http断点续传简单实现（java)

/* ^4v*W;Q  
**SiteFileFetch.java Q}A=jew  
*/ qu6DQ@ ~YC  
package NetFox; $trAC@3O@  
import java.io.*; r!N]$lB  
import java.net.*; w-N1.^  
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public class SiteFileFetch extends Thread { \'?#i@O  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]"fsW 9s  
long[] nStartPos; //开始位置 &B{8uge1
 
long[] nEndPos; //结束位置 |-2}j2'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IF k  
long nFileLength; //文件长度 &217l2X /  
boolean bFirst = true; //是否第一次取文件 u3tZ[Y2 c  
boolean bStop = false; //停止标志 (9fdljl],:  
File tmpFile; //文件下载的临时信息 a?cn9i)#  
DataOutputStream output; //输出到文件的输出流 5iFV;W  
@=]8^?$t 0  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MN;/*t  
public SiteFileFetch(SiteInfoBean bean) throws IOException cJ}QXuuUv  
{ oholt/gb+0  
siteInfoBean = bean; CidM(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eo#^L}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #$'"cfRxc  
if(tmpFile.exists ()) j;P+_Hfe/E  
{
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bFirst = false; ^gro=Bp(  
read_nPos(); h=RDO  
} YwT-T,oD  
else 5a8>g [2U  
{ \Xg?Ug*9w  
nStartPos = new long[bean.getNSplitter()]; )+Or  
nEndPos = new long[bean.getNSplitter()]; Il~01|3+m  
} ('o&Q_  
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} :9d\Uj,  
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public void run() \ a-CN>  
{ Fq,N  
//获得文件长度 ddpl Pzm#  
//分割文件 FbSa~uN  
//实例FileSplitterFetch *crw^e  
//启动FileSplitterFetch线程 ')PVGV(D+  
//等待子线程返回
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try{ ij)Cm]4(2  
if(bFirst) 7t(Y;4<2  
{ : 1)}Epo,  
nFileLength = getFileSize(); ' lo.h""  
if(nFileLength == -1) wgd<3 X  
{ B1T5f1;uY  
System.err.println("File Length is not known!"); =d20Xa  
} pz}mF D&[  
else if(nFileLength == -2) #+sF`qR,  
{ 0'ZYO
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System.err.println("File is not access!"); mc@M,2@D  
} {K.rl%_|N  
else iK}v`xq  
{ H*U`  
for(int i=0;i<nStartPos.length;i++) z&'f/w8  
{ f~gS
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); L~0& Q  
} 71iRG*O  
for(int i=0;i<nEndPos.length-1;i++) -
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{ LF=c^9t  
nEndPos = nStartPos[i+1]; wL eHQ]  
} !]DuZ=  
nEndPos[nEndPos.length-1] = nFileLength; Yw"P)Zp  
} el@XK}<dr  
} (wL3 +  
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//启动子线程 !UNNjBBP7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^87
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for(int i=0;i<nStartPos.length;i++) ?V+wjw  
{ P>htQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V/H@vKN2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), STT2o=  
nStartPos,nEndPos,i); T Oy7?;|=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8W{~wg`  
fileSplitterFetch.start(); G' Hh{_:  
} u6_jn
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fPE?hG<x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^CQ1I0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O)5#Fcp(  
nEndPos = " + nFileLength); ]gP8?s|  
// fileSplitterFetch[nPos.length-1].start(); UH40~LxIma  
c^-YcGwa  
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//等待子线程结束 syFI$rf _  
//int count = 0; )fCMITq.|  
//是否结束while循环 f'_S1\  
boolean breakWhile = false; \!PV*%P  
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while(!bStop) A+2oh3  
{ TzY!D*%z  
write_nPos(); ,kE=TR.|  
Utility.sleep(500); Tf l;7w.(A  
breakWhile = true; 7|~:P$M  
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for(int i=0;i<nStartPos.length;i++) !fZ
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{ {y/-:=S)A  
if(!fileSplitterFetch.bDownOver) \\iK'|5YG  
{ $h]NXC6J  
breakWhile = false; RUc\u93n  
break; RIo'X@zb  
} 00qZw?%K  
} QZ0R:TY  
if(breakWhile) w{P6i<J  
break; 62NkU)u  
;&`:|Hf*  
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//count++; IDmsz  
//if(count>4) ^je528%H  
// siteStop(); KL~AzL
I  
} `t9.xB#Z  
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System.err.println("文件下载结束！"); q(1r<2  
} _=T]PSauI  
catch(Exception e){e.printStackTrace ();} + o
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} f-]><z  
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//获得文件长度 TPqvp|~2  
public long getFileSize() aZxO/b^j  
{ r$?Vx_f`Q  
int nFileLength = -1; i"fCpkAP  
try{ ;r=?BbND?  
URL url = new URL(siteInfoBean.getSSiteURL()); f~v"zT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b\M b*o  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3 9yz~  
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int responseCode=httpConnection.getResponseCode(); EFv4=OWB  
if(responseCode>=400) :'ihE\j  
{ um{e&5jk  
processErrorCode(responseCode); Xiw@  
return -2; //-2 represent access is error 64b<0;~  
} ze$Y=<S  
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String sHeader; iGQ n/Xdo  
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for(int i=1;;i++) @oA0{&G{  
{ ,aYU$~o#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0ZT 0
 
