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http断点续传简单实现(java)

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/* w~ O)DhC  
**SiteFileFetch.java t*wV<b  
*/ Q`!<2i;  
package NetFox; +ux170Cd3  
import java.io.*; gQ$0 |0O  
import java.net.*; xp%LXx j  
L*zfZ&  
R47tg&k6[  
public class SiteFileFetch extends Thread { chXTFLC~  
4$ ^rzAi5  
mk[<=k~  
SiteInfoBean siteInfoBean = null; //文件信息Bean RU+F~K<  
long[] nStartPos; //开始位置 (".WJXB\  
long[] nEndPos; //结束位置 R_gON*9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |vY|jaV}  
long nFileLength; //文件长度 5"z~BE7  
boolean bFirst = true; //是否第一次取文件 :Fdk`aC  
boolean bStop = false; //停止标志 N4w&g-  
File tmpFile; //文件下载的临时信息 }*,z~y}V#  
DataOutputStream output; //输出到文件的输出流 >x8~?)7z  
J~lKN <w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9d8U@=  
public SiteFileFetch(SiteInfoBean bean) throws IOException (|sqN8SbA  
{ r<pt_Cd  
siteInfoBean = bean; Y0g6zHk7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AME<V-5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Oee>d<  
if(tmpFile.exists ()) ;fB!/u  
{ :tp{(MF  
bFirst = false; aj}#~v1  
read_nPos(); wj9 Hh  
} =' &TqiIv"  
else <zp|i#~  
{ hSXZu?/  
nStartPos = new long[bean.getNSplitter()]; w%eEj.MI|i  
nEndPos = new long[bean.getNSplitter()]; Rip[  
} !uN_<!  
`sM^m`yE  
%$=}ePD  
>:P-3#e*  
} X_#,5t=7  
5mg] su&#  
g&d tOjM  
public void run() yOE N*^6  
{ ;w^{PZBg  
//获得文件长度 J4jL%5t  
//分割文件 gF&HJF 0x  
//实例FileSplitterFetch /^b=| +Do  
//启动FileSplitterFetch线程 $ -M'  
//等待子线程返回 'Ug-64f>  
try{ no8FSqLUS~  
if(bFirst) PZhpp"  
{ qWw{c&{Q],  
nFileLength = getFileSize(); ]`\~(*;[W9  
if(nFileLength == -1) qrY]tb^K  
{ v v]rXJu1  
System.err.println("File Length is not known!"); 2IFEl-IB[  
} 7_ao?}g  
else if(nFileLength == -2) C%;J9(r  
{ 5+Hw @CY3  
System.err.println("File is not access!"); nHIW_+<Mf  
} EALgBv>#ZL  
else R2dCp|6A  
{ -+&sPrQ  
for(int i=0;i<nStartPos.length;i++) Xv?'*2J  
{ |Whkq/Zg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !T1)tGrH  
} !z?;L_Lb  
for(int i=0;i<nEndPos.length-1;i++) =l1O9/\9  
{ O"f|gc)GLz  
nEndPos = nStartPos[i+1]; THz=_L6  
} IW- BY =C  
nEndPos[nEndPos.length-1] = nFileLength; 1n EW'F  
} ~\[\S!"  
} Dt]*M_  
2[Vs@X  
^26}8vt  
//启动子线程 btv.M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v>p}f"$`  
for(int i=0;i<nStartPos.length;i++) 17@#"uT0  
{ 5/4q}U3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *)um^O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QHbjZJ N  
nStartPos,nEndPos,i); AOR(1Qyo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p$zj2W+sN  
fileSplitterFetch.start(); S'%!KGVe  
} R^tDL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VT5o#NR{R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uI+^8-HZ;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IjnO2X  
nEndPos = " + nFileLength); Qj(|uGqm3  
// fileSplitterFetch[nPos.length-1].start(); FAF+}  
lb[\Lzdvmu  
W5zlU2  
//等待子线程结束 UN7J6$!Cx7  
//int count = 0; ^HI}bS1+|  
//是否结束while循环 wsyAq'%L  
boolean breakWhile = false; b%D}mxbS  
qn#f:xltu  
l]KxUkA+  
while(!bStop) -`} d@x  
{ Kf'oXCs  
write_nPos(); J?84WS  
Utility.sleep(500); `HJRXoLySW  
breakWhile = true; 9zD^4j7  
Sz'JOBp  
,[|4{qli\  
for(int i=0;i<nStartPos.length;i++) dEWI8Q]  
{ I-o |~  
if(!fileSplitterFetch.bDownOver)  ylBjuD+  
{ i9quP"<9  
breakWhile = false; J#jx)K!  
