http断点续传简单实现（java)

/* a:]yFi:Su  
**SiteFileFetch.java MR6vr.~  
*/ %`\
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package NetFox; Y\x Xo?  
import java.io.*; |ZKchd8Yq  
import java.net.*; |3cR'|<Ual  
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public class SiteFileFetch extends Thread { 6a!X`%N=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d$Xvax,C  
long[] nStartPos; //开始位置 TP^0`L  
long[] nEndPos; //结束位置 n#fg7d%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @'
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long nFileLength; //文件长度 ouI0"R&@  
boolean bFirst = true; //是否第一次取文件 ;Os3 !  
boolean bStop = false; //停止标志 GgYomR:  
File tmpFile; //文件下载的临时信息 C!P6Z10+j  
DataOutputStream output; //输出到文件的输出流 \#}%E h b  
h 2zCX  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !1_:nD  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3N21[i2/m  
{ lb('r"*.  
siteInfoBean = bean; lo#,zd~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *$1)&2i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1&<@(S<  
if(tmpFile.exists ()) G~Sfpf  
{ eTRx6Fri(  
bFirst = false; Nk7eiQ  
read_nPos(); |]!Ky[P  
} pM'IQ3N  
else $aPHl  
{ ctUF/[_w;  
nStartPos = new long[bean.getNSplitter()]; CBnouKc:  
nEndPos = new long[bean.getNSplitter()]; U>_\  
} )\D40,
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} fzFvfMAU  
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public void run() 1S[5#ewB;j  
{ #u<oEDQ  
//获得文件长度 'f?&EsIV?  
//分割文件 n@07$lY@;  
//实例FileSplitterFetch R|)2Dg  
//启动FileSplitterFetch线程 78a
-3){  
//等待子线程返回 `k}l$ih`X  
try{ (&P0la1  
if(bFirst) d7_g u  
{ I~]Q55  
nFileLength = getFileSize(); $uFh$f  
if(nFileLength == -1) .KU
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{ e
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System.err.println("File Length is not known!"); mj(&`HRs4  
} O{B e )E~  
else if(nFileLength == -2) V^`?8P8d  
{ @`kiEg'Q  
System.err.println("File is not access!"); :B*vkwT  
} CEX}`I*-  
else Rgfc29(8  
{ r}y[r}vk  
for(int i=0;i<nStartPos.length;i++) I>kiah*  
{ .W@(nQ-<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uFm+Y]h  
} $p0 /6c  
for(int i=0;i<nEndPos.length-1;i++) X@yr$3vC  
{ _Vo)<--+I  
nEndPos = nStartPos[i+1]; W3jXZ>  
} \=w'HZH#+  
nEndPos[nEndPos.length-1] = nFileLength; dDqr B-G  
} %l
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} h5&
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//启动子线程 t":W.q
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vedyy\TU  
for(int i=0;i<nStartPos.length;i++) jNe(w<',P  
{ M q^|M~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "+n4c'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C@y}*XV[b  
nStartPos,nEndPos,i); XdGpW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c?!YFm  
fileSplitterFetch.start(); }xkLD!  
} *3_f&Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KMK&[E#r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >Lw}KO`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4#^'lKIx  
nEndPos = " + nFileLength); HDF!`  
// fileSplitterFetch[nPos.length-1].start(); 9TVB<}0G  
p~Hvl3SxR  
 JJ/1daj  
//等待子线程结束 y:[BP4H?y  
//int count = 0; )%iRZ\`f  
//是否结束while循环 LbJtpwz>z  
boolean breakWhile = false; c N
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2qZa9^}  
while(!bStop) .q0218l:dF  
{ uQGz;F x  
write_nPos(); K
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Utility.sleep(500); hD nM+4D  
breakWhile = true; kAZC"qM%i  
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for(int i=0;i<nStartPos.length;i++) X}oj_zsy;^  
{ )t|^Nuj
8  
if(!fileSplitterFetch.bDownOver) )
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{ X^zYQ6t  
breakWhile = false; h [nH<m  
break; R<f#r03@|  
} 79)A%@YHQQ  
} Gs[Vu@*  
if(breakWhile) =2^Vgc  
break; [RAj3Fr0  
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2HcsQ*H]G  
//count++; j((hqJr  
//if(count>4) '5'3_
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// siteStop(); x!'7
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} f?,-j>[.=f  
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System.err.println("文件下载结束！"); 7^ 4jcfJH  
} Pj'62
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catch(Exception e){e.printStackTrace ();} }l~]b3@qu  
} )T>8XCL\}  
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//获得文件长度 A2Q[%A  
public long getFileSize() r)VLf#3B  
{ )))2fskZ  
int nFileLength = -1; h~ $&  
try{ f%c06Un=  
URL url = new URL(siteInfoBean.getSSiteURL()); A:/}`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d!o.ASL{  
httpConnection.setRequestProperty("User-Agent","NetFox"); zVdKYs i^  
=(%*LY!Xc  
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int responseCode=httpConnection.getResponseCode(); Zb]/nP1P  
if(responseCode>=400) .>P~uZiX!  
