http断点续传简单实现（java)

/* wR@&C\}9  
**SiteFileFetch.java "g;^R/sfq  
*/ JL5 )  
package NetFox; ]vo&NE  
import java.io.*; J!b v17H"  
import java.net.*; />=)=CGv;  
NokAP|<y  
t
gCEz%  
public class SiteFileFetch extends Thread { uH!uSB2  
Q(=}
PF  
vPz$jeA  
SiteInfoBean siteInfoBean = null; //文件信息Bean d:cs8f4>  
long[] nStartPos; //开始位置 ;.>CDt-E]  
long[] nEndPos; //结束位置 a NhI<.v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *8{PoD   
long nFileLength; //文件长度 Y3KKskhLx  
boolean bFirst = true; //是否第一次取文件 puEuv6F  
boolean bStop = false; //停止标志 @0H}U$l  
File tmpFile; //文件下载的临时信息 8@pY:AY  
DataOutputStream output; //输出到文件的输出流 n]c6nX:'  
-T3 z@k  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pB*8D  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~5g2~.&*  
{ xXkP(^ Y  
siteInfoBean = bean; 53=5xE= `D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *M6' GT1%c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >1u!(-A  
if(tmpFile.exists ()) sx7;G^93  
{ ^'9:n\SKQ  
bFirst = false; o,}`4_N||  
read_nPos(); 4JV/Ci5  
} qYjR  
else 2 u:w  
{ ?XO
l>IO  
nStartPos = new long[bean.getNSplitter()]; ]
'+PJdA  
nEndPos = new long[bean.getNSplitter()]; UolsF-U}'  
} 'e @`HG  
TrA&yXXL  
lAYyxG#  
)\oLUuL`;  
} bn$a7\X-  
D2<(V,h9  
6_xPk`m  
public void run() W:s`;8iM$  
{ ]rk8Jsg  
//获得文件长度 R<wPO-dX  
//分割文件 R)}ab{A  
//实例FileSplitterFetch -36pkC 6 \  
//启动FileSplitterFetch线程 +Wgp~$o4  
//等待子线程返回 l}\q }7\)  
try{ ,gYbi-E  
if(bFirst) i|M^QKvF  
{ y$-;6zk\]  
nFileLength = getFileSize(); G!Gbg3:4e5  
if(nFileLength == -1) m3Ma2jLWC  
{ S:b-+w|*  
System.err.println("File Length is not known!"); MLVrL r t  
} 8n
KZ  
else if(nFileLength == -2) {|:ro!&  
{ _d<xxF^q  
System.err.println("File is not access!"); VH*4fcT'D  
} acG4u+[ ]  
else ONr}{T%@/  
{ p0r:U<&  
for(int i=0;i<nStartPos.length;i++) >s*ZT%TF  
{ jEaU;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RH^!7W*  
} MTyBGrs(  
for(int i=0;i<nEndPos.length-1;i++) jPum2U_  
{ <4{Jm8zJ  
nEndPos = nStartPos[i+1]; DAvF ND$=  
} Ej;BI#gx=  
nEndPos[nEndPos.length-1] = nFileLength; ;&K +x@  
} d<,'9/a>  
} IXA3G7$)  
)P|&o%E  
>^odV ;^  
//启动子线程 1ha 8)L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #.KVT#%~{  
for(int i=0;i<nStartPos.length;i++) R}T8cVxc  
{ TAE@KSPvo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OQ=0>;>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4Y.o RB  
nStartPos,nEndPos,i);
8gIf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zyh #ygH  
fileSplitterFetch.start(); .5s#JL  
} m,3H]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iYPlgt/Y!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |<2g^ZK)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Lo{g0~?x*  
nEndPos = " + nFileLength); <F%c"Rkh  
// fileSplitterFetch[nPos.length-1].start(); |mS-<e8LY4  
Kn#CIFbBN  
OZSM2~  
//等待子线程结束 To!` T$Xh  
//int count = 0; 50E?K!  
//是否结束while循环 f6$$e+  
boolean breakWhile = false; :4\=xGiY  
R?Ou=p .  
