http断点续传简单实现（java)

/* {C+blzh6  
**SiteFileFetch.java &/XRiK1"0  
*/ d
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package NetFox; OCR`1  
import java.io.*; ~<[$.8*  
import java.net.*; byA
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public class SiteFileFetch extends Thread { %eK=5Er jx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &>Zm gz  
long[] nStartPos; //开始位置 1%Yd] 1c(  
long[] nEndPos; //结束位置 -*`7Q'}%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b,vSE,&xP  
long nFileLength; //文件长度 GWb=X cx  
boolean bFirst = true; //是否第一次取文件 &<??,R14  
boolean bStop = false; //停止标志 ^y" #2Ov  
File tmpFile; //文件下载的临时信息 &Pk #v  
DataOutputStream output; //输出到文件的输出流 |qUi9#NUo  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） OH.lAF4E(  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1!N|a< #  
{ !e>+O^  
siteInfoBean = bean; )Z4i

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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r7dwj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z4CqHS~%  
if(tmpFile.exists ()) 4oxAC; L  
{ &6ymGo  
bFirst = false; n1yIQ8F  
read_nPos(); Ep>} S  
} \#)|6w-  
else W4MU^``   
{ B{}<DP.  
nStartPos = new long[bean.getNSplitter()]; NUSb7<s,&Y  
nEndPos = new long[bean.getNSplitter()]; & OO0v*@{  
} 18*M  
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} YK xkO  
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public void run() Jcy{ ~>@7  
{ FX
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//获得文件长度 pCacm@(hG  
//分割文件 "Zh3,  
//实例FileSplitterFetch P8&BtA  
//启动FileSplitterFetch线程 `kE ;V!n?  
//等待子线程返回 RA];hQI?  
try{ DxM$4  
if(bFirst) KM-d8^\:  
{ N.~zQVO#R  
nFileLength = getFileSize(); -hd@<+;E  
if(nFileLength == -1) #BLx +mLq  
{ L0lqm0h  
System.err.println("File Length is not known!"); ( *&E~g  
} t,bQ@x{zVC  
else if(nFileLength == -2) >O;V[H2[  
{ u; ]4ydp  
System.err.println("File is not access!"); 9~7s*3zI  
} 0|i3#G_~  
else )~X.x"}8k  
{ jw 4B^2}  
for(int i=0;i<nStartPos.length;i++) +,g3Xqs}X  
{ I$0O4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &':Ecmo~`  
} $@Bd}35 J  
for(int i=0;i<nEndPos.length-1;i++) F<V.OFt  
{ 2gasH11M  
nEndPos = nStartPos[i+1]; *\$m1g7b  
} m%ec=%L9  
nEndPos[nEndPos.length-1] = nFileLength; !B*l'OJw  
} +nAbcBJAl  
} 4*U5o!w1{  
6 2*p*t  
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//启动子线程 VY#
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #ETy#jKL  
for(int i=0;i<nStartPos.length;i++) E4QLXx6Wa&  
{ ,K WIuCU;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7oy}
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7:C_{\(  
nStartPos,nEndPos,i); wU}%]FqtZ=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &7J-m4BI  
fileSplitterFetch.start(); %&iodo,EP'  
} +0l-zd\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q\W?qB_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {*PbD;/f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WGwIc7  
nEndPos = " + nFileLength); ` n#Db  
// fileSplitterFetch[nPos.length-1].start(); :L+%5Jq  
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//等待子线程结束 o#K*-jOfiH  
//int count = 0; \[9^,QP  
//是否结束while循环 <B&vfKO^h  
boolean breakWhile = false; Nsf>b8O  
~K/_51O'  
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while(!bStop) `s8o2"12  
{
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write_nPos(); Tlm:
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Utility.sleep(500); j 06mky  
breakWhile = true; V(5*Dn84  
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for(int i=0;i<nStartPos.length;i++) R wTzS;  
{ jwL\|B oE  
if(!fileSplitterFetch.bDownOver) E[ttamU  
{ l`<1Y|  
breakWhile = false; ^)p+)5l   
break; J kxsua  
} .<zN/
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} z -c1,GOD  
if(breakWhile) 6Zl#$>P  
break; ?={S"qK(q  
JfsvK2I  
]iYO}JuX  
//count++; ]!X[[w)  
//if(count>4) S
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// siteStop(); -pHUC't  
} 3}}8ukq  
.% 79(r^  
TE9Iyl|=  
System.err.println("文件下载结束！");
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} LzQOzl@z  
catch(Exception e){e.printStackTrace ();} >{)\GK0i7  
} -V&nlP  
~l8w]R3A  
JT!
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//获得文件长度 }X/>WiGh:  
public long getFileSize() Ye|(5f  
{ b]4\$rW7  
int nFileLength = -1; W#@6e')d  
try{ j#jwK(:]  
URL url = new URL(siteInfoBean.getSSiteURL()); 7?;ZE:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /K(l[M  
httpConnection.setRequestProperty("User-Agent","NetFox"); M`&78j  
;4QE.&s`  
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int responseCode=httpConnection.getResponseCode(); < V*/1
{  
if(responseCode>=400) Y?6}r;<  
{ dsn(h5,Q'  
processErrorCode(responseCode); ,<BV5~T.|  
return -2; //-2 represent access is error SyI\ulmL  
} QM24cm T  
}` YtXD-o  
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String sHeader; ZPG~@lU  
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for(int i=1;;i++) y>X(GF^  
{ Px3I+VP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PLJDRp 2o  
//Utility.log(in.readLine()); \S_Ae;  
sHeader=httpConnection.getHeaderFieldKey(i); q`3HHq  
if(sHeader!=null) eH V#Mey[  
{ UX'q64F!  
if(sHeader.equals("Content-Length")) ,e^~(I
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{ Zu*7t<W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G{!(2D4!  
break; 8!{ }WLwb  
} u+O"c  
} "rrw~  
else vm7ag 7@O  
break; q|}O-A*wa  
} <TTBIXV  
} /:v}Ni"6nF  
catch(IOException e){e.printStackTrace ();} !sp`oM  
catch(Exception e){e.printStackTrace ();} q"5\bh1"  
82 dmlPwJC  
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Utility.log(nFileLength); J|F!$m{  
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return nFileLength; / */"gz%  
} }qJ`nN8  
/BN=Kl]  

