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http断点续传简单实现(java)

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/* Z<W`5sop^  
**SiteFileFetch.java d8% sGH  
*/ _>4Qh#6K  
package NetFox; @zi_@B  
import java.io.*; tr-muhuK  
import java.net.*; &09g0K66  
!lk9U^wnd  
C*&FApG  
public class SiteFileFetch extends Thread { S?e*<s9k  
Y7WU4He L  
\z[L=  
SiteInfoBean siteInfoBean = null; //文件信息Bean At)\$GJ  
long[] nStartPos; //开始位置 FC }r~syqA  
long[] nEndPos; //结束位置 RC+`sZ E9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (U^f0wJg  
long nFileLength; //文件长度 ZDTp/5=?K/  
boolean bFirst = true; //是否第一次取文件 ]B=2r^fn  
boolean bStop = false; //停止标志 .$N8cYu0  
File tmpFile; //文件下载的临时信息 [E6ZmMB&  
DataOutputStream output; //输出到文件的输出流 sQgJ`+Y8_  
H0?Vq8I?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) W}rLHAaDh  
public SiteFileFetch(SiteInfoBean bean) throws IOException {mmQv~|5q  
{ NK$BF(HBi  
siteInfoBean = bean; =At)?A9[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "HrZv+{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #B &%Y6E5  
if(tmpFile.exists ()) E0aJ~A(Hv  
{ v%!'vhf_K  
bFirst = false; Ae|bAyAK  
read_nPos(); j,CVkA*DY  
} K~Z$NS^W&  
else ;b;Bl:%?  
{ Zil<*(kv{  
nStartPos = new long[bean.getNSplitter()]; ],xvhfZ"dn  
nEndPos = new long[bean.getNSplitter()]; 53O}`xX!6  
} 08F~6e6a8  
I6RF;m:Jw  
bm#/ KT_8  
Yrmd hSY  
} PIZK*Lop  
=v49[i  
2 3*OuY  
public void run() Bl/Z _@  
{ RAAu3QKu  
//获得文件长度 NNn sq@?6  
//分割文件 5[|ZceY  
//实例FileSplitterFetch 'NSfGC%7R  
//启动FileSplitterFetch线程 &9Xn:<"`)  
//等待子线程返回 5 ]l8l+  
try{ TpAso[r  
if(bFirst) ~Zo;LSI  
{ U]64HuL  
nFileLength = getFileSize(); %WAaoR&u  
if(nFileLength == -1) W:V.\  
{ lCiRvh1K  
System.err.println("File Length is not known!"); e(Y5OTus  
} a}5/?/  
else if(nFileLength == -2) &"mWi-Mpl  
{ ~R  C\  
System.err.println("File is not access!"); zp:EssO=Q  
} <(W:Q3?s  
else xY<*:&  
{ NEff`mwm5)  
for(int i=0;i<nStartPos.length;i++) X^7n/|%*.  
{ 3eR c>^wh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VX]Ud\(  
} -E>LB\[t)  
for(int i=0;i<nEndPos.length-1;i++) _<6B.{$\7m  
{ `=19iAp.  
nEndPos = nStartPos[i+1]; zr^"zcfz&  
} E?cf#;2h8m  
nEndPos[nEndPos.length-1] = nFileLength; Bz4;R9_%I  
} ;(Kj-,>  
} rB}2F*eT  
^C70b)68  
8&c:73=?X  
//启动子线程 R7 ^f|/l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u -A_l<K  
for(int i=0;i<nStartPos.length;i++) wrAcVR  
{ bD<hzOa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H-jxH,mJmW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (Ky$(Ubb#6  
nStartPos,nEndPos,i); ,)Z1&J?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *Z2#U ?_  
fileSplitterFetch.start(); +XpQ9Cd  
} \vF*n Z5/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aqKrf(Rv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )W |_f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _FP'SVa}D  
nEndPos = " + nFileLength); Eu`K2_b  
// fileSplitterFetch[nPos.length-1].start(); p61F@=EL  
@f`s%o  
iG+=whvL  
//等待子线程结束 ChRCsu~  
//int count = 0; O ~D]C  
//是否结束while循环 grTwo  
boolean breakWhile = false; !]l;n Fd  
g4}K6)@  
Nc:0opPM  
while(!bStop) :aWC6"ik-W  
{ $\q}A:  
write_nPos(); l,:> B-FV  
Utility.sleep(500); 5~{s-Ms  
breakWhile = true; *_/n$& I%&  
F~wqt7*  
O]80";Uv  
for(int i=0;i<nStartPos.length;i++) $aDkZj  
{ y4Lh:;  
if(!fileSplitterFetch.bDownOver) tG*HUN?*  
{ bj7r"_  
breakWhile = false; 1R"Z+tNB  
break; g96]>]A<{  
} F&$~]R=&  
} /TY=ig1z  
if(breakWhile) ~qkn1N%'  
break; DvY)n<U1qA  
>(C5&3^  
v%;Ny ab6$  
//count++; f J+  
//if(count>4) (x140_TH~  
// siteStop(); wG X\ub#!  