S A\_U::T  
while(!bStop) nmN3Z_  
{ pl4:>4l/  
write_nPos(); ey/=\@[p  
Utility.sleep(500); Uv|?@zy#  
breakWhile = true; '<R::M,  
Acl?w
}Y  
+qiI;C_P\  
for(int i=0;i<nStartPos.length;i++) V/dL-;W;  
{ 4))5l9kc.  
if(!fileSplitterFetch.bDownOver) t`!@E#VK  
{ :G8:b.  
breakWhile = false; x^XP<R{D  
break; 04E S>'@  
} k;~*8i=%,\  
} %8hx3N8>  
if(breakWhile) 8bf~uHAr  
break; c`agrS:P  
K2@],E?e%|  
XlaGR2-%  
//count++; =c34MY(#X  
//if(count>4) i%3q*:A]2  
// siteStop(); $a.,;:  
} VTl\'>(Cl  
k"pN  
6=3;(2u[C"  
System.err.println("文件下载结束！"); FE4P EBXvu  
} pm>$'z!.):  
catch(Exception e){e.printStackTrace ();} {;^GKb+  
} Lyy:G9OV  
?Hrj}K27  
=}OcMM`f  
//获得文件长度 h{/lW#[  
public long getFileSize() ["~T)d'  
{ l\"wdS}  
int nFileLength = -1; Lz:Q6  
try{ "59"HVV  
URL url = new URL(siteInfoBean.getSSiteURL()); h~-cnAMt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $X ]t}
=  
httpConnection.setRequestProperty("User-Agent","NetFox"); k*e$_  
=EQaZ8k  
K]H [A,  
int responseCode=httpConnection.getResponseCode();
^tRy6zG  
if(responseCode>=400) O3En+m~3n)  
{ iL8:I)z  
processErrorCode(responseCode); D^<5gRK?  
return -2; //-2 represent access is error <gLq?~e|A  
} |576)  
$l/w.z  
V:h3F7  
String sHeader; ^CfWLL&
c  
#``Alh8  
[+(fN  
for(int i=1;;i++) Y5R|)x  
{ +T8]R7b9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9
|x{z  
//Utility.log(in.readLine()); [{-5  
sHeader=httpConnection.getHeaderFieldKey(i); #m6W7_  
if(sHeader!=null) 5]F4.sa  
{ <Url&Z  
if(sHeader.equals("Content-Length")) `^'0__<M  
{ yo]8QO]97  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }@<Ru  
break; 1pJ
?YV  
} !~!\=e
tm  
} / 0y5/  
else J"?jaa2~  
break; (Nn)_caVb  
} 5z@QAQ  
} IiZXIG4H  
catch(IOException e){e.printStackTrace ();} b.mWB`59  
catch(Exception e){e.printStackTrace ();} 9HG"}CGZP  
+1>\o|RF  
RWdx)qj{  
Utility.log(nFileLength); m=qyPY  
qLk7C0  
wt1Y&D  
return nFileLength; #|;;>YnZ  
} ,%$Cfu  
m4 :"c"  
:,pdR>q%(y  
//保存下载信息（文件指针位置） ~09kIO)  
private void write_nPos() )O$T; U  
{ TykY>cl   
try{ oG' 'my#3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =aCd,4B}  
output.writeInt(nStartPos.length); <59G  
for(int i=0;i<nStartPos.length;i++) #bCzWg  
{ 7da~+(yhr  
// output.writeLong(nPos); 0*50uK=5  
output.writeLong(fileSplitterFetch.nStartPos); q|S,^0cU  
output.writeLong(fileSplitterFetch.nEndPos); Py~N.@(:1u  
} ?Suv.!wfLl  
output.close(); 3im2 `n  
} xG|n7w*  
catch(IOException e){e.printStackTrace ();} BBHoD:l  
catch(Exception e){e.printStackTrace ();} ?RU_SCp-  
} o{xA{ @<  
C0-,<X  
"xp>Vj  
//读取保存的下载信息（文件指针位置） zD): yEc  
private void read_nPos() EQ2HQz]  
{ e\WG-zi/  
try{ 3y]rhB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {^6<Ohe4j  
int nCount = input.readInt(); 7U`8W\-  
nStartPos = new long[nCount]; {!37w[s~  
nEndPos = new long[nCount]; vlx\hJ<I  
for(int i=0;i<nStartPos.length;i++) jU_#-<'r  
{ &d i=alvv1  
nStartPos = input.readLong(); QI{<q<  
nEndPos = input.readLong(); U?(+ {4l  
} <:I]0|[  
input.close(); 8npjQ;%4>  
} *}Nh7>d(  
catch(IOException e){e.printStackTrace ();} L0>w|LpRc  
catch(Exception e){e.printStackTrace ();} 0=c:O  
} g33Y]\  
}W$}blbp  
Z$
2Vd`XP  
private void processErrorCode(int nErrorCode) Aj "SSX!L  
{  Sn-D|Z  
System.err.println("Error Code : " + nErrorCode); TDY =!  
