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http断点续传简单实现(java)

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/* #oaX<,  
**SiteFileFetch.java c!c!;(  
*/ DIY WFVh  
package NetFox; s$Mj4_p3l  
import java.io.*; YAO0>T<F  
import java.net.*; 97lwPjq  
:3k(=^%G!  
*-7O| ''  
public class SiteFileFetch extends Thread { `WVQp"m  
R[b?kT-%  
AbB%osz}Ed  
SiteInfoBean siteInfoBean = null; //文件信息Bean >.A{=?   
long[] nStartPos; //开始位置 +.=a R<Q  
long[] nEndPos; //结束位置 kciH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F n\)*; ^  
long nFileLength; //文件长度 y(HR1v Q;Z  
boolean bFirst = true; //是否第一次取文件 q(C+D%xB  
boolean bStop = false; //停止标志 %}@^[E)  
File tmpFile; //文件下载的临时信息 &\A$Rj)  
DataOutputStream output; //输出到文件的输出流 F[lHG,g-  
x|Dj   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) |cH\w"DcXw  
public SiteFileFetch(SiteInfoBean bean) throws IOException lp6GiF  
{ 7Y-GbG.'  
siteInfoBean = bean; i<l)To-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X- zg  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'uh6?2)wG  
if(tmpFile.exists ()) _+GCd8d  
{ d(tq;2-  
bFirst = false; W];4P=/  
read_nPos(); VGSe<6Hh  
} 9%x[z%06  
else \ZA%"F){  
{ pJqayzV  
nStartPos = new long[bean.getNSplitter()]; | .PLfc;  
nEndPos = new long[bean.getNSplitter()]; qYE-z( i  
} U7OW)tUf  
~ 60J  
Tsa&R:SE  
9s}--_k?F2  
} 5)}xqE"x  
W>Zce="_gN  
?wmr~j  
public void run() |XQ!xFB  
{ '1d-N[  
//获得文件长度 yd2ouCUV  
//分割文件 8g<3J-7Mm  
//实例FileSplitterFetch ^ H'|iju  
//启动FileSplitterFetch线程 9%4rO\q  
//等待子线程返回 e|`&K"fnq  
try{ hI"I#(*jA%  
if(bFirst) s3q65%D  
{ _:{XL c  
nFileLength = getFileSize();  @521 zi  
if(nFileLength == -1) zITXEorF!J  
{ sYvO"|  
System.err.println("File Length is not known!"); mFT[[Z#  
} uvT]MgT  
else if(nFileLength == -2) l?ofr*U&-x  
{ *p VKMmU  
System.err.println("File is not access!"); b.$Gc!g  
} =!7yX ;|  
else K%S k{'  
{ Zf|f $1-  
for(int i=0;i<nStartPos.length;i++) xD1w#FMlQs  
{ K2&pTA~OR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }lhJt|qc  
} /q8n_NR  
for(int i=0;i<nEndPos.length-1;i++) \OOj]gAe  
{ eI- ~ +.  
