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http断点续传简单实现(java)

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/* r} ,|kb  
**SiteFileFetch.java *=sU+x&X  
*/ ]7VK&YfN  
package NetFox; t 1&p> v  
import java.io.*; db4&?55Q  
import java.net.*; f a\cLC  
]Ny]Ox<  
{==Q6BG*  
public class SiteFileFetch extends Thread { tP:xx2N_  
F;_;lRAb  
)b-G2< kb  
SiteInfoBean siteInfoBean = null; //文件信息Bean %2L9kw'  
long[] nStartPos; //开始位置 H~$|y9>qI  
long[] nEndPos; //结束位置 ##n\9ipD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -#i%4[v  
long nFileLength; //文件长度 S3=J1R,  
boolean bFirst = true; //是否第一次取文件 ILVbbC`D  
boolean bStop = false; //停止标志 ZU@V]+ww  
File tmpFile; //文件下载的临时信息 1U9iNki  
DataOutputStream output; //输出到文件的输出流 brVT  
HwGtLeB"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) l%U9g  
public SiteFileFetch(SiteInfoBean bean) throws IOException pTN_6=Y"  
{ |/(5GX,X  
siteInfoBean = bean; eU12*(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j=gbUXv/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C4G)anT  
if(tmpFile.exists ()) y>#j4%D~4  
{ Vnl~AQfk|  
bFirst = false; dKMuo'H'%  
read_nPos(); H}$#aXEAn  
} c49#aN R  
else K)v(Z"  
{ Y9%yjh  
nStartPos = new long[bean.getNSplitter()]; K l4",  
nEndPos = new long[bean.getNSplitter()]; O]Hg4">f  
} QxkfP%_g  
~ 52  
4R0_%x6vG  
-@73"w/  
} v_ J.M]  
}E=kfMu  
Po_9M4kU  
public void run() K1hw' AaQ  
{ 2Fh_  
//获得文件长度 SB;Wa%  
//分割文件 63f/-64?7  
//实例FileSplitterFetch f&`*x t/  
//启动FileSplitterFetch线程 q[#\qT&QU  
//等待子线程返回 7q?Yd AUz  
try{ <V, ?!}V  
if(bFirst) c`>\R<Z ]  
{ 5>=tNbk"s  
nFileLength = getFileSize(); -`RJ k(  
if(nFileLength == -1) EvYw$ j  
{ zPmVECS  
System.err.println("File Length is not known!"); %,^7J;  
} Cam}:'a/`  
else if(nFileLength == -2) *Z]| Z4Q/`  
{ J!H5{7.efN  
System.err.println("File is not access!"); A`r9"([-A  
} -3V~YhG  
else ^DH*@M  
{ !69^ kIi$  
for(int i=0;i<nStartPos.length;i++) </%H'V@  
{ T/K.'92S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lVFX@I=pI  
} `8-aHPF-  
for(int i=0;i<nEndPos.length-1;i++) y"hM6JI  
{ J'EK5=H  
nEndPos = nStartPos[i+1]; xo%iL  
} 0 mQ3P.9  
nEndPos[nEndPos.length-1] = nFileLength; v Y\O=TZT  
} KH7]`CU  
} w(U/(C7R  
qh'BrYu*  
pxbNeqK@p  
//启动子线程 5 QeGx3'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IX(yajc[~M  
for(int i=0;i<nStartPos.length;i++) >SJ$41"E  
{ GW#kaqC1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fs|;>Up0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 85fDuJ9$Z"  
nStartPos,nEndPos,i); z|<oxF.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EVL;"   
fileSplitterFetch.start(); ]aRD6F:L  
} "{k )nr+7U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TxvPfU?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @e,Zmx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xdM#>z`;  
nEndPos = " + nFileLength); IpJv\zH7  
// fileSplitterFetch[nPos.length-1].start(); %MJ7u}  
AL7O-D  
`.W;ptZ6  
//等待子线程结束 Zsogx}i-  
//int count = 0; orHD3T%&  
//是否结束while循环 |w2AB7EU  
boolean breakWhile = false; 0_ \ g  
=.oWguzu  
P` F'Nf2U  
while(!bStop) D,j5k3< #  
{ 3x0wk9lND  
write_nPos(); A4FDR#  
Utility.sleep(500); ~k0)+D}  
breakWhile = true; :"^< aLj  
B9DxV>mr\r  
BDRVT Y(s  
for(int i=0;i<nStartPos.length;i++) \,gZNe&Vv  
{ ('-}"3  
if(!fileSplitterFetch.bDownOver) g <4M!gi  
{ Z{4aGp*  
breakWhile = false; SWsv,  
break; TQd FC\@f"  
} B 9Q. s  
} Ju7C?)x  
if(breakWhile) h&M RQno  
break; T;r];Y(b*  
fsc~$^.~\  
wV&f|JO0+  
//count++; ;T{/;  
//if(count>4) y6Epi|8  
// siteStop(); yLO &(Mb  
} wv.Ul rpx.  