} B6"pw0  
<7yn:  
H
'wh0K(  
//停止文件下载 VIg=|Oe),  
public void siteStop() e3x;(@j  
{ } f+hB  
bStop = true; HQtUNtZ  
for(int i=0;i<nStartPos.length;i++) Ps9YP B-  
fileSplitterFetch.splitterStop(); tqT-9sEXX.  
IXt cHAgX  
iYl$25k/1  
} f f_| 3G  
} (]*!`(_b  
//负责部分文件的抓取 kJ:zMVN  
**FileSplitterFetch.java v9+1[Y";  
*/ a#i%7mfn  
package NetFox; {#J1D*?
$"  
3:G94cp5  
,Z p9,nf  
import java.io.*; 8WRxM%gsH  
import java.net.*; .47tj`L  
@AAkEWo)_  
"f3KE=cUm  
public class FileSplitterFetch extends Thread { f+Da W  
/e4#DH  
vV+>JM6<K  
String sURL; //File URL 6N]V.;0_5  
long nStartPos; //File Snippet Start Position >m&r,
z  
long nEndPos; //File Snippet End Position +jpC%o}C  
int nThreadID; //Thread's ID 'c|Y*2@  
boolean bDownOver = false; //Downing is over O.~@V(7ah  
boolean bStop = false; //Stop identical <u85>x  
FileAccessI fileAccessI = null; //File Access interface NK0hT,_  
^7&0Pm  
9dXtugp|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~TEKxgU  
{ jt8% L[  
this.sURL = sURL; WmT(>JBO  
this.nStartPos = nStart; Nd.Tda!Kg  
this.nEndPos = nEnd; ewb/Z[4  
nThreadID = id; 4yu ^cix(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (6Sf#M  
} ,-[dr|.  
niIjatT  
UCP4w@C  
public void run()
pr(16P  
{ >{]mN5  
while(nStartPos < nEndPos && !bStop) Fl^}tC  
{ T c{]w?V  
3e.v'ccK&  
:,^pLAt  
try{ ^"d!(npw  
URL url = new URL(sURL); (W l5F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ii:h E=  
httpConnection.setRequestProperty("User-Agent","NetFox"); j!H\hj/]  
String sProperty = "bytes="+nStartPos+"-"; wbaXRvg  
httpConnection.setRequestProperty("RANGE",sProperty); {!C';^  
Utility.log(sProperty); ToHCS/J59  
F+@E6I'g  
SEc3`y;j%  
InputStream input = httpConnection.getInputStream(); )2P4EEs[  
//logResponseHead(httpConnection); {A2SG#}  
_~`\TS8  
<k^P>Irb3t  
byte[] b = new byte[1024]; S)0bu(a`Z,  
int nRead; Eqg(U0k0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .bYDj&]P{  
{ fFfH9cl!  
nStartPos += fileAccessI.write(b,0,nRead); .FnO  
//if(nThreadID == 1) 3?vasL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 61Nj&1Ze  
} w\'Zcw,d  
Lj$yGdK<  
\"qXlTQ1_9  
Utility.log("Thread " + nThreadID + " is over!"); WRJ+l_81  
bDownOver = true; :ji_dQ8k  
//nPos = fileAccessI.write (b,0,nRead); w49Wl>M  
} +SmcZ^\OZ  
catch(Exception e){e.printStackTrace ();} ]rDf3_!m(  
} HB$*xS1  
} ,$habq=;  
k})Ag7c  
x,js}Mlw  
//打印回应的头信息 }`$:3mb&f  
public void logResponseHead(HttpURLConnection con) *_$%Tv.]  
