http断点续传简单实现（java)

/* JN_# [S$  
**SiteFileFetch.java s><co]  
*/ i7FEjjGtG  
package NetFox; :z\STXq  
import java.io.*; \+xsJbEV  
import java.net.*; 4"sP= C  
c'b,=SM  
~"k'T9QBY  
public class SiteFileFetch extends Thread { D6w0Y:A{.  
9\F^\h{  
r
y'(mM  
SiteInfoBean siteInfoBean = null; //文件信息Bean Lmb<)YY  
long[] nStartPos; //开始位置 \IKr+wlN8  
long[] nEndPos; //结束位置 ]NCOi?Odx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F~1R.r_Lu  
long nFileLength; //文件长度 scdT/|(U$  
boolean bFirst = true; //是否第一次取文件 &>o)7H];  
boolean bStop = false; //停止标志 :R)IaJ6)  
File tmpFile; //文件下载的临时信息 DI_mF#5q  
DataOutputStream output; //输出到文件的输出流 amRtFrc|  
H|Ems}b  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a|.u;  
public SiteFileFetch(SiteInfoBean bean) throws IOException )-(NL!?`  
{ o0 Ae*Y0  
siteInfoBean = bean; <  -Nj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l_:%?4MA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )
7^jq|  
if(tmpFile.exists ()) KjadX&JD  
{ c\Dv3bF  
bFirst = false; utr_fFu  
read_nPos(); XL:7$  
} ]9' \<uR  
else rhrlEf@  
{ ]Uu/1TT
f  
nStartPos = new long[bean.getNSplitter()]; |fUSq1//  
nEndPos = new long[bean.getNSplitter()]; y{&,YV&_h  
} nMhc3t  
.NKN2  
DCj!m<Y&  
!>Xx</iD1  
} L|<Mtw  
{'1,JwSmb  
<6@Db$-  
public void run() $Ix^Rm9c  
{ }^H_|;e1p  
//获得文件长度 zSu2B6YU}  
//分割文件 Xy._&&pt  
//实例FileSplitterFetch J8jbtL O'  
//启动FileSplitterFetch线程 g0l- n  
//等待子线程返回 9;PtYdJ8  
try{ <t8})
 
if(bFirst) 2h=RNU|  
{ wNlp4Z'[  
nFileLength = getFileSize(); fRiHs\+  
if(nFileLength == -1) Rh=h{O  
{ {?8rvAjY  
System.err.println("File Length is not known!"); ?^dyQhb  
} 9:1ZL_yf  
else if(nFileLength == -2) z8oSh t`+  
{ ;.iy{&$  
System.err.println("File is not access!"); 5q\]]LV>  
} TtzB[F  
else [Y[|:_+5  
{ M-n +3E9  
for(int i=0;i<nStartPos.length;i++) 8g3 6-8  
{ gY%-0@g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )lZb=t  
} u URf  
for(int i=0;i<nEndPos.length-1;i++) Pu=YQ #F'  
{ J? C"be=  
nEndPos = nStartPos[i+1]; K$4Ky&89  
} Ae"B]Cxb_X  
nEndPos[nEndPos.length-1] = nFileLength; ]]+"`t,-  
} O?@AnkOhn  
} R8HFyP  
8qT/1b  
;yr'K  
//启动子线程 WaYT\CG7y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zQ6otDZx  
for(int i=0;i<nStartPos.length;i++) %NvY~,  
{ BwR)--75  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IMj{n.y4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NOvN8.K%  
nStartPos,nEndPos,i); .A E(D7d6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yv>% 5`  
fileSplitterFetch.start(); =dPrG=A  
} +S$x}b'5q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nkxVc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zJPzI{-w|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \QVL%,.%M  
nEndPos = " + nFileLength); 8{AzB8xp  
// fileSplitterFetch[nPos.length-1].start(); 'Ag?#vB  
SO|$X  
p?5zwdX+`  
//等待子线程结束 "_lSw3  
//int count = 0; O%OeYO69  
//是否结束while循环 "bJWyUb  
boolean breakWhile = false; ./u3z|q1  
,a}+Jj{  
uKK+V6}!kj  
while(!bStop) *t63c.S  
{ WawOap  
write_nPos(); Ls( &.  