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//保存下载信息（文件指针位置） S5:&_&R8[  
private void write_nPos()
8>9MeDE  
{ I/%L,XyRI  
try{ 29l bOi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); RG=i74a  
output.writeInt(nStartPos.length); ->*~e~T  
for(int i=0;i<nStartPos.length;i++) ]T{v~]7:{  
{ &7,::$cu  
// output.writeLong(nPos); [Op^l%BC  
output.writeLong(fileSplitterFetch.nStartPos); ILx4[m7  
output.writeLong(fileSplitterFetch.nEndPos); )%b 5uZ  
} Vry*=X&Q  
output.close(); [&
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} (+6N)9rj`/  
catch(IOException e){e.printStackTrace ();} VN0KK 1I  
catch(Exception e){e.printStackTrace ();} ^ZIs
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} Av0(zA2  
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//读取保存的下载信息（文件指针位置） oVr:ZwkG3  
private void read_nPos() ;<*USS6X  
{ gi>W&6  
try{ 0e07pF/!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (5A8#7a  
int nCount = input.readInt(); F-F1^$]k  
nStartPos = new long[nCount]; Fn0|v66  
nEndPos = new long[nCount]; 6b%IPbb  
for(int i=0;i<nStartPos.length;i++) ArjRoXDE  
{ (w#)|9Cxm  
nStartPos = input.readLong(); 'BUfdb8d  
nEndPos = input.readLong(); &'`ki0Xh;  
} NHQoP&OG  
input.close(); WFzM s  
} DZ1.Bm0  
catch(IOException e){e.printStackTrace ();} )G;Hf?M  
catch(Exception e){e.printStackTrace ();} As5-@l`@  
}
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private void processErrorCode(int nErrorCode) *&I _fAh]  
{ >K&chg@Hv  
System.err.println("Error Code : " + nErrorCode); .'.bokl/  
} ;>/yY]F7  
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//停止文件下载 ujl?!  
public void siteStop() vRn]u57O  
{ ~W={"n?=  
bStop = true; `DE_<l  
for(int i=0;i<nStartPos.length;i++) R+t]]n6#  
fileSplitterFetch.splitterStop(); `m
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} Tm9sQ7Oj(  
} 1M6^Brx  
//负责部分文件的抓取 =HB(N|9_d  
**FileSplitterFetch.java db=S*LUbl  
*/ , Y,^vzX6  
package NetFox; V2xvuDHI  
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a@Zolz_Z  
import java.io.*; e2BC2K0  
import java.net.*; %pH|2VB#  
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public class FileSplitterFetch extends Thread { Q1{9>NI  
@
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String sURL; //File URL 0rQr#0`  
long nStartPos; //File Snippet Start Position KX3A|
  
