http断点续传简单实现（java)

/* &6YIn|}  
**SiteFileFetch.java u TK,&  
*/ k+Czj  
package NetFox; 8b-Q F  
import java.io.*; A?%H=>v$  
import java.net.*; r)~ T@'y  
5$&%re!{Z  
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public class SiteFileFetch extends Thread { s<_)$}  
}O^zl#  
K]0:?h;%Ld  
SiteInfoBean siteInfoBean = null; //文件信息Bean f[a}aZ9)  
long[] nStartPos; //开始位置 ytoo~n  
long[] nEndPos; //结束位置 ps%q9}J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `t9?=h!  
long nFileLength; //文件长度 QQ~-  
boolean bFirst = true; //是否第一次取文件 @&:ar
 
boolean bStop = false; //停止标志 DV-;4AxxRq  
File tmpFile; //文件下载的临时信息 0#&5.Gr)  
DataOutputStream output; //输出到文件的输出流 B$!)YD;  
V'T ,4  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O8u j`G 9  
public SiteFileFetch(SiteInfoBean bean) throws IOException -}=%/|\FG  
{ ,:H\E|XeBw  
siteInfoBean = bean; qA$*YI
lK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cmg^J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O#k6' LN?  
if(tmpFile.exists ()) S=nzw-(I  
{ MIoEauf  
bFirst = false; &[/w_|b  
read_nPos();
)Es"LP]  
} MLWM&cFG
 
else ;\Y&ce  
{ 9Hu/u=vB<  
nStartPos = new long[bean.getNSplitter()]; JS
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nEndPos = new long[bean.getNSplitter()]; X+}1  
} PGBQn#c<  
;YX4:OBqr  

}'/`2!lY  
I'iGt~4$  
} 0_"fJ~Y^J  
*c*0PdV  
q
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public void run() Boz@bl mCB  
{ ?yR&/a  
//获得文件长度 &n?^$LTPY  
//分割文件 9;Ox;;w  
//实例FileSplitterFetch "zFNg';  
//启动FileSplitterFetch线程 ur@Z|5  
//等待子线程返回 \lC   
try{ d'$T4yA  
if(bFirst) JJ'.((  
{ *B{j.{ p(  
nFileLength = getFileSize(); @reeO=  
if(nFileLength == -1) C@W"yYt  
{
,o,I5>`  
System.err.println("File Length is not known!"); h{p=WWK  
} >ByXB!Wi+  
else if(nFileLength == -2) ``e$AS  
{ *nsAgGKKM^  
System.err.println("File is not access!"); oDYRQozo>  
} GBFtr
 
else [7S} g  
{ _DNHc*  
for(int i=0;i<nStartPos.length;i++) j;3[KLmuK%  
{ :WL'cJ9a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #x3ujJ  
} FE!lok  
for(int i=0;i<nEndPos.length-1;i++) p>;_e(  
{ `zXO_@C  
nEndPos = nStartPos[i+1]; u[/m
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} q]N:Tpm9  
nEndPos[nEndPos.length-1] = nFileLength; /&{$ pM|?  
}
)!:Lzi  
} m"jV}@agX  
) ^3avRsC  
p4i]7o@  
//启动子线程 /BV03B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x61U[/r  
for(int i=0;i<nStartPos.length;i++) <_Q:'cx'  
{ hq/k*;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $g+[
yb7@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5N*Ux4M  
nStartPos,nEndPos,i); 7=OQ8IM!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nn"+w|v[ev  
fileSplitterFetch.start(); *b}lF4O?  
} | j a-
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i?:_:"^x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [[Y
0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JPWOPB'H  
nEndPos = " + nFileLength); ~JDnKo  
// fileSplitterFetch[nPos.length-1].start(); `zt_7MD  
Vy,^)]  
;~u{56  
//等待子线程结束 pBP.x#|  
//int count = 0; FEW_bP/4  
//是否结束while循环 z2hc.29t  
boolean breakWhile = false; X2i}vjkY  
${nX:!
)  
3LTcEd  
while(!bStop) n` TSu$  
{ ?
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write_nPos(); B8%{}[q  
Utility.sleep(500); GMZv RAui  
breakWhile = true; j"@93D~  
*[R eb%  
0Ir<y  
for(int i=0;i<nStartPos.length;i++) G
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{ ;6{@^  
if(!fileSplitterFetch.bDownOver) N**g]T 0`  
{ ee#): -p  
breakWhile = false; 4T<Lgb  
break; )){9&5,0:  
} IMl!,(6;  
} ^~HQC*  
if(breakWhile) [j:[  
break; F0UV