Utility.sleep(500); Hd :2  
breakWhile = true; -Wf 2m6t  
)<%GHDWL  
T{Av[>M  
for(int i=0;i<nStartPos.length;i++) LBTf}T\  
{ n;[d{bU  
if(!fileSplitterFetch.bDownOver) [S4<bh!  
{ XLB7 E  
breakWhile = false; )Zox;}WK+  
break; H?PaN)_6-+  
} kIyif7  
} m
k}8Cu4  
if(breakWhile) 1$4dzI()  
break; ->d3FR  
q.*k J/L  
_G@)Bj^*  
//count++; [:Sl^ Z&6M  
//if(count>4) G22u+ua  
// siteStop(); 'vBuQinn  
} C1hp2CW$5/  
0`:0m/fsU  
NbH;@R)L  
System.err.println("文件下载结束！"); arm26YA-,  
} X-=49)  
catch(Exception e){e.printStackTrace ();} o!:   
} K1Mn
_)%  
y-9Mm9J  
12.|Ed*72  
//获得文件长度 *y0TtEd;  
public long getFileSize() 05Ak[OOU>  
{ f-^JI*hj  
int nFileLength = -1; #mFIZMTRd  
try{ J
.$N<.  
URL url = new URL(siteInfoBean.getSSiteURL()); f<<1.4)oSV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  (cx Q<5  
httpConnection.setRequestProperty("User-Agent","NetFox"); tw,uV)xm  
';Y0qitGB  
Ko:<@h  
int responseCode=httpConnection.getResponseCode(); 
!Wgi[VB  
if(responseCode>=400) )vn{?Ulj  
{ ;ry~x:7L7  
processErrorCode(responseCode); EN^5Hppb  
return -2; //-2 represent access is error JD9)Qelw^$  
} @cukoLAn  
]V^ >aUlj  
8u6*;*o  
String sHeader; G0)}?5L1J  
1aDx 6Mq  
4}`z^P<C  
for(int i=1;;i++) EV/DJ$C }  
{ )\Am:?RH;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DZ"'GQSg  
//Utility.log(in.readLine()); ^M0
  
sHeader=httpConnection.getHeaderFieldKey(i); ]jjHIFX  
if(sHeader!=null) zc K`hS  
{ *PM#ngLX}r  
if(sHeader.equals("Content-Length")) }]<0!q &xB  
{ 4 Fl>XM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]Q$Sei5  
break; t^ Ge"  
} !Ah v07SI  
} \xG_q>1_  
else LGB}:;$AL  
break; 6+!$x?5|NP  
} -!q^/ux  
} TXdo,DPv7  
catch(IOException e){e.printStackTrace ();} {.eo?dQ  
catch(Exception e){e.printStackTrace ();} *O_>3Hgl  
w{mw?0  
xu\s2x$  
Utility.log(nFileLength); s5h}MXIXw  
Np7+g`nG  
tTOBKA89  
return nFileLength; ~[<C6{  
} #zRHYZc'T|  
fYSH]!  
galzk$D  
//保存下载信息（文件指针位置） LY-,cXm&|  
private void write_nPos() G>=Fdt7Oc  
{ 9A~w2z\G  
try{ L>LIN 1
A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U$|q]N  
output.writeInt(nStartPos.length); PzOnS   
for(int i=0;i<nStartPos.length;i++) ;6:9EEd  
{ MX? *jYl  
// output.writeLong(nPos); ?8N^jjG  
output.writeLong(fileSplitterFetch.nStartPos); o%7-<\qS  
output.writeLong(fileSplitterFetch.nEndPos); Jr5dw=B gw  
} DSQ2|{   
output.close(); S4\a"WYg  
} +-C.E
 
catch(IOException e){e.printStackTrace ();} F/x2}'
 
catch(Exception e){e.printStackTrace ();} 4O<sE@X  
} IdqCk0lVD  
!0dQfj^_  
i-PK59VZ8f  
//读取保存的下载信息（文件指针位置） =^1jVaAL  
private void read_nPos() EQN)y27poW  
{ tk]D)+{u&c  
try{ Om^(CAp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &(oA/jFQ  
int nCount = input.readInt(); aq)g&.dw?  
