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http断点续传简单实现(java)

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/* 7Mxw0 J  
**SiteFileFetch.java 41luFtE9  
*/ j?Ki<MD1  
package NetFox; +RexQE  
import java.io.*; xEBiBsk d  
import java.net.*; k)D:lpxv  
Pf s_s6  
(uG.s%I  
public class SiteFileFetch extends Thread { olPV"<;+pO  
=PXQ X(_  
n`";ctQT  
SiteInfoBean siteInfoBean = null; //文件信息Bean w[w{~`([",  
long[] nStartPos; //开始位置 #~um F%#  
long[] nEndPos; //结束位置 ND[u$N+5x"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 JpN]j`  
long nFileLength; //文件长度 EL+6u>\- k  
boolean bFirst = true; //是否第一次取文件 %V-\|cw   
boolean bStop = false; //停止标志 D*+uH;ws  
File tmpFile; //文件下载的临时信息 " @!z+x[8  
DataOutputStream output; //输出到文件的输出流 1aKYxjYM  
]@OGp:Hz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0'!v-`.  
public SiteFileFetch(SiteInfoBean bean) throws IOException m#SDB6l  
{ hQ&S*f&='  
siteInfoBean = bean; Dt,b\6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); & f7{3BK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [.DSY[!8U  
if(tmpFile.exists ()) ?29zcuRaru  
{ @xR7>-$0p  
bFirst = false; t1p}   
read_nPos(); 6zK8-V?9F  
} wH1 E7LY|R  
else %Kd&A*  
{ hNB;29r~  
nStartPos = new long[bean.getNSplitter()]; .$b]rx7$ ~  
nEndPos = new long[bean.getNSplitter()]; e*_8B2da  
} lcgT9 m#  
96;17h$  
:+ksmyW  
Tj@}O:q7:  
} GSg|Gz""J0  
/0QGU4=  
dw,Nlf~*0  
public void run() <>GWSW  
{ 6GCwc1g  
//获得文件长度 xN wKTIK$  
//分割文件 R? Y#>K  
//实例FileSplitterFetch YK*2  
//启动FileSplitterFetch线程 4kGA`XhS*  
//等待子线程返回 h: :'s&|  
try{ "pq#A*  
if(bFirst) ]#]m_+} Z  
{ 9 v)p0  
nFileLength = getFileSize(); ul~>eZ  
if(nFileLength == -1) PT4Xr=z =  
{ rP.qCl+J  
System.err.println("File Length is not known!"); <tK 6+isc  
} CBx1.xL  
else if(nFileLength == -2) LXj2gsURu%  
{ >nmby|XtW  
System.err.println("File is not access!"); DZ~w8v7V  
} BMU}NZA  
else _3<J!$]&p  
{ lbrob' '+  
for(int i=0;i<nStartPos.length;i++) \FN"0P(G  
{ 21GjRPs\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,c"_X8Fkx$  
} QytqO {B^  
for(int i=0;i<nEndPos.length-1;i++) ~k+"!'1  
{ P0U=lj/ b  
nEndPos = nStartPos[i+1]; x8%Q TTY  
} 7uJy<O  
nEndPos[nEndPos.length-1] = nFileLength; kXS_:f;M  
} lZCvH1&"  
} yA*~O$~Y  
*v3/8enf  
aNb=gjLpt  
//启动子线程 kRNr`yfN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1\q(xka{  
for(int i=0;i<nStartPos.length;i++) Sr~zN:wn  
{ }Q_IqI[7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yrO'15TB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FT73P0!8.  