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13&0rLS  
.eO?Z^  
//count++; h"[+)q%L  
//if(count>4) la?Wnw  
// siteStop(); t/PlcV_M"  
} $4T2z-  
p/ >`[I  
$<|lE/_]  
System.err.println("文件下载结束！"); ?cEskafb>  
} tpTAeQ*:d  
catch(Exception e){e.printStackTrace ();} I]y.8~xs  
} %9#gB  
:BGA.  
D\YE^8/  
//获得文件长度 !GQ\"Ufs>  
public long getFileSize() vuFBET,  
{ |s)?cpb  
int nFileLength = -1; \Ro^*4B  
try{ BiZ=${y  
URL url = new URL(siteInfoBean.getSSiteURL()); z|(+|pV(
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ii0Ce}8d~  
httpConnection.setRequestProperty("User-Agent","NetFox"); wB{;bB{  
q;wLa#4)J  
"A)("  
int responseCode=httpConnection.getResponseCode(); xN@Pz)yo  
if(responseCode>=400) R1W}dRE}  
{ c$QX)V  
processErrorCode(responseCode); Vax^8 -  
return -2; //-2 represent access is error 5 VA(tzmCt  
} q0bHB_|wL  
?`Y\)'}  
<x),,a=X  
String sHeader; :g\rQazxO  
LR,7,DH$9'  
gxGrspqg  
for(int i=1;;i++) kzS=g|_  
{ ^v@4|E$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F("#^$  
//Utility.log(in.readLine()); [|3>MZ2/  
sHeader=httpConnection.getHeaderFieldKey(i); 92'wkS  
if(sHeader!=null) KYxBVgJ  
{ GBC*>Y  
if(sHeader.equals("Content-Length")) N=)z  
{ io3yLIy,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *+b6B_u]  
break; <p?&udqD  
} X}6#II  
} *$M'`
vj:  
else [!VOw@uz  
break; U#o'H @  
} 6R29$D|HFO  
} *AIEl"29  
catch(IOException e){e.printStackTrace ();} !"TZ:"VZU  
catch(Exception e){e.printStackTrace ();} -gz0md|Y  
KZBrE$@%5  
D8# on!  
Utility.log(nFileLength); V=:_d,  
pNE(n4v  
~/tKMS6T  
return nFileLength; }p9F#gr  
} sF+=KH  
'iLH `WE  
;bX4(CMe &  
//保存下载信息（文件指针位置） H2-28XG
c  
private void write_nPos() @lUlY2  
{ 3v!~cC~cI  
try{ (,xZGa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mty1p'^KQ  
output.writeInt(nStartPos.length); qUF1XJZ}z  
for(int i=0;i<nStartPos.length;i++) 0X(]7b&~R  
{ !z zW2>  
// output.writeLong(nPos); qYp$fmj  
output.writeLong(fileSplitterFetch.nStartPos); efuK  
output.writeLong(fileSplitterFetch.nEndPos); kDz>r#%  
} wn11\j&  
output.close(); 2PSTGG8JV  
} 7> Pgc
 