//Utility.log(in.readLine());
`M6YblnJZ  
sHeader=httpConnection.getHeaderFieldKey(i); Ba<#1p7_  
if(sHeader!=null) YkVRl [  
{ @7]\y7D  
if(sHeader.equals("Content-Length")) vQcUaPm\$  
{ :Ip
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b+_hI)T  
break; e %&  
} :=Nb=&lst  
} uh1S 7!^  
else a6P!Wzb  
break; K
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} }*Dd/'2+1  
} c0SX]4} G  
catch(IOException e){e.printStackTrace ();} n'Bmz  
catch(Exception e){e.printStackTrace ();} +L n M\n  
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Utility.log(nFileLength); u5/t2}^T  
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return nFileLength; q1P :^<[  
} 2S'AIuIew
 
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//保存下载信息（文件指针位置） ?${V{=)*X'  
private void write_nPos() 3L*+8a  
{ \
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try{ 1x8(I&i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U>bP}[&S  
output.writeInt(nStartPos.length); g&q^.7c}  
for(int i=0;i<nStartPos.length;i++) 8b{U tT  
{ f8R+7Ykx  
// output.writeLong(nPos);  sN;(/O  
output.writeLong(fileSplitterFetch.nStartPos); 9A(n_Rs7?  
output.writeLong(fileSplitterFetch.nEndPos); G]at{(^Vz  
} EgFl="0  
output.close(); l<s :%%CX  
} d8D yv#gT  
catch(IOException e){e.printStackTrace ();} /(y4
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catch(Exception e){e.printStackTrace ();} _d/GdeLs  
} rtcJ=`)0`  
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//读取保存的下载信息（文件指针位置） %C6|-?TAd  
private void read_nPos() \f6lT3"VN  
{ ,zc"udpKF  
try{ t`) 'LT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PnI)n=(\  
int nCount = input.readInt(); 1V#0\1sj  
nStartPos = new long[nCount]; 8rla0d@  
nEndPos = new long[nCount]; FYxUOO  
for(int i=0;i<nStartPos.length;i++) t;
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{ t>XZ3  
nStartPos = input.readLong(); :O5Tr03z  
nEndPos = input.readLong(); G[ ,,L  
} ?Ozk^#H[  
input.close(); i:MlD5 F  
} lkI8{  
catch(IOException e){e.printStackTrace ();} [^h/(a`  
catch(Exception e){e.printStackTrace ();} oZ?IR#^
 
