http断点续传简单实现（java)

/* mi$*,fz  
**SiteFileFetch.java 5SmgE2}  
*/ aG/L'weR  
package NetFox; &io*pmUm6  
import java.io.*; }TAHVcX*p  
import java.net.*; D*o[a#2_  
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public class SiteFileFetch extends Thread { nV+]jQ~o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F5;
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long[] nStartPos; //开始位置 s9}VnNr  
long[] nEndPos; //结束位置 X|X~|&j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rJ}k!}G  
long nFileLength; //文件长度 'CO3b,  
boolean bFirst = true; //是否第一次取文件 ]NgEN  
boolean bStop = false; //停止标志 :6X?EbXhK  
File tmpFile; //文件下载的临时信息 m;"dLUb  
DataOutputStream output; //输出到文件的输出流 U `<?~Bz  
[P?.(*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6N.+  
public SiteFileFetch(SiteInfoBean bean) throws IOException 60&4?<lR4  
{ "<I*ViZ  
siteInfoBean = bean; dTW3mF4=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X7gtR|[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Rt10:9Kz$  
if(tmpFile.exists ()) YXWlg%s  
{ -?&s6XA%#  
bFirst = false; .~Z@y#  
read_nPos(); F),wj8#~>-  
} a4iq_F#NF  
else |=9=a@l]P  
{ j9Y'HU5"  
nStartPos = new long[bean.getNSplitter()]; +HOHu*D  
nEndPos = new long[bean.getNSplitter()]; SvD^'( x  
} V}UYr Va#9  
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} -^%YrWgd?  
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public void run() QL4BD93v  
{ J|A:C[7 2  
//获得文件长度 f.&((z?rC  
//分割文件 t*'U|K4L/  
//实例FileSplitterFetch -N]%)Hy  
//启动FileSplitterFetch线程 nm597WeZp  
//等待子线程返回 6$|!_94>*)  
try{ 9s}y*Vp  
if(bFirst) pZv>{=2hOS  
{ +P?^Yx0d  
nFileLength = getFileSize(); (]l}QR%Bxu  
if(nFileLength == -1) a9CK4Kg  
{ (ug^2WG Yq  
System.err.println("File Length is not known!"); ?nya;Z-~Hc  
} 56
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else if(nFileLength == -2) *3>$f.
QU  
{ :UgCP ~Y  
System.err.println("File is not access!"); R%Y#vUmBV{  
} 'U"ub2j  
else $J]b+Bp  
{ fq2t^c|$  
for(int i=0;i<nStartPos.length;i++)
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{ OAhCW*B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /Ky xOb)  
} \-?@ &' :  
for(int i=0;i<nEndPos.length-1;i++) >(aGk{e1  
{ b\l +S2  
nEndPos = nStartPos[i+1]; i!jR>+  
} u(!@6%?-  
nEndPos[nEndPos.length-1] = nFileLength; (3>Z NTm  
} 5#SD$
^  
} &b#O=LF  
n 7Bua  
j\Z/R1RcW  
//启动子线程 )j[rm   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UvtSNP&/2d  
for(int i=0;i<nStartPos.length;i++) 8=#J:LeXj  
{ dfmxz7V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eaI!}#>R+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8 )w75+&  
nStartPos,nEndPos,i); 7Q(5Nlfcz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6H\apgHm  
fileSplitterFetch.start(); &Jr~)o   
} D/$$"AT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J,bE[52
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QlHxdRK`.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n2JwZ?  
nEndPos = " + nFileLength);
BWbM$@'x  
// fileSplitterFetch[nPos.length-1].start(); `6.rTs$<  
HktvUJ(Ii  
;&N;6V"}  
//等待子线程结束 _Co*"hl>2  
//int count = 0; BN?OvQ  
//是否结束while循环 Uo
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boolean breakWhile = false; Zljj  
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y3 R+060\3  
while(!bStop) Kug_0+gI  
{ "Yo.]PU  
write_nPos(); GJLlMi  
Utility.sleep(500); ib4shaN`  
breakWhile = true; lJfn3  
ctv=8SFv(  
}K!)Z}8  
for(int i=0;i<nStartPos.length;i++) uHv9D%R  
{ n6PXPc  
if(!fileSplitterFetch.bDownOver) ;BsPms@U  
{ Q.q'pJ-  
breakWhile = false; ov{  
break; VFZ_Vw  
} }=':)?'-.  
} cI9}YSk  
if(breakWhile) 5AWIk,[  
break; qjsS2,wM  
@w)Vt$+b]  
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//count++; J!$q"0G'WT  
//if(count>4) p*T`fOL  
// siteStop(); io[$QTY  
} q F\a]e  
`g2DN#q[0  
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System.err.println("文件下载结束！"); bp06xHMu  
} E1U~ew  
catch(Exception e){e.printStackTrace ();} ;TAf[[P  
} f\W1u#;u)  
JsfX&dX0  
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//获得文件长度 w&eX)!  
public long getFileSize() )Q_^f'4  
{ Q3t9J"=1g  
int nFileLength = -1; ;+%(@C51GE  
try{ p#VA-RSUQ|  
