http断点续传简单实现（java)

/* -hnNaA  
**SiteFileFetch.java {ax]t-ZwJ5  
*/ Fvk=
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package NetFox; }w4OCN\1  
import java.io.*; )=GPhC/sw  
import java.net.*; #^VZJ:2=|  
@*vVc`;  
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public class SiteFileFetch extends Thread { i=<;$+tW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )@DDs(q=i  
long[] nStartPos; //开始位置 =!SV;^-q  
long[] nEndPos; //结束位置 5;KJ0N*-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -51LF=(!L  
long nFileLength; //文件长度 5T.U=_ag  
boolean bFirst = true; //是否第一次取文件 e4=FO;%  
boolean bStop = false; //停止标志 xRc+3Z= N  
File tmpFile; //文件下载的临时信息 !o`7$`%Wz\  
DataOutputStream output; //输出到文件的输出流 /Yi4j,8!|  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nyPeN?-  
public SiteFileFetch(SiteInfoBean bean) throws IOException rGNa[1{kRs  
{ 0e0)1;t\  
siteInfoBean = bean; H'#06zP>5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h9 DUS,G9,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pdJ]V`m  
if(tmpFile.exists ()) fD[O tc  
{ OcV,pJ  
bFirst = false; KS(H_&j  
read_nPos(); AjEy@/  
}  ( y!o  
else HUjX[w8  
{ 1LS1 ZY  
nStartPos = new long[bean.getNSplitter()]; f$^wu~  
nEndPos = new long[bean.getNSplitter()]; qZF&^pCF}  
} X[Ufq^fyA  
/v9qrZ$$  
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} 4r4 #u'Om  
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public void run() B /uaRi%  
{ %C`P7&8m=O  
//获得文件长度 N,lr~6)  
//分割文件 ]:LlOv$  
//实例FileSplitterFetch U%bm{oVn  
//启动FileSplitterFetch线程 z<9C-  
//等待子线程返回 *;}xg{@  
try{ D*2*FDGI  
if(bFirst) 5QK%BiDlr  
{ J/P[9m30[  
nFileLength = getFileSize(); +pG+ xI  
if(nFileLength == -1) t[+bZUS$~  
{ 2F*>&n&Db7  
System.err.println("File Length is not known!"); zx<PX
 
} kiJ=C2'&  
else if(nFileLength == -2) &!4E3&+2m  
{ <o|fH~?X  
System.err.println("File is not access!"); c6 &k?Puy  
} rzHBop-8  
else rK'Lvt@w  
{ .?s jr4   
for(int i=0;i<nStartPos.length;i++) o@gceZuk  
{ Tk[]l7R~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (bv{17K  
} :@jctH~  
for(int i=0;i<nEndPos.length-1;i++) })<u~r  
{ U&6A)SW,k  
nEndPos = nStartPos[i+1]; (${
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} ,Tar?&C:  
nEndPos[nEndPos.length-1] = nFileLength; \&+Y;:6  
} .9e5@@VR  
} qdZ ^D  
}Fu1Y@M%  
X<IW5*  
//启动子线程 oS$7k3s fj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :(ql=+vDb4  
for(int i=0;i<nStartPos.length;i++) D$4GNeB+#  
{ 'z,kxra|n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "{~FEx4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]cP%d-x}  
nStartPos,nEndPos,i); zAM9%W2v_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *w0|`[P+h  
fileSplitterFetch.start(); *
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} @!oN]0`F;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \( V1-,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I,#E`)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i[9gcL"  
nEndPos = " + nFileLength); \?t8[N\_[(  
// fileSplitterFetch[nPos.length-1].start(); @` Pn<_L  
`lE&:)  
=(hBgNH  
//等待子线程结束 mD7NQ2:wA  
//int count = 0; _4) t  
//是否结束while循环 :Ef!gpS}?R  
boolean breakWhile = false; 8tSY|ME  
oQh;lb  
lHM} E$5  
while(!bStop) 0~ nCT&V  
{ FJH>P\+  
write_nPos(); \EU3i;BNT%  
Utility.sleep(500); 8K9HFT@yV  
breakWhile = true; w^8Q~3|7  
|sr\SCx  
*:d``L  
for(int i=0;i<nStartPos.length;i++) r3?8nQ$  
{ yLLA:5Q1  
if(!fileSplitterFetch.bDownOver) U@).jpN  
{ ]vB^%  
breakWhile = false; N[O .p]8  
break; } 'xGip@W  
} $/ "+t.ir3  
} G"&$7!6[Y  
if(breakWhile) H+I,c1sF  
break; :I7qw0?  