nEndPos = nStartPos[i+1]; $L?stgU  
} <#:"vnm$j  
nEndPos[nEndPos.length-1] = nFileLength; Y1+f(Q  
} WO]dWO6Mm  
} __)9JF  
<MY_{o8d  
x }-rAr  
//启动子线程 #[IQmU23  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zc(- dMlK  
for(int i=0;i<nStartPos.length;i++) t0/fF'GZD  
{ N~SG=\rP;o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "xw2@jGpG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z[|(}9v?~  
nStartPos,nEndPos,i); N1_nBQF )  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^/c&Ud  
fileSplitterFetch.start(); =8[HC}s|$  
} 0LxA+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;gf^;%FK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w+P bT6;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]U]{5AA6  
nEndPos = " + nFileLength); gg5`\}  
// fileSplitterFetch[nPos.length-1].start(); i4AmNRs  
Krz[ f  
NFsMc0{  
//等待子线程结束 < jfi"SJu  
//int count = 0; 2U i)'0  
//是否结束while循环 {4UlJ,Z.n  
boolean breakWhile = false; "#(]{MY  
IS"UBJ6p  
Yk[yG;W  
while(!bStop) FD[* mCGZ  
{ )'92{-A0  
write_nPos(); pkhZW8O  
Utility.sleep(500); Aqq%HgY:t  
breakWhile = true; \S3C"P%w  
/8lGP! z  
8xlj:5;(w  
for(int i=0;i<nStartPos.length;i++) 0/;T\9  
{ +\SbrB P  
if(!fileSplitterFetch.bDownOver) "h\{PoG  
{ DqbN=[!X~n  
breakWhile = false; [K,&s8N5  
break; 6dV92:  
} Bx2E9/S3  
} Q']:k}y  
if(breakWhile) e%#9|/uP  
break; Bm1yBKjO  
dX` _Y  
g;Bq#/w  
//count++; #N wlKZ-  
//if(count>4) Sw>AgES  
// siteStop(); zAS&L%^tV  
} Gb\}e}TB[  
^<7)w2ns  
{6*h';~  
System.err.println("文件下载结束!"); 's+ Fd~ '  
} TAIcp*)ZM  
catch(Exception e){e.printStackTrace ();} IYb@@Jzo  
} xqX~nV#TB  
}>fL{};Z"  
4, 8gf2  
//获得文件长度 mbU[fHyV  
public long getFileSize() &$|k<{j[<f  
{ Cj,fP[p#7  
int nFileLength = -1; ZI-)'  
try{ Ju Kj  
URL url = new URL(siteInfoBean.getSSiteURL()); 9-I;'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P*Uu)mG)G  
httpConnection.setRequestProperty("User-Agent","NetFox"); |&o%c/  
/\(0@To  
mq do@  
int responseCode=httpConnection.getResponseCode(); tNoo3&  
if(responseCode>=400) /EA4-#uw  
{ =&< s*-l[  
processErrorCode(responseCode); &CG3_s<2  
return -2; //-2 represent access is error \ @3i=!  
} +kmPQdO;*/  
x/R|i%u-s  
l0 r Zril  
String sHeader; {eMu"<  
>n{(2bcFs  
9co1+y=i{  
for(int i=1;;i++) k5P&F  
{ Kw+?Lowp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UXnd~DA  
//Utility.log(in.readLine()); z{7&=$  
sHeader=httpConnection.getHeaderFieldKey(i); Y6,< j|  
if(sHeader!=null) p (:\)HP)R  
{ ;spuBA)[X  
if(sHeader.equals("Content-Length")) 5a&[NN  
{ 25o + ?Y<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &Dgho  
break; Jr==AfxyT  
} j"7 z  
} L Lm{:T7  
else ]+{Cy\*kR  
break; bo4 :|Z  
} ebcGdC/%>  
} b Bb$0HOF  
catch(IOException e){e.printStackTrace ();} O sbY}*S  
catch(Exception e){e.printStackTrace ();} 25NZIal<  
]4@_KKP  
1}}.e^Tsfr  
Utility.log(nFileLength); D N GNc  
GTyS8`5E*  
j|A *rzL8  
return nFileLength; mpIRe@#Z  
} 5M;fh)fT  
~6Vs>E4G  
b`usRoD{+  
//保存下载信息(文件指针位置) g>CF|Wj  
private void write_nPos() C7[_#1Oz  
{ TwqyQ49  
try{ |)B&-~a+p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @{:E&K1f  
output.writeInt(nStartPos.length); *1$rg?yGf  
for(int i=0;i<nStartPos.length;i++) ~ b!mKyrZ  
{ Ola>] 0l  
// output.writeLong(nPos); BOQ2;@:3  
output.writeLong(fileSplitterFetch.nStartPos); W7c(] tg.  
