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http断点续传简单实现(java)

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/* <(-3_s6-  
**SiteFileFetch.java  AT9q3  
*/ R$[#+X!  
package NetFox; i|T)p_y(!a  
import java.io.*; 4zJtOK?r"  
import java.net.*; :|Ad:fEs  
DTa N"{  
89\n;5'f4  
public class SiteFileFetch extends Thread { Ytz)d/3T  
bty/  
`0P$#5?  
SiteInfoBean siteInfoBean = null; //文件信息Bean #;%JT   
long[] nStartPos; //开始位置 kMtwiB|7j  
long[] nEndPos; //结束位置 F'B8v 3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J]&y$?C  
long nFileLength; //文件长度 4F{)i  
boolean bFirst = true; //是否第一次取文件 LM7$}#$R  
boolean bStop = false; //停止标志 `FYv3w2  
File tmpFile; //文件下载的临时信息 XVKfl3'%  
DataOutputStream output; //输出到文件的输出流 5]HS^II"  
RAG3o-  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qQ"Fv|]~>  
public SiteFileFetch(SiteInfoBean bean) throws IOException NR -!VJQ  
{ !1q 9+e  
siteInfoBean = bean; E}sO[wNPf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q)Fq i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e'0{?B  
if(tmpFile.exists ()) Md0 s K  
{ AgFVv5  
bFirst = false; -PS#Z0>  
read_nPos(); ve% xxn:  
} \8<BLmf4U  
else Hm$=h>rY9[  
{ \>C YC|  
nStartPos = new long[bean.getNSplitter()]; @6mBqcE'?  
nEndPos = new long[bean.getNSplitter()]; 'Y56+P\u  
} xZ4~Oo@@_'  
Z00+!Tnd  
P?t" jKp'  
qIY~dQ|  
} P@,nA41,j  
KuMF^0V%c  
DdVF,  
public void run() kAu+zX>S+  
{ pek%08VSEU  
//获得文件长度 wi4=OU1L)a  
//分割文件 'ow.=1N-  
//实例FileSplitterFetch =li|  
//启动FileSplitterFetch线程 'g$(QvGF 9  
//等待子线程返回 4\6N~P86  
try{ _cc#Qlw 7  
if(bFirst) s VJ!FC  
{ *e-A6S h  
nFileLength = getFileSize(); emdoA:w+   
if(nFileLength == -1) {K9/H qH  
{ _>9.v%5cs(  
System.err.println("File Length is not known!"); Ti'}MC+0  
} co9 .wB@  
else if(nFileLength == -2) ,(;lIP  
{ 3:8{"md@2  
System.err.println("File is not access!"); K91)qI;BD  
} P&b19K'  
else f|R"u W +  
{ u%/goxA  
for(int i=0;i<nStartPos.length;i++) [o.B  
{ 3bDQk :L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'k4E4OB  
} cOPB2\,  
for(int i=0;i<nEndPos.length-1;i++) "dI;  
{ Sr%;fq  
nEndPos = nStartPos[i+1]; ap{2$k ,  
} O9g{+e`  
nEndPos[nEndPos.length-1] = nFileLength; :%sXO  
} FIbp"~  
} i:u1s"3~  
$6CwkM:  
(s{RnD  
//启动子线程 2'5]~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vq!_^F<  
for(int i=0;i<nStartPos.length;i++) 7f~Sf  
{ _L@2_#h!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *P#WDXRwd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?}m']4p  
nStartPos,nEndPos,i); Q4*fc^?u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jq+A-T}@  
fileSplitterFetch.start(); ,:`ND28V7  
} JB>b`W9   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A0fFv+RN3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (sQr X{~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bk)g;+@  
nEndPos = " + nFileLength); 'sxNDnGg  
// fileSplitterFetch[nPos.length-1].start(); {'AWZ(  
;q:jl~  
($L Ll;1  
//等待子线程结束 jaa"~5TO8  
//int count = 0; 2KQoy;  
//是否结束while循环 cZ<A0  
boolean breakWhile = false; 6<'21  
P1NJ^rX  
wN2QK6Oc  
while(!bStop) O)Y?=G)  
{ gt/zpiKmV  
write_nPos(); ;L,mBQB?0b  
Utility.sleep(500); Y& F=t/U2  
breakWhile = true; &`fhEN  
{&"L~>/o  
(I@rLvZr{  
for(int i=0;i<nStartPos.length;i++) eQVZO>)P1+  
{ iC*F  
if(!fileSplitterFetch.bDownOver) [xT:]Pw}  
{ EZYBeqv  
breakWhile = false; P) uDLFp]  
break; 8o/}}=m$  
} 5r?m&28X  
} !xwG% {_  
if(breakWhile) ]XTu+T.aT  
break; Z( 9 u<  
[|lB5gi4t!  