URL url = new URL(siteInfoBean.getSSiteURL()); 2qY`*Y.2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zj ;'0Zu  
httpConnection.setRequestProperty("User-Agent","NetFox"); TG\3T%gH/s  
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[ 7W@/qqv  
int responseCode=httpConnection.getResponseCode(); l2))StEm  
if(responseCode>=400) R^`#
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{ RR u1/nam  
processErrorCode(responseCode); _b+=q:$/  
return -2; //-2 represent access is error >tfy\PY:  
} W}<'Y@[,  
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String sHeader; }B{bM<dF  
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$ e<&7  
for(int i=1;;i++) A4lh`n5%  
{ O1+2Z\F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yF&"'L  
//Utility.log(in.readLine()); A.aUWh  
sHeader=httpConnection.getHeaderFieldKey(i); ,J|8P{ZO  
if(sHeader!=null) J.
 ;9-  
{ ,qF;#nB-  
if(sHeader.equals("Content-Length")) -!OFt}  
{ Ccmo(W+0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,/O,j SRk  
break; 4{?Djnh  
} =2[5g!qX  
} 1wX0x.4d  
else bLrC_  
break; 26yjQ  
} :"Vfn:Q  
} Nf.6:=  
catch(IOException e){e.printStackTrace ();} Tw|cgB  
catch(Exception e){e.printStackTrace ();} |5o0N8!b[  
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E
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Utility.log(nFileLength); _^+z2m+~N  
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return nFileLength; biTET|U`$  
} h,-8( S  
\ /(;LHWQ  
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//保存下载信息（文件指针位置） mJBvhK9%  
private void write_nPos() 1bW[RK;GE  
{ dd+[FU  
try{ 0G-M.s}A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .VFa,&5;3  
output.writeInt(nStartPos.length); N*~G ]  
for(int i=0;i<nStartPos.length;i++) 3l?D%E]P  
{ vYT%e:8)q  
// output.writeLong(nPos); `mN*"1p-  
output.writeLong(fileSplitterFetch.nStartPos); 5,3Yt~\m  
output.writeLong(fileSplitterFetch.nEndPos); GfEg][f  
} ';g]!XsY)  
output.close(); V2< 4~J2:9  
} :JBvCyj4PE  
catch(IOException e){e.printStackTrace ();} E^uWlUb{  
catch(Exception e){e.printStackTrace ();} !+qy~h  
} h,:8TMJRRN  
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//读取保存的下载信息（文件指针位置） oLJP@J  
private void read_nPos() w Phs1rL  
{ W0vdU;?%  
try{ {fi:]|<1h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $tGk,.#j  
int nCount = input.readInt(); ![ & go  
nStartPos = new long[nCount]; NXQdyg,  
nEndPos = new long[nCount]; m2!y;)F0  
for(int i=0;i<nStartPos.length;i++) seT?:PCA  
{ i3T]<&+j5  
nStartPos = input.readLong(); *],]E;  
nEndPos = input.readLong(); D8u_Z<6IjI  
} &|t*9D  
input.close(); B+yr 6Q.  
} `(j}2X'[  
catch(IOException e){e.printStackTrace ();} (A.%q1h  
catch(Exception e){e.printStackTrace ();} jl# )CEx  
} %xE9vN;  
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private void processErrorCode(int nErrorCode) ^j1?LB  
{ K1S)S8.EZ8  
System.err.println("Error Code : " + nErrorCode); uj@rv&  
} zY@|KV"^r  
aBX^Wd  
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//停止文件下载 tOn_S@/r  
public void siteStop() Y{]RhRR  
{ %T3
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bStop = true;
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for(int i=0;i<nStartPos.length;i++) K2J DG.<  
fileSplitterFetch.splitterStop(); vAW+ ,Rfj  
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} h#K863  
} X(m&  
//负责部分文件的抓取 psb$rbu7[  
**FileSplitterFetch.java ;\yVwur  
*/ ]ee%=+'  
package NetFox; IaDc hI  
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import java.io.*; ADoxma@  
import java.net.*; q5il9*)d(  
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public class FileSplitterFetch extends Thread { HhfuHZ<  
MH{$"^K  
Vw7NLTE}`  
String sURL; //File URL S?.2V@Ic  
long nStartPos; //File Snippet Start Position m S[Vl6  
long nEndPos; //File Snippet End Position eup#.#J  
int nThreadID; //Thread's ID 0w?\KHT  
boolean bDownOver = false; //Downing is over ;Wjb}_
V:_  
boolean bStop = false; //Stop identical !2oe;q2X[G  
FileAccessI fileAccessI = null; //File Access interface OyVd
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7[)4k7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z IfhC'  
{
"qEHK;  
this.sURL = sURL; Q>s>@hw  
this.nStartPos = nStart; <'H^}gQow  
this.nEndPos = nEnd; U#v??Sl
 