output.writeLong(fileSplitterFetch.nEndPos); hCD0Zel  
} hHm &u^xY  
output.close(); +^iUY%pm  
} By]XD~gcP  
catch(IOException e){e.printStackTrace ();} &jT>)MXPu  
catch(Exception e){e.printStackTrace ();} U@@#f;&  
} Nq/,41  
NIY0f@1z-  
,2qJXMg"=$  
//读取保存的下载信息(文件指针位置) |<96H8  
private void read_nPos() U}x2,`PI  
{ mVcpYyD|k  
try{ 5wmH3g#0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S#8wnHq  
int nCount = input.readInt(); YR@@:n'TP  
nStartPos = new long[nCount]; 1Thr74M  
nEndPos = new long[nCount]; #I'W[\l~+  
for(int i=0;i<nStartPos.length;i++) q.yS j  
{ <UQaRI[55  
nStartPos = input.readLong(); $W<H[k&(B  
nEndPos = input.readLong(); j7K9T  
} 7[rn ,8@  
input.close(); rRRiqmq  
} 3k` "%R.H  
catch(IOException e){e.printStackTrace ();} idMb}fw>  
catch(Exception e){e.printStackTrace ();} 'ejuzE9  
} @Y 1iEL%\y  
R rs?I,NV  
&^Zo}F2V  
private void processErrorCode(int nErrorCode) D}XyT/8G3  
{ b8P/9D7K?  
System.err.println("Error Code : " + nErrorCode); v`A^6)U#M  
} @s}I_@  
OB)Vk  
S7N3L."  
//停止文件下载 ,%w_E[2  
public void siteStop() @Ck6s  
{ OkGg4X|9  
bStop = true; 8  k9(iS  
for(int i=0;i<nStartPos.length;i++) nyWA(%N1  
fileSplitterFetch.splitterStop(); M=HW2xn  
"^u  
DmEmv/N=  
} &W:Wv,3  
} s-Q-1lKV,  
//负责部分文件的抓取 tSV}BM,  
**FileSplitterFetch.java 7h?PVobe  
*/ TviC1 {2  
package NetFox; @C62%fU{5  
:WIbjI=  
!MS z%QcO  
import java.io.*; =24)`Lyb  
import java.net.*;  TOdH  
A)Wp W M  
"#z4  
public class FileSplitterFetch extends Thread { -l+ &Bkf  
VI,z7 \  
\[Op:^S  
String sURL; //File URL i;;CU9`E2q  
long nStartPos; //File Snippet Start Position gV1&b (h  
long nEndPos; //File Snippet End Position 4- ^|e  
int nThreadID; //Thread's ID <?kr"[cQeP  
boolean bDownOver = false; //Downing is over @a#qq`b;  
boolean bStop = false; //Stop identical VQ5T$,&  
FileAccessI fileAccessI = null; //File Access interface v|t_kNX;v*  
9:4PJ%R9  
`e .;P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O6LZ<}oUR  
{ ;ob-'  
this.sURL = sURL; [7q~rcf,Z  
this.nStartPos = nStart; w~y+Pv@   
this.nEndPos = nEnd; rVowHP  
nThreadID = id; 4j|]=58  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x tg3~/H  
} >gM|:FG  
:P #   
!SEHDRp  
public void run() $'btfo4H  
{ }@=m[Zx#  
while(nStartPos < nEndPos && !bStop) Un@B D}@\  
{ 4SCb9| /Q  
yS p]+  
A ^ $9[_  
try{ $j0] +vT  
URL url = new URL(sURL); QFU;\H/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ';us;xR#  
httpConnection.setRequestProperty("User-Agent","NetFox"); I1^0RB{~  
String sProperty = "bytes="+nStartPos+"-"; S1(. AI~  
httpConnection.setRequestProperty("RANGE",sProperty); ${0+LhST  
Utility.log(sProperty); k<wX??'  