nStartPos,nEndPos,i); ?KpHvf'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !o~% F5|t  
fileSplitterFetch.start(); V1Dwh@iS  
} (:E_m|00;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9F)v=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x P{L%.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XG ]yfux`  
nEndPos = " + nFileLength);  Py\xN  
// fileSplitterFetch[nPos.length-1].start(); $K^"a  
Z@&_ T3M  
+B^ / =3P  
//等待子线程结束 aB<~T[H%h  
//int count = 0; B, nCx=\S  
//是否结束while循环 x3>K{  
boolean breakWhile = false; CF9a~^+%  
dluNA(Xc-  
T8>:@EL-k  
while(!bStop) Fh& ` v0  
{ `g6XVa*%#  
write_nPos(); w[\*\'Vm0  
Utility.sleep(500); wl^bvHG  
breakWhile = true; t ),~w,7(J  
&W fs6g  
t3u"2B7oG  
for(int i=0;i<nStartPos.length;i++) bO1J#bcZ  
{ 'p-jMD}O  
if(!fileSplitterFetch.bDownOver) dgpo4'c}  
{ I<|)uK7  
breakWhile = false; (: 2:_FL  
break; VaQ>g*(I  
} mbv\Gn#>  
} ,@%1q)S?A  
if(breakWhile) {YWj`K  
break; S%uH*&`  
xc Wr hg  
'#$% f  
//count++; !y$H r[v  
//if(count>4) {%. _cR2  
// siteStop(); q,V JpqQ  
} 3 1KMn  
Tn2Z{.q$  
@gENv~m<OI  
System.err.println("文件下载结束!"); )u]J`.OA  
} 4;Z`u.1  
catch(Exception e){e.printStackTrace ();} '|&}rLr:+  
} w{)*'8oCB  
UBqA[9  
hLGUkG?6G  
//获得文件长度 ]B=B@UO@.  
public long getFileSize() <(`dU&&%"}  
{  Fwyv>U  
int nFileLength = -1; ^Tc&?\3  
try{ K CJ zE>  
URL url = new URL(siteInfoBean.getSSiteURL()); 1qbd6D|t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (7`goi7M  
httpConnection.setRequestProperty("User-Agent","NetFox"); GjE/!6b  
|M#b`g$JO,  
P 482D)  
int responseCode=httpConnection.getResponseCode(); iN+Dmq5  
if(responseCode>=400) j(F%uUpN  
{ 6=A2Y:8  
processErrorCode(responseCode); }M?GqA=  
return -2; //-2 represent access is error sY7:Lzs.,  
} 2,puu2F  
Z!G_" 3  
&}32X-~y  
String sHeader; ^i_mGeu  
?;> s<  
c.6u)"@$  
for(int i=1;;i++) rEfk5R  
{ |TF,Aj   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \D?6_ ,O  
//Utility.log(in.readLine()); hD{+V!{  
sHeader=httpConnection.getHeaderFieldKey(i); B<DvH"+$  
if(sHeader!=null) l@Ma{*s6=5  
{ (ZQ{%-i?qR  
if(sHeader.equals("Content-Length")) ]8ua>1XS  
{ E:xpma1Qf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nf+8OH7  
break; }cgEC-  
} )52:@=h*l  
} 15VOQE5Fl`  
else ps"crV-W  
break; uljd)kLy4O  
} Gv>,Ad ka  
} dr^pzM!N  
catch(IOException e){e.printStackTrace ();} dm,7OQ  
catch(Exception e){e.printStackTrace ();} ,$Qa]UN5Q  
"p.MJxH  
.x$+R%5U  
Utility.log(nFileLength); ]kbmbO?M  
 rmUT l  
&|iFhf[o  
return nFileLength; pA='(G  
} K8Gc5#OF  
|@]J*Kh  
=+~e44!~D  
//保存下载信息(文件指针位置) Un^QNd>  
private void write_nPos() !jMa%;/  
{ [0yKd?e  
try{ [|d:QFx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oc?,8I[P5  
output.writeInt(nStartPos.length); iOPv % [  
for(int i=0;i<nStartPos.length;i++) D#x D-c  
{ + htTrHjt  
// output.writeLong(nPos); %*e6@Hm  
output.writeLong(fileSplitterFetch.nStartPos); CY)/1 # J  
output.writeLong(fileSplitterFetch.nEndPos); !~04^(  
} p&B98c  
output.close(); &zlwV"W  
} :g2?)Er-  
catch(IOException e){e.printStackTrace ();} uT8/xNB!  