} Bj* M W  
 |Fe*t  
:&BE-f  
System.err.println("文件下载结束!"); F5%IsAH  
} mO&zE;/[  
catch(Exception e){e.printStackTrace ();} n7pjj  
} ]:.9:RmEV  
cHX~-:KOr  
0`Y"xN`'i  
//获得文件长度 Ti&v9re%wO  
public long getFileSize() V?-SvQIk1  
{ _bSn YhS  
int nFileLength = -1; nHl{'|~  
try{ J=Hyoz+9  
URL url = new URL(siteInfoBean.getSSiteURL()); ^b6yN\,S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *}=z^;_oq  
httpConnection.setRequestProperty("User-Agent","NetFox"); !'*1;OQ  
3Uy(d,N  
`gz/?q  
int responseCode=httpConnection.getResponseCode(); _:+ k|I  
if(responseCode>=400) lf}%^od~6  
{ %a|m[6+O  
processErrorCode(responseCode); i Ie{L-Na  
return -2; //-2 represent access is error "z4V@gk   
} Eg4_kp0Lq  
}ZJ*N Y  
G3j'A{  
String sHeader; VvTi>2(.  
='Yg^:n  
K(rWM>Jv  
for(int i=1;;i++) '1rO&F  
{ XPT@ LM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m.ejGm?  
//Utility.log(in.readLine()); =DwY-Ex  
sHeader=httpConnection.getHeaderFieldKey(i); Lc_cB`  
if(sHeader!=null) );d"gv(]D  
{ 4rUOk"li  
if(sHeader.equals("Content-Length")) ,P^4??' o  
{ r>g5_"FL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U U@  
break; b)7v-1N  
} Un Ocw  
} K[l5=)G0L  
else MY l9 &8  
break; +^ `n- m  
} N1Dr'aw*  
} ;nAI;Qw L  
catch(IOException e){e.printStackTrace ();} 4P^CqD&i  
catch(Exception e){e.printStackTrace ();} v0KJKrliGO  
k1~? }+<e  
="de+S8W  
Utility.log(nFileLength); >*WT[UU  
Z+2 j(  
1!Afq}|  
return nFileLength; "mc ]^ O  
} Or :P*l  
mq+<2 S  
]MnQ3bWq"j  
//保存下载信息(文件指针位置) @|<qTci  
private void write_nPos() _&aPF/  
{ h6Cqc}P  
try{ uLSuY}K0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y=Om0=v  
output.writeInt(nStartPos.length); WkDXWv\{,{  
for(int i=0;i<nStartPos.length;i++) W^)'rH  
{ <aQ5chf7  
// output.writeLong(nPos); O3tw@ &k  
output.writeLong(fileSplitterFetch.nStartPos); id [caP=`  
output.writeLong(fileSplitterFetch.nEndPos); d[oHjWk  
} f7:}t+d  
output.close(); pyp0SGCM:  
} q_Z6s5O  
catch(IOException e){e.printStackTrace ();} #,9#x]U#v  
catch(Exception e){e.printStackTrace ();} qm< mw"]  
} xM![  
6 tl#AJ-  
W~/{ct$Y  
//读取保存的下载信息(文件指针位置) k,-0OoCL-!  