[r>hKZU2  
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//count++; l opl  
//if(count>4) gzi=+oJ|4  
// siteStop(); lwt,w<E$  
} )|v du  
-"ZNkC=
 
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System.err.println("文件下载结束！"); )G/
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} u,iiS4'Ze  
catch(Exception e){e.printStackTrace ();} "JmbYb#Z  
} 037\LPO  
s1]Pv/a=y  
}N-UlL(  
//获得文件长度 =>PX~/o  
public long getFileSize() W (TTsnnx  
{ .(Ux1.0C  
int nFileLength = -1; }Y.@:v j  
try{ 5YPIv-  
URL url = new URL(siteInfoBean.getSSiteURL()); :|k!hG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +7OE,RoQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); W:n\,P  
4J,6cOuW4  
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int responseCode=httpConnection.getResponseCode(); <5KoK!H  
if(responseCode>=400) Eyf17  
{ b?0WA.[{  
processErrorCode(responseCode); 0P$19TN  
return -2; //-2 represent access is error XdIno}pN  
} 8bMw.u=F  
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+1qvT_  
String sHeader; 'p[6K'Uq5  
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O  
for(int i=1;;i++) o|n;{zT"  
{ 
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h\#4[/  
//Utility.log(in.readLine()); I
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sHeader=httpConnection.getHeaderFieldKey(i); ~hk!N!
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if(sHeader!=null) IA1O]i S  
{ (*eX'^Q)d  
if(sHeader.equals("Content-Length")) mhIGunK;+  
{ zB y%$5~Fw  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u]B b^[  
break; L ~Vw`C  
} nq7)0F%e  
} >/.jB/q  
else ~qb?#IY]`  
break; D.AiqO<z  
} wMF1HT<*  
} 056yhB  
catch(IOException e){e.printStackTrace ();} n$j B"1  
catch(Exception e){e.printStackTrace ();} i)@vHh82  
/-<]v3J  
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Utility.log(nFileLength); A+Je?3/.  
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return nFileLength; (ce)A,;  
} jj `0w@  
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z}5'TV=^  
//保存下载信息（文件指针位置） mNe908Yw  
private void write_nPos() ND9;%
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{ 2 (ux  
try{ 2s 9U&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IP !zg|c,  
output.writeInt(nStartPos.length); uTbMp~cYB  
for(int i=0;i<nStartPos.length;i++) Q(8W5Fb?  
{ mMhe,8E&  
// output.writeLong(nPos);  ;XYfw)  
output.writeLong(fileSplitterFetch.nStartPos); nYRD>S?uz  
output.writeLong(fileSplitterFetch.nEndPos); qj*BV  
} OZObx  
output.close(); [MC}zd'/  
} y;9K
 
catch(IOException e){e.printStackTrace ();} ; zy;M5l5.  
catch(Exception e){e.printStackTrace ();} *OE>gg&?Nh  
} n |,}   
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//读取保存的下载信息（文件指针位置） MT&q~jx*  
private void read_nPos() x~yd/ R  
{ @D<Q'7mLh  
try{ 0j/i):@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zgpPu4t  
int nCount = input.readInt(); >yq
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nStartPos = new long[nCount]; {24Pv#ZG#^  
nEndPos = new long[nCount]; C$B?|oUJc  
for(int i=0;i<nStartPos.length;i++) |om3*]7  
{ U`'w{~"D%  
nStartPos = input.readLong(); @1[LD[<  
nEndPos = input.readLong(); [c6_6q As  
} `[1]wV5(5@  
input.close(); Md m(x
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}  })w5`?Y  
catch(IOException e){e.printStackTrace ();} a-DE-V Uls  
catch(Exception e){e.printStackTrace ();} &9g#Vq%   
} *KV]MdS  
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private void processErrorCode(int nErrorCode) WI'csM;M#  
{ ma*9O |v^  
System.err.println("Error Code : " + nErrorCode); z#*GPA8Em:  
} kQBVx8Uq]  
<~8W>Y\m  
tv|=`~Y  
//停止文件下载 oq<#  
public void siteStop() Bp6Evi  
{ 7y`
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bStop = true; 2W~2Hk=0+%  
for(int i=0;i<nStartPos.length;i++) p|bpE F=U  
fileSplitterFetch.splitterStop(); +Q_Gm3^  
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} $S cjEG:6  
} d ly 0874  
//负责部分文件的抓取 &k{@:z  
**FileSplitterFetch.java AU$5"kBE  
*/ %I=J8$B]f  
package NetFox; 42Ffx?Qmv  
{5z?5i ?D  
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import java.io.*; pcl_$2_  
import java.net.*; YGn:_9  
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public class FileSplitterFetch extends Thread { <*5D0q#~"  
3 \WdA$Wx  
>) :d38M  
String sURL; //File URL b
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long nStartPos; //File Snippet Start Position Tp6ysjao  
long nEndPos; //File Snippet End Position },L[bDOV07  
int nThreadID; //Thread's ID ohyUvxvj  