&9_\E{o%]  
HL}~W}!j  
System.err.println("文件下载结束!"); u?3NBc$~A  
} Rfc&OV  
catch(Exception e){e.printStackTrace ();} '#i]SU&*  
} N%r L=zE  
9>&tMq  
4_762Gu%  
//获得文件长度 .hlQ?\  
public long getFileSize() t-m9n*\j1  
{ nuO3UD3  
int nFileLength = -1; TflS@Z7C  
try{ JM-ce8U  
URL url = new URL(siteInfoBean.getSSiteURL()); Ym.l@(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  LbX6p  
httpConnection.setRequestProperty("User-Agent","NetFox"); nN`Z0?  
EdAR<VfleA  
}\939Y  
int responseCode=httpConnection.getResponseCode(); q= yZx)  
if(responseCode>=400) y+";  
{ 8f,'p}@!d  
processErrorCode(responseCode); ('* *nP  
return -2; //-2 represent access is error (}FW])y  
} Wz-3?EQ  
(' Ko#3b  
|)?aH2IL  
String sHeader; CaYos;Pl  
- Y8ks7  
C~KWH@  
for(int i=1;;i++) YQ @dl  
{ =(.mf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >'ksXA4b  
//Utility.log(in.readLine()); -4vHK!l  
sHeader=httpConnection.getHeaderFieldKey(i); rv,NQZ  
if(sHeader!=null) "$W|/vD+  
{ ,qe]fo >  
if(sHeader.equals("Content-Length")) \]U<hub  
{ =XMD+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /lr1hW~Dbk  
break; {UdcX~\~  
} X;OsH  
} P /c Q1  
else Z6IJo%s  
break; O&#S4]Y   
} =mKfFeO.  
} _K0izKTA.  
catch(IOException e){e.printStackTrace ();} g[EM]q,  
catch(Exception e){e.printStackTrace ();} k5 aa>6K  
YPha9M$AgU  
ZDOF  
Utility.log(nFileLength); C#U< k0R  
0i8[=  
H.YIv50E  
return nFileLength; sf |oNOz  
} Rwc[:6;fn  
]aC ':55(  
L_THU4^j  
//保存下载信息(文件指针位置) z(g%ue\  
private void write_nPos() ~\IF9!  