{ QV0M/k<'  
processErrorCode(responseCode); s}wO7Df=+  
return -2; //-2 represent access is error oew|23Ytb  
} 3c b[RQf  
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String sHeader; *|oPxQCtK  
cv= \g Z  
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for(int i=1;;i++) W,Ty=:qm*  
{ `|Ey)@w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )!A 2
>  
//Utility.log(in.readLine()); >5.zk1&H  
sHeader=httpConnection.getHeaderFieldKey(i); [<yz)<<  
if(sHeader!=null) ^p,3)$  
{ AuAT]`  
if(sHeader.equals("Content-Length")) #7o0dE;Kg9  
{ k{a)gFH O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QWw"K$l  
break; .3
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} -,^WaB7u\  
} `y2ljIWJ  
else 9\AS@SH{^T  
break; Atd1qJ  
} KSc~GP_  
} !Av1Leb9$  
catch(IOException e){e.printStackTrace ();} t@)my[!  
catch(Exception e){e.printStackTrace ();} d@ZoV  
=:gjz4}_8  
^>^\CP]  
Utility.log(nFileLength); dQ<(lz
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return nFileLength; >! oF0R_<  
} aM$=|
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//保存下载信息（文件指针位置） K6hfauWd[  
private void write_nPos() zmb
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{ 5mavcle{4r  
try{ E~RV1)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b@6:1x  
output.writeInt(nStartPos.length); vTd-x>n  
for(int i=0;i<nStartPos.length;i++) <Y>3  
{ :G 5C ]'t  
// output.writeLong(nPos); uoCGSXsi  
output.writeLong(fileSplitterFetch.nStartPos); 4.Z(:g  
output.writeLong(fileSplitterFetch.nEndPos); T
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} p+[}Hxx=  
output.close(); !BUi)mo  
} Q>=-ext}q  
catch(IOException e){e.printStackTrace ();} :Fw?{0  
catch(Exception e){e.printStackTrace ();} <tuS,.  
} 9|=nV|R'6  
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//读取保存的下载信息（文件指针位置） 9"ugz^uKt  
private void read_nPos() Q]#Z9H  
{ a5?A!k\2  
try{ ao$):,2*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tOH0IE c  
int nCount = input.readInt(); !M(:U,?B  
nStartPos = new long[nCount]; s}(X]Gx1  
nEndPos = new long[nCount]; TwFb%YM  
for(int i=0;i<nStartPos.length;i++) 2ykCtRe  
{ iBoEZEHjw  
nStartPos = input.readLong();
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nEndPos = input.readLong(); gz61FW  
} m}5q]N";x  
input.close(); sPCMckt  
} nxQ}&n  
catch(IOException e){e.printStackTrace ();} G),db%,X2  
catch(Exception e){e.printStackTrace ();} 8lwM{?k$  
} fxtxu?A>  
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private void processErrorCode(int nErrorCode) |$e:*  
{ RmOyGSO  
System.err.println("Error Code : " + nErrorCode); ?"j@;/=  
} T~J?AKx  
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//停止文件下载 t5)J;0/  
public void siteStop() <xlm K(  
{ c7qwNs*f  
bStop = true; 4#:\?HAu!  
for(int i=0;i<nStartPos.length;i++) vg(K$o{BT  
fileSplitterFetch.splitterStop(); ce'TYkPM  
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} p)/ p!d[T/  
} e<5Y94YE  
//负责部分文件的抓取 U9#WN.noG  
**FileSplitterFetch.java SRCOs1(EK9  
*/ J#7y< s  
package NetFox; 16$y`~c-z  
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import java.io.*; a+?~;.i~  
import java.net.*; xK;e\^v  
j}RzXJ~t  
 U:|H9+5  
public class FileSplitterFetch extends Thread { &1GUi{I  
H06Bj(Y!  