boolean bDownOver = false; //Downing is over p]g/iLDZ  
boolean bStop = false; //Stop identical 2I4P":q  
FileAccessI fileAccessI = null; //File Access interface 1-[{4{R  
(jyJ-qe  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *:_hOOT+[  
{ f3h9CV  
this.sURL = sURL; nb!m>0*/  
this.nStartPos = nStart; CUd'*Ewu  
this.nEndPos = nEnd; V7v,)a" L  
nThreadID = id; |3cR'|<Ual  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )T+htD)  
} J\0YL\jw1K  
!%(B2J  
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public void run() gy[uqm_ T  
{ *Ee# x!O  
while(nStartPos < nEndPos && !bStop) %qv7;E2C  
{ 87/{\h  
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try{ u!S{[7 FY  
URL url = new URL(sURL); A|+{x4s`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Aws TDM  
httpConnection.setRequestProperty("User-Agent","NetFox"); _[7uLWyC
9  
String sProperty = "bytes="+nStartPos+"-"; zBR]bk\  
httpConnection.setRequestProperty("RANGE",sProperty); Dx%fW`  
Utility.log(sProperty); ;g*6NzdA  
(^4%Fk&I-  
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InputStream input = httpConnection.getInputStream(); 5-QXvw(TH  
//logResponseHead(httpConnection); ~!OjdE!u  
/L 4WWQ5  
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byte[] b = new byte[1024]; 'huLv(Uu  
int nRead; RPWYm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ro{MDs  
{ M>#{
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nStartPos += fileAccessI.write(b,0,nRead); >j?uI6Uw  
//if(nThreadID == 1) M@3H]t?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zYNJF>^<  
} U|QDV16f  
]9:G
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Utility.log("Thread " + nThreadID + " is over!"); :[&X*bw[  
bDownOver = true; /_|1,x-Kx  
//nPos = fileAccessI.write (b,0,nRead); T_dd7Ym'8  
} \NqC i'&  
catch(Exception e){e.printStackTrace ();} (65p/$Vh  
} 2S4z$(x3  
} +1%6-g4"  
7$;$4.'  
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//打印回应的头信息 U8mu<
)  
public void logResponseHead(HttpURLConnection con) pf_ /jR  
{ 8FITcK^  
for(int i=1;;i++) A0ToX) |C  
{ !Z
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String header=con.getHeaderFieldKey(i); SOL=3hfb^  
if(header!=null) ~83P09\T%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bW]+Og  
Utility.log(header+" : "+con.getHeaderField(header)); +*q@=P,  
else ,L;vN6~  
break; ;<A/e  
} YovY0nO  
} ccSSau5N  
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public void splitterStop() 96avgyc  
{ luT8>9X^:a  
bStop = true; qu%s 7+  
} 8gNEL+  
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} +q$|6?  
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/* Cs{f'I  
**FileAccess.java (Nahtx!/9  
*//文件访问(定位，写) Ev16xL8B  
package NetFox; wrU[#g,uvr  
import java.io.*; -wfV  
*zWn4BckN  
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public class FileAccessI implements Serializable{ A\)X&vR[6  
,GIqRT4K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YP,PJnJU8  
RandomAccessFile oSavedFile; t^5_;sJQ  
long nPos; Bl];^W^P  
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public FileAccessI() throws IOException HV.7IyBA^  
{ #8jd,I%L  
this("",0); 3)a29uc:U  
} MavO`m&Cg  
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public FileAccessI(String sName,long nPos) throws IOException FF/R_xnx  
{ K~-XDLh5Nu  
oSavedFile = new RandomAccessFile(sName,"rw"); ZZ*k3Ce  
this.nPos = nPos; +.I'U9QeUN  
oSavedFile.seek(nPos); . $YF|v[=  
} =1\wZuK#  
AtDrQ<>y'  

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public synchronized int write(byte[] b,int nStart,int nLen) )g_zPt  
{ ^E17_9?  
int n = -1; a7G2C oM8  
try{ di2=P)3  
oSavedFile.write(b,nStart,nLen); KCE-6T  
n = nLen; dAl<'~g  
} Zd ,=  
catch(IOException e) 0)V-|v`  
{ {2^@jD  
e.printStackTrace (); 3H2;mqq  
} I>Q,]S1h  
_ZBR<{  
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return n; qI*1+R}  
} :j<JZs>`R  
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} 5Suc#0y  
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/* f"N3;,Oc  
**SiteInfoBean.java uTGvXKL7  
*/ MPN=K|*  
package NetFox; ^\jX5)2{  
W%K8HAP"  
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public class SiteInfoBean { '/g+;^_cB  
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D ;$+]2  
private String sSiteURL; //Site's URL bGc|SF<V  
private String sFilePath; //Saved File's Path 3>)BI(Wl  
private String sFileName; //Saved File's Name Lu.tRZ`$38  
private int nSplitter; //Count of Splited Downloading File '<S:|$$  
>[4|6k|\x  
.WyX/E$I^!  