catch(IOException e){e.printStackTrace ();} hD<f3_k  
catch(Exception e){e.printStackTrace ();} XL}<1-}  
} L6i|:D32p  
%E27.$E_  
~-F?Mc  
//读取保存的下载信息（文件指针位置） 6bZ[Kt  
private void read_nPos() 7=*VpX1  
{ |H ;+1  
try{ 7XyOB+aQO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lg1PE7  
int nCount = input.readInt(); Jll-X\O`-  
nStartPos = new long[nCount]; O hR1Jaed  
nEndPos = new long[nCount]; rFL$QC2  
for(int i=0;i<nStartPos.length;i++) 396R$\q  
{ 5GAy "Xd  
nStartPos = input.readLong(); emA!Ew(g  
nEndPos = input.readLong(); (5uJZ!m  
} :a<hQ|p  
input.close();
}IlP:  
} ]5v:5:H  
catch(IOException e){e.printStackTrace ();} ?4)v`*  
catch(Exception e){e.printStackTrace ();} r[Zq3  
} q?~Rnv  
3#<*k>1G?  
/axTh  
private void processErrorCode(int nErrorCode) QlW=_Ymv{  
{ <kD#SV%"  
System.err.println("Error Code : " + nErrorCode); y?N Nz0  
} LN!W(n(  
/b.oEGqZX  
Y&'8VdW  
//停止文件下载 8HoP(+?  
public void siteStop() =V^@%YIn  
{ i|\{\d  
bStop = true; !g0cC.'  
for(int i=0;i<nStartPos.length;i++) XSB8z   
fileSplitterFetch.splitterStop(); ?(im+2  
amB@N6*  
\}i
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} +|C[-W7Sw  
} :J(sXKr[C  
//负责部分文件的抓取 @PcCiGZ  
**FileSplitterFetch.java nJVp.*S  
*/ {(vOt'  
package NetFox; ,{j4  
+*t|yKO>[  
TV{)n'aA  
import java.io.*; t^@T`2jL  
import java.net.*; jFj~]]j  
vg5NY =O  
B2hfD-h,>  
public class FileSplitterFetch extends Thread { P&t;WPZ  
DcFCKji  
R^Bk]  
String sURL; //File URL } 21j  
long nStartPos; //File Snippet Start Position .u< U:*  
long nEndPos; //File Snippet End Position '>^Xqn  
int nThreadID; //Thread's ID "r-l8r,  
boolean bDownOver = false; //Downing is over vO$ra5Z  
boolean bStop = false; //Stop identical 7>x;B  
FileAccessI fileAccessI = null; //File Access interface A'DVJ9%xB  
b
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@ u1Q-:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J#7(]!;F  
{ R[yL_>  
this.sURL = sURL; z Z%/W)t  
this.nStartPos = nStart; )
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this.nEndPos = nEnd; zeTszT)  
nThreadID = id; 5L&:_iQZy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 IH3FK!>6  
} <-|SIF  
`)tK^[,<W  
98<zCSe\]  
public void run() C.E[6$oVc  
{ UpeQOC  
while(nStartPos < nEndPos && !bStop)
$'$>UFR  
{ /w~C~6z @!  
>i8~dEbB  
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try{ z]>9nv`b  
URL url = new URL(sURL); 
{mYx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #'NY}6cb$  
httpConnection.setRequestProperty("User-Agent","NetFox"); <R~KM=rL  
String sProperty = "bytes="+nStartPos+"-"; Cj$H[K}>  
httpConnection.setRequestProperty("RANGE",sProperty); d[U1.SNL  
Utility.log(sProperty); tQ0=p| T]  
]hUKuef  

