http断点续传简单实现（java)

/* GlDl0P,*r  
**SiteFileFetch.java sQT0y(
FW  
*/ T1@]:`&  
package NetFox; YdgaZJs  
import java.io.*; j
HOE%  
import java.net.*; Q6cF<L`bW  
V9 pKbX  
v:YW[THre  
public class SiteFileFetch extends Thread { rZ~.tT|(  
F1@gYNbI,  
#du!tx ( _  
SiteInfoBean siteInfoBean = null; //文件信息Bean (aX5VB**  
long[] nStartPos; //开始位置 zl: 5_u=T  
long[] nEndPos; //结束位置 W@^O'&3d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H1,;Xrm  
long nFileLength; //文件长度 `]^JOw5o  
boolean bFirst = true; //是否第一次取文件 N'fE^jqU  
boolean bStop = false; //停止标志 %#rH~E  
File tmpFile; //文件下载的临时信息 3N)
bJ  
DataOutputStream output; //输出到文件的输出流 +3 2"vq)_  
Og`6>?>97  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rZDmZm?=  
public SiteFileFetch(SiteInfoBean bean) throws IOException xQ `>\f  
{ 29?{QJb  
siteInfoBean = bean; /x6,"M[97  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NU*6MT4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xj/ +Z!,9  
if(tmpFile.exists ()) nQc]f*  
{ Ojx1IL  
bFirst = false; v
ZM.gn  
read_nPos(); !\a'GO[  
} 1{oq8LB  
else p;dH[NW  
{ r^?Qo  
nStartPos = new long[bean.getNSplitter()]; RZ!-,|"cwL  
nEndPos = new long[bean.getNSplitter()]; ta*B#2D>  
} ,%+i}H,3  
1/Pou)D  
\c&%F=1+*  
4VjP:>*p  
} lPh>8:qFM  
qV$\.T>x  
v1yNVs\}  
public void run() IYq)p /  
{ y>vr Uxgo  
//获得文件长度 (u81
p  
//分割文件 'AX/?Srd  
//实例FileSplitterFetch -hf)%o$  
//启动FileSplitterFetch线程 CT@JNG$<"  
//等待子线程返回 .kSx>3  
try{ 6@-VLO))O  
if(bFirst) Kr!(<i  
{ }fW@8ji\  
nFileLength = getFileSize(); P1b5=/}:V  
if(nFileLength == -1) %aU4d e^  
{ 6mJa  
System.err.println("File Length is not known!"); cn$E?&-
 
} \4q% n  
else if(nFileLength == -2) (yv&&Jc  
{ O_#Ag K<A  
System.err.println("File is not access!"); XV+s 5C  
} '~{^c}  
else YFD'&N,sx  
{ 'W5r(M4U  
for(int i=0;i<nStartPos.length;i++) 9x/HQ(1  
{ ?Gc9^bB I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >|L,9lR_b  
} i DV.L  
for(int i=0;i<nEndPos.length-1;i++) , ;L  
{ q;a`*gX^  
nEndPos = nStartPos[i+1]; "8wRxDr+  
} ~y%8uHL:  
nEndPos[nEndPos.length-1] = nFileLength; <N11$t&_  
} |:SBkM,  
} 1;<J] S$$  
O1pBr=+j+{  
xQX,1NbH5  
//启动子线程 >OVi{NyT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w#wlZ1f  
for(int i=0;i<nStartPos.length;i++) N\?%944R  
{ Y,OS
QBgk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TTaSg\K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9^Q:l0|  
nStartPos,nEndPos,i); *a*\E R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a;J{'PHu  
fileSplitterFetch.start(); 5 T1M:~u i  
} _D:#M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N.OC _H&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o0b}:`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /238pg~Cw5  
nEndPos = " + nFileLength); 3Xgf=yG:M  