catch(Exception e){e.printStackTrace ();} $Eg|Qc-1  
} -LzHCO/7(  
rK)So#'  
!e&ZhtTuC  
//读取保存的下载信息(文件指针位置) `Q1S8i$  
private void read_nPos() r|:|\"Yk  
{ A`Z!=og=  
try{ j;<Yje&Wz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -2o4v#d  
int nCount = input.readInt(); VxLq,$B76  
nStartPos = new long[nCount]; <oI{:KH  
nEndPos = new long[nCount]; w3PE.A"Q  
for(int i=0;i<nStartPos.length;i++) djS?$WBpU  
{ b(_PCVC  
nStartPos = input.readLong(); -_ .f&l8  
nEndPos = input.readLong(); bRJYw6oA<  
} GbwcbfH  
input.close(); SOE#@{IXBa  
} a)MjX<y  
catch(IOException e){e.printStackTrace ();} dI5Z*"`R9  
catch(Exception e){e.printStackTrace ();} lu`\6  
} ^HLi1w|  
Z6!MX_ep  
UA!h[+Z  
private void processErrorCode(int nErrorCode) }C/u>89%q  
{ C#emmg!a\  
System.err.println("Error Code : " + nErrorCode); pM@|P,w {  
} |]RV[S3v  
/gL(40  
v{i'o4  
//停止文件下载 q5 I2dNE  
public void siteStop() x|_%R v  
{ Zd1+ZH  
bStop = true; /[VafR!  
for(int i=0;i<nStartPos.length;i++) (BVLlOo?J  
fileSplitterFetch.splitterStop(); M-K<w(,X  
'C1=(PE%`  
3Ku!;uo!u  
} ; @ h{-@  
} AT<gV/1l  
//负责部分文件的抓取 00Tm0rY  
**FileSplitterFetch.java V=VL@=  
*/ +&jWM-T"-  
package NetFox; u ?7(A %  
H;k;%Zg;  
;/N[tO?Q  
import java.io.*; >>rW-&  
import java.net.*; ?t'ZX~k  
4HVZ;,q  
!.zUY6  
public class FileSplitterFetch extends Thread { ?O8NyCeb7  
Nb>|9nu O  
%:h)8e-;  
String sURL; //File URL >T%Jlj3ZG  
long nStartPos; //File Snippet Start Position lJ3/^Htn  
long nEndPos; //File Snippet End Position _J 6|ju\  
int nThreadID; //Thread's ID $)mq  
boolean bDownOver = false; //Downing is over p/:)Z_  
boolean bStop = false; //Stop identical _b<Fz`V  
FileAccessI fileAccessI = null; //File Access interface ;9q3FuR  
YPDc /  
)-Zpr1kD  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6dV@.(][a  
{ xrA(#\}f$  
this.sURL = sURL; GxLoNVr  
this.nStartPos = nStart; j?jEWreq]~  
this.nEndPos = nEnd; ?g}n$%*5y!  
nThreadID = id; 4};!nYey!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bS3qX{5  
} KunK.m  
"6~pTHT  
e!l!T@ pf  
public void run() aa_&WHXkt  
{ RsIEY5Q  
while(nStartPos < nEndPos && !bStop) Q nDymVF  
{ q =b.!AZy  
!aeL*`;  
d0>V^cB'?  
try{ V,<,;d fR  
URL url = new URL(sURL); K8pfk*NZ_@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rwtSn?0z"  
httpConnection.setRequestProperty("User-Agent","NetFox"); QBR9BR  
String sProperty = "bytes="+nStartPos+"-"; k)'hNk"x  
httpConnection.setRequestProperty("RANGE",sProperty); :M`|*~V~$  
Utility.log(sProperty); [zm&}$nnN  
%/oOM\} ++  
?|%^'(U}  
InputStream input = httpConnection.getInputStream(); T$06DS  
//logResponseHead(httpConnection); 8d-; ;V  
25l6@7q.  
1T%Y:0  
byte[] b = new byte[1024]; G#HbiVH9  
int nRead; 0(Vbji  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z9i,#/  
{ {v+i!a'+  
nStartPos += fileAccessI.write(b,0,nRead); &s"&rFFO[  
//if(nThreadID == 1) wHBkaPO!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a { L`C"rJ  
} K-)*S\<}  
Y` LZ/Tgk  
~{n_rKYV  
Utility.log("Thread " + nThreadID + " is over!"); UQ$dO2^  
bDownOver = true; m1gJ"k6 `j  
//nPos = fileAccessI.write (b,0,nRead); ]"dZE2!  