S9d+#6rn  
gm~Ka%O|F  
InputStream input = httpConnection.getInputStream(); NX&mEz  
//logResponseHead(httpConnection); km,}7^?F0r  
mV^+`GWvo  
I$xfCu  
byte[] b = new byte[1024]; G`!#k!&r  
int nRead; a9 7A{7I&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u:& gp  
{ Yf&x]<rkCp  
nStartPos += fileAccessI.write(b,0,nRead); ,+<NP}Yg#G  
//if(nThreadID == 1) pm$,B7Q`oO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KGd L1~  
} ,pE{N&p9  
Zm& X $U  
,u7: l  
Utility.log("Thread " + nThreadID + " is over!"); !q=ej^(S  
bDownOver = true; |0:< Z(  
//nPos = fileAccessI.write (b,0,nRead); jjL(=n<J<"  
} u'M \m7  
catch(Exception e){e.printStackTrace ();} |K| c  
} s <Pk[7`*  
} ]n1@!qa48  
.9{Sr[P  
[U@#whEO  
//打印回应的头信息 r7o63]  
public void logResponseHead(HttpURLConnection con) G/>upnA{w  
{ 5VdF^.:u  
for(int i=1;;i++) wG6>.`:  
{ hd1(q33  
String header=con.getHeaderFieldKey(i); iI ji[>qz  
if(header!=null) Tn,'*D@l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); XBe!9/'k>  
Utility.log(header+" : "+con.getHeaderField(header)); W}#eQ|oCV  
else 1.U5gW/3L  
break; $Q*h+)g<  
} K.4t*-<`[  
} JYA$_T  
RhIRCN9  
?ORG<11a  
public void splitterStop() dPgN*Bdv  
{ Jj4!O3\I  
bStop = true; +#7 e?B  
} W- 5Z"m1I  
O`1_eK~1<  
pe$" nUy|  
} \)'s6>58|  
ts/ rV#s~  
F B-?{78~  
/* jPU:&1(_ n  
**FileAccess.java iV;X``S  
*//文件访问(定位,写) u^T)4~(  
package NetFox; &QFg=  
import java.io.*; bzD <6Z  
Y ]&D;w  
Uu ~BErEC  
public class FileAccessI implements Serializable{ SE/GT:}  
Y5 e6|b|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p'z fo!  
RandomAccessFile oSavedFile; 0)n#$d>  
long nPos; Tl"GOpH\]  
m[7@l  
}@%A@A{R  
public FileAccessI() throws IOException > 5-z"f  
{ G6wBZ?)k  
this("",0); !j[Oy r|  
} h}r64<Y2{  
?4v&TB@  
Jk=E"I6  
public FileAccessI(String sName,long nPos) throws IOException HLm6BtE  
{ ]FV,}EZ  
oSavedFile = new RandomAccessFile(sName,"rw"); k)j, ~JH  
this.nPos = nPos; W@U<GF1  
oSavedFile.seek(nPos); w:%3]2c  
} V("@z<b|  
gFlUMfKh  
`Mx&,;x  
public synchronized int write(byte[] b,int nStart,int nLen) at"-X?`d  
{ e]F4w(*=  
int n = -1; <nDuN*|  
try{ @H[)U/.  
oSavedFile.write(b,nStart,nLen); .`qw8e}y#'  
n = nLen; x&>zD0\ :\  
} Q${0(#Nu  
catch(IOException e) sbn|D\p  
{ \`3YE~7J/  
e.printStackTrace (); "cSH[/  
} V ':?rEN|  
 ;LEO+,6  
{]Tb  
return n; B^Y AKbY  
} 6t@kft>Nv  
A'Q=Do E  
I- oY@l`  
} pIcvsd  
HUUN*yikj  
k$]-fQM  
/* }4G/x;D  
**SiteInfoBean.java W$&{jr-p  
*/ #nG?}*#  
package NetFox; a&oz<4oT  
klSzmi4M  
vzDoF0Ts*p  
public class SiteInfoBean { S5B12P  
#+$pE@u7A  
n?uVq6c  
private String sSiteURL; //Site's URL L[v-5u)  
private String sFilePath; //Saved File's Path nO-1^HUl  
private String sFileName; //Saved File's Name $&IF#uDf  
private int nSplitter; //Count of Splited Downloading File ]6JI((  
sXe=4`O  
ig G8L  
public SiteInfoBean() Y:UDte[Lb  