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InputStream input = httpConnection.getInputStream(); 6{^*JC5nj  
//logResponseHead(httpConnection); cMtJy"kK  
/.-m}0h|W-  
:
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byte[] b = new byte[1024]; 3"B+xbe=  
int nRead; 4sd-zl$Of  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U$$3'n  
{ 8DT@h8tA  
nStartPos += fileAccessI.write(b,0,nRead); ?zE<  
//if(nThreadID == 1) 4[H,3}p9H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -wIM0YJ  
} R`7n^,  
c'lIWuL)  
'WzUu MCx  
Utility.log("Thread " + nThreadID + " is over!"); Q=XA"R  
bDownOver = true; $9m5bQcV  
//nPos = fileAccessI.write (b,0,nRead); htg'tA^CtS  
} G4"lZM  
catch(Exception e){e.printStackTrace ();} Wy,"cT  
} w#d}TY  
} 165WO}(;/  
2HVCXegq  
D`fc7m  
//打印回应的头信息 Wbs^(iUU}  
public void logResponseHead(HttpURLConnection con) 9!S^^;PN&  
{ D
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for(int i=1;;i++) cqHw^{'8  
{ ;;6\q!7`  
String header=con.getHeaderFieldKey(i); I tgH>L'  
if(header!=null) Qf~| S9,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;y,NC2Xj  
Utility.log(header+" : "+con.getHeaderField(header)); ;<VR2U`  
else intvlki]be  
break; |N6m
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} Qq>ElQ@  
} m^c%]5$  
KY8^BjY@  
=
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public void splitterStop() ~W/}:;  
{ Bx%=EN5.  
bStop = true; .^GFy   
} <M`-`v6H  
"j +v,js  
@p"NJx"  
} hF9B?@n?B  
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7~lB}$L  
/* NB3/A"}"02  
**FileAccess.java `lvh\[3^  
*//文件访问(定位，写) sV&`0N  
package NetFox; &8juS,b  
import java.io.*; uq]iMz>  
4=UI3 2v3  
j@_nI~7f}  
public class FileAccessI implements Serializable{ r8<JX5zyuo  
{Wr\DVp  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 dY 6B%V  
RandomAccessFile oSavedFile; (J/>Gy)d  
long nPos; d[yrNB6|  
r \9:<i8  
i~(#S8U4d  
public FileAccessI() throws IOException cyDiA(ot&  
{ ~S!L!qY  
this("",0); -aA<.+  
} my=*zziN  
Y]?Kqc  
]C+eJ0"A  
public FileAccessI(String sName,long nPos) throws IOException [3GKPX:OA/  
{ -uO%[/h;N  
oSavedFile = new RandomAccessFile(sName,"rw"); THb A(SM  
this.nPos = nPos; V5cb}xx  
oSavedFile.seek(nPos); IOn`cbV:  
} %~ ;nlDw  
il=?of\,i  
[p2g_bI8yK  
public synchronized int write(byte[] b,int nStart,int nLen) o&WRta>V
P  
{ a\.//?  
int n = -1; @ 8A{ 9i  
try{ Hu[8HzJo  
oSavedFile.write(b,nStart,nLen); r .{rNR  
n = nLen; u;$I{b@M]  
} }FuVY><l  
catch(IOException e) v4X_v!CQ  
{ _QD/!~O  
e.printStackTrace (); yIM.j;5:~5  
} [))gn  
b;SFI^  
>9<_s ^_  
return n; 6R0D3kW  
} }3bQ>whF  
K lPm=  
U$MWsDn   
} [B.W1 GL!  
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y-D>xV
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/* p!. /  
**SiteInfoBean.java F%w\D9+P  
*/ E `?S!*jm  
package NetFox; e-&L\M  
JkRGtYq  
9)8*FahW  
public class SiteInfoBean { R:SIs
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wn&[1gBxM  
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private String sSiteURL; //Site's URL 4da^d9ZOy  
private String sFilePath; //Saved File's Path bWhJ^LD  
private String sFileName; //Saved File's Name bk
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private int nSplitter; //Count of Splited Downloading File hhN(;.  
?*B;514  
tsCz+MP  
public SiteInfoBean()  ^xBb$  
{//nSplitter的缺省值为5 F Bd+=bx,Z  
//default value of nSplitter is 5 FjK Ke7  
this("","","",5); *Cc$eR]-  
} O e0KAn  
/&y,vkZTT  
@^w!% ?J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n=lggBRx  
{ c80"8r  
sSiteURL= sURL; 11nO<WH  
sFilePath = sPath; C@l +\M(  
sFileName = sName; $`cy'ZaF  
this.nSplitter = nSpiltter; s|Imz<IE  
{X{01j};8  
S(q4OQB{  
} #JX|S'\x  
;,[EJR^CI  
%D%e:se  
public String getSSiteURL() ua6*zop  
{ PW(_yB;  
return sSiteURL; ?S;et2f  
} h8Dtq5t4  
?h>(&HjWV  
Gl3 `e&7  
public void setSSiteURL(String value) ee__3>H"/  
{ rd f85%%7  
sSiteURL = value; ?j},O=JFn  
} _rWTw+ L  
(7 ]\p  
{Tjtj@-  
public String getSFilePath() *X"F:7  
{ ^MF=,U'8  
return sFilePath; >?:i6&4o  
} Qe'PAN=B  
5d!z<{`  
fb;hf:B:  
public void setSFilePath(String value) AZBY, :>D  
{ ]G$!/vXP  
sFilePath = value; ;NvhL|R  
} lcuH]z  
{Hrr:hC  
OP\^c  
public String getSFileName() O~c+$(  
{ ~a0d.dU  
return sFileName; r;5 AY  
} ]VO,} `  
0^|$cvYiL  
.1l[
l5$  
public void setSFileName(String value) w|3fioLs  
{ x&6i@Jl  
sFileName = value; 7D9h;gsP  
} A=l?IC@O  
AH ?MJKY@Z  
Z:}2F^6  
public int getNSplitter() $$)<(MP3  
{ v@<lEG#$"|  
return nSplitter; /Wta$!X{-  
} P89Dg/P  
:W1tIB  
)GF
 