{ 8kih81tx"U  
for(int i=1;;i++) /c`)Er6d  
{ Fz16m7.  
String header=con.getHeaderFieldKey(i); :YB:)wV,P  
if(header!=null) qeCx.Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^\cB&<h  
Utility.log(header+" : "+con.getHeaderField(header)); ehXj.z  
else mj<(qZh  
break; 4T6dju  
} 8^zI  
} Xt/T0.I  
d'Z|+lq:  
'=x  
public void splitterStop() zp4Jd"XBX  
{ !xMyk>%2  
bStop = true; .*D~ .!  
} _"J-P={=  
'M+iVF6  
Qg?^%O'  
} d> Y9g  
!l_1r$  
XN]kNJX  
/* GS~jNZx  
**FileAccess.java E/LR(d_  
*//文件访问(定位，写) ;,Sl+)@h  
package NetFox; ^MUtmzh  
import java.io.*; }MrRsvN  
DI**fywu[3  
~tDV{ml  
public class FileAccessI implements Serializable{ E<'3?(D9hL  
$t-HJ<!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j$zw(EkN  
RandomAccessFile oSavedFile; +|Xx=1_?BK  
long nPos; uFb&WIo1  
9pStArF?F0  
,;H)CUe1"  
public FileAccessI() throws IOException WU{G_Fqaz  
{  HlPf   
this("",0); xc8MOm  
} ^{-J Y  
zfO0+fMH  
k%/Z.4vQG  
public FileAccessI(String sName,long nPos) throws IOException r3/H_Z  
{ (m=-oQ&Ro  
oSavedFile = new RandomAccessFile(sName,"rw"); [$]vi`c2  
this.nPos = nPos; O@'/B" &  
oSavedFile.seek(nPos); 4iRcmsP  
} L=VJl[DL  
tV@!jaj\  
3uz@JY"mK  
public synchronized int write(byte[] b,int nStart,int nLen) zy8W8h(?  
{ |JSj<~1ki  
int n = -1; ,S2D/Y^>  
try{ l^%Ez?-:s  
oSavedFile.write(b,nStart,nLen); `3SY~&X  
n = nLen; @.a[2,o_  
} 0tC+
?  
catch(IOException e) 5K;jW  
{ !GURn1vcAe  
e.printStackTrace (); TV#pUQ3K  
} Nqk*3Q"f  
M8ZpNa  
:xm,Ok  
return n; w{UVo1r:  
} BYyR-m  
b/Z=FS2T  
/d&zE|!  
} "b8<C>
wY  

[:  
"Up3W%]SB  
/* =[FNZ:3  
**SiteInfoBean.java (2[tQ`~  
*/ 'mXf8   
package NetFox; "6w-jT  
(xBS~}e  
1\=)b< y  
public class SiteInfoBean { eqb8W5h'  
3E$M{l  
G<#9`  
private String sSiteURL; //Site's URL a"EX<6"  
private String sFilePath; //Saved File's Path NBwxN  
private String sFileName; //Saved File's Name "G].hKgbk*  
private int nSplitter; //Count of Splited Downloading File ARGtWW~:  
PxNp'PZr9  
&q^\*<B.^  
public SiteInfoBean() zt/b S/  
{//nSplitter的缺省值为5 WUm83"  
//default value of nSplitter is 5 OS;qb:;  
this("","","",5); yl/-!  