} j23OgbI  
catch(Exception e){e.printStackTrace ();} n8w|8[uV^  
} ;J2U5Y NO  
} Gnl6>/L,  
$9y]>R  
}kT;UdIu;  
//打印回应的头信息 %{yr#F=t#]  
public void logResponseHead(HttpURLConnection con) nqBZp N ^  
{ bFVz ;  
for(int i=1;;i++) 9| v  
{ vROl}s;  
String header=con.getHeaderFieldKey(i); * <x]gV  
if(header!=null) .Ap[C? mV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >RHK6c  
Utility.log(header+" : "+con.getHeaderField(header)); q+~z# jFX  
else go]d+lhFB  
break; ]RPv@z:V  
} J,;; `sf  
} Ufq"_^4  
%pc0a^iB  
D ,mFme  
public void splitterStop() Ki^m&P   
{ R=i$*6}a  
bStop = true; L -b~#  
} vn .wM  
RL~\/#  
`.MM|6  
} q .tVNKy%  
_( w4\]  
KAgiY4  
/* ZZ!d:1'7  
**FileAccess.java `vDg~o  
*//文件访问(定位,写) 9=rYzA?)+  
package NetFox; \&R}JK  
import java.io.*; ,<R/x[  
IqfR`iAix  
b=F"  
public class FileAccessI implements Serializable{ &m'O :ZS2  
PX?tD:,[-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 csRba;Z[  
RandomAccessFile oSavedFile; PaMi5Pq  
long nPos; YxS*im[%]  
(Uv{%q.n6  
0w< iz;30  
public FileAccessI() throws IOException tOnaD]J  
{ :lgIu .  
this("",0); \Y>^L{  
} I4m)5G?O2  
2}[rc%tV:?  
d;D^<-[i  
public FileAccessI(String sName,long nPos) throws IOException q1r\ 60M  
{ tK g%5;v  
oSavedFile = new RandomAccessFile(sName,"rw"); xW/J ItF  
this.nPos = nPos; 5c{=/}Y  
oSavedFile.seek(nPos); XwX1i!'54  
} 7; T S  
66:|)  
r\@"({q}_-  
public synchronized int write(byte[] b,int nStart,int nLen) ;NRm ,  
{ Jfo|/JQ  
int n = -1; )lB-D;3[_  
try{ zL OmtZ(['  
oSavedFile.write(b,nStart,nLen); g\rujxHlH  
n = nLen; PA`b~Ct  
} jd]MC*%  
catch(IOException e) "N4c>2Q  
{ xqP0Z) ,Ow  
e.printStackTrace (); m$QFtrvy  
} -W!g>^.  
" 8;D^  
/Klwh1E  
return n; js;IUSj.  
} LFen!FnM  
8'^eH1d'  
~+l%}4RZ  
} oWs&W  
 vFl|  
_32ltnBX  
/* !Z%QD\knY  
**SiteInfoBean.java @m6pAo4P  
*/ CtjjN=59  
package NetFox; o S_'@u.5  
uKpl+>  
86R}G/>>e  
public class SiteInfoBean { -6+HA9zz@C  
pNVao{::5  
G<Lm}  
private String sSiteURL; //Site's URL xs.[]>nQN  
private String sFilePath; //Saved File's Path kwWO1=ikz@  
private String sFileName; //Saved File's Name iW* 0V3  
private int nSplitter; //Count of Splited Downloading File FuEHO6nx  
*aG0p&n}  
@3VL _g:  
public SiteInfoBean() =%2 E|/  
{//nSplitter的缺省值为5 [jAhw>  
//default value of nSplitter is 5 cv#H  
this("","","",5); (O?z6g  
} <6v7_  
B-@f.NO/s  
<@JU0Z"a=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #GWQ]r?  