break; &/tGT3)  
} I+_u?R)$  
} } 2P,Z6L  
if(breakWhile) 2]/[  
break; !i*bb~  
OAd}#R\U  
( | X?  
//count++; )|CF)T-  
//if(count>4) kSH|+K\M4  
// siteStop(); ?(P3ZTk?.  
} :igURr  
V j"B/@  
;PF!=8dW  
System.err.println("文件下载结束!"); KI~M.2pk  
} n0< I  
catch(Exception e){e.printStackTrace ();} K!BS?n;  
} >r~!'Pd!  
Gs)2HR@>  
`]3A#y)v  
//获得文件长度 mQy!*0y  
public long getFileSize() Y> f 6  
{ 1*u i|fuK  
int nFileLength = -1; <zhN7="  
try{ k^v P|*eu  
URL url = new URL(siteInfoBean.getSSiteURL()); Mo_(WSs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "0#d F:qt  
httpConnection.setRequestProperty("User-Agent","NetFox"); H:>i:\J/M9  
1.y|bB+kB  
K`#bLCXEV0  
int responseCode=httpConnection.getResponseCode(); :{ Q[kYj  
if(responseCode>=400) f*& 4d  
{ MW$ X4<*KD  
processErrorCode(responseCode); UgjY  
return -2; //-2 represent access is error d1=fA%pJ  
} WwBs_OMc  
z~y=(T  
'k?*?XxG  
String sHeader; o9#8q_D9  
R@Kzdeo  
2%*mL98WK  
for(int i=1;;i++) YqSkz|o}m  
{ Y6r<+#V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x=~$ik++  
//Utility.log(in.readLine()); '#p2v'A  
sHeader=httpConnection.getHeaderFieldKey(i); 7lYiufg  
if(sHeader!=null) G>yTv`-  
{ >^q7:x\  
if(sHeader.equals("Content-Length")) 0281"aO  
{ c-gpO|4>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); POtwT">z  
break; 6o!Y^^/U  
} }:2GD0Ru  
} rS^+y{7  
else ]E!b&  
break; ytg' {)  
} c mI&R(  
} uF89B-t  
catch(IOException e){e.printStackTrace ();} 236,o {9e  
catch(Exception e){e.printStackTrace ();} TowRY=#jiS  
! >l)*jN8  
V$';B=M  
Utility.log(nFileLength); i r/-zp_  
MX\v2["FoV  
zv}3Sl@  
return nFileLength; 3}lT"K  
} F vt5vQ  
;+-M+9"?O  
:$J4T;/{  
//保存下载信息(文件指针位置) "{F e  
private void write_nPos() Oj~4uT&"  
{ MhXJ /bup  
try{ +#a_Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \Q m1+tg  
output.writeInt(nStartPos.length); />,KWHR|:  
for(int i=0;i<nStartPos.length;i++) 9yt)9f  
{ PBo;lg`  
// output.writeLong(nPos); oYn|>`+6:y  
output.writeLong(fileSplitterFetch.nStartPos); oPCtLz}z  
output.writeLong(fileSplitterFetch.nEndPos); x'IYWo ]  
} (_aM26s  
output.close(); gJUawK  
} ndCHWhi  
catch(IOException e){e.printStackTrace ();} &W@#p G  
catch(Exception e){e.printStackTrace ();} WMw^zq?hd@  
} Nxd<#p  
{ *&Wc Os  
y.PsC '  
//读取保存的下载信息(文件指针位置) rE[:j2HF  
private void read_nPos() n?=d)[]  
{ B{ptP4As-  
try{ VwKo)zH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rM y(NAo_  
int nCount = input.readInt(); zs<2Ozv  
nStartPos = new long[nCount]; d=v{3*a_4,  
nEndPos = new long[nCount]; =Mby;wQ?|  
for(int i=0;i<nStartPos.length;i++) ;Or]x?-  
{ 8'}D/4MUr  
nStartPos = input.readLong(); pDloew  
nEndPos = input.readLong(); ,6iXlch  
} Je1'0h9d  
input.close(); f%2>pQTq@)  
} xh) h#p.  