} qxRT1B]{Wx  
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private void processErrorCode(int nErrorCode) I|GV :D  
{ J11dqj  
System.err.println("Error Code : " + nErrorCode); Pw0{.W~r  
} `'dX/d  
Bk\*0B  
"(9=h@@Y"  
//停止文件下载 W
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public void siteStop() FRb&@(;  
{ mMel,iK=  
bStop = true; $_4oN(WSz  
for(int i=0;i<nStartPos.length;i++) jI@bTS o  
fileSplitterFetch.splitterStop(); U/}AiCdj@  
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} MBnK&GS  
} Lr!L}
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//负责部分文件的抓取 u40b? n.  
**FileSplitterFetch.java oVKsic?  
*/ ]9bh+  
package NetFox; -U/I'RDLEz  
$}^Rsv(  
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import java.io.*; okd ``vG  
import java.net.*; \c5#\1<  
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public class FileSplitterFetch extends Thread { jM|YW*zNZ  
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String sURL; //File URL `?Y_0Nh>  
long nStartPos; //File Snippet Start Position d;@E~~o?B]  
long nEndPos; //File Snippet End Position ^sr:N5~z`  
int nThreadID; //Thread's ID C*Y :w  
boolean bDownOver = false; //Downing is over _47j9m]f  
boolean bStop = false; //Stop identical r"HbrQn  
FileAccessI fileAccessI = null; //File Access interface X^?|Sz<^E  
7]<F>97  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p*(U*8Q  
{ M ,.0[+  
this.sURL = sURL; )'/nS$\E:  
this.nStartPos = nStart; j\jL[hG_  
this.nEndPos = nEnd; x mrugNRg  
nThreadID = id; vTe$77n
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >*<6 zQf  
} +73=2.C0  
=:
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public void run() e0G}$ as  
{ lEVQA*u[  
while(nStartPos < nEndPos && !bStop) 2l\D~ y  
{ 7g4M/?H}K  
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try{ [~Z'xY y  
URL url = new URL(sURL); Lk8W&|;0|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v"G%5pq*\  
httpConnection.setRequestProperty("User-Agent","NetFox"); ? bUpK  
String sProperty = "bytes="+nStartPos+"-"; ]%WD} 4e  
httpConnection.setRequestProperty("RANGE",sProperty); ]ft~OqLg!  
Utility.log(sProperty); E'Fv *UA  
N4Fy8qU;  
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InputStream input = httpConnection.getInputStream(); FBwncG$]F*  
//logResponseHead(httpConnection); ;?O883@r8  
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byte[] b = new byte[1024]; tNi%}~Z  
int nRead; tehI!->l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {YO%JTQ  
{ } Khq  
nStartPos += fileAccessI.write(b,0,nRead); U||w6:W5  
//if(nThreadID == 1) h.}t${1ZC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6Mf3)o2  
} J6^Ct  
,:dEEL+>c  
9 z8<[>  
Utility.log("Thread " + nThreadID + " is over!"); *]E7}bqb  
bDownOver = true; iz%A0Z+`bg  
//nPos = fileAccessI.write (b,0,nRead); wn A%Nh7  
} 3Q!J9t5dc  
catch(Exception e){e.printStackTrace ();} w$U/;C  
} t}c}@i_c  
} $<>EwW  
bVAgul=__  
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//打印回应的头信息 bCaPJ!ZO  
public void logResponseHead(HttpURLConnection con) 4HJZ^bq9|  
{ +D
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for(int i=1;;i++) "o5gQTwb  
{ 33,JUQ2u  
String header=con.getHeaderFieldKey(i); 9,EaN{GM  
if(header!=null)
0Z);.l^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ==jw3_W  
Utility.log(header+" : "+con.getHeaderField(header)); &8_#hne_  
else ;MRC~F=  
break; ;~gd<KK  
} cf[u%{ 6Y  
} $ DZQdhv  
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public void splitterStop() sG1]A:_<C  
{ j~L1~@  
bStop = true; %[\Ft  
} !qw=I(  
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@y\{<X.F\1  
} vo( j@+dz  
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/* u0oYb_Yv  
**FileAccess.java ~ Dp:j*H  
*//文件访问(定位，写) #G , *j  
package NetFox; Pdm6u73  
import java.io.*; L..X)-D2n  
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public class FileAccessI implements Serializable{ q[|`&6B  
3Llj_lf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W6xjqNU  
RandomAccessFile oSavedFile; #L IsL  
long nPos; k'I_,Z<,  
/E4}d=5L  
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public FileAccessI() throws IOException C}P \kDM  
{ ?'/5%f`  
this("",0); ox=7N{+`J  
} F)5B[.ce  
!|:q@|- %@  
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public FileAccessI(String sName,long nPos) throws IOException QH' [(  
{ BQ}.+T\  
oSavedFile = new RandomAccessFile(sName,"rw"); >wS:3$Q  
this.nPos = nPos; E#2k|TpH4  
oSavedFile.seek(nPos); `w=H'"Zv  
} dK;\`>8  
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public synchronized int write(byte[] b,int nStart,int nLen) B%g:
Z  
{ Nb!6YY=Ez-  
int n = -1; ;7n*PBUJJ  
try{ $t H.np  
oSavedFile.write(b,nStart,nLen); BfE-s<  
n = nLen; -J7,Nw  
} c'#J{3d  
catch(IOException e) "`3^MvC  
{ pOI`,i}.  
e.printStackTrace (); 6p=xgk-q  
} (DMnwqr  
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return n; ^}7t:  
} IS 9q 5/]  
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} s
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/* ftH%, /,  
**SiteInfoBean.java {5IG3'  
*/ 1HWJxV"  
package NetFox; ZpctsCz]  
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public class SiteInfoBean { 71&+
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3 DHA^9<q  
private String sSiteURL; //Site's URL `h3}"js  
private String sFilePath; //Saved File's Path XK-x*|  
private String sFileName; //Saved File's Name "}+/0$F  
private int nSplitter; //Count of Splited Downloading File .);:K  
\` ^Tbn:  
xLK0~|_#!  
public SiteInfoBean() 
eniR}  
{//nSplitter的缺省值为5 l'%R^  
//default value of nSplitter is 5 jyH_/X5i7  
this("","","",5); %ys}Q!gR  
} aB!Am +g  
`#8R+c=$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hbc&.W;g7[  
{ r+pjv_R  
sSiteURL= sURL; J\D3fh97-  
sFilePath = sPath; VDY1F_Fk  
sFileName = sName; O9)}:++T  
this.nSplitter = nSpiltter; " z'!il#  
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} {~I_rlo n  
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public String getSSiteURL() :?k=Yr  
{ ta.,4R&K  
return sSiteURL; n`Iy7X  
} ScoHtX3  
s2=X>,kz?  
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public void setSSiteURL(String value) V<pjR@  
{ 5305N!  
sSiteURL = value; j!7Uj]  
} Pv.@Y30  
p,Hk"DSs%  
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public String getSFilePath() TN`:T.B  
{ 7'uc;5:  
return sFilePath; lXKZNCL  
} K.m[S[cy  
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public void setSFilePath(String value)
nB0ol-<  
{ rtE,
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sFilePath = value; Dx'e+Bm  
} y8z%s/gRh  
]#n4A|&H  
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public String getSFileName() P$I\)Q H  
{ +(%[fW  
return sFileName; <=M
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} ;xwQzu%M>5  
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public void setSFileName(String value) Shz;)0To  
{ `0:@`)&g1  
sFileName = value; yk{alSF  
} KL4/"$l]  
sf0U(XYQ^  
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public int getNSplitter() uLF55:`<  
{ D9en  
return nSplitter; h[T3WE  
} e AjtWqg  
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9MxGyGz$  
public void setNSplitter(int nCount) hgGcUpJy?  
{ |=s3a5sl  
nSplitter = nCount; KK</5Aw9p  
} MzD0F#Y  
} $ 1U%E  
@4$E.q<0  
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/* v<1;1m  
**Utility.java QUf_fe!,|  
*/ qv\yQ&pj  
package NetFox; t ,$)PV
 