// fileSplitterFetch[nPos.length-1].start(); rK W<kQT  
8;YeEW5  
)&}\2NK6L  
//等待子线程结束 $}0q=Lg%wv  
//int count = 0; w?6"`Mo  
//是否结束while循环 60P^aj$V  
boolean breakWhile = false; +U9Gj#  
DTrS9j?z  
pqO}=*v@  
while(!bStop) pmd=3,D'u  
{ *joy%F  
write_nPos(); jy`jxOoG~Z  
Utility.sleep(500); ;hi+.ng_  
breakWhile = true; jA R@?X  
hc}dS$=C  
DQM\Y{y|3  
for(int i=0;i<nStartPos.length;i++) $F-qqkR$  
{ W!pLk/|ls  
if(!fileSplitterFetch.bDownOver) Qhb].V{utV  
{ 0UeDM*  
breakWhile = false; @BWroNg{  
break;
0
lR/6CB  
} 1J<Wth{  
} A6Ttx{]  
if(breakWhile) v]|^.x:  
break; 9E^IEwq'  
bj4cW\b(  
_y&m4Vuu  
//count++; %;kr%%t%  
//if(count>4) =s`\W7/;{-  
// siteStop(); 1UX"iOx(  
} 6%Ap/zvCZ>  
ALS\}_8  
%1fH-:c=C0  
System.err.println("文件下载结束！"); (KR$PLxDK  
} YXxaD@  
catch(Exception e){e.printStackTrace ();} _7
>$'V{  
} cUssF%ud]  
\D(6
t!Ox  
9,=3D2x&  
//获得文件长度 Y<M,/Y_ !  
public long getFileSize() MVU5+wX  
{ ]5W0zNb*  
int nFileLength = -1; WUx}+3eWv  
try{ v;"
[1w}  
URL url = new URL(siteInfoBean.getSSiteURL()); I`kaAOe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BsiHVr  
httpConnection.setRequestProperty("User-Agent","NetFox"); pASNiH698  
VH7VJ [  
Qi`Lj5;\F  
int responseCode=httpConnection.getResponseCode(); #4"(M9kf  
if(responseCode>=400) MkZm =Sf  
{ w!o[pvyR$  
processErrorCode(responseCode); ;rWgt!l  
return -2; //-2 represent access is error A\Rkt;:  
} CrC1&F\dq  
8#NtZ  
YKq,`7"%  
String sHeader; r=6-kC!T9  
62K7afH  

^Ts|/+}'i  
for(int i=1;;i++) MjCD;I:C.  
{ uc9t0]o=h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /,dcr*  
//Utility.log(in.readLine()); @G< J+pm  
sHeader=httpConnection.getHeaderFieldKey(i); BYt#aqf  
if(sHeader!=null) :iJ+ImBpK  
{ nPh5(&E  
if(sHeader.equals("Content-Length")) w1B!z  
{ rlr)n\R#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :&ir5xHS  
break; <4SY'-w  
} 4hdxqI!y2  
} T!e]=  
else YL
\d2  
break; W]MKc&R  
} XB,  2+  
} KB49~7XjQ@  
catch(IOException e){e.printStackTrace ();} t98t&YUpm  
catch(Exception e){e.printStackTrace ();} s*{l}~fPkW  
~
*RG|4#  
Br.$:g#  
Utility.log(nFileLength); B}_*0D  
0A\OZ^P8  
xayo{l=uGv  
return nFileLength; wJM})O%SQ  
} <EFA^,3t%  
,K=\Y9l3  
Zyxr#:Qm  
//保存下载信息（文件指针位置） o-\ K]  
private void write_nPos() 8P5yaS_  
{ Rhh5r0 \5  
try{ P3X;&iT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); '<_nL8A^  
output.writeInt(nStartPos.length); `%}SK~<R  
for(int i=0;i<nStartPos.length;i++) $,$bZV  
{ K|nh`r   
// output.writeLong(nPos); - &u]B$  
output.writeLong(fileSplitterFetch.nStartPos); Jm&7&si7  
output.writeLong(fileSplitterFetch.nEndPos); GJN"43  
} Iko1%GJ1Z  
output.close(); U_ n1QU  
} =W'a6)WE  
catch(IOException e){e.printStackTrace ();} %PozxF:  