long nEndPos; //File Snippet End Position uJlW$Oc:.  
int nThreadID; //Thread's ID @y'ZM  
boolean bDownOver = false; //Downing is over @v:Eh  
boolean bStop = false; //Stop identical `8tstWYa]Y  
FileAccessI fileAccessI = null; //File Access interface y<wd~!>Ubu  
*0?@/2&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SjY|aW+wAL  
{ )m[<lJbw  
this.sURL = sURL; ycwkF$7  
this.nStartPos = nStart; CW/<?X<!n  
this.nEndPos = nEnd; LEe{fc?{  
nThreadID = id; -"{g kjuv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,%BDBZ  
} G,c2?^
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public void run() Zy.ls&<:  
{ 9[W >`JKo  
while(nStartPos < nEndPos && !bStop) e ky1}  
{ gHkHAOe/  
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try{ @|sBnerE  
URL url = new URL(sURL); m2YsE  j7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U* c'xoP  
httpConnection.setRequestProperty("User-Agent","NetFox"); -'L~Y~'.  
String sProperty = "bytes="+nStartPos+"-"; ~R~.D  
httpConnection.setRequestProperty("RANGE",sProperty); ~)`\j  
Utility.log(sProperty); <3/_'/C  
*9w-eK1{  
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InputStream input = httpConnection.getInputStream(); `@WJ_-$#  
//logResponseHead(httpConnection); g]c6_DMfb1  
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byte[] b = new byte[1024]; Ziub%C[oV  
int nRead; bBXLW}W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C@Go]*c  
{ ,FH1yJ;Y&  
nStartPos += fileAccessI.write(b,0,nRead);  UBj&T^j  
//if(nThreadID == 1) #d*gWwnx"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vceD/N8  
} b62B|0i  
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&l!T2PX!  
Utility.log("Thread " + nThreadID + " is over!"); &zJ\D`\,O  
bDownOver = true; S-ZN}N{,6  
//nPos = fileAccessI.write (b,0,nRead); w)RedJnf  
} _Y/*e<bU  
catch(Exception e){e.printStackTrace ();} #qR6TM&;  
} 5XzsqeG|  
} A+frKoi  
ZZHzC+O#^  
Iz'Et'w8!  
//打印回应的头信息 z}.6yHS  
public void logResponseHead(HttpURLConnection con) ?*yB&(a:8  
{ ^,t@HN;gA  
for(int i=1;;i++) GUqG1u z9  
{ Rg\4#9S JF  
String header=con.getHeaderFieldKey(i); nf<I  
if(header!=null) )8eb(!}7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @Tq-3Um  
Utility.log(header+" : "+con.getHeaderField(header)); Lj#xZ!mQS  
else qO8:|q1%;\  
break; V/#J>-os}W  
} afna7TlS  
} 5 r_Z3/%  
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public void splitterStop() Eu"8IM!%-  
{ +]( y  
bStop = true; E{e  
} mvc ;.+  

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zS|4@t\__  
} Njr;Wa.r+  
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/* a~a:mM>p  
**FileAccess.java 2 'D,1F  
*//文件访问(定位，写) W2fcY;HZ  
package NetFox; =3A4.nW  
import java.io.*; c2,g%(  
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)?{!7/H F@  
public class FileAccessI implements Serializable{ Q_!tn*  
2#3`[+g<n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <H-kR\HF  
RandomAccessFile oSavedFile; C4`&_yoP4-  
long nPos;
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public FileAccessI() throws IOException `w`N5 !  
{ <nG}]Smd7  
this("",0); o#1Ta7Ro  
} &"gX 7cK8  
U<=d@knH  
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public FileAccessI(String sName,long nPos) throws IOException cn/&QA"  
{ ~6Fh,S1?  
oSavedFile = new RandomAccessFile(sName,"rw"); 5mpql[v3P  
this.nPos = nPos; -3~S{)  
oSavedFile.seek(nPos); He5y;5  
} =q)+_@24>d  
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public synchronized int write(byte[] b,int nStart,int nLen) X[H.t$w5A  
{ 7-n HP
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int n = -1; V9}\0joM  
try{ K@%T5M4j  
oSavedFile.write(b,nStart,nLen); km5gO|V>m  
n = nLen; SqRM*Cf=  
} 8v8-5N  
catch(IOException e) -!qjBK,`X  
{ NIQ}+xpC  
e.printStackTrace (); ZsXw]Wa  
} T ,!CDm$=  
u,`3_I^  
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return n; 1!;~Y#  
} Qt{V&Z7  
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5 -|7I7(G$  
} nvLdgu4P>  
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:@P6ibcX  
/* xoj,>[7 D  
**SiteInfoBean.java QGV#AID3XW  
*/ S^|`*%pq  
package NetFox; qzA_ ~=g
 