nThreadID = id; LO8V*H(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +.UdEIR";M  
} 0tVZvXgTu  
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public void run() cPe0o'`[  
{ gD0O7KO  
while(nStartPos < nEndPos && !bStop) Y2i:ZP  
{ ^S*~<0NQ'  
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try{ ;'!G?)PZ  
URL url = new URL(sURL); b!VaEK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )&[S*g  
httpConnection.setRequestProperty("User-Agent","NetFox"); d[ql7  
String sProperty = "bytes="+nStartPos+"-"; Tvr2K84l  
httpConnection.setRequestProperty("RANGE",sProperty); `9SRiy  
Utility.log(sProperty); (Nd5VuI  

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" SkTVqm  
InputStream input = httpConnection.getInputStream(); GD?4/HkF  
//logResponseHead(httpConnection); #)`N  
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byte[] b = new byte[1024]; 0?525^   
int nRead; Y9fktg.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9:N@+;|T  
{ h32QEz-+  
nStartPos += fileAccessI.write(b,0,nRead); E!;giPq*n  
//if(nThreadID == 1) !kZ9Ox9^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uu xbN-u  
} ur^)bp<n  
gZ6]\l]J{  
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Utility.log("Thread " + nThreadID + " is over!"); )`?Es8uW  
bDownOver = true; n@[&SgZq  
//nPos = fileAccessI.write (b,0,nRead); jt-Cy  
} kxU<?0  
catch(Exception e){e.printStackTrace ();} -miWXEe@l  
} C=L_@{^Rgb  
} 
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//打印回应的头信息 NBzyP)2)  
public void logResponseHead(HttpURLConnection con) ed$g=qs>  
{ |UvM[A|+  
for(int i=1;;i++) )3g7dtq}  
{ jH26-b<  
String header=con.getHeaderFieldKey(i); y&T(^EA;  
if(header!=null) p#HbN#^Hy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4Eh 2sI  
Utility.log(header+" : "+con.getHeaderField(header)); +#~=QT9  
else K2PV^Y  
break; DIO @Zo  
} X^mvsY  
} AA&398F  
| _/D-m*  
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public void splitterStop() &>kklP  
{ $c4Q6w  
bStop = true; csZIBi  
} EacqQFErl  
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} <1#v}epD#  
/5M@>A^?'  
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/* o3*If
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**FileAccess.java ;n?72&h  
*//文件访问(定位，写) #q.Q tDz  
package NetFox; c|q!C0X[  
import java.io.*; ct='Z E  
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public class FileAccessI implements Serializable{ Hm2}xnY  
5fi6>>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IE*GF27n  
RandomAccessFile oSavedFile; ;EstUs3  
long nPos; is&A_C7yg  
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public FileAccessI() throws IOException 5P_%Vp`B2  
{ ]Cy1yAv={  
this("",0); t6p}LNm(V  
} AkdONKO8{  
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public FileAccessI(String sName,long nPos) throws IOException lV!ecJw$  
{ rqk1 F~j|  
oSavedFile = new RandomAccessFile(sName,"rw"); 3c] oU1GfF  
this.nPos = nPos; 
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oSavedFile.seek(nPos); wWm1G
)  
} ^SnGcr|a'  
]F5?>du@~
 
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public synchronized int write(byte[] b,int nStart,int nLen) +P,hT  
{ UlQZw*ce  
int n = -1; 5sui
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try{ zt{?Ntb  
oSavedFile.write(b,nStart,nLen); I12WOL q  
n = nLen; !J ")TP=  
} i/QE)"B"q  
catch(IOException e) w^tNYN,i  
{ prE~GO7Z  
e.printStackTrace (); 9?B}CCE<LR  
} J =o,: 3"  
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return n; $ hwJjSZ0  
} s6SG%Vd  
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} LY}%|w  
# JHicx\8l  
:9H=D^J  
/* WCxt-+#  
**SiteInfoBean.java b['Jr% "O  
*/ ~M`-sSjZs  
package NetFox; JSX-iHhW  
/CX_@%m}e=  
v-2_#  
public class SiteInfoBean { Arh0m. w  
[ L% -lJ  
cn (-{dCXM  
private String sSiteURL; //Site's URL P!yE{_%  
private String sFilePath; //Saved File's Path 0g% `L_e_  
private String sFileName; //Saved File's Name 6jjmrc[#}X  
private int nSplitter; //Count of Splited Downloading File '5zolp%St  
7J$
 