{ cBz!U 8(  
try{ .cg=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wr$cK'5ZL  
output.writeInt(nStartPos.length); ;cv.f>Cm  
for(int i=0;i<nStartPos.length;i++) FOOQ'o[}  
{ ^>N8*=y  
// output.writeLong(nPos); M82.khm~jM  
output.writeLong(fileSplitterFetch.nStartPos); >Z#uFt0<Pm  
output.writeLong(fileSplitterFetch.nEndPos); pN\)(:"8v  
} NuC-qG#  
output.close(); V";mWws+?#  
} J+ Jt4  
catch(IOException e){e.printStackTrace ();} e >L5.~i  
catch(Exception e){e.printStackTrace ();} J[ e}  
} 2y3?!^$  
0JmFQ ^g(  
+7| [b  
//读取保存的下载信息(文件指针位置) @%6)^]m}r  
private void read_nPos() ppAmN0=G  
{ ]i-P-9PA4  
try{ z-n>9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7~_{.f  
int nCount = input.readInt(); x&at^Fp  
nStartPos = new long[nCount]; 2>F\&  
nEndPos = new long[nCount]; h/,R{A2mO  
for(int i=0;i<nStartPos.length;i++) !Tv?%? 2l  
{ nN>J*02(  
nStartPos = input.readLong(); r eGm>  
nEndPos = input.readLong(); b6 $,Xh  
} ^#]c0  
input.close(); iJFr4o/R  
} ):e+dt  
catch(IOException e){e.printStackTrace ();} z)}3**3'y  
catch(Exception e){e.printStackTrace ();} j:7* 3@f  
} 59V#FWe-  
}$l8d/_$[  
}K2 /&kZ  
private void processErrorCode(int nErrorCode) ?N:B  
{ :*^:T_U  
System.err.println("Error Code : " + nErrorCode); $30oc Tt{  
} X4a^m w\"  
Odm#wL~E  
2z4<N2! M  
//停止文件下载 N1%p"(  
public void siteStop() z<hFK+j,'^  
{ C@1CanL@3  
bStop = true; +#4]o }6G  
for(int i=0;i<nStartPos.length;i++) l';pP^.q  
fileSplitterFetch.splitterStop(); UH[<&v  
o7.e'1@  
u#1%P5r&X  
} GD!- qH  
} Y,C=@t@_  
//负责部分文件的抓取 </= CZy5w  
**FileSplitterFetch.java {3LA%xO  
*/ #b'N}2'p#V  
package NetFox; E!zX)|Z<  
k'Gw!p}  
ygN>"eP  
import java.io.*; s.VA!@F5  
import java.net.*; )>\4ULR83  
^-hErsK  
/t*YDWLg  
public class FileSplitterFetch extends Thread { /%!~x[BeJ>  
:$?Q D  
u^=`%)  
String sURL; //File URL fxd0e;NAAh  
long nStartPos; //File Snippet Start Position ~h! 13!  
long nEndPos; //File Snippet End Position b HE7yv [  
int nThreadID; //Thread's ID }x:0os  
boolean bDownOver = false; //Downing is over oaK.kOo  
boolean bStop = false; //Stop identical h./P\eDc  
FileAccessI fileAccessI = null; //File Access interface eCWPhB 6l  
iCP~O  
pISp*&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h d2'AlB  
{ *nRNg.i3D  
this.sURL = sURL; *)'Vvu<  
this.nStartPos = nStart; v*z(@<Y  
this.nEndPos = nEnd; dY!u)M;~~  
nThreadID = id; NLyXBV[hV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O-#TZ   
} ZSB?Y 1wG  
M&KyA  
]a?bzOr,  
public void run() A_R!uRD8-  
{ U%>'"  
while(nStartPos < nEndPos && !bStop) ;h Hi@Z 9  
{ booRrTS  
.WX,Nd3@  
~Y7dH Dn  
try{ |quij0_'e  
URL url = new URL(sURL); ^A9 M;q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 63 2bN=>  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7 ^$;  
String sProperty = "bytes="+nStartPos+"-"; D#Kuo$  
httpConnection.setRequestProperty("RANGE",sProperty); z-r2!^q27  
Utility.log(sProperty); |^a;77nE_^  
eGL<vX  
!yJICjXj  
InputStream input = httpConnection.getInputStream(); 3<:jx~y>  
//logResponseHead(httpConnection); Da.G4,vLh  
)C~9E 5E  
H:QhrL+7_  
byte[] b = new byte[1024]; O )d[8jw"  
int nRead; C vDxq:x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `@Oa lg  
{ w7TJv4_  
nStartPos += fileAccessI.write(b,0,nRead); =(o']ZaaA  
//if(nThreadID == 1) 2C=Q8ayvX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (xpn`NA  
} k N7Bd}  
Um` !%  
&,:h)  
Utility.log("Thread " + nThreadID + " is over!"); b:W-l?  
bDownOver = true; vB'>[jvA|  
//nPos = fileAccessI.write (b,0,nRead); >''U  
} P8Qyhc  
catch(Exception e){e.printStackTrace ();} vB\]u.  