catch(IOException e){e.printStackTrace ();} n B .?=eUa  
catch(Exception e){e.printStackTrace ();} <bbC &O\  
} z +NwGVk3  
UcI;(Va  
b|'{f?  
private void processErrorCode(int nErrorCode) ,K>q{H^  
{ 4[o/p8*/  
System.err.println("Error Code : " + nErrorCode); cU  
} c?H@HoF  
6myF!  H=  
(n+FEE<  
//停止文件下载 @3_[NI%  
public void siteStop() jMV9r-{*+  
{ -Y=o  
bStop = true; Qf:#{~/  
for(int i=0;i<nStartPos.length;i++) #i1z&b#@  
fileSplitterFetch.splitterStop(); yy(.|  
a2!;$B%  
P1>?crw  
} &4R -5i2a  
} ]QJWqY  
//负责部分文件的抓取 ![l`@NH[U  
**FileSplitterFetch.java 2C59fXfd  
*/ vkgAI<  
package NetFox; q0y#Y  
Fk*C8  
KW 78J~u+  
import java.io.*; u4QBD5T"  
import java.net.*; dum(T  
(l ]_0-Z  
zS<idy F`  
public class FileSplitterFetch extends Thread { px>g  
#x|IEjoa  
7~2c"WE  
String sURL; //File URL .FWi$B';  
long nStartPos; //File Snippet Start Position 5%K(tRc|  
long nEndPos; //File Snippet End Position ucwUeRw,  
int nThreadID; //Thread's ID JMVh\($,x  
boolean bDownOver = false; //Downing is over ]qPrXuS/  
boolean bStop = false; //Stop identical p.@_3^#|  
FileAccessI fileAccessI = null; //File Access interface ["7]EW\!:  
>)6d~  
id:6O+\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iR39lOr  
{ \>N"{T  
this.sURL = sURL; L2}p<?f  
this.nStartPos = nStart; n{8v^x  
this.nEndPos = nEnd; _p^&]eQ+k#  
nThreadID = id; agUdPl$e\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \{K~x@`  
} ^9`S`Bhp  
9tBE=L=  
(D~NW*,9  
public void run() <Dq7^,}#  
{ {wwkbc*  
while(nStartPos < nEndPos && !bStop) 9>7w1G#  
{ t}x^*I$*  
mVVL[z2+  
sOb=+u$$9  
try{ m(rd\3d  
URL url = new URL(sURL); &++tp5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FL?Ndy"I  
httpConnection.setRequestProperty("User-Agent","NetFox"); h4geoC_W2  
String sProperty = "bytes="+nStartPos+"-"; G+V?c1Me  
httpConnection.setRequestProperty("RANGE",sProperty); :211T&B%A_  
Utility.log(sProperty);  5JggU  
+ )lkHv$R  
DNmP>~  
InputStream input = httpConnection.getInputStream(); ( *Fb/  
//logResponseHead(httpConnection); 2'T uS?  
\_|g}&}6Y  
*DS>#x@3*i  
byte[] b = new byte[1024]; 8Luw< Q  
int nRead; ,WgEl4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qx2M"uFJ  
{ R Y ";SfYb  
nStartPos += fileAccessI.write(b,0,nRead); 8;GuJP\  
//if(nThreadID == 1) B82SAV/O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j~C-T%kYa  
} Zy&?.d[z  
8h'*[-]70u  
Q8?:L<A  
Utility.log("Thread " + nThreadID + " is over!"); dSPye z  
bDownOver = true; 7AuzGA0y  
//nPos = fileAccessI.write (b,0,nRead); 1%Su~Z"W>  
} |Q*OA  
catch(Exception e){e.printStackTrace ();} HBiUp$(mB  
} nz_1Fu>g|  
} >(BAIjF E\  
:/~TV   
CEEAyip-c  
//打印回应的头信息 Qf.]Mw?Bm  
public void logResponseHead(HttpURLConnection con) 3#Qek2  
{ p|RFpn2ygF  
for(int i=1;;i++) \wM8I-f!  