doB  
//count++; 4&HXkRs:  
//if(count>4) /l{ &iLz[  
// siteStop(); m~>Y{F2  
} 3 E3qd'  
_$p$")  
j+^oz'q  
System.err.println("文件下载结束!"); N |1>ooU[  
} OKHX)"j\\  
catch(Exception e){e.printStackTrace ();} ^::EikpF%  
} P1zdK0TM  
?\#N9 +{W  
IJJ%$%F/  
//获得文件长度 F|& {Rt  
public long getFileSize() k2xHH$+{#=  
{ 7y`}PMn  
int nFileLength = -1; cS.-7  
try{ (4@lKKiU%H  
URL url = new URL(siteInfoBean.getSSiteURL()); 5o/&T"]@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RID]pek  
httpConnection.setRequestProperty("User-Agent","NetFox"); fl;s9:<  
jA(>sz  
zSE<"(a  
int responseCode=httpConnection.getResponseCode(); .c#y%S  
if(responseCode>=400) rS0DSGDq  
{ VqE~c  
processErrorCode(responseCode); < Z|Ep1W  
return -2; //-2 represent access is error oxj3[</'k  
} vm'5s]kdh  
@w>zF/  
WsFk:h'r  
String sHeader; tV9L D>3  
(Z}>1WRju  
nkv(~ej(  
for(int i=1;;i++) @vMA=v7a  
{ QaGlR`Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9 C{;h  
//Utility.log(in.readLine()); 4G@nZn  
sHeader=httpConnection.getHeaderFieldKey(i); \j2;4O?`  
if(sHeader!=null) hb/]8mR  
{ X]loJoM9  
if(sHeader.equals("Content-Length")) |e a~'N1  
{ 7?v#'Ie s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2qi'g:qe  
break; /cK%n4l.y  
} SSBg?H'T  
} JxjI]SF02  
else ~O 3D[PNW~  
break; xvNo(>  
} f/kI| Z  
} W- $a Y2  
catch(IOException e){e.printStackTrace ();} 5/QRL\  
catch(Exception e){e.printStackTrace ();} cE iu)2*e  
SI_iI71  
3M0+"l(X  
Utility.log(nFileLength); ez3Z3t`  
fZKt%m  
Wy]^Ub gW  
return nFileLength; ,&Wn [G<2  
} rtQHWRUn  
J4=_w  
81%8{yn!$"  
//保存下载信息(文件指针位置) =V97;kq+v  
private void write_nPos() &ff&Y.q~  
{ WhBpv(q}.  
try{ ^2o dr \  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H +bdsk  
output.writeInt(nStartPos.length); Og%U  
for(int i=0;i<nStartPos.length;i++) fn CItK~y  
{ <e%F^#y_  
// output.writeLong(nPos); J!ntXF  
output.writeLong(fileSplitterFetch.nStartPos); f&4,?E;6%  
output.writeLong(fileSplitterFetch.nEndPos); Lz DI0a.  
} L5IbExjV  
output.close(); 65,(4Udz!  