public void setNSplitter(int nCount) 07E".T%Ts  
{ _3-,3ia  
nSplitter = nCount; RvZryA*vu  
} 'ra_Zg[j  
} OHXeqjhy  
`04Y ;@w  
$4fjSSB~  
/* //@sktHsw(  
**Utility.java (kD?},Z  
*/  _j
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package NetFox; tL 9e~>,`  
)l/C_WEK  
p-ii($~}  
public class Utility { v6, o/3Ex  
EJ[iOYx  
 &~f*q?xR  
public Utility() *? orK o  
{ kK_>*iCMo  
Mz#S5 s  
o::ymAj  
} z8rh*Rfxd  
A?<"^<A^  
//线程睡眠 gJ}'O4*b  
public static void sleep(int nSecond) ;L/T}!Dx  
{ 62KW HB9S  
try{ >G-?e!  
Thread.sleep(nSecond);  MYW 4@#  
} OYCFx2{  
catch(Exception e) 9dhFQWz"  
{ YfYL?G  
e.printStackTrace (); u8)r W  
} ;z=C^'  
} ^SelqX  
6!Ap;O^*  
//日志 d+wNGN  
public static void log(String sMsg) R;I-IZS:  
{ P+h<{%:*  
System.err.println(sMsg); l2_E6U"  
} 5&7?0h+I  
fn"jYSy  
~O3uje_  
public static void log(int sMsg) A_$Mt~qKi^  
{ d4rJ?qw  
System.err.println(sMsg); _}%#Yz  
} */@bNT9BgO  
} ^IegR>  
[!|d[  
!t [%'!v  
/* BsG[#4KM:  
**TestMethod.java &-.eu  
*/ 97=YFK~*  
package NetFox; 1Yx[,GyC>&  
b|C,b"$N0  
XdXS^QA.s  
public class TestMethod { ^i,0
n}>  
F[qIfh4  
7'
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public TestMethod() x#xO {  
{ ///xx/weblogic60b2_win.exe ;@UX7NA  
try{ _-2n3py  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _|V+["IS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J!
gWRw5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %)@(Tye -  
fileFetch.start(); 7]+'%Uwu)  
} t~=@r9`S  
catch(Exception e){e.printStackTrace ();} IF21T  
oXOO 10  
4OgGZ  
} in|7ucSlg  
At_Y$N:
 
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public static void main(String[] args) RwLdV+2\R`  
{ ^oZs&+z  
new TestMethod(); L,ey3i7a\  
} 61;5Yo  
} Wn</",Gf  
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