} @e8b'w3  
(/UW}$] h  
c>#T\AEkF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l=ehoyER  
{ y3{'s>O6  
sSiteURL= sURL; 4{=zO(>  
sFilePath = sPath; %nk]zf..  
sFileName = sName; dQT A^m  
this.nSplitter = nSpiltter; UmUw>+A  
Z0uo. H@.N  
Tw*:Vw  
} YRa{6*M  
@M-i$ q[4  
&*}`uJt  
public String getSSiteURL() W=:4I[a6Q  
{ ;rXkU9  
return sSiteURL; XHs>Q>`  
} 1BK!<}yI{  
(k/[/`3ST  
-< D7  
public void setSSiteURL(String value)  kDbDG,O  
{ b* k=
  
sSiteURL = value; R+{QZ'K.qg  
} HHVCw7r0  
+yY
xHIOZ(  
p}H:t24Cr5  
public String getSFilePath() ere h!  
{ {9?++G"\  
return sFilePath; .TZ0FxW  
} eajctkzj  
zwJB.4@  
Q^13KWvuV  
public void setSFilePath(String value) c=d` DJ  
{ 1g_p`(  
sFilePath = value; {zzc/!|  
} dpAj9CX(  
o]T-7Gs4p  
4`E[WE:Q  
public String getSFileName() <"/b 5kc  
{
cPaz-  
return sFileName; @}9*rWJIE  
} &[ oW"Q{  
*^[m?3"W  
hc7"0mVd{  
public void setSFileName(String value)
hA=.${uIO  
{ ul(pp+%S  
sFileName = value; CE,0@%6F*  
} (F=/r]Q  
[A jY~  
ycD.X"  
public int getNSplitter() `L~gERW#  
{ EBQ,Ypv  
return nSplitter; n[[2<s*YJ  
} 813t=A  
]?p 9)d=%<  
=;L44.,g  
public void setNSplitter(int nCount) jJ.isr|`  
{ kB#;s  
nSplitter = nCount; 0*J},#ba$  
} m!Y4+KTwD`  
} H8
!; XB  
My6a.Kl  
!)r1zSY"g  
/* "udA-;!@&  
**Utility.java 5,_DM  
*/ z:1"d R   
package NetFox; R1cOUV,y[/  
/Fj*sS8  
Mq~g+` '  
public class Utility { TI5<' U)  
Vq&}i~  
5M v<8P~  
public Utility() "?AJ(>wP  
{ pQ,|l$^m  
#1)#W6 h\  
|S6L[Uo  
} ~'#yH#o  
aG&t gD{  
//线程睡眠 \"7U,y',  
public static void sleep(int nSecond) 0<[g7BbR  
{ j
R[b7s  
try{ ]q`'l_O  
Thread.sleep(nSecond); ooA%/  
} @ JfQ}`  
catch(Exception e) A$jf#,  
{ [QDM_n  
e.printStackTrace (); GMKY1{   
} {>Yna"p  
} ]?*'[  
Uz_OUTFM  
//日志 "'3QKeM1  
public static void log(String sMsg) ,p' ;Xg6ez  
{ ,a34=,  
System.err.println(sMsg); RI2/hrW  
} fR&x5Ika0  
 myOdf'=  
6f*Q
Uw~  
public static void log(int sMsg) /?%1;s:'  
{ v*JXrB&x  
System.err.println(sMsg); %CV.xDE8  
} miUjpXt  
} jaL#  
*&BS[0
;  
[:MFx6  
/* 
!j%#7  
**TestMethod.java \Lg{GN.  
*/ p~yGp]yJ9  
package NetFox; VmON}bb[zz  
Utj4f-M  
R4%}IT^%P  
public class TestMethod {
T9?8@p\}(  
"ph[)/u;  
PUEEfq!%  
public TestMethod() .#{m1mr  
{ ///xx/weblogic60b2_win.exe b *Ca*!  
try{ y_M,p?]^,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n{"e8vQx
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c7@[RG !  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a8 .x=j<  
fileFetch.start(); \:jJ{bl^A  
} !bBx'  
catch(Exception e){e.printStackTrace ();} GhR%fxe  
TJ>$ ~9&Sy  
G O[u  
} ^wD@)Dz  
8X#\T/U  
#{g
6'9PMz  
public static void main(String[] args) ^=arKp,?5  
{ mJ'5!G  
new TestMethod(); e=Q{CsP  
} Q\pI\]p:  
} ' 1D1y'  
点击下载更多相关资料