nStartPos = new long[nCount]; , #=TputM  
nEndPos = new long[nCount]; s_ t/  
for(int i=0;i<nStartPos.length;i++) @R%*;)*F  
{ tn#cVB3  
nStartPos = input.readLong(); G9NI`]k  
nEndPos = input.readLong(); 3Q'vVNFh<  
} /poGhB1k  
input.close(); <8(
=Lv`)q  
} 4GbfA .u  
catch(IOException e){e.printStackTrace ();} LaO8)lqR  
catch(Exception e){e.printStackTrace ();} a*-9n-U@[k  
} _V4O#;%?  
!KMl'kswe:  
<rtKPlb//  
private void processErrorCode(int nErrorCode) /jNvHo^B  
{ fcxg6W'  
System.err.println("Error Code : " + nErrorCode); P0yDL:X[  
} ynv{ rMl  
3_<l`6^Ns/  
").gPmC  
//停止文件下载 $33E-^  
public void siteStop() WG A1XQ{  
{ Da615d  
bStop = true; /v^'5j1o  
for(int i=0;i<nStartPos.length;i++) h;,1BpbM  
fileSplitterFetch.splitterStop(); [0EWIdT*b  
=* G3Khz!  
D%~tU70a  
} 7mq&]4-G  
} .<zKBv  
//负责部分文件的抓取 d\uN  
**FileSplitterFetch.java o2X95NiH  
*/ :`e#I/,  
package NetFox; JcUU#>  
}/dk2!?ig  
0KnL{Cj   
import java.io.*; M^[;{p2uZ  
import java.net.*; j*@@H6G  
jB8Q% {%  
]Cj@",/3#  
public class FileSplitterFetch extends Thread { ;Ax-f04gG  
)
w0x{_  
& ?xR  
String sURL; //File URL 0S^&A?$=  
long nStartPos; //File Snippet Start Position

qmFG  
long nEndPos; //File Snippet End Position kL%ot<rt)w  
int nThreadID; //Thread's ID 0CX,"d_T,  
boolean bDownOver = false; //Downing is over ]o8]b7-  
boolean bStop = false; //Stop identical &y5"0mA  
FileAccessI fileAccessI = null; //File Access interface 3("C'(W  
KEtV  
+9w[/n^,G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .ojEKu+EJ'  
{ gYhY1Mym  
this.sURL = sURL; `p
&[b]b  
this.nStartPos = nStart; >*RU:X  
this.nEndPos = nEnd; <mQXS87  
nThreadID = id; LP6p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i}VF$XN  
} SK l
vZ  
jd](m:eG  
\= v.$u"c  
public void run() /QY F|%7!  
{ iqvLu{  
while(nStartPos < nEndPos && !bStop) K f/[Edn  
{ ~.aR=m\#  
W}f)VC;D  
}:m/@LKB  
try{ ux<|8S  
URL url = new URL(sURL); *Jgi=,!m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8 MQq3  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^FKiVKI:  
String sProperty = "bytes="+nStartPos+"-"; T9 /;$6s*  
httpConnection.setRequestProperty("RANGE",sProperty); cc|W1,q  
Utility.log(sProperty); 7pm'b,J<  
r }lGcG)  
N[po)}hp  
InputStream input = httpConnection.getInputStream(); ?qNU*d  
//logResponseHead(httpConnection); -N8r
s[c  
x="Wqcnj{  
`Gqe]ZE#"  
byte[] b = new byte[1024]; <Z]#vrq  
int nRead; /~Y\KOH|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r,Uk)xa/^  
{ !?nbB2,  
nStartPos += fileAccessI.write(b,0,nRead); hyH[`wiq  
//if(nThreadID == 1) 5p (zhfuG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _K o#36.S  
} C`hdj/!A  
eR$@Q  
3[ xdls  
Utility.log("Thread " + nThreadID + " is over!"); ECOJ .^  
bDownOver = true; e0TYHr)X>3  
//nPos = fileAccessI.write (b,0,nRead); }:0_%=)N<  
} ob\-OMNs@  
catch(Exception e){e.printStackTrace ();} K6k
z{R%`  
} hx9{?3#  
} --WQr]U/  
/K#k_k  
S"cTi[9  
//打印回应的头信息 m\56BP-AM  
public void logResponseHead(HttpURLConnection con) 5dePpFD5  
{ xU.1GI%UPu  
for(int i=1;;i++) fzIs^(:fl  
{ ; ~pgF_  
String header=con.getHeaderFieldKey(i); |-Uh3WUE6  
if(header!=null) J#I RbO)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +/ZIs|B4,z  
Utility.log(header+" : "+con.getHeaderField(header)); i>YS%&O?  
