http断点续传简单实现（java)

/* A+@&"  
**SiteFileFetch.java UR:aD_h  
*/ 4|A>b})H  
package NetFox; v}WR+)uFQ  
import java.io.*; }68i[v9Njk  
import java.net.*; Nn>'^KZNG  
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public class SiteFileFetch extends Thread { 0"~i^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean O25lLNmO  
long[] nStartPos; //开始位置 R^{)D3  
long[] nEndPos; //结束位置 =4d (b ;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HF|oBX$_  
long nFileLength; //文件长度 w+1Gs ;  
boolean bFirst = true; //是否第一次取文件 Y8flrM2CwG  
boolean bStop = false; //停止标志 J>d.dq>r  
File tmpFile; //文件下载的临时信息 5zON}"EC  
DataOutputStream output; //输出到文件的输出流 8p[)MiC5W^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1CLL%\V  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5n
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{ )O:0]=#))  
siteInfoBean = bean; 26CS6(sn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6(PM'@i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @{Gncy|  
if(tmpFile.exists ()) E7-@&=]v  
{ Ov<NsNX]  
bFirst = false; A!^q J#  
read_nPos(); &^4++  
} z3?o|A}/W  
else w3jO6*_ M  
{ vq34/c^  
nStartPos = new long[bean.getNSplitter()]; r(gXoq_w  
nEndPos = new long[bean.getNSplitter()]; !?Wp+e6  
} }@.|?2b +  
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} 7gRgOzWfV  
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public void run() YuB+k^  
{ Ar~"R4!  
//获得文件长度 HaIM#R32T  
//分割文件 qWw\_S  
//实例FileSplitterFetch $AHQmyg<  
//启动FileSplitterFetch线程 EqI(|bFwy  
//等待子线程返回 k{t`|BnPKB  
try{ I}R0q  
if(bFirst) P;4w*((} ~  
{ 37}D9:#5C  
nFileLength = getFileSize(); w3$   
if(nFileLength == -1) #c2ymQm  
{ utr:J  
System.err.println("File Length is not known!"); Y))NK'B5  
} J=/5}u_gw  
else if(nFileLength == -2) *2jK#9"MP  
{ r&FDEBh  
System.err.println("File is not access!"); 6-O_\Cq8  
} bJs9X/E  
else @B}aN@!/  
{ _YRE (YZ/  
for(int i=0;i<nStartPos.length;i++) 43=,yz2Ef  
{ ,a#EW+" Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5atYOep  
} 8_N]e'WUh  
for(int i=0;i<nEndPos.length-1;i++) ;| 1$Q!4  
{ $8BPlqBIZ  
nEndPos = nStartPos[i+1]; i~r l o^  
} z;y:9l  
nEndPos[nEndPos.length-1] = nFileLength; 3do)Vg4  
} |fo0  
} 5eWwgA  
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//启动子线程 p)+k=b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n0is\ZK 0  
for(int i=0;i<nStartPos.length;i++) m)oJFF  
{ ^Ox3XC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zl`h~}I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wl}&?v&@  
nStartPos,nEndPos,i); 7F'`CleU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j)q\9#sI/(  
fileSplitterFetch.start(); &4_qF^9J  
} i&n'N8D@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CD8}I85K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mx=BD'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vhhC> 7  
nEndPos = " + nFileLength); U,LTVYrO  
// fileSplitterFetch[nPos.length-1].start(); !kC*g  
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"!EcbR  
//等待子线程结束 Fgh]KQ/5  
//int count = 0; QPq7R  
//是否结束while循环 b6*!ACY  
boolean breakWhile = false; ]~Z6;  
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while(!bStop) %'T #
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{ =)7s$ p  
write_nPos(); 2@ Z(P.Gh  
Utility.sleep(500); "]G\9b)  
breakWhile = true; AQ='|%  
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for(int i=0;i<nStartPos.length;i++) >+[&3u  
{ 2;?I>~  
if(!fileSplitterFetch.bDownOver) L{c q, jk  
{ FLY Ca  
breakWhile = false; ,`aq+K  
break; FKmFo^^0  
}
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} LlSZr)X  
if(breakWhile) `[n("7,  
break; %$DI^yS  
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//count++; &@3H%DP}Ql  
//if(count>4) 5+wAzVA  
// siteStop(); |ely|U. Tf  
} vEn4L0D  
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System.err.println("文件下载结束！"); jkvg
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} tzh1s i  