catch(Exception e){e.printStackTrace ();} vI3L <[W  
} i"mN0%  
"L^]a$&  
a^_\#,}  
//读取保存的下载信息（文件指针位置） vw VeHjR  
private void read_nPos() Q qGf*  
{ .%;`:dtj  
try{ 1y@d`k`t:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pEgQ) 9\  
int nCount = input.readInt(); 8qGK"%{ ~  
nStartPos = new long[nCount]; ("-Co,4ey  
nEndPos = new long[nCount]; ApHs`0=(  
for(int i=0;i<nStartPos.length;i++) +{U0PI82  
{ A\p'\@f  
nStartPos = input.readLong(); c,nE@~ul2  
nEndPos = input.readLong(); Hx[YHu KL^  
} 5%,5Xe4p  
input.close(); Hhx"47:  
} 3V~871:-~  
catch(IOException e){e.printStackTrace ();} dbM~41C6  
catch(Exception e){e.printStackTrace ();} ssaEAm:  
} \6o%gpUkD  
ZDEz&{3U;  
=@(&xfTC  
private void processErrorCode(int nErrorCode) ~+w'b7T,=  
{ kt?G\H!}  
System.err.println("Error Code : " + nErrorCode); Sy|fX_i  
} IcmTF #{D  
AyHhq8Y  
}jHS  
//停止文件下载 MH@=Qqx#=t  
public void siteStop() "TW%-67  
{ KMC]<  
bStop = true; rTTde^^_  
for(int i=0;i<nStartPos.length;i++) iAD'MB  
fileSplitterFetch.splitterStop(); PyQt8Qlz  
UhKC:<%  
]DVZeI03@  
} Qj;wklq  
} K|Jp
kEw  
//负责部分文件的抓取 U-~cVk+LI  
**FileSplitterFetch.java dqF]kP,VG  
*/ IoO tn  
package NetFox; )e&U'Fx  
/)RyRS8c  
ILi{5L  
import java.io.*; FW* k O  
import java.net.*; P^9y0Q  
BG ,ln(Vz  
kaM=Fk=t  
public class FileSplitterFetch extends Thread { zq]I"0Bi.  
2I'gT$h  
S -$ L2N  
String sURL; //File URL qw^kA?  
long nStartPos; //File Snippet Start Position cGF_|1`  
long nEndPos; //File Snippet End Position wEd+Ds]$  
int nThreadID; //Thread's ID a#3+PB#  
boolean bDownOver = false; //Downing is over Ws;S=|9,7~  
boolean bStop = false; //Stop identical (gW#T\Eln  
FileAccessI fileAccessI = null; //File Access interface wW2b?b{*Z  
,U`:IP/L  
-u
)f@e  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =' %r"_`}  
{ \j C[|LM&  
this.sURL = sURL; 0 D^d-R,  
this.nStartPos = nStart; fny|^F]w  
this.nEndPos = nEnd; BK>3rjXi>a  
nThreadID = id; {jz?LM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B=dF\.&Z  
} ]b5E

_/P  
HUR
rk~[  
iCd$gwA>F  
public void run() ^a+W!  
{ MnToL@  
while(nStartPos < nEndPos && !bStop) r?cDyQE  
{ _0HCtx ;  
R1'tW=  
scr`] tD  
try{ pO]{Y?X:  
URL url = new URL(sURL); %[3?vX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HC1jN8WDY  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2ed4xhV  
String sProperty = "bytes="+nStartPos+"-"; /%qw-v9qPV  
httpConnection.setRequestProperty("RANGE",sProperty); R<\5q%@G  
Utility.log(sProperty); HJ5 Ktt  
jnF-kia  
!97U2L4  
InputStream input = httpConnection.getInputStream(); +]?/c>M  
//logResponseHead(httpConnection); wWq(|"  
Buxn!s  
X8(H#Ef[  
byte[] b = new byte[1024]; aTi2=HL=S  
int nRead; kdmmfw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :Q\Es:y  
{ U
Xs=7H".  