} J wmT /  
catch(IOException e){e.printStackTrace ();} )U:2z-X&e  
catch(Exception e){e.printStackTrace ();} /$"[k2 N  
} QFPfIb/  
O;HY%  
L?Yoh<  
//读取保存的下载信息(文件指针位置) N:VX!w  
private void read_nPos() W YW|P2*  
{ o$.e^XL  
try{ r,(e t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nsb4S {  
int nCount = input.readInt(); I1U7.CT  
nStartPos = new long[nCount]; @OV-KT[>  
nEndPos = new long[nCount]; k;dXOn  
for(int i=0;i<nStartPos.length;i++) z5Qs @dG  
{ .7ayQp  
nStartPos = input.readLong(); /q\_&@  
nEndPos = input.readLong(); ~n!!jM:N  
} M!M!Ni  
input.close(); = \ , qP  
} f DgD@YCD  
catch(IOException e){e.printStackTrace ();} %m{U& -(l@  
catch(Exception e){e.printStackTrace ();} kJs^ z  
} 5wC* ?>/  
]>i~6!@  
jx_4B%kzq  
private void processErrorCode(int nErrorCode) jY!ZkQsVe  
{ $mA5@O~C5\  
System.err.println("Error Code : " + nErrorCode); IB9%QW"0  
} T:asm1BC[  
 17g^ALs  
 1;eX&  
//停止文件下载 pN[0YmY#  
public void siteStop() IO.<q,pP!_  
{ /DS?}I.*]  
bStop = true; Wx)K* 9  
for(int i=0;i<nStartPos.length;i++) 4YU/uQm  
fileSplitterFetch.splitterStop(); sTHq&(hLUG  
 PWgDFL?  
smAC,-6 ]~  
} ^a9 oKI9n  
} ^ons:$0h  
//负责部分文件的抓取 R@T6U:1  
**FileSplitterFetch.java +:jT=V"X  
*/ YJ7V`N p  
package NetFox; !$XHQLqF2  
 ZC^C  
}UyQ#U  
import java.io.*; 3mt%!}S  
import java.net.*; 6\d X  
Md; /nJO~{  
VU!w!GN]Y  
public class FileSplitterFetch extends Thread { -[#n+`M  
~bA,GfSn0  
_.18z+  
String sURL; //File URL SjcL#S($&Y  
long nStartPos; //File Snippet Start Position BZ+-p5]-  
long nEndPos; //File Snippet End Position w3*-^: ?j  
int nThreadID; //Thread's ID R -elIp  
boolean bDownOver = false; //Downing is over :_dICxaLZT  
boolean bStop = false; //Stop identical K3$` Kv>I  
FileAccessI fileAccessI = null; //File Access interface rE!1wc>L  
MXAEX2xmme  
&w~Xa( uu  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 73NZ:h%=  
{ [!*xO?yCJ  
this.sURL = sURL; EH9Hpo  
this.nStartPos = nStart; ,qFA\cO*  
this.nEndPos = nEnd; q@#BPu"\l  
nThreadID = id; L0h G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1-;?0en&0  
} \x\.  
uVU`tDzd:  
K!8zwb=fq  
public void run() Aa(<L$e!`  
{ Ns~&sE:  
while(nStartPos < nEndPos && !bStop) (RF>s.B<  
{ !)H*r|*[  
(7q^FtjA#  
,I*X) (  
try{ +$beo2x6  
URL url = new URL(sURL); I ,FqN}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^o<[. )  
httpConnection.setRequestProperty("User-Agent","NetFox"); s^|\9%WD  
String sProperty = "bytes="+nStartPos+"-"; 99ASIC!  
httpConnection.setRequestProperty("RANGE",sProperty); w^VSj%XH!  