private void read_nPos() Z u/w>  
{ qO[_8's8  
try{ r0q?e`nsA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OM81$Xo=  
int nCount = input.readInt(); iH8V]%  
nStartPos = new long[nCount]; RaOLy \  
nEndPos = new long[nCount]; ~L:H]_8F l  
for(int i=0;i<nStartPos.length;i++) wY"BPl]b  
{ Y6m:d&p=}  
nStartPos = input.readLong(); 8wMwS6s:  
nEndPos = input.readLong(); <YvW /x  
} a"^rOiXR{  
input.close(); wY3| 5kbDj  
} eu'S~c-l  
catch(IOException e){e.printStackTrace ();} h}Lrpr2r  
catch(Exception e){e.printStackTrace ();} GK1oS  
} S=G2%u!;  
[F 24xC+  
h_6c9VI  
private void processErrorCode(int nErrorCode) i?f;C_w  
{ !V-(K_\t  
System.err.println("Error Code : " + nErrorCode); >Q:h0b_$U  
} K9ek  
@a,} k<@E  
1NkJs&  
//停止文件下载 dUv(Pu(.#  
public void siteStop() 6pbtE]  
{ 9ePom'1f1  
bStop = true; \LM.>vJ  
for(int i=0;i<nStartPos.length;i++) >L433qR  
fileSplitterFetch.splitterStop(); ~.CmiG.7  
N v6=[_D  
qWD(rq+9  
} O bc>f|l]  
} u}89v1._Jn  
//负责部分文件的抓取 b-RuUfUn0  
**FileSplitterFetch.java Uh+6fE]p  
*/ ]q/USVj{  
package NetFox; k:URP`w[X=  
(*9-Fa  
3~?m?vj|Y  
import java.io.*; n?"("Fiw  
import java.net.*; *t_Q5&3L+U  
pA6A*~QE  
QW_BT ^d"  
public class FileSplitterFetch extends Thread { 49YN@ PXC  
$e:bDZ(hjj  
#I\" 'n5M  
String sURL; //File URL V3ExS1fNf  
long nStartPos; //File Snippet Start Position <==6fc>s  
long nEndPos; //File Snippet End Position Cv [1HO<  
int nThreadID; //Thread's ID nPk&/H%5hn  
boolean bDownOver = false; //Downing is over +'wO:E1( w  
boolean bStop = false; //Stop identical `><E J'h  
FileAccessI fileAccessI = null; //File Access interface &0]5zQ  
vRH2[{KQ9  
bnJ4Edy  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L%+mD$@u  
{ G&08Qb ,N  
this.sURL = sURL; $laUkD#vz  
this.nStartPos = nStart; #7@p  
this.nEndPos = nEnd; [S9"' ^H  
nThreadID = id; BZ(I]:oDL  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1x8wQ/p|  
} b@O{eQB  
H4$f+  
tG~[E,/`  
public void run() #Hy\l J  
{ <h~=d("j  
while(nStartPos < nEndPos && !bStop) MaPI<kYQv  
{ -A zOujSS  
UG[r /w5(F  
v-wZHkdd1  
try{ GJ F &id  
URL url = new URL(sURL); MjWxfW/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mF4y0r0  
httpConnection.setRequestProperty("User-Agent","NetFox"); .A0fI";Q  
String sProperty = "bytes="+nStartPos+"-"; )S;3WnQ)  
httpConnection.setRequestProperty("RANGE",sProperty); txE+A/>i9  
Utility.log(sProperty); :(@P *"j  
)_Z^oH ]<  
Jt0U`_  
InputStream input = httpConnection.getInputStream(); o#=C[d5BV  
//logResponseHead(httpConnection); XlnSh<e  
]B$J8.{q0  
a ,"   
byte[] b = new byte[1024]; RhC|x,E  
int nRead; `3`.usw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7C R6ew~  
{ 1jO%\uR/  
nStartPos += fileAccessI.write(b,0,nRead); ?a)Fm8Y  
//if(nThreadID == 1) 0Ua=&;/2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }9&dY!h +  
} nxNHf3   
;e< TEs  
%NM={X|'  
Utility.log("Thread " + nThreadID + " is over!"); ci/qm\JI<<  
bDownOver = true; D$@2H>.-  
//nPos = fileAccessI.write (b,0,nRead); 3_`)QYU'  
} \0vs93>?  