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public SiteInfoBean() q9rY++Tv  
{//nSplitter的缺省值为5 -g8G47piX:  
//default value of nSplitter is 5 "PH}\Dl=  
this("","","",5); b:Oa4vBa  
} dcUaZfON  
_r+2o-ZR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nDx}6}5)  
{ ?EF[OyE  
sSiteURL= sURL; V'(yrz!  
sFilePath = sPath; t|q@~B :  
sFileName = sName; ^eke,,~  
this.nSplitter = nSpiltter; 0Q>f,}W%>  
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} Vg9nb  
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!}7FC>Cx  
public String getSSiteURL() sd|5oz)  
{ Y?G9d6]Lk6  
return sSiteURL; h^ wu8E  
} BUR96YN.  
aOZSX3;wg  
`
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public void setSSiteURL(String value) r|2Y|6@  
{ 4D(5WJ&  
sSiteURL = value; ]6)^+(zU  
} C-Y~T;53  
1FC'DH!  
x {Z_rD  
public String getSFilePath() jG8W|\8  
{ Q;A1&UA2  
return sFilePath; :^~I@)"ov  
} v eP)ElX  
Ni]V)wGE;  
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public void setSFilePath(String value) 7Gg3$E+#*  
{ }pk)\^/w/  
sFilePath = value; ;!H<W[  
} 2JY]$$K7  
~,j52obR6Z  

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public String getSFileName() @'UbTB!  
{ .W4P/Pw'  
return sFileName; XL9smFq  
} \*] l'>x1  
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public void setSFileName(String value) Cq mtO?vne  
{ hp ?4w),
 
sFileName = value; 6&jW.G8/  
} KVQ^-^  
@)[Q6w
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}J=>nL'B  
public int getNSplitter() p5RnFe
l  
{ @E Srj[  
return nSplitter; vTE3-v[i  
} +fh@m h0[  
$;GH -+  
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public void setNSplitter(int nCount) 3y#0Lb-y  
{ '
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nSplitter = nCount; _p;>]0cc.  
} c*>8VW>  
} 4oxAC; L  
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uJxT)m!/  
/* An0DqjR  
**Utility.java h2k"iO}  
*/ ^,-2";2Xh  
package NetFox; +pcGxje\  
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public class Utility { qr$h51C&  
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SSr#MIS?
 
public Utility() AW{"9f4  
{ \zCw&#D0Z  
h7r*5E  
I 68Y4s  
} asEk3  
pW[KC!  
//线程睡眠 -BV8,1  
public static void sleep(int nSecond) |B{@noGX  
{ rXh*nC  
try{ +aY]?]  
Thread.sleep(nSecond); ey/{Z<
D  
} ]Rk4"i  
catch(Exception e) ;!~&-I0l  
{ G'#f*) f  
e.printStackTrace (); b((>?=hh  
} 5%r:hO @S  
} PTS dW~3  
4Tdp;n
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//日志 uM"_3je{W2  
public static void log(String sMsg) rp&XzMwC4  
{ pie8 3Wy>  
System.err.println(sMsg); o;kxu(>yL'  
} qr@<'wp/  
-){a
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,K WIuCU;  
public static void log(int sMsg) f>CJ1;][{  
{ GQH15_  
System.err.println(sMsg); 5+DId7d'n  
} v\Y8+dD  
} Q8H+=L:  
-F$v`|(O+  
v ^R:XdH  
/* UdOO+Z_K%  
**TestMethod.java YB}m1g`  
*/ 0$g;O5y"i  
package NetFox; _LSp \{Z  
\\ZCi`O  
e"(SlR  
public class TestMethod { I7 = 4%)A  
;F;Vm$  
FP<mFqy  
public TestMethod() .du2;`[$r  
{ ///xx/weblogic60b2_win.exe BUs={"Pa  
try{ T -p~8=I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3\ {?L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "wR1=&gk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ie]k/qw+Y  
fileFetch.start(); =E w<s5C@  
} eH]9"^> o  
catch(Exception e){e.printStackTrace ();} 8-"D.b4  
G]n_RP$G  
6r.#/' "  
} 2!_DkE  
w9w=2 *  
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public static void main(String[] args) 9e*o$)j_  
{ UOpSH{N  
new TestMethod(); ,m Nd#  
} wEF"
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} ][dst@?8Oz  
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