Utility.log(sProperty); whkJpK(  
#+sF`qR,  
0'ZYO.y  
InputStream input = httpConnection.getInputStream(); mc@M,2@D  
//logResponseHead(httpConnection); nX x=1*X  
iK}v`xq  
H*U`  
byte[] b = new byte[1024]; ]O{_O&w  
int nRead; NtZ6$o<Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,Q2N[Jwd$  
{ Sni=gZK  
nStartPos += fileAccessI.write(b,0,nRead); # 3.)H9  
//if(nThreadID == 1) 71iRG*O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @&R1wr1>I5  
} 1i?=JAFfM  
m4**>!I  
O2#S: ~h  
Utility.log("Thread " + nThreadID + " is over!"); D zDj)7  
bDownOver = true; 1$["79k  
//nPos = fileAccessI.write (b,0,nRead); 23E 0~O  
} 5d 5t9+t  
catch(Exception e){e.printStackTrace ();} O3_B<Em  
} co]Gmg6p  
} Va9q`XbyO  
T^)plWw  
Xem| o&  
//打印回应的头信息 p{H0dj^|  
public void logResponseHead(HttpURLConnection con) G,DOBA  
{ "a( 1s} ,  
for(int i=1;;i++) S%+R#A1  
{ t"YIq/08  
String header=con.getHeaderFieldKey(i); d^aNR Lv  
if(header!=null) Y+|PY? ~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %Dyh:h   
Utility.log(header+" : "+con.getHeaderField(header)); Mvof%I  
else NWISS  
break; [ -12]3  
} [h", D5  
} *)%dXVf  
&:8T$U V  
GVObz?Z]SB  
public void splitterStop() &:auB:b  
{ 9t }xXk  
bStop = true; 8eww7k^R  
} G2@KI-  
)5i* /I\  
qc-C>Ra  
} \dNhzd#  
3:" &Z6t#  
q%.bnF/Yd  
/* 0^iJlR2  
**FileAccess.java .;Z.F7{q  
*//文件访问(定位,写) 5&%fkZ0  
package NetFox; j];G*-iv{  
import java.io.*; Kw*~W i  
bA+[{  
9RcM$[~  
public class FileAccessI implements Serializable{ i@{*O@m  
>nNl^ yqW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T{;=#rG<  
RandomAccessFile oSavedFile; =+(Q.LmhC  
long nPos; l'2H 4W_+  
y*|L:!   
x~(y "^ph  
public FileAccessI() throws IOException jNqVdP]d\  
{ J(hA^;8:  
this("",0); UC#"=Xd 4  
} <[5#c*A  
u2,H ]-  
E@]sq A  
public FileAccessI(String sName,long nPos) throws IOException ]W|RtdF3.N  
{ K Dz]wNf  
oSavedFile = new RandomAccessFile(sName,"rw"); %%x0w^  
this.nPos = nPos; r4S=I   
oSavedFile.seek(nPos); k) 3s?  
} ;r=?BbND?  
f~v"zT  
b\M b*o  
public synchronized int write(byte[] b,int nStart,int nLen) 3 9yz~  
{ VK$zq5D  
int n = -1; tzmETRwG  
try{ EFv4=OWB  
oSavedFile.write(b,nStart,nLen); :'ihE\j  
n = nLen; f:FpyCo=9  
} :4]J2U\@  
catch(IOException e) JQH7ZaN  
{ tKX}Ok:V%  
e.printStackTrace (); )?9\$^I  
} U>1b9G"_  
VX&WlG`wa  
:OX$LCi  
return n; E6JV}`hSk  
} [nC4/V+-  
$&Ac5Zo%}  
+qZc} 7rJF  
} k)Zn>  
P_mi)@  
2gH _$  
/* AW62~*  
**SiteInfoBean.java mMslWe  
*/ ?}v}U^  
package NetFox; lnjL7x  
`L;OY 4  
Bjtj{B  
public class SiteInfoBean { CJ:uYXJJ:z  
/xF 9:r  
6VGo>b;  
private String sSiteURL; //Site's URL $oc9 |Q 7  
private String sFilePath; //Saved File's Path {Bc#?n  
private String sFileName; //Saved File's Name =_uol8v  
private int nSplitter; //Count of Splited Downloading File ?|)rv  
gDMAc/V`l  
6g8M7<og9R  
public SiteInfoBean() K^8@'#S  
{//nSplitter的缺省值为5 mUiOD$rO  
//default value of nSplitter is 5 8Y7 @D$=w  
this("","","",5); srhFEmgN7)  
} !4_!J (q%  
;i/"$K  
/jvO XS\M  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) we }#Ru*  
{  Hl!1h%  
sSiteURL= sURL; G}s;JJax  
sFilePath = sPath; Q^vGj</u  
sFileName = sName; SC]6F*  
this.nSplitter = nSpiltter; 7 s7}?l9  
]u~Os<   
W.z$a.<(rF  
} fHLFeSfH  
aQxe)  
A}gYcc85Z  
public String getSSiteURL() $m{{,&}k  
{ CJ0$;et  
return sSiteURL; wXP_]-  
} /#@LRN<oCq  
o}d2N/T  
PVZEB  
public void setSSiteURL(String value) 9x4wk*z  
{ +BU0 6lLD  
sSiteURL = value; 3e#x)H/dr  
} 8 f|9W%jt  
Z4=_k{*  
N'I?fWN!;R  
public String getSFilePath() P Q6T| >  
{ r$94J'_  
return sFilePath; "sdcP8])d  
} <.;@ksCPW{  
vM5k4%D  
(H'_KPK  
public void setSFilePath(String value) GOUY_&}tL  
{ ?Ozk^#H[  
sFilePath = value; i:MlD5 F  
} l kI8 {  
[^h/(a`  
oZ?IR#^  
public String getSFileName() qxRT1B]{Wx  
{ 22l|!B%o  
return sFileName; I|GV :D  
} 6wa<'!   