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String sURL; //File URL \+Y!ILOI  
long nStartPos; //File Snippet Start Position Z@J.1SaB  
long nEndPos; //File Snippet End Position m mw-a0  
int nThreadID; //Thread's ID Dg2uE8k  
boolean bDownOver = false; //Downing is over inF6M8 A1  
boolean bStop = false; //Stop identical Nl*i5 io  
FileAccessI fileAccessI = null; //File Access interface >;nS8{2o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G;]:$J  
{ /cY^]VLe  
this.sURL = sURL; {4rQ7J4Ux  
this.nStartPos = nStart; @vs@>CYdz  
this.nEndPos = nEnd; AS;.sjgk  
nThreadID = id; N5 n>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3s(Ia^  
} nq;#_Rkr  
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public void run() -<W2PY<  
{ +LzovC@^  
while(nStartPos < nEndPos && !bStop) i'tp1CI  
{ xl] ;*&  
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try{ :oa9#
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URL url = new URL(sURL); K.DXJ UR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1D{#rA.X  
httpConnection.setRequestProperty("User-Agent","NetFox"); {}\CL#~y  
String sProperty = "bytes="+nStartPos+"-"; 9 5 H?{  
httpConnection.setRequestProperty("RANGE",sProperty); >oqZ !V5[  
Utility.log(sProperty); H(qm>h$bU  
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InputStream input = httpConnection.getInputStream(); B\_[R'Pf&  
//logResponseHead(httpConnection); 6 =gp:I  
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byte[] b = new byte[1024]; nj2g
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int nRead; M|%c(K#E,3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^:DyT@hQB5  
{ rn" pKUd  
nStartPos += fileAccessI.write(b,0,nRead); "#S>I8d  
//if(nThreadID == 1) 1K[(ou'rl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D4Sh9
:\  
} 0IzZKRw  
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Utility.log("Thread " + nThreadID + " is over!"); 7~vqf3ON4J  
bDownOver = true; >saI+u'o  
//nPos = fileAccessI.write (b,0,nRead); 4/MNqit+  
} 8:{q8xZ=k  
catch(Exception e){e.printStackTrace ();} 6tdI6  
} knSuzq%
*  
} 9X]f[^  
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//打印回应的头信息 j>!sN`dBj  
public void logResponseHead(HttpURLConnection con) /DU*M,  
{ yXF|Sqv  
for(int i=1;;i++) ma]? )1<{  
{ (~#G'Hd  
String header=con.getHeaderFieldKey(i); ;BI)n]L  
if(header!=null) k
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); (6k>FSpg  
Utility.log(header+" : "+con.getHeaderField(header)); t!jwY/T  
else F<r4CHfh;  
break; Yu3_=: <C  
} Ae3,^  
} H8i+'5x,?  
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public void splitterStop() NI\H \#bJ  
{ xOIg|2^8  
bStop = true; Wk[)+\WQ?  
} EUZq$@uWL  
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} 7@P656{  
/*P7<5n0  
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/* GP]TnQ<*;  
**FileAccess.java !!+Da>  
*//文件访问(定位，写) %#9P?COs&W  
package NetFox; XU-*[\K  
import java.io.*; <gcmsiB|  
#=x+ [d+  
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public class FileAccessI implements Serializable{ i4VK{G~g"  
.. UoyBV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g)cY\`&W8  
RandomAccessFile oSavedFile; CJA+v-  
long nPos; ;]@exp5  
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public FileAccessI() throws IOException p
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{ 9K$]h2  
this("",0); ,Hh*3rR^  
} v= 8VvT8  
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public FileAccessI(String sName,long nPos) throws IOException 1p=&WM  
{ %,;gP.dh7  
oSavedFile = new RandomAccessFile(sName,"rw"); * gHCy4u{  
this.nPos = nPos; Yj3*)k  
oSavedFile.seek(nPos); dyl 0]Z  
} 9A<0zt  
J{!'f| J  
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public synchronized int write(byte[] b,int nStart,int nLen) qp@m&GH  
{ q_pmwJ:UL  
int n = -1; P'F~\**5  
try{ k-vA#  
oSavedFile.write(b,nStart,nLen); @it/$>R^)  
n = nLen; L,W:,i/C
 
} fOLnK y#  
catch(IOException e) J7Sx
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{ j^{b^!4~}  
e.printStackTrace (); q55M8B 4w  
} LGXZx}4@;  
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return n; df yrn%^Ia  
} :U8k|,~f  
^} tuP  