nStartPos += fileAccessI.write(b,0,nRead); v67utISNI  
//if(nThreadID == 1) -@*[   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >.sdLA Si  
} 6?B'3~r  
K;uOtbdOK  
|[6jf!F  
Utility.log("Thread " + nThreadID + " is over!"); M:[rH  
bDownOver = true; &P2tzY'  
//nPos = fileAccessI.write (b,0,nRead); Q4~/Tl;  
} [Eq7!_3  
catch(Exception e){e.printStackTrace ();} KImBQ2^Tu  
} K!AW8FnHkZ  
} XSfl'Fll D  
U2hPsF4f  
#:q$sKQ_$  
//打印回应的头信息 FJI%+$]  
public void logResponseHead(HttpURLConnection con) wl^7.IR  
{ Z}X oWT2f  
for(int i=1;;i++) pt/UY<@yoN  
{ /Kw}R5l  
String header=con.getHeaderFieldKey(i); Kp]\r-5UD>  
if(header!=null) z2.9l?"rfQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %#AM }MWIa  
Utility.log(header+" : "+con.getHeaderField(header)); Ai*R%#  
else ^4G%*-   
break; G`;YB  
} Pn?,56SD=  
} ]t2zwHo#  
OEZ`5"j  
3y#U|&]{  
public void splitterStop() ?$chO|QY  
{ zcqv0lM '  
bStop = true; [ GcH4E9r  
} vk:k~  
YGdzA]3>  
^-wdIu~p?  
} n0\k(@+k  
r%:Q(|v?  
$Gy&  
/* kzkrvC+u  
**FileAccess.java lwVo%-  
*//文件访问(定位，写) U{`Q_Uw@$:  
package NetFox; 7%MD0qm-  
import java.io.*;
e7O9q8b  
)2pOCAjL2  
MBIlt 1P  
public class FileAccessI implements Serializable{ a+-X\qN  
c}-ADr9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t^k^e{,q#  
RandomAccessFile oSavedFile; z~m{'O`  
long nPos; Q *]d[  
*ku}.n  
_L^(CFE  
public FileAccessI() throws IOException 8*bEsc|  
{ x$SxGc~4gb  
this("",0); <<SUIY@X  
} vC [uEx:  
 S6d&w6  
,P>xpfdK  
public FileAccessI(String sName,long nPos) throws IOException xj!G9x<!  
{ dvc=<!"'S  
oSavedFile = new RandomAccessFile(sName,"rw"); #9/^)^k  
this.nPos = nPos; ?'8('
]/  
oSavedFile.seek(nPos); HxAN&g*:  
} 39yp1  
#/,WgsAC  
f{HjM? Mb3  
public synchronized int write(byte[] b,int nStart,int nLen) S- N [  
{ Y[R;UJE`5  
int n = -1; i"_@iN0N  
try{ \@8.BCWK  
oSavedFile.write(b,nStart,nLen); m)q e  
n = nLen; zbL8 pp  
} Iq?#kV9)  
catch(IOException e) qlU"v)Mx  
{ /
19ZyQw9  
e.printStackTrace (); >WZ_) `R  
} 6OPYq*|  
,_
iR  
>^Z==1  
return n; p"dK,A5#)  
} x|=]Xxco  
J1\H^gyW)  
uD0<|At/  
} i]
{-KZC  
W1!Nq`  
j*fs [4  
/* H[DBL  
**SiteInfoBean.java vU9j|z  
*/ Z(|'zAb^  
package NetFox; 3 q^^Os  
sy(8-zbI  
!uc"|S?  