8''9@xz  
~3LhcU-  
public void setSFileName(String value)  s$K@X `  
{ z?8zFP  
sFileName = value; P9 W<gIO  
} mvUVy1-c  
cpP.7ZR  
9|us<k  
public int getNSplitter() %Y#[% ~|(  
{ r0rJ.}!  
return nSplitter; &f (sfM_n  
} AaJ,=eQ  
@SX%? mk8G  
[GcA.ABz  
public void setNSplitter(int nCount) A}az m>  
{ d,Im&j_Z  
nSplitter = nCount; ]9bh+  
} -U/I'RDLEz  
} X; e`y:9  
CUAg{]  
KfJ c  
/* l:>qR/|m  
**Utility.java |;x fe"]  
*/ ^EnNbFI  
package NetFox; nPQZI6>  
 r*~n`  
' [7C~r{%  
public class Utility { l4R<`b\Jt  
k1~nd=p  
JKEXYE  
public Utility() ?yK%]1O  
{ p,_6jdz  
T%N~oa  
Z&?+&q r^  
} "<g?x`iz  
-f-O2G=  
//线程睡眠 t-?KKU8  
public static void sleep(int nSecond) uIVTs9\  
{ *!wO:< -  
try{ .3S\Rrv  
Thread.sleep(nSecond); ,_wm,  
} E@\d<c.  
catch(Exception e) p@!@^1j=  
{ X#f+m) S  
e.printStackTrace (); .=et{\  
} USHlb#*  
} _E x*%Qf.  
Q]2sj:  
//日志 yhJA;&}>  
public static void log(String sMsg) *Bb|N--jI  
{ YU ]G5\UU  
System.err.println(sMsg); cq@_*:~Or  
} L*SSv wSL  
hPEp0("  
W>t&N  
public static void log(int sMsg) 1DI"LIL  
{ N4Fy8qU;  
System.err.println(sMsg); ci{9ODN  
} FBwncG$]F*  
} ;?O883@r8  
xqi*N13  
]IbPWBX  
/* r=iMo7q  
**TestMethod.java @?^LxqAWA  
*/ d =B@EyN  
package NetFox; J;Z>fAE7  
yccuTQvz  
Wzf1-0t  
public class TestMethod { f3%^-Uy*b  
+UpMMh q  
#sm_.?P  
public TestMethod() Zh fD`@>&  
{ ///xx/weblogic60b2_win.exe ="'P=Xh!8  
try{ J6^Ct  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fW4cHB 9|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [iO$ c]!H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,;+91lR3  
fileFetch.start(); P(YG@  
} NP<F==,  
catch(Exception e){e.printStackTrace ();} HIWmh4o/.  
0F0Q=dZ  
Aa\=7  
} $ <>EwW  
bVAgul=__  
%t5BB$y  
public static void main(String[] args) bCaPJ!ZO  
{ 4 HJZ^bq9|  
new TestMethod(); +DbWMm  
} "o5gQTwb  
} mC[U)` ey  
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