public SiteInfoBean() =[os<+  
{//nSplitter的缺省值为5 .oN Sg.jG  
//default value of nSplitter is 5 bCUh^#]x  
this("","","",5); os^SD&hL  
} M|e n>P  
(Gc`3jJ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <|Eby!KXR  
{ |S`yXsg  
sSiteURL= sURL; 'xoE [0!  
sFilePath = sPath; W;]UP$5l  
sFileName = sName; M`pTT5r  
this.nSplitter = nSpiltter; .t[ZXrd|0  
.+L_!A  
l!V| T?  
} 0lr4d Y  
i}F;fWZ`  
)"jn{%/t  
public String getSSiteURL() ]{+M>i[  
{ [k7N+W8  
return sSiteURL; JD`;,Md  
} udI:]:,P  
|O+>#  
qS}RFM5|  
public void setSSiteURL(String value) BBE1}V!u  
{ ^^3va)1{!  
sSiteURL = value; ZfCr"aL  
} gdFoTcHgO|  
NG!cEo:2aa  
3nC#$L-   
public String getSFilePath() cW\Y?x   
{ Yk@s"qm3  
return sFilePath; ::Q);  
} G|oB'~{&  

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public void setSFilePath(String value) pXj/6+^  
{ Q*&aC|b&  
sFilePath = value; 
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} fZ~kw*0*  
vp
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2n;;Tso"  
public String getSFileName() !^bB/e  
{ r2F  
return sFileName; 3et2\wOX1x  
} V&j.>Y  
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A.C278^O8  
public void setSFileName(String value) imCl{vt(kj  
{ DEp%\sj?  
sFileName = value; lJ]\  
} 4OZ5hH h  
mx(%tz^t  
O-!fOdX8_k  
public int getNSplitter() Nw>T$RzS  
{ Nk7eiQ  
return nSplitter; MD ?F1l"}%  
} |]!Ky[P  
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LVFsd6:h  
public void setNSplitter(int nCount) uyRA`<&w  
{ 7}tZ?vD  
nSplitter = nCount; s!;VUr\  
} pg}+lYGP  
} .Uh
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U>_\  
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/* CVSsB:H6e  
**Utility.java /mBBeg^a  
*/ BXK::M+  
package NetFox; Ril21o! j  
&Wz`>qYL*  
@wdB%  
public class Utility { qzlMn)e  
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q>|[JJ*6_N  
public Utility() &A9A#It  
{ #C,f/PXfaB  
bu"68A;>  
3+
8"  
} ,+f0cv4  
m~j\?mb{+  
//线程睡眠 ~Riu*<  
public static void sleep(int nSecond) '
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{ R|)2Dg  
try{ |N=@E,33  
Thread.sleep(nSecond); [ 4Y `O  
} `k}l$ih`X  
catch(Exception e) e9Ul A  
{ Il^\3T+  
e.printStackTrace (); BvZ^^IUb  
} <`p75B  
} oLqbR?  
2htA7V*dD  
//日志 !,6v=n[Nz  
public static void log(String sMsg) _D2bGZN  
{ n:bB$Ai2  
System.err.println(sMsg); [6_Du6\h  
} -
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Dd5xXs+c  
u$%D9Z^  
public static void log(int sMsg) +i`Q 7+d  
{ -#S)}NEn  
System.err.println(sMsg); CEX}`I*-  
} 4g6ksdFQ  
} ?lc[hH  
te\h?H  
7dlKdKH  
/* b,rH&+2H  
**TestMethod.java 2i7i\?<.  
*/ s?@)a,C%k  
package NetFox; <nb3~z1  
}ED nLou  
vlPl(F1  
public class TestMethod { FV^4  
aucZJjH  
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public TestMethod() R*Xu(89  
{ ///xx/weblogic60b2_win.exe sMz^!RX@  
try{ ?}=-eJ(7e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dDqr B-G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yWv<A^C&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +w k]iH  
fileFetch.start(); h5&
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} %su}Ru  
catch(Exception e){e.printStackTrace ();} YH'$_,8peM  
{HIR>])o  
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} +-H}s`  
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@@%i(>4Z  
public static void main(String[] args) 83 i1  
{ Z@uTkqG)  
new TestMethod(); %qS]NC  
} bSrRsgKvT  
} 8:P*z  
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