{ fA" VLQE  
String header=con.getHeaderFieldKey(i); -v &  
if(header!=null) |@Sj:^cJD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l0nm>ps'D  
Utility.log(header+" : "+con.getHeaderField(header)); _,bDv`>Ra  
else C<yjGt VD  
break; G^&P'*  
} ?CSv;:  
} #Zj3SfU~`  
.ovG_O  
"?r_A*U  
public void splitterStop() \?~cJMN  
{ t~kh?u].j  
bStop = true; 'H8;(Rw  
} u)9YRMl  
716r/@y$6  
/M5R<rl  
} C|-QU  
^j *H  
wS @-EcCB  
/* Cu`ty] -'  
**FileAccess.java GB8>R  
*//文件访问(定位,写) Y@2v/O,\  
package NetFox; ;Yu|LaI\<m  
import java.io.*; ,ocAB;K  
i>{.Y};  
RZbiiMC>  
public class FileAccessI implements Serializable{ 1;"DIsz@d  
zY2o;-d|4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 cg).b?g  
RandomAccessFile oSavedFile; &at>sQ'  
long nPos; ]%eyrbU  
%[WOQ.Sh  
Y0xn}:%K  
public FileAccessI() throws IOException SI9PgC  
{ ]CGH )4Pe  
this("",0); < gu>06  
} mJ JF  
K %.>o  
XkEE55#>|  
public FileAccessI(String sName,long nPos) throws IOException jSdW?IH  
{ 3F?_{A  
oSavedFile = new RandomAccessFile(sName,"rw"); iCNJ%AZ H  
this.nPos = nPos; I~) A!vp  
oSavedFile.seek(nPos); n# "N"6s  
} PsO>&Te2  
3e ?J#;  
g66x;2Q  
public synchronized int write(byte[] b,int nStart,int nLen) EWK?vs  
{ P\{ }yd  
int n = -1; 8[L]w^  
try{ q"Th\? }%  
oSavedFile.write(b,nStart,nLen); 6L,"gF<n  
n = nLen; s7"5NU-  
} Y_,Tm  
catch(IOException e) d]+2rt}]hL  
{ z6uHe{|  
e.printStackTrace (); ;&`6b:ug  
} PaZd^0'!Z  
MoC@n+Q+@  
>TG#  
return n; -fT}Nj\  
} 7_CX6:  
5 [X,?  
P 9?I]a)G  
} -muP.h/  
I/)*pzt8  
N?><%fra  
/* ~'VVCtA  
**SiteInfoBean.java gPcOm b  
*/ gVI T6"/  
package NetFox; ^a?g~G  
X]c>clk,  
~*hCTqH vN  
public class SiteInfoBean { r:--DKt  
Ls/*&u  
|u_fVQj  
private String sSiteURL; //Site's URL d5#z\E??  
private String sFilePath; //Saved File's Path XVzsqi*Z  
private String sFileName; //Saved File's Name 3T~DeqAyw  
private int nSplitter; //Count of Splited Downloading File K96N{"{iI%  
_3zJ.%  
Iwe  
public SiteInfoBean() i0'g$  
{//nSplitter的缺省值为5 F!zGk(Pu  
//default value of nSplitter is 5 =k##*%  
this("","","",5); {Lugdf'  
} ?eDZ-u9)  
&EJ/Rl  
z C 7b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7}puj%JS /  
{ tu6<>  
sSiteURL= sURL; <6.?:Jj  
sFilePath = sPath; y/;DA=  
sFileName = sName; 3*#$:waGd  
this.nSplitter = nSpiltter; " 1%\Fil  
}%`f%/  
V?"1&m& E  
} TTD#ovo'  
w}0rDWuR[  
@YbZ"Jb  
public String getSSiteURL() @nOuFX4  
{ 2[i(XG{/  
return sSiteURL; (&Mv!6]  
} K)GpQ|4:<  
?^WX] SAl  
5V8`-yO9  
public void setSSiteURL(String value) cp2a @  
{ *0x!C8*`Xe  
sSiteURL = value; =55V<VI  
} J+l#!gk$!  