} @N@F,~[RR2  
} 9+=gke  
p@ NaD=9  
fmX!6Kv  
//打印回应的头信息 q5DEw&UZJ  
public void logResponseHead(HttpURLConnection con) TrS8h^C  
{ hX:"QXx  
for(int i=1;;i++) Kn`M4 O  
{ <y.]ImO  
String header=con.getHeaderFieldKey(i); I:98 $r$  
if(header!=null) ULJmSe  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @(g_<@Jz  
Utility.log(header+" : "+con.getHeaderField(header)); WJH\~<{mP  
else Lh.b 5Q|  
break; "R>FqX6FB  
} co8"sz0(U  
} $;N*cH~  
yw-8#y  
E H:T  
public void splitterStop() nI.x  
{ ElhRF{R  
bStop = true; \NZIEu)5?  
} m,i,n9C->  
RGKYW>$0RR  
a8k;(/  
} PXzsj.  
U1_@F$mq<  
b V+(b9  
/* Dl(3wgA  
**FileAccess.java i':ydDOOHA  
*//文件访问(定位,写) e}/Lk5q!  
package NetFox; Q 1d'~e  
import java.io.*; wI]"U2L5  
h,aAw#NE*  
4;n6I)&.(  
public class FileAccessI implements Serializable{ >(uZtYM\j  
g8qgk:}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X[ q+619  
RandomAccessFile oSavedFile; ]H-S, lmV  
long nPos; (~CLn;'  
;c~cet4  
_v Sn`  
public FileAccessI() throws IOException L^2FQti>  
{ Q_* "SRz  
this("",0); ku$$ 1xq  
} 5^']+5_vb  
t!*+8Q !e  
];.pK  
public FileAccessI(String sName,long nPos) throws IOException 5` Te \H  
{ l^ZI* z7N  
oSavedFile = new RandomAccessFile(sName,"rw"); yjfat&$  
this.nPos = nPos; rSXh;\MfB4  
oSavedFile.seek(nPos); =mA: ctu~v  
} l @^3Exwt  
y_\p=0t8  
O3TQixE  
public synchronized int write(byte[] b,int nStart,int nLen) =]:>"_jN  
{ 'F>'(XWWQ  
int n = -1; *`ZH` V  
try{ G}&Sle]  
oSavedFile.write(b,nStart,nLen); n 1!?"m!  
n = nLen; XsnF~)YW  
} aLIBD'z  
catch(IOException e) (`y*V;o4  
{ =Umw$+fJr  
e.printStackTrace (); ;&1V0U,fx  
} !\&;h  
yAoe51h?  
X]P:CY  
return n; ^]{R.(#z  
} E<yW\  
7o8{mp'_  
(SKVuR%Jj  
} v4C{<8:X  
m1Y >Nj[f  
'fW6 .0fXa  
/* _YF%V;X  
**SiteInfoBean.java 9K9DF1SOa  
*/ &hRvol\J  
package NetFox; Yo[;W vu  
foQ#a  
wE~V]bmtW  
public class SiteInfoBean { E9~Ghx.   
i&VsW7  
]xuG&O"SBV  
private String sSiteURL; //Site's URL qi_Jywd:w  
private String sFilePath; //Saved File's Path #5V9o KM  
private String sFileName; //Saved File's Name ]\!?qsT3}  
private int nSplitter; //Count of Splited Downloading File By%=W5  
gG/!,Q.Qh  
Y.*y9)#S6  
public SiteInfoBean() \EVBwE,  
{//nSplitter的缺省值为5 6L)%T02C  
//default value of nSplitter is 5 q5?# 3T=  
this("","","",5); i9/aAH0  
} *hw\35%P`?  