catch(Exception e){e.printStackTrace ();} jAU&h@  
} hRMya#%-  
} (4Nj3x o  
{e q378d  
CD%Cb53  
//打印回应的头信息 XMdCQ=  
public void logResponseHead(HttpURLConnection con) .rS. >d^n  
{ dMCoN8W  
for(int i=1;;i++) bwj{5-FU  
{ (.X)=  
String header=con.getHeaderFieldKey(i); 1 b 86@f   
if(header!=null) jsx&h Y%(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); crN*eFeW  
Utility.log(header+" : "+con.getHeaderField(header)); klH?!r&  
else K:GEC-  
break; E@yo/S  
} j=Izwt>   
} :Z x|=  
bE{Y K  
T]nAz<l),  
public void splitterStop() >239SyC-,  
{ boHbiE  
bStop = true; fx>U2  
} o OC&w0  
x/wgD'?  
lfre-pS+  
} 3z u6#3^  
*ra>Kl0   
Ga-cto1Y  
/* cpALs1j:  
**FileAccess.java ch25A<O<R.  
*//文件访问(定位,写) #9Ect@?N0  
package NetFox; V1pBKr)v  
import java.io.*; `*BV@  
6q>}M  
+cSc0:  
public class FileAccessI implements Serializable{ {dm>]@"S  
~KYzEqy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ' QMcQvU  
RandomAccessFile oSavedFile; u&^KrOM@#  
long nPos; GM?s8yZ<  
nj1o!+9>$  
YB<nz<;JR  
public FileAccessI() throws IOException jT}={[9b  
{ MtaGv#mJ  
this("",0); ^m&I^ \  
} C=]<R< Xy  
MkL2I+*  
_U-`/r o  
public FileAccessI(String sName,long nPos) throws IOException 9} m?E<6&  
{ GBT|1c'i  
oSavedFile = new RandomAccessFile(sName,"rw"); GqR|hg  
this.nPos = nPos; sZT~ 5c8  
oSavedFile.seek(nPos); ^D6TeH  
} goA=U  
elQjPvb  
Z\xnPhV  
public synchronized int write(byte[] b,int nStart,int nLen) *OznZIn  
{ BAY e:0  
int n = -1; I`H&b& .`  
try{ 8V 4e\q  
oSavedFile.write(b,nStart,nLen); xPPA8~Dm*  
n = nLen; Y0T:%  
} af %w|M  
catch(IOException e) AU}kIm_+  
{ Nw$OJ9$L>  
e.printStackTrace (); IGQBTdPUa  
} At?|[%< `  
Q?1J<(oq9  
{59 >U~  
return n; 7C 0xKF  
} !%ju.Xs8  
E;{RNf|  
m*A b<$y  
} GWWg3z.o"W  
f? @Qt<+k  
\)rMC]  
/* jwa6`u  
**SiteInfoBean.java s_XCKhN:  
*/ `Wg"m~l$N  
package NetFox; B=L!WGl<!  
( _6j@?u  
GDSXBa*7  
public class SiteInfoBean { +pwTM]bV  
H-+U^@w  
fmj}NV&ma  
private String sSiteURL; //Site's URL n qO*z<  
private String sFilePath; //Saved File's Path G)%V 3h  
private String sFileName; //Saved File's Name Um{) ?1  
private int nSplitter; //Count of Splited Downloading File 3qf#NJN}  
I9qFXvqL  
-^2p@^  
public SiteInfoBean() 3*~`z9-z  
{//nSplitter的缺省值为5 SsTBjIX  
//default value of nSplitter is 5 6qFzo1LO  
this("","","",5); uX3yq<lK"  
} vJ}WNvncVF  
qnboXGaFu  
RQ =$, i`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zKGZg>q  
{ yuBRYy#E|%  
sSiteURL= sURL; F:T(-,  
sFilePath = sPath; } &+]UGv  
sFileName = sName; V 97ORI  
this.nSplitter = nSpiltter; Mf#@8"l  
1F,U^O  
oo\^}jb  
} %%}l[W  
AXHY$f|  
BInSS*L  
public String getSSiteURL() Lv['/!DJ|  
{ dN3^PK  
return sSiteURL; RU7+$Z0K  
} q"<=^vi  
t3Gy *B  
Os-Z_zSl6  
public void setSSiteURL(String value) 9dNkKMc@  
{ SNOc1c<~  
sSiteURL = value; rIPfO'T?  