catch(Exception e){e.printStackTrace ();} 2rZxSg  
} ,tg0L$qC  
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//获得文件长度
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public long getFileSize() o-Ga3i 8  
{ ZR'H\Z  
int nFileLength = -1; i _%Q`i  
try{ h3;bxq!q  
URL url = new URL(siteInfoBean.getSSiteURL()); RG4sQ0
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O &-wxJ]S  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]H1I,`=@  
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int responseCode=httpConnection.getResponseCode(); %?Ev|:i`@  
if(responseCode>=400) qQH]`#P  
{ ,#kIr  
processErrorCode(responseCode); pt}X>ph{  
return -2; //-2 represent access is error wLH] <k  
} nxl[d\ap+n  
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String sHeader; d09k5$=gJ  
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for(int i=1;;i++) f-71~  
{ x UD-iSY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0/oyf]HR  
//Utility.log(in.readLine()); 9,"L^W8"k  
sHeader=httpConnection.getHeaderFieldKey(i); Y(cGk#0  
if(sHeader!=null) ,YMp<C  
{ NSDv;|f  
if(sHeader.equals("Content-Length")) _zwUE  
{ 'uxX5k/D@t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ) v,:N.@Q  
break; Ck|8qUz-  
} Ht4;5?/y  
} 5kz)5,KjM  
else ,c)uX#1  
break; 4%3Mb-#Y]  
} >cCR2j,r  
} go<W(
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catch(IOException e){e.printStackTrace ();} =>! Y{: y(  
catch(Exception e){e.printStackTrace ();} '^
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Utility.log(nFileLength); BV[5}  
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return nFileLength; ;{%\9nS  
} {
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//保存下载信息（文件指针位置） ut I"\1hQ  
private void write_nPos() Aj4T"^fv  
{ UTH_^HAN#G  
try{ Sh8"F@P8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d|yAs5@  
output.writeInt(nStartPos.length); }-6)gWe  
for(int i=0;i<nStartPos.length;i++) vt9)pMs  
{ e;[F\ov%  
// output.writeLong(nPos); L-k@-)98  
output.writeLong(fileSplitterFetch.nStartPos); ynhmMy%  
output.writeLong(fileSplitterFetch.nEndPos); V:c;-)(  
} "PpN0Rr  
output.close(); c. 2).Jt,  
} &@yo;kB  
catch(IOException e){e.printStackTrace ();} W!>.$4Q9  
catch(Exception e){e.printStackTrace ();} k|H:  
} 9c6gkt9eB  
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//读取保存的下载信息（文件指针位置） &E=>Hj(dTG  
private void read_nPos() UaB @  
{ 8{X"h#  
try{ 3^6 d]f  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9B7^lR  
int nCount = input.readInt(); SV~~Q_U9  
nStartPos = new long[nCount]; PJL=$gBgKk  
nEndPos = new long[nCount]; S :<Nc{C  
for(int i=0;i<nStartPos.length;i++) Gnq?"</  
{ }=]M2}  
nStartPos = input.readLong(); 3S}Pm2D2  
nEndPos = input.readLong(); ftF@Wq1f  
} / :n#`o=;  
input.close(); ^*Yh@4\{JH  
} ^kB8F"X  
catch(IOException e){e.printStackTrace ();} Evjj"h&0J  
catch(Exception e){e.printStackTrace ();} 7G>dTO  
} Q{5kxw1ZF  
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private void processErrorCode(int nErrorCode) n$ou- Q  
{ 4s*ZS}] o  
System.err.println("Error Code : " + nErrorCode); u;/ Vyu  
} x}"uZ$g  
N<-gI9_  
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//停止文件下载 5X:*/FuS@  
public void siteStop() xM&Wgei]10  
{ 8;+B*+%@n  
bStop = true; 'GS"8w~j  
for(int i=0;i<nStartPos.length;i++) @dPTk"P  
fileSplitterFetch.splitterStop(); |* ;B  
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} 6U R2IxbE  
} [c|]f_ZdK  
//负责部分文件的抓取 &bfA.& `  
**FileSplitterFetch.java Pf\D-1gi  
*/ m4l& eEp  
package NetFox; 5?F__Hx*2  
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import java.io.*; ([m mPyp>L  
import java.net.*; Lja>8m  
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public class FileSplitterFetch extends Thread { 2bkX}FWd;  
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String sURL; //File URL ^Uf]Q$uCjE  
long nStartPos; //File Snippet Start Position G'ei/Me6{  
long nEndPos; //File Snippet End Position .@@?Pj?)  