{ *D4H;P#  
sSiteURL= sURL; >4h4t/G  
sFilePath = sPath; P-+^YN,  
sFileName = sName; fK4laDB TO  
this.nSplitter = nSpiltter; 8 eh C^Cg  
Xk7zXah  
zoUW}O  
} TuaT-Z~U{  
zYls>fbp,  
r9b`3yr=  
public String getSSiteURL() K''b)v X4  
{ !Y\hF|[z  
return sSiteURL; HnOF_Twq  
} /Zm@.%.  
<a$cB+t  
YRC`2)_'  
public void setSSiteURL(String value) NA0hQGN}  
{ 3P #1fI(c  
sSiteURL = value; z,2m7C  
} Dt r'X@U  
5O*+5n  
ve K  
public String getSFilePath() vP,WV9Q1u  
{ *}mtVa_|  
return sFilePath; _10#rucr  
} @XmMD6{<  
?.4.Ubc\  
7[u&%  
public void setSFilePath(String value) -P.) 0d(  
{ sjaG%f&h  
sFilePath = value; 5R o5Cg~  
} yM\ 1n  
8, B9y D  
\OY2|  
public String getSFileName() m m`:ci  
{ xmVK{Q YT$  
return sFileName; rNgE/=X  
} 8|J%IE  
}>tUkXlhJ<  
-Tz9J4xU&  
public void setSFileName(String value) -n Hc52,  
{ E"w7/k#3}C  
sFileName = value; & JF^a  
} d6M d~$R  
cDAO5^  
$"_D"/*  
public int getNSplitter() Z ,T TI>P  
{ pl7!O9bo  
return nSplitter; x&;{4F Nw  
} ?np` RA  
cFH,fj  
R0m}I5Frs  
public void setNSplitter(int nCount) =(hEr=f>7  
{ X7n~Ws&s@  
nSplitter = nCount; B*?v`6  
} ?!A{n3\<  
} JFZZ-t;*  
e@I?ESZ5  
Y$,]~Qzq  
/* IHB{US1G  
**Utility.java ?;i6eg17<  
*/ RS$:]hxd>_  
package NetFox; hVR=g!e#X  
X59~)rH,  
v"bOv"!al  
public class Utility { yWX:`*GV  
^M,Q<HL  
g4-HUc zk  
public Utility() Yoaz|7LS  
{ "}ZD-O`!  
85H8`YwPh  
. e]!i(5I  
} [!DLT6Qk  
F%< 0pi  
//线程睡眠 rV1JJ.I  
public static void sleep(int nSecond) ) tsaDG-E  
{ e`C'5`d]  
try{ Bj\0RmVa1  
Thread.sleep(nSecond); m >'o&Hj  
} K_}vmB\2l  
catch(Exception e) %=_ Iq\lC  
{ rb,&i1  
e.printStackTrace (); *8MU,6  
} b$M? _<G  
} ]Oe#S"-Oo  
B)Gm"bLCOZ  
//日志 XmXHs4  
public static void log(String sMsg) y]@_DL#J=  
{ 9]d$G$Kv9  
System.err.println(sMsg); Kk#8r+ ,  
} BWQ (>Z"  
*t*yozN  
Eb#0 -I  
public static void log(int sMsg) !".@Wg$  
{ c%v%U &  
System.err.println(sMsg); U?@UIhtM|  
} qwVpGNc45  
} ;O.U-s  
``zg |h  
O5e9vQH  
/* Gn&)*qCO  
**TestMethod.java <0Q`:'\.>  
*/ UT>\u  
package NetFox;  \ 1|T  
&@{ Ba~S  
=f{r+'[;^  
public class TestMethod { ~KrzJp=5F  
J *^|ojX  
]D<r5P%  
public TestMethod() x{IOn;>R  
{ ///xx/weblogic60b2_win.exe /G</ [N5  
try{ whRc YnJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |\elM[G"g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .dl1sv U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9jJ&QACn  
fileFetch.start(); x?f3XEA_  
} R$cg\DD  
catch(Exception e){e.printStackTrace ();} {n |Ra[9_  
^oPf>\),C  
x'n J_0  
} |J~;yO SD  
$ V}s3  
*I>1O*  
public static void main(String[] args) 4Mnne'7  
{ o6oZk0  
new TestMethod(); :)%Vahu  
} 1Te: &d  
} X0p=jBye~>  
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