>yULC|'F&~  
at)~]dG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '#k0a,<N  
{ utIX  %0  
sSiteURL= sURL; ,lyb!k8  
sFilePath = sPath; kXf'5p1  
sFileName = sName; &uO%_6J  
this.nSplitter = nSpiltter; \_lod kf  
HaP}Y :p  
$C `;fA  
} +(h\fm7*-  
8?%-'z.  
p>upA)W]  
public String getSSiteURL() Y*UA, <-  
{ nVi[  
return sSiteURL;  jrS[f  
} ?:)]h c  
={z*akn,  
7R`mf   
public void setSSiteURL(String value) mFi&YpH u3  
{ 49vcoHlf  
sSiteURL = value; o|$AyS{1  
} :AE&Ny4  
{j7uv"|X7  
]bK=FIK2  
public String getSFilePath() `5C,N!d8X  
{ f` ;j:O  
return sFilePath; {QwHc5Bf  
} }yz (xH  
RS^lKJ1 U  
7:2WgL o  
public void setSFilePath(String value) gy_>`16K  
{ sNLs\4v  
sFilePath = value; |g//g\dd  
} |fHV2Y`:g  
hUF5fZqii  
tfGHea)M  
public String getSFileName() EUxGAj$-  
{ dzDqZQY$  
return sFileName; hX=A)73(  
} +Nt2 +Y:O  
ekWePL;rR2  
<x<"n t  
public void setSFileName(String value) v uoQz\  
{ "t~  
sFileName = value; 5.MGaU^Z$  
} Y4v|ko`l%  
JW3B'_0  
MpF$xzh  
public int getNSplitter() G{6;>8h  
{ l p(8E6  
return nSplitter; LyAn&h}  
} /!3@]xz*  
mD^ jd+  
`pGa~!vl  
public void setNSplitter(int nCount) 3GUZ;jdn  
{ :(M(>4t  
nSplitter = nCount; ;e1ku|>$  
} t},/}b  
} +Zaj,oEE  
,}K7Dg^1  
x3o ]U)^  
/* F;7dt@5;  
**Utility.java w tiny,6  
*/ NnT1X;0W  
package NetFox; <gQIq{B?  
j,"@?Wt7  
fmb} 2h  
public class Utility { 4*Hgv:0?kI  
RT.D"WvT  
=AEBeiz  
public Utility() i;_tI#:A  
{ XYZ4TeW\1  
paD!Z0v&  
qa0 yg8,<  
} 6er-{.L=  
=9fajRFTt  
//线程睡眠 .ZJRO>S  
public static void sleep(int nSecond) /Z@tv .f  
{ Is{KN!Hw  
try{ 9*{[buZX  
Thread.sleep(nSecond); 'U\<IL#U  
} b"#WxgaF  
catch(Exception e) \l]DQaOEe  
{ Dk(1}%0U/  
e.printStackTrace (); 'gTbA?+@5  
} <7j87  
} S|]X'f  
Te<}*qvD  
//日志 3G`aHTWk  
public static void log(String sMsg) ]Zyur`  
{ tm#nUw  
System.err.println(sMsg); \4-"L>  
} + EGD.S{  
eFL=G%  
}l],.J\BGX  
public static void log(int sMsg) {:]9Q Tq  
{ 7 D^gMN%p  
System.err.println(sMsg); }L#_\  
} "6us#T  
} %Ntcvp)  
Y[$!`);Ye  
|>tKq;/  
/* 83Q 4On  
**TestMethod.java RkBb$q9F]  
*/ :QB<?HaS'  
package NetFox; fM^qQM[lG  
49dd5ddr  
b{]z w pf  
public class TestMethod { H=Y{rq@  
lJis~JLd`  
_PlKhv}  
public TestMethod() Ft;^g3N  
{ ///xx/weblogic60b2_win.exe L&%s[  
try{ O^^C;U@U<1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]A<~XIu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +(1zH-^.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !`M|C?b  
fileFetch.start(); 8=Z9T<K  
} _q{c##K f  
catch(Exception e){e.printStackTrace ();} <\pfIJr$  
N,;5{y1;J  
HFaj-~b  
} kAC&S!n  
H s"HID  
B9H@e#[  
public static void main(String[] args) KNLfp1!  
{ JAX*hGhkh  
new TestMethod(); 9)gC6 IiW  
} OC<5E121>Y  
} KjE+QUa  
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