int nThreadID; //Thread's ID K)DDk9*  
boolean bDownOver = false; //Downing is over j;-1J_e5  
boolean bStop = false; //Stop identical ^5h]Y;tx  
FileAccessI fileAccessI = null; //File Access interface ;E3>ay6m8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [nrYpb4  
{ dE4L=sTEsy  
this.sURL = sURL; sE Q=dcK  
this.nStartPos = nStart; yEhTNBa*h{  
this.nEndPos = nEnd; bj>v|#r^  
nThreadID = id; rzm:Yx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fj;y}t1E]  
} n O\"HLM  
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public void run() P'Ux%Q+B>  
{ /7|V+6jV  
while(nStartPos < nEndPos && !bStop) yl7&5)b#9  
{ <~n"m  
@oV9)  
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try{ Wp!%-vzy&  
URL url = new URL(sURL); XH}\15X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NnDxq%l%  
httpConnection.setRequestProperty("User-Agent","NetFox"); 10q'Z}34  
String sProperty = "bytes="+nStartPos+"-"; $ us]35Z3  
httpConnection.setRequestProperty("RANGE",sProperty); QD:{U8YbF$  
Utility.log(sProperty); LXC9I/j/  
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InputStream input = httpConnection.getInputStream(); GS a[ oh  
//logResponseHead(httpConnection); )GM41t1i  
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byte[] b = new byte[1024]; r0+6evU2  
int nRead; SEGri#s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @,cowar*  
{ ,D]QxbwZ  
nStartPos += fileAccessI.write(b,0,nRead); DVB{2~7 4  
//if(nThreadID == 1) -ZRO@&tMD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N343qU  
} Q;43[1&3w  
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Utility.log("Thread " + nThreadID + " is over!"); x7jC)M<k0  
bDownOver = true; Rn9m]x  
//nPos = fileAccessI.write (b,0,nRead); (`c [#0=n  
} -bT)]gA2  
catch(Exception e){e.printStackTrace ();} 'E/^8md>  
} D(AXk8Vub  
} C/vIEYG4  
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//打印回应的头信息 'rO!AcdLU  
public void logResponseHead(HttpURLConnection con)
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{ 17oa69G  
for(int i=1;;i++) Q@<S[Qh[.  
{ S+atn]eU@  
String header=con.getHeaderFieldKey(i); VC\S'z  
if(header!=null) \n8]M\<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T|7}EAR=b  
Utility.log(header+" : "+con.getHeaderField(header)); .<x&IJ 
/  
else gv)P]{%^  
break; lOuHVa*}  
} \{Z;:,S  
} pb ~uE  
]* F\"C@  
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public void splitterStop() 5q;GIw^L  
{ UEM(@zD]  
bStop = true; GqaDL3Niqs  
} 7=TF.TW)  
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} zr+zhpp  
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/* ;#xmQi'`  
**FileAccess.java 4'`{H@]tb  
*//文件访问(定位，写) 6K-_pg]  
package NetFox; '=nQ$/!q  
import java.io.*; % NA9{<I  
fPn>v)lN{  
/ ';0H_  
public class FileAccessI implements Serializable{ juka0/  
pQ=>.JU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y;@>b{s  
RandomAccessFile oSavedFile; 1zm ulj%&  
long nPos; Z~oo;xE  
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public FileAccessI() throws IOException B$ajK`x&I  
{ .aAL]-Rj  
this("",0); u frW\X  
} i'H/ZwU  
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public FileAccessI(String sName,long nPos) throws IOException Hv so
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{ &]e'KdXF  
oSavedFile = new RandomAccessFile(sName,"rw"); b J=Jg~&  
this.nPos = nPos; TUV&vz{  
oSavedFile.seek(nPos); ,SynnE68  
} iYORu3  
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public synchronized int write(byte[] b,int nStart,int nLen) Bg5Wba%NK  
{ PP;}e  
int n = -1; +BVym~*^  
try{ zVXC1u9B  
oSavedFile.write(b,nStart,nLen); Ir`eL  
n = nLen; /<@SFF.  