else 2!{D~Gfl=  
break; fB8, )&  
} #7]Jz.S  
} ,U~A=bsa  
g'7E6n"!,  
+>"s)R43  
public void splitterStop() J8qFdNK  
{ XwY,xg&o  
bStop = true; jr=9.=jI8k  
} >v]^nJl  
iH8we,s'  
wXIRn?z  
} ubwM*P  
jH< #)R  
1&|]8=pG7  
/* {DRk{>K,  
**FileAccess.java *?FVLE  
*//文件访问(定位，写) .d<K`.O;  
package NetFox; UxGu1a  
import java.io.*; (BEe^]f  
 [E1qv;   
#L*\^ c  
public class FileAccessI implements Serializable{ Lc{AB!Br  
|V a:*3u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
@G4
Z  
RandomAccessFile oSavedFile; ], lLDUZ\  
long nPos; Tn&_ >R  
#`VAw ) eV  
;z'&$#pA  
public FileAccessI() throws IOException 8ymdg\I+L  
{ BJjic%V  
this("",0); ,"EaZ/Bl/  
} ~/L:$  
(!* l+}  
*ERV\/  
public FileAccessI(String sName,long nPos) throws IOException _4by3?
<c  
{ J :O!4gI  
oSavedFile = new RandomAccessFile(sName,"rw"); cYA:k  
this.nPos = nPos; Xdn&%5rI  
oSavedFile.seek(nPos); tgF~5 o}?  
} g88k@<Y  
0t7N yKU  
p*Z<DEh#  
public synchronized int write(byte[] b,int nStart,int nLen) ,X|Oe@/  
{ 0Y8gUpe3P6  
int n = -1; $gl|^
c\  
try{ zG9FO/@av  
oSavedFile.write(b,nStart,nLen); H8eEBMGo  
n = nLen; %g9ym@s  
} 0z>IYw|UB  
catch(IOException e) `=(<!nXJx  
{ C m:AU;  
e.printStackTrace (); bBi>BP=  
} ),x0G*oebj  
}b456J  
%3`*)cp@  
return n; ,;pUBrz/[  
} dcf,a<K\  
jr`swyg  
2xNR=u`  
} 7nB4(A2[S4  
b7sfr!t_d  
W>jKWi,{  
/* QRju9x  
**SiteInfoBean.java A?MM9Y}K  
*/ TAYh#T=S  
package NetFox; [j6]!p]S$  
V D
#q\  
sl$6Zv-l%0  
public class SiteInfoBean { 9C7Npf?~M  
R>b
g3j  
mnA_$W3~I  
private String sSiteURL; //Site's URL Bl+\|[yd  
private String sFilePath; //Saved File's Path uuM1_nD[  
private String sFileName; //Saved File's Name sVh)Ofn  
private int nSplitter; //Count of Splited Downloading File OLx;j+p  
}ILBX4c  
2hHRitt36  
public SiteInfoBean() WOO3z5 La  
{//nSplitter的缺省值为5 L(
3&,!@  
//default value of nSplitter is 5 "]eB2k_>  
this("","","",5); T6/P54S  
} U6-47m0%  
Mi.#x_  
.rBU"Rbo  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0Z2XVq~T$  
{ ep8UWxB5  
sSiteURL= sURL; |sGJum&=  
sFilePath = sPath; ,a>Dv@$Y  
sFileName = sName; pLu5x<  
this.nSplitter = nSpiltter; aVR!~hvFs  
;MQl.?vj  
N:B<5l '  
} k~)CJ6}
 
!60U^\  
ndFVP;q  
public String getSSiteURL() X@kgc&`0  
{ 1tY
+0R  
return sSiteURL; 6$OmOCA%  
} g%J\YRo  
u0W6u} 4;  
eBa#Z1Z  