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public class SiteInfoBean { V#.pi zb  
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private String sSiteURL; //Site's URL %3TioM[B  
private String sFilePath; //Saved File's Path tWzBQx   
private String sFileName; //Saved File's Name $uFvZ?w&  
private int nSplitter; //Count of Splited Downloading File cr]b
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public SiteInfoBean() \?Z7|  
{//nSplitter的缺省值为5 x0{B7/FN  
//default value of nSplitter is 5 S#oBO%!  
this("","","",5); }1[s,  
} /U!B2%vq_  
8d8jUPFQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W.cc!8  
{ 3X;>cv#B  
sSiteURL= sURL; _%Xp2`
m  
sFilePath = sPath; -zJV(`  
sFileName = sName; {{_v.d~1  
this.nSplitter = nSpiltter; cfv:Ld m  
1BW9,Xr  

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} ?f3R+4  
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public String getSSiteURL() J1cz D|(  
{ u*5}c7)uId  
return sSiteURL; [.xc`CF  
} NT5##XOB  
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public void setSSiteURL(String value) sKKc_H3YSH  
{ V9Mr&8{S4  
sSiteURL = value; +_*NY~  
} ]3='TN8aQF  
"x$L2>9  
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public String getSFilePath() fJ _MuAv  
{ N TDmOS\,  
return sFilePath; _yH">x<  
} 3kUb cm  
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public void setSFilePath(String value) j1->w8  
{ W+=j@JY}q9  
sFilePath = value; hS &H*  
} g@M5_I(W  
<3N\OV2  
j x< <h_j  
public String getSFileName() rwW"B  
{ "M2WK6?O5  
return sFileName; #?D[WTV  
} >d"\  
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vRW;{,d  
public void setSFileName(String value) QQ{*j7i)  
{ {g1R?W\LZ  
sFileName = value; :(/1,]bF  
} L>WxAeyu1K  
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>$CNR*}@  
public int getNSplitter() lH/"47  
{ [N%InsA9k  
return nSplitter; Ez-AQ'  
} ;g+fY6  
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public void setNSplitter(int nCount) ^qBm%R(  
{ @cxM
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nSplitter = nCount; O0BDUpH  
} ;ZcwgsxTM  
} 4L`,G:J,;  
:2NV;7Wke6  
[)8O\/:  
/* <_*5BO  
**Utility.java 5&L*'k
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*/ 'x?|tKzd  
package NetFox; 8dt=@pwx&  
mRyf+O[  
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public class Utility { jVGAgR=[G  
%yKcp5_  
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public Utility() AA ~7"2e  
{ 47*2QL^zj  
E#tfCM6  
&6Lh>n(  
} ^b$G.h{o!E  
Rc D5X{qS#  
//线程睡眠 fwzyCbks  
public static void sleep(int nSecond) BonjK#  
{ =F/R*5:T  
try{ pBBKfv  
Thread.sleep(nSecond); (M{wkQTO  
} |d6/
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catch(Exception e) ;O,&MR{;|n  
{ g}hNsU=$5~  
e.printStackTrace (); +gBDE:  
} u|"YS-dH  
} pK_zq  
rij%l+%@#  
//日志 ~mah.8G  
public static void log(String sMsg) 'aD"v>  
{ <j#IR  
System.err.println(sMsg); CV{ZoY  
} :U'n0\  
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uP8 cW([  
public static void log(int sMsg) k`[>Bk%b  
{ P$AHw;n[R  
System.err.println(sMsg); }waZGJLN  
} <.BY=z=H  
} =*+f2  
Iw#[K  
tId,Q>zH  
/* )ytP$,r![S  
**TestMethod.java }y+a)2  
*/ .S=|ZP+  
package NetFox; !rqs!-cCQ  
M 0G`P1
o  
tN.BI1nB  
public class TestMethod { ,5t_}d|3C=  
@ZV>Cl@%2  
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public TestMethod() Qch'C0u  
{ ///xx/weblogic60b2_win.exe m)6-D-&7  
try{ =
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qf[J-"o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KiC,O7&<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YLSDJ$K6  
fileFetch.start(); /9P7;1?  
} _wW"Tn]  
catch(Exception e){e.printStackTrace ();} $mf6!p4  
ci 22fw0  
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o  
} fG.6S"|M  
+>a(9r|:  
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public static void main(String[] args) L!ms{0rJ  
{ * "
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new TestMethod(); Xo.3OER  
} q_>=| b  
} %t:13eM  
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