} *c~T@m~DR  
catch(IOException e) !46RGU:I  
{ k9  "[H'  
e.printStackTrace (); uD1e!oU  
} D7lK30  
4]G?G]lS>  
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return n; '(f&P=[b  
} <3xyjX'NE  
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} uw[<5  
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/* LR.H
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**SiteInfoBean.java 6+.uU[x@  
*/ N^HUijw<  
package NetFox; 2^mJ+v<  
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public class SiteInfoBean { g!$!F>[  
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private String sSiteURL; //Site's URL Ge-CY  
private String sFilePath; //Saved File's Path tk!t Y8j  
private String sFileName; //Saved File's Name TD'L'm|2  
private int nSplitter; //Count of Splited Downloading File aGJC1x  
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public SiteInfoBean() :`-,Lbg  
{//nSplitter的缺省值为5 OTGofd2zf  
//default value of nSplitter is 5 <KE 1f7c  
this("","","",5); )~+E[|  
} +=q$x Ia
 
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: >6F+XZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MHh~vy'HB5  
{ Wc,~{  
sSiteURL= sURL; 0~ZFv Wv  
sFilePath = sPath; X9p.gXF  
sFileName = sName; 9z}uc@#D=m  
this.nSplitter = nSpiltter; M)eO6oX|  
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} JRSSn]pw  
19O,a#{KHf  
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public String getSSiteURL() =+U `-J}g  
{ ue4Vcf  
return sSiteURL; 0J?~N`#O|  
} -R57@D>j\  
 Fy`(BF\  
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public void setSSiteURL(String value) ~i~7na|  
{ E=e*VEjy  
sSiteURL = value; l^|UCgRn  
} ]8Q4BW  
k 8UO9r[  
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public String getSFilePath() 6
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{ E"+Q
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return sFilePath; Svondc 4  
} LXbP 2  
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public void setSFilePath(String value) 7on.4/;M  
{ ?Cl%{2omO  
sFilePath = value; |K.mP4CKY  
} Qa.<K{m#?  
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public String getSFileName() f!s=(H;  
{ Zb1<:[  
return sFileName; 2^^`n1?'  
} X:6c}p%,!  
&?q/1vLa  
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public void setSFileName(String value) _59huC.  
{ g=QDu7Ux  
sFileName = value; LL2=&VK  
} 8g&? Cc  
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public int getNSplitter() S-k8jm  
{ '7+4`E  
return nSplitter; cIav&Zko  
} $u9K+>.  
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rcMwFE?|xq  
public void setNSplitter(int nCount) +n#V[~~8AI  
{ %kdEun  
nSplitter = nCount; $Hj.{;eC/k  
} }HY-uQ%@g  
} w+yC)Rmz  
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/* R~)\3] "2m  
**Utility.java @7?#Y|`  
*/ DpUbzr41+k  
package NetFox; #7MUJY+ 9  
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public class Utility { `-3Ow[  
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public Utility() cUA7#1\T=  
{ 89o/F+_b  
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} kP-3"ACG  
7PtN?;rP  
//线程睡眠 ^R# E:3e  
public static void sleep(int nSecond) I~ok4L?VB  
{ !t gi  
try{ >U%gctIg  
Thread.sleep(nSecond); 9D7+[`r(-  
} i'#E)  
catch(Exception e) hJZV}a|  
{ y *fDwd~  
e.printStackTrace (); f}x.jxY?  
} H^s<{E0<  
} n p\TlUc  
wM2*#  
//日志 K%^V?NP*{Z  
public static void log(String sMsg) fpFhn  
{ R)mu2^  
System.err.println(sMsg); hRK/T7v  
} 1+}{8D_F  
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public static void log(int sMsg) vTJ}8  
{ ~])t 6i  
System.err.println(sMsg); @Ub"5Fl4  
} 80Gn%1A9  
} g7OqX \  
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px}|Mu7z~  
/* >_|O1H./4  
**TestMethod.java ][?G/*k  
*/ Ry%Mej:  
package NetFox; .6`9H 1  
@wE5S6! B\  
(X?%^^e!  
public class TestMethod { 4cl\^yD  
z7Q?D^miy  
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public TestMethod() kPF9Z "l  
{ ///xx/weblogic60b2_win.exe (Q.waI  
try{ LIZRoG8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ha(Z<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .y@oz7T5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wPwXM!  
fileFetch.start(); *=+td)S/1  
} *#tJM.Z  
catch(Exception e){e.printStackTrace ();} <8d^^0  
<N_+=_  
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} RPE5K:P  
il:$sd  
%l,,_:7{  
public static void main(String[] args)  B[Zjfc  
{ V3c l~  
new TestMethod(); Ahk8  
} E#ul IgD  
} }Ub6eXf(2  
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