException e){e.printStackTrace ();} uA7~`78  
catch(Exception e){e.printStackTrace ();} %+YLe-\?  
\RyOexNZ  
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Utility.log(nFileLength); R<@s]xX_  
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return nFileLength; I4:4)V?  
}
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//保存下载信息（文件指针位置） ,y>,?6:>  
private void write_nPos() I3]-$  
{ ?*|AcMw5
 
try{ im|( 4f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); trcG^uV  
output.writeInt(nStartPos.length); Q{T6t;eH  
for(int i=0;i<nStartPos.length;i++) 7T9m@  
{ MWl?pG!Y  
// output.writeLong(nPos); [X]yj  
output.writeLong(fileSplitterFetch.nStartPos); IL`X}=L_  
output.writeLong(fileSplitterFetch.nEndPos); G?CaCleG  
} q,3_)ZOq  
output.close(); A94ZG:  
} '=K [3%U  
catch(IOException e){e.printStackTrace ();} bhDV U(%I6  
catch(Exception e){e.printStackTrace ();} ma[%,u`  
} O*xC}$OOn  
u9My.u@-*%  
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//读取保存的下载信息（文件指针位置） hJ$o+sl  
private void read_nPos() !|;^  
{ M3ihtY  
try{ gR}>q4b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $#4Qv5}  
int nCount = input.readInt(); pQAG%i^mF  
nStartPos = new long[nCount]; _jg&}HM  
nEndPos = new long[nCount]; u:AKp<'  
for(int i=0;i<nStartPos.length;i++) xDU>y  
{ ;[TC`DuNj0  
nStartPos = input.readLong(); 'QW/TJ=7r  
nEndPos = input.readLong(); 6x|"1 G{  
} 'RK.w^  
input.close(); V/5.37FSb  
} CZ"~N`  
catch(IOException e){e.printStackTrace ();} ?,
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catch(Exception e){e.printStackTrace ();} _
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} a,g3/  
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private void processErrorCode(int nErrorCode) idW
=  
{ b5K6F:D22  
System.err.println("Error Code : " + nErrorCode); !=%0  
} )rcFBD{vM  
\JmfQrBQ  
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//停止文件下载 .XDY1~w0  
public void siteStop() U$jw8I'.  
{ D#Qfa
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bStop = true; afrU>#+"  
for(int i=0;i<nStartPos.length;i++) "!43,!<  
fileSplitterFetch.splitterStop(); \ldjW
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} W[Kv Qt3%  
} 8axz`2`  
//负责部分文件的抓取 !-%fCg(B  
**FileSplitterFetch.java I3sH8/*  
*/ gwVfiXR4  
package NetFox; 7OuzQzhcK  
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import java.io.*; n.9k<  
import java.net.*; vC$Q4>m  
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public class FileSplitterFetch extends Thread { \i1>/`F  
;VM',40  
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String sURL; //File URL j7r!N^  
long nStartPos; //File Snippet Start Position :eIPPh|\  
long nEndPos; //File Snippet End Position j{}-zQ]n  
int nThreadID; //Thread's ID w&&uk[Gh/a  
boolean bDownOver = false; //Downing is over 9{&APxm  
boolean bStop = false; //Stop identical P(iZGOKUs=  
FileAccessI fileAccessI = null; //File Access interface :(IPrQ  
2K >tI9);  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V
e/"9?Y_  
{ ]LGp3)T-  
this.sURL = sURL; +Smt8O<N  
this.nStartPos = nStart; nT7{`aaQl  
this.nEndPos = nEnd; <eWGvIEP[  
nThreadID = id; $xx5+A%,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 38Rod]\E  
} $7Sbz&)y3  
#bRr|`  
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public void run() JiF
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{ W40GW  
while(nStartPos < nEndPos && !bStop) oL?[9aww  
{ t:A,p
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try{ 1-z*'Ghys  
URL url = new URL(sURL); xL.T}f~y2>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {sn:Lj0  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Na \9b(  
String sProperty = "bytes="+nStartPos+"-"; -I, _{3.S  
httpConnection.setRequestProperty("RANGE",sProperty); 44s K2  
Utility.log(sProperty); ]J=S\  
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InputStream input = httpConnection.getInputStream(); n])-+[F  
//logResponseHead(httpConnection); M~&|-Hm  
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byte[] b = new byte[1024]; re.%$D@  
int nRead; s3G\L<~mB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p(2j7W-/  
{ ,H{ /@|RW  
nStartPos += fileAccessI.write(b,0,nRead); K?l1Gj  
//if(nThreadID == 1) |=OO$z;q|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R=D\VIu,Z  
} mtfyhFk  
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%9_wDfw~  
Utility.log("Thread " + nThreadID + " is over!"); jgiP2k[Xom  
bDownOver = true; v\9:G  
//nPos = fileAccessI.write (b,0,nRead); mwuFXu/  
} )9,*s!)9  
catch(Exception e){e.printStackTrace ();} 2>{_O?UN  
} \L#BAB6z  
} uj.~/W1,!  
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//打印回应的头信息 f;/t7=>d  
public void logResponseHead(HttpURLConnection con) * *?mZtF  
{ (wJtEoB9^  
for(int i=1;;i++) ;OYwZ  
{ /)80@  
String header=con.getHeaderFieldKey(i); ] =Js5  
if(header!=null) //--r5Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {$iJYS\  
Utility.log(header+" : "+con.getHeaderField(header)); (xU+Y1*g"%  
else {Y5h*BD>  
break; my#qmI  
} Isq3YY  
} 9Ao0$|@b  
{GF>HHQb  
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public void splitterStop() vOYcS$,^X%  
{ .js4
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bStop = true; -;$+`<%  
} UQ|zSalv,  
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} oH+UuP2a-J  
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/* Y
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**FileAccess.java FV/xp}nz  
*//文件访问(定位，写) da@y*TO#i  
package NetFox; 1{ #Xa=  
import java.io.*; !2x"'o  
Q6S[sTKR  
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public class FileAccessI implements Serializable{ IidZ
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l,/q#)5[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $8&HpX#h$  
RandomAccessFile oSavedFile; ,8uu,,c  
long nPos; ;U<)$5  
f5a%/
1?  
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public FileAccessI() throws IOException @];#4O  
{ MW9B -x  
this("",0); ,IUMH]D  
} U]sU b3  
(2@b ,w^  
4qda!%  
public FileAccessI(String sName,long nPos) throws IOException 4x'^?0H@  
{ 1elx~5v1.=  
oSavedFile = new RandomAccessFile(sName,"rw"); y_"GMw  
this.nPos = nPos; )EO/P+&  
oSavedFile.seek(nPos); EpGe'S  
} [[D}
vL8d  
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)ymF:]QC  
public synchronized int write(byte[] b,int nStart,int nLen) *DkA$Eu3u  
{ ,WOF)
  