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} <a fO 6?`  
z:?:  
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/* wZ O@J|  
**SiteInfoBean.java lZBv\JE  
*/ C,(j$Id  
package NetFox; m$)YYpX  
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public class SiteInfoBean { Agz=8=S%  
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private String sSiteURL; //Site's URL N7a[B>+`  
private String sFilePath; //Saved File's Path d0TgqO{  
private String sFileName; //Saved File's Name k 5t{  
private int nSplitter; //Count of Splited Downloading File VYHOk3  
aw]8V:)$J  
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public SiteInfoBean() 3eJ\aVI>pE  
{//nSplitter的缺省值为5 fG3wc l~  
//default value of nSplitter is 5 " xlJs93c  
this("","","",5); raSF3b/0  
} 75<el.'H  
]LMiMj  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 80dSQ"y  
{
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sSiteURL= sURL; `..EQBM  
sFilePath = sPath; wQ@Zwbx  
sFileName = sName; *Gf&
q  
this.nSplitter = nSpiltter; ]!q }|bP  
DZ,<Jmg&e*  
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} HhzkMJR8  
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public String getSSiteURL() .vN)A *  
{ !'+\]eA  
return sSiteURL; X #

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} xAeZ7.Q&  
j)<;g(  
*Rz!i m|  
public void setSSiteURL(String value) u}^a^B$  
{ w{RNv%hJ$=  
sSiteURL = value; ?0? x+  
} *sjj"^'=  
6\%r6_.d  
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public String getSFilePath() 7YoofI  
{ d&O'r[S  
return sFilePath; _3s~!2  
} -bv>iIC  
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'#;,oX~5  
public void setSFilePath(String value) #FrwfJOV  
{ ^vYVl{$bT  
sFilePath = value; =1%zI%  
} Xw&QrTDS`  
:!r9 =N9  
=>gyc;{2K<  
public String getSFileName() t-3v1cv"  
{ 8<wtf]x  
return sFileName; 2tm~QL  
} eD>-`'7<  
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@9n #vs  
public void setSFileName(String value) Zkwy.Hq^  
{ jx^|2  
sFileName = value; }CB=c]p  
} =NVZ$KOZ  
?^+#pcX]t|  
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public int getNSplitter() qat45O4A1  
{ _ Yb Eo+  
return nSplitter; clPZd  
} YyQf  
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d/ 'A\"o+  
public void setNSplitter(int nCount) ~frPV8^DP  
{ Im0+`9Jw  
nSplitter = nCount; Zzt
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} ];d5X  
} a"v"n$  
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/* >#"jfjDuR
 
**Utility.java u8{@PlS  
*/ W<cW;mO  
package NetFox; ^C,/T2>  
7gZVg@  
dw{#||  
public class Utility { ,q'gG`M N  
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public Utility() 5'{qEZs^QU  
{ ~vjr;a(B  
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} A .jp<>  
?@g;[310`  
//线程睡眠 }v'PY/d.  
public static void sleep(int nSecond) R&x7Iq:=D  
{ , $D&WH  
try{ j]ln :?\  
Thread.sleep(nSecond); yp^[]Mz=  
} 2EqsfU* I  
catch(Exception e) <L!~f`nH2  
{ >zfZw"mEP  
e.printStackTrace (); >2/wzs
W  
} I 1VEm?CQ  
} CwEWW\Bu  
\/x)BE,  
//日志 ~Hyyq-  
public static void log(String sMsg) -UD~>s  
{ JQbMw>Y  
System.err.println(sMsg); _A~~L6C  
} ;+TF3av0zq  
die2<'\4%  
^*?B)D=,  
public static void log(int sMsg) . ;ea]_Z  
{ #by9D&QP]  
System.err.println(sMsg); Q 2SSJ  
} Z,8+@  
} Ae{4AZ  
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%9-#`  
/* q$u\ q.  
**TestMethod.java C$..w80/1  
*/ ,T21z}r  
package NetFox; ~a8G 5M  
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XB!`*vZ/<  
public class TestMethod { He71h(BHm  
9snyX7/!L  
tx1m36a"  
public TestMethod() NV:XPw/  
{ ///xx/weblogic60b2_win.exe z:Zn.e*$b  
try{ -JQg ~1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cmGj0YUQ1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M_.,c Vk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xMfv&q=k@  
fileFetch.start(); k4AE`[UE  
} t ]I(98pY  
catch(Exception e){e.printStackTrace ();} @01D1A  
W.6JnYLQ&  
+_XbHjhN/  
} &F*QYz[  
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t>h i$NX{p  
public static void main(String[] args) DEwtP  
{ UG?C=Tf  
new TestMethod(); .lF\bA|  
} J)yy}[Fx  
} F?,&y)ri  
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