public void setSSiteURL(String value) ]WNY"B>+  
{ lW"0fZ_x'E  
sSiteURL = value; ~C{:G;Iy0  
} VP!4Nob  
S:z|"u:+  
>$ZhhM/} J  
public String getSFilePath() GJ
dL1ptc  
{ 3/gR}\=  
return sFilePath; +X#6dv$  
} m^FKE:  
g{Av =66Z  
ASdW!4.p  
public void setSFilePath(String value) W$X/8K bn  
{ Fug4u?-n  
sFilePath = value; <<-L,0  
} `Ij EwKra  
*SJ[~  
Ab[o~X"  
public String getSFileName() b"\lF1Nf&o  
{ fTpG>*{p  
return sFileName; jUD^]
Qs  
} sSh." H  
i=/hLE8T*  
^zTe9:hz/\  
public void setSFileName(String value) @(c^u;  
{ 8AW}7.<5  
sFileName = value; v#gXXO[P1  
} B.=n U  
)@9Eq|jMC  
"O r1 fC  
public int getNSplitter() gdCit-3  
{ H*G(`Zl}  
return nSplitter; }bRn&)e  
} I
Tl>HlS  
7#wB  
yT:2*sZRc
 
public void setNSplitter(int nCount) WZ`i\s1#  
{ ~rb]u Ny-  
nSplitter = nCount; Qq6'[Od  
} dG+$!*6Z  
} E!ZLVR.K  
q0q-Coh>  
?Sh"%x  
/* )o:sDj`b]  
**Utility.java 8N)Lck2PR  
*/ Cgln@Rz  
package NetFox; G(?1 Urxi  
dfAw\7v/  
l1kHFeq  
public class Utility { <r <{4\%}  
p5qfv>E8)  
:YRHO|  
public Utility() NL:dyV}  
{ &*o4~6pQ#  
5MG4S  
` Ft-1eE  
} b5MU$}:  
`oe=K{aX  
//线程睡眠 //N="9)@  
public static void sleep(int nSecond) YFu>`w^Y  
{ <o9i;[+H-  
try{ tJ_Y6oFm=  
Thread.sleep(nSecond); f?ycZ  
} @H$8;CRM  
catch(Exception e) 02J(*_o  
{ _R|_1xa=  
e.printStackTrace (); EKO'S+~  
} ?f9M59(l  
} Ge({sy>X  
&0f/F:M  
//日志 phG*It}  
public static void log(String sMsg) F3vywN1$,  
{ 0'f\>4B  
System.err.println(sMsg); 59$PWfi-\  
} ?7pn%_S  
> dVhIbG  
~-NSIV:f  
public static void log(int sMsg) #/Ob_~-?j  
{ =\u,4  
System.err.println(sMsg); |Isn<|_  
} >`3F`@1L0  
} !YpH\wUyvP  
8&HBR #  
;F- mt(Y  
/* IR]5,K^l  
**TestMethod.java *jQ$\|Y  
*/ <V}q8k  
package NetFox; Lj|wFV  
b&@]f2/  
l z"o( %D  
public class TestMethod { %CYo, e  
%}H 2  
o"0~  
public TestMethod() /Z]nV2$n)V  
{ ///xx/weblogic60b2_win.exe I9L3Y@(f6m  
try{ QKEtV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^w%%$9=:r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b3_P??yp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3n)Kzexh  
fileFetch.start(); '/XP4B\(E  
} .|u`s,\  
catch(Exception e){e.printStackTrace ();} ,[ppETz  
\z6UWZ  
d 4tL  
} !0? B
=yA  
byE0Z vDM  
2gklGDJD  
public static void main(String[] args) z&n2JpLY7  
{ ;X]B0KFe7  
new TestMethod(); I)#8}[vK  
} <sm"3qs"_  
} vO$cF*  
点击下载更多相关资料