int n = -1; 9[N'HpQ3  
try{ nVG\*#*]|  
oSavedFile.write(b,nStart,nLen); NQfIY`lt'  
n = nLen; Vm8;{Sq  
} ]_BG"IR!..  
catch(IOException e) [v-?MS  
{ 6@2p@eYo  
e.printStackTrace (); af{;4Cr  
} !W$3p'8Tu  
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9r1pdG_C@  
return n; E08AZOY&g  
} B4R,[WE"  
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} ! # tRl  
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/* qw87B!D  
**SiteInfoBean.java O8u"Y0$*w  
*/ 2|}p&~G(  
package NetFox; 
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y8+?:=N.  
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public class SiteInfoBean { 4)j<(5  
]^ O<WD  
3UC8iq*  
private String sSiteURL; //Site's URL W\f7fVU  
private String sFilePath; //Saved File's Path d+T]EpQJ*  
private String sFileName; //Saved File's Name n]Dq  
private int nSplitter; //Count of Splited Downloading File L&3=5Bf9  
Tjs-+$P+  
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public SiteInfoBean() !W$Br\<  
{//nSplitter的缺省值为5 62(WZX%b  
//default value of nSplitter is 5 flLmZ1"  
this("","","",5); [RpFC4W  
} p'w[
5'  
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9:~,TH  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $E7yJ|p{
 