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public class Utility { Kl?1)u3^4  
Q*:
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public Utility() =%LS9e^7D  
{ t At+5H  
D#0}/  
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} x%1Rp[  
RS~oSoAE  
//线程睡眠 I/g]9 y  
public static void sleep(int nSecond) U*cj'`eqC  
{ lV
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try{ UWI5/R  
Thread.sleep(nSecond); x>cu<,e$d\  
} \XC1/LZQ  
catch(Exception e) 6%TV X  
{ X`&E,;bIb  
e.printStackTrace (); 3?:}lY<,  
} eIJQ|p<v  
} rgr> ;   
2sngi@\  
//日志 y03l_E,  
public static void log(String sMsg)  l}JVRU{  
{ n):VuOjm  
System.err.println(sMsg); 9 wc=B(a|  
} U
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ec|IT0;  
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public static void log(int sMsg)
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{ ]^!#0(  
System.err.println(sMsg); ZP1EO Z  
} rie1F,  
} <iMLM<J<w  
|$Td-M^)  
:H~r _>E  
/* :M Md@  
**TestMethod.java uaiG(O   
*/ OA+W$
  
package NetFox; 3'8~H]<W  
%BL+'&q  
qFay]V(O|  
public class TestMethod { Xr@0RFdr[  
T6tJwSS4:  
Q?~l=}2  
public TestMethod() #N*~Q  
{ ///xx/weblogic60b2_win.exe m
V-MJ$3r  
try{ 6uDNqq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Xs4`bbap  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5z0S
jQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wEdXaOEB5  
fileFetch.start(); Q.x3_+CX  
} ZW2U9  
catch(Exception e){e.printStackTrace ();} !aLL|}S  
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} #U^@)g6  
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public static void main(String[] args) 7uYJ_R  
{ 3iDRt&y=.  
new TestMethod(); WO|#`HM2  
} }_K7}] 1  
} JD.WH|sZ5  
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