&Xh=bM'/%m  
uTNy{RBD+  
public String getSFilePath() uoTc c|Kc  
{ A9y@v{txN  
return sFilePath; ]sJjV A  
} Uj^Y\w-@Z  
j+[oZfH  
|}Mthj9n  
public void setSFilePath(String value) ^+x,211f  
{ ]-jaIvM  
sFilePath = value; 5? *Iaw  
} 4@=[r Zb9  
P5__[aTD  
00pe4^U  
public String getSFileName() x\8gb#8  
{ zQoJ8i>  
return sFileName; R~BFZF>:  
} _7<G6q2(  
<K <|G  
<SiJA`(7  
public void setSFileName(String value) )i[K1$x2  
{ F&HvSt}l5  
sFileName = value; _mTNK^gB  
} `2`h4[^ [X  
# blh9.V&F  
pV*d"~T  
public int getNSplitter() @ 1FWBH~  
{ jQ['f\R  
return nSplitter; [ nLd>2P  
} `KUL 4) g~  
g ,yB^^%  
GW2v&Ul7(  
public void setNSplitter(int nCount) K~+x@O*  
{ A>6_h1  
nSplitter = nCount; Awe'MGp%  
} x\pygzQ/  
} :=\`P  
d?><+!a  
?f*>=;7=  
/* j-v/;7s/B  
**Utility.java Sg1 ,9[pb  
*/ m}t`43}QE  
package NetFox; rEoOv  
p1s|JI  
q#`;G,rs  
public class Utility { |#EI(W?`  
B-V   
4KY@y?H g  
public Utility() e?WI=Og  
{ P_(< ?0l  
{6iHUK   
n1)].`  
} 0>:`|IGnT2  
NN~PWy1opa  
//线程睡眠 $'KhA6u  
public static void sleep(int nSecond) ~R7{gCqdr  
{ $E^*^({  
try{ FYH^axpp  
Thread.sleep(nSecond); ;Bat--K7+  
} [Vj|fy4  
catch(Exception e) SDO~g~NTp  
{ +'a G{/J  
e.printStackTrace (); mV}eMw  
} L08" 8\  
} n6{nx[%7N7  
BR tT 7  
//日志 xLw[ aYy4  
public static void log(String sMsg) eNrwkV^  
{ c+jnQM'  
System.err.println(sMsg); i}>} %l|  
} Oyp)Wm;@  
|`Be(  
%3T:W\h  
public static void log(int sMsg) GuQ#  
{ yn04[PN2  
System.err.println(sMsg); jR{t=da  
} wV'_{ /WM  
} =<U'Jtu6'  
j2jUrl  
JB HnJm  
/* r6 L  
**TestMethod.java !%QbE[Kl>  
*/ Tx/KL%X  
package NetFox; s "l ^v5  
F>at^6^  
]CgZt' h{  
public class TestMethod { :U-yO 9!j  
uN6xOq/  
uR82},r$m  
public TestMethod() to)Pl}9QkK  
{ ///xx/weblogic60b2_win.exe &sGLm~m#  
try{ Zk0?=f?j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h|ja67VG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y|Y hDO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =GLMdhD]  
fileFetch.start(); `(8RK  
} uQkQ#'e|  
catch(Exception e){e.printStackTrace ();} ,J'@e+jV  
qb5IpI{U  
o Hrx$>W]  
} 4<U6jB5  
@fd{5 >\  
F=yE>[! LB  
public static void main(String[] args) ~PCS_  
{ T7Yg^ -"  
new TestMethod(); E5$uvxCI  
} ;MjOs&1f0K  
} fwaM;YN_  
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