{ N_0&3PUSM  
sSiteURL= sURL; [q.W!l4E  
sFilePath = sPath; qE,%$0g  
sFileName = sName; O1#rCFC|y  
this.nSplitter = nSpiltter; I:6xDDpZG`  
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RM<\bZPc  
} M2xUs  
bkOm/8k|4  
5 #kvb$97  
public String getSSiteURL() !d(!1fC  
{ g<.8iW 'c  
return sSiteURL; |e< U%v  
} coLn};W2  
0>e>G(4(8  
!-MG"\#Wq  
public void setSSiteURL(String value) p`d:g BZ  
{ ]hf4= gm  
sSiteURL = value; rz7yAm  
} ]`4QJ;#  
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*<0g/AL  
public String getSFilePath() t3s}U@(C  
{ JnsXEkM)  
return sFilePath; gSe{S  
} moo>~F _^  
mmjB1L  
t!iF(R\  
public void setSFilePath(String value) wUV%NZB  
{ LB{a&I LG  
sFilePath = value; 8 Zj>|u  
} 73<iK]*c  
qJ!oH&/cD  
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public String getSFileName() [&`>&u@MK  
{ =:0(
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return sFileName; 11-uJVO~*  
} ^y6CV4T+  
h`GV[Oo:  
O0{v`|w9+  
public void setSFileName(String value) RCX4;,DHx  
{ B+Bv(p  
sFileName = value; RI*%\~6t?  
} L"-&B$B:  
ut,"[+J  
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public int getNSplitter() U&/S  
{ >S3 >b  
return nSplitter; <A&R%5Vs  
} *oWzH_  
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=~S   
public void setNSplitter(int nCount) o{Ep/O`  
{ uJ y@  
nSplitter = nCount; vSL{WT]m  
} h/VYH(Tj  
} CFA>  
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/* (1HN, iJy  
**Utility.java 0zxeA+U  
*/ MtB:H*pM  
package NetFox; ;Dgp !*v=  
#P@r[VZ{6  
{p\KB!Y-  
public class Utility { 24T
w1'mW  
18HHEW{  
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public Utility() +~v(*s C  
{ %jf gncW  
l`]!)j|+  
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} !Ch ya  
e_;6UZ+  
//线程睡眠 igL^k`&5^"  
public static void sleep(int nSecond) /Rz,2jfRx'  
{ `qgJE_GC  
try{ l{AT)
1;^  
Thread.sleep(nSecond); <>oW
 f  
} Uwk|M?94  
catch(Exception e) ;v'Y'!-J  
{ "8]170  
e.printStackTrace (); c 1GP3
 
}  f#nmr5F  
} u"T^DrRlQ  
HXQrtJ  
//日志 lTP02|eK  
public static void log(String sMsg) 'W*F[U*&HP  
{ rY= #^S  
System.err.println(sMsg); 463dLEd  
} }{y$$X<:  
BSf"'0I&
 
u\wd<<I']  
public static void log(int sMsg) iE`aGoA  
{ l:"*]m7o_  
System.err.println(sMsg); 7KIQ)E'kG|  
} :[39g;V}c  
} c53`E U  
k#&SWp=  
.#J3UZ  
/* 0}V'\=F454  
**TestMethod.java ~
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*/ nSi
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package NetFox; H%N+Vr3O,  
||HIp9(3  
uSJP"Lw  
public class TestMethod { pAuwSn#i  
5XHkRcESZ  
{LDb*'5Cy  
public TestMethod() h_L '_*  
{ ///xx/weblogic60b2_win.exe cFvx*n  
try{ #VE$C3<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HWBom8u0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5aNDW'z`f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c,wU?8Nc|$  
fileFetch.start(); /f<(K-o]  
} i#=X#_ +El  
catch(Exception e){e.printStackTrace ();} @k,(i=**  
7p$*/5fk  
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} #^ #i]{g  
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public static void main(String[] args) {SJ7Yfs  
{ ?<QFW#:)  
new TestMethod(); B
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} :nUsC+oBS  
} bicL%I2h  
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