{//nSplitter的缺省值为5 xZ2^lsY  
//default value of nSplitter is 5 ~Q<h,P  
this("","","",5); ?+6w8j%\  
} `Hj{XIOx  
=)tU]kp  
Gp*U2LB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $TU)O^c  
{ mx\b6w7  
sSiteURL= sURL; jm~(OLg  
sFilePath = sPath; dC&{zNG  
sFileName = sName; -<e8\Z`  
this.nSplitter = nSpiltter; TNgf96) y  
X{2))t%  
r(qAe{  
} "p,TYjT?R  
xnz(hz6  
Wp5w}8g  
public String getSSiteURL() +%Y`>1I^#  
{ }<G"w 5.<  
return sSiteURL; "^?|=sQ  
} +-8u09-F  
gN"Abc  
`2}H$D  
public void setSSiteURL(String value) /m#!<t7  
{ E<=h6Ha  
sSiteURL = value; C8^=7H EB  
} `{1` >5  
(jQ]<q%P  
tzl`|UwF  
public String getSFilePath() #s"|8#  
{ AH?T}t2  
return sFilePath; NR98I7  
} 5Z (1&  
gie.K1@|  
VE_%/Fs,  
public void setSFilePath(String value) LHy-y%?i  
{ X0G Mly  
sFilePath = value; fK-tvP0}*  
} "v%|&@  
R 2.y=P8N  
XLG6f(B=F  
public String getSFileName() {~cG'S Y%  
{ W=Y?_Oz  
return sFileName; -s ]  
} JQ9JWu%a  
"l83O8 L  
2y_R05O0  
public void setSFileName(String value) M{sn{  
{ >$^v@jf  
sFileName = value; =^nb-9.  
} e G8Zn<:s  
RDFOUqS  
X9:4oMux7  
public int getNSplitter() g7>p,  
{ 8Xo`S<8VS  
return nSplitter; 1w30Vj2<  
} I @sXmC2$\  
CqF= 5z:A  
]m ED3#  
public void setNSplitter(int nCount) t,CC~  
{ <OYy ;s  
nSplitter = nCount; x{=@~c%eh  
} hu=b ,  
} kTCWyc  
Kr;7~`$[  
G"_ 8`l  
/* \W^+aNbv=8  
**Utility.java :Fv d?[  
*/ 7&I+mw/X  
package NetFox; RU r0K#]  
PP+-D~r`}  
u0 & aw  
public class Utility { r$=YhI/=  
J~\`8cds  
fi/[(RBG  
public Utility() Kzv*`  
{ sg=mkkD!g  
M@R_t(&=   
x37pj)i/  
} R78=im7  
/Dh[lgF0C  
//线程睡眠 n_8wYiBs(  
public static void sleep(int nSecond) $ N7J:Q  
{ rSGt`#E-s.  
try{ GQU9UXe  
Thread.sleep(nSecond); t&GjW6]W  
} ch^tq",1>  
catch(Exception e) ;,z[|"y  
{  xr }jw  
e.printStackTrace (); +N~?_5lv\s  
} &HS6}  
} 3n\eCdV-b<  
vai.w-}Z  
//日志 oH[4<K>  
public static void log(String sMsg) ig] hY/uT  
{ jjs1Vj1@<  
System.err.println(sMsg); uude<d"U  
} .H.#W1`  
e~wuoE:M3  
=*ZQGM3w  
public static void log(int sMsg) aa:97w~s0  
{ &7gL&AY8  
System.err.println(sMsg); L `7~~  
} ,g2oqq ?  
} .:<-E%  
!3E %u$-}  
gEejLyOag  
/* =z=$S]qN  
**TestMethod.java `2 vv8cg^  
*/ _A8x{[$  
package NetFox; w Ud6xR  
EQ;,b4k?&g  
>:2Br(S  
public class TestMethod { z x7fRd$  
~Sr`Tlp  
ka3(sctZ5  
public TestMethod() 3L;GfYr0  
{ ///xx/weblogic60b2_win.exe ujo3"j[b  
try{ 6NvdFss'A{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p4ML } q8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >o#5tNm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iMrNp  
fileFetch.start(); "zT#*>U  
} (x.O]8GKP  
catch(Exception e){e.printStackTrace ();} 71nI`.Z  
/& qN yo  
f*+eu @  
} h{dR)#)GF<  
hQm"K~SW=  
(#4   
public static void main(String[] args) ?1r>t"e5  
{ q~3dbj  
new TestMethod(); O<@S,/Q4  
} U[!x 0M  
} $@[`/Uh   
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