public class SiteInfoBean { K\VL[HP-  
wfMtWXd;KB  
sQ aP:@  
private String sSiteURL; //Site's URL X4$86  
private String sFilePath; //Saved File's Path 1 k\~%  
private String sFileName; //Saved File's Name uLq%Nu  
private int nSplitter; //Count of Splited Downloading File v?L
`aj1ox  
%2ZWSQD  
[h0.k"&[  
public SiteInfoBean() Pw|J([  
{//nSplitter的缺省值为5 GE!fh1[[u  
//default value of nSplitter is 5 .QLjaEja  
this("","","",5); KmX?W/%R  
} *=)kR7,]9d  
>g+e`!;6  
RQ*oTsq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EG#mNpxE  
{ A>Y#-e;<d  
sSiteURL= sURL; $v\o14v  
sFilePath = sPath; !?aL_{7J  
sFileName = sName; x@Ze%$'  
this.nSplitter = nSpiltter; '\wZKYVN  
hhr!FQ.+/  
Naa "^  
} d) $B  
k.6gX<T  
o/\f+iz7  
public String getSSiteURL() 6!A+$"  
{ &fRZaq'2R  
return sSiteURL; =8W'4MC  
} RA3!k&8?#  
@UwDsx&2(t  
p->b Vt  
public void setSSiteURL(String value) XdV(=PS!a@  
{ \2OjIEQ
Q  
sSiteURL = value; 9>!B .Z?!#  
} )+dd  

ud$*/ )/  
LEJn 1  
public String getSFilePath() O <#H5/Tq  
{ 8h$f6JE  
return sFilePath; 7blo<|9  
} TO]7%aB  
F- l!i/  
=67tQx58  
public void setSFilePath(String value) E,gpi  
{ Bxf]Lu,\U@  
sFilePath = value; >`)IdX  
} Xo/0lT  
'FC#O%l  
}~+_|
  
public String getSFileName() Uy;e5<<  
{ U%4s@{7  
return sFileName; ATkx_1]KM-  
} )9~-^V0A^>  
%"=qdBuk  
vE$n0bL2  
public void setSFileName(String value) >pj)va[Q  
{ <F&53N&Zc  
sFileName = value; =&x u"V  
} me
t`f0jw  
Y<)9TU:D!  
JL:\\JT.  
public int getNSplitter() ,k+F8{Q.  
{ ?:c:D5N  
return nSplitter; oeF0t'%  
} ~Bls
j9a2  
}:xj%?ki  
x2$Y"b?vz  
public void setNSplitter(int nCount) MgrJ ;?L  
{ 4)z*Vux  
nSplitter = nCount; 5169E*  
} ;Sw%t(@  
} >>R,P Ow-  
9 =zZ,dg  
f6U i~  
/* aF5=k:k  
**Utility.java N*6lyFcg  
*/ Y:KIaYkk  
package NetFox; %C=?Xhnv  
/PTk296@  
=BVBCh  
public class Utility { }U_z XuUz  
NKRI|'Y,  
AEO7I f@  
public Utility() ;(0|2I'"  
{ *^s^{0Ad  
&A)u!l Ue  
)Bpvi4O  
} %?i~`0-:n%  
BU=;r
z!;  
//线程睡眠 ZO\x|E!b  
public static void sleep(int nSecond) *sYvV,  
{ ;T\'|[bY   
try{ Vohd d_x  
Thread.sleep(nSecond); xt=ELzu$  
} k^e;V`(  
catch(Exception e) lL6W:Fq@(  
{ Y9ipy_@_?  
e.printStackTrace (); bO6LBSZx]  
} i=aK ?^+  
} xk@fBa }  
|>!tqgq  
//日志 &eY&6I  
public static void log(String sMsg) 65>}Q.p  
{ ~pG,|\9  
System.err.println(sMsg); o@@, }  
} %}1v-z  
;^9y#muk  
'FN+BvD  
public static void log(int sMsg) u~\l~v^mj  
{ @; 0t+  
System.err.println(sMsg); ~xakz BE  
} 1b`WzoJgH  
} L2`a| T=  
:~4M9  
,!Q^"aOT:  
/* j@C*kj;-  
**TestMethod.java 4elA<<  
*/ Jx3fS2  
package NetFox; ! w2BD^V-  
MVXy)9q  
v|@1W Uc,g  
public class TestMethod { N5jJ,iz  
/^Ng7Mi!  
![3l K  
public TestMethod() %mr6p}E|  
{ ///xx/weblogic60b2_win.exe 84jA)  
try{ .u\xA7X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q@5v> `  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i;I!Jc_b'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6 TSC7jO  
fileFetch.start(); {~{</ g/  
} &T2qi'  
catch(Exception e){e.printStackTrace ();} 6:3F,!J!  
;'P<#hM[$  
a`_w9r+v  
} (MnK \^Y  
qfa[KD)!aB  
o7 1f<&1  
public static void main(String[] args) M TOZ:b  
{ H`EsFKw\%  
new TestMethod(); hYY-Eq4TC  
} U8GvUysB!  
} !7y:|k,ac  
点击下载更多相关资料