} +;lDU}$  
A{ T9-f@X  
E> GmFw  
public String getSFilePath() <b,WxR`  
{ 2PyuM=(Wt  
return sFilePath; 4"kc(J`c  
} t2)uJN`a$X  
f?tU5EX  
Q4-d|  
public void setSFilePath(String value) 7FcZxu\  
{ ]pBEoktp  
sFilePath = value; z2YYxJ c&w  
} 9DhM 9VU  
ygnZ9ikh<-  
hRX9Du`$  
public String getSFileName() =Pw{1m|k  
{ $I*}AUp v?  
return sFileName; #X'-/q`.  
} Y GOkqI  
W7WHDL^  
\99'#]\_/E  
public void setSFileName(String value) !7I07~&1  
{ "[~yu* S  
sFileName = value; ]sb?lAxh{  
} 36(qe"s  
8iaMr278W  
&?bsBqpN  
public int getNSplitter() ~/K&=xE  
{ NzyEsZ]$  
return nSplitter; ai$l7]7  
} pP":,8Q{  
^g6v#]&WA  
aSIb0`(3  
public void setNSplitter(int nCount) hbJy<e1W  
{ =t-Ud^3  
nSplitter = nCount; !9 kNL  
} |OF3O,5z  
} vw!7f|Pg ~  
"KK}} $>  
,H"}Rw  
/* S;#:~?dU  
**Utility.java a%m )8N;C  
*/ 5*Zz_ .  
package NetFox; ^2$b8]q  
)yb~ kbe  
d^RcJ3w  
public class Utility { 9_5>MmiB  
6jc5B#  
b}Gm{;s!  
public Utility() L]z8'n,  
{ 1$E[`` n  
/]z #V'  
Fz(;Eo3  
} 153*b^iDBh  
18%$Z$K,  
//线程睡眠 A,EG0yb  
public static void sleep(int nSecond) 8Gy]nD  
{ 2EpQ(G J  
try{ vzI>:Bf  
Thread.sleep(nSecond); i=n;rT  
} liPrxuP`  
catch(Exception e) L@[}sMdq(  
{ A}9^,C$#  
e.printStackTrace (); 3l~7  
} 1YMi4.  
} n]#YL4j  
!O!:=wq  
//日志 paV1o>_Rd  
public static void log(String sMsg) b*h:e.q  
{ o'$-  
System.err.println(sMsg); 2(GY k  
} i`l;k~rP  
- i2^ eZl  
.$cX:"_Mk  
public static void log(int sMsg) XkqsL0\  
{ "6%{#TZ  
System.err.println(sMsg); wS|k3^OV%  
} ',[AKXJ  
} h& 4#5{=  
ZK t{3P  
'j'6x'[> ]  
/* THOYx :Nr;  
**TestMethod.java uaP5(hUI  
*/ nX7F<k4G2  
package NetFox; -2}ons(  
y{(Dv}   
j07A>G-=  
public class TestMethod { Cd^1E]O0{  
!U4YA1>>  
g/$RuT2U  
public TestMethod() qmn l  
{ ///xx/weblogic60b2_win.exe 8SroA$^n  
try{ "kcix!}&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [Y`E"1f2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6W YVHG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z"Lr5'}  
fileFetch.start(); 4s|qxCks  
} \anOOn@  
catch(Exception e){e.printStackTrace ();} 3%9XJ]Qao  
`*Wg&u  
RRy D<7s1  
} mnZfk  
VgbT/v  
GBS+ 4xL|  
public static void main(String[] args) 7R5ebMW V  
{ *\:sHVyG(  
new TestMethod(); GE] QRKf  
} -XnIDXM  
} &$T7eOiZ  
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