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http断点续传简单实现(java)

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/* nQdNXv<(  
**SiteFileFetch.java bxyEn'vNvQ  
*/ !H{)L@f  
package NetFox; Wa #,>  
import java.io.*; `~UCWK  
import java.net.*; 8A"[n>931  
Kv:UQdnU[  
Q\z3YUk  
public class SiteFileFetch extends Thread { `]\4yTd  
RKdf1C  
3:<+9X  
SiteInfoBean siteInfoBean = null; //文件信息Bean F+*>q  
long[] nStartPos; //开始位置 \hdR&f5q  
long[] nEndPos; //结束位置 c=I!?a"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L$zT`1Hy  
long nFileLength; //文件长度 aQCbRS6  
boolean bFirst = true; //是否第一次取文件 4U<'3~RN  
boolean bStop = false; //停止标志 %2^C  
File tmpFile; //文件下载的临时信息 l<PGUm:_  
DataOutputStream output; //输出到文件的输出流 E87/B%R  
fpM 4q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -?e~dLu  
public SiteFileFetch(SiteInfoBean bean) throws IOException M~I M;my  
{ Vm'ReH  
siteInfoBean = bean; L'6_~I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v!t*Ng  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7 tF1g=\  
if(tmpFile.exists ()) (*&6XTV(  
{ ,Ot3N\%yn  
bFirst = false; q\O'r[&V  
read_nPos(); 6ecr]=Cv  
} V J){@  
else .Y_RI&B!L  
{  ^wb -s  
nStartPos = new long[bean.getNSplitter()]; / Zz2=gDY  
nEndPos = new long[bean.getNSplitter()]; |?s%8c'w=  
} EYGJDv(S  
L45&O *%  
1(w0* `  
AbZ:AJ(  
} XT{1!I(  
a&#Z=WK4  
X_ H R$il  
public void run() <^R\N#  
{ lADi  
//获得文件长度 b$PNZC8f  
//分割文件 &BG^:4b  
//实例FileSplitterFetch i.cSD%*  
//启动FileSplitterFetch线程 -5p=gO  
//等待子线程返回 8f,jC+(  
try{ 85 "DS-+e  
if(bFirst) ;TmwIZ  
{ =_%:9FnQ0  
nFileLength = getFileSize(); 5y=X?hF~)  
if(nFileLength == -1) ~Ufcy{x#  
{ v&H&+:<  
System.err.println("File Length is not known!"); F__DPEAc_  
} Rr%]/%  
else if(nFileLength == -2) '(2G qX!  
{ S wC,=S  
System.err.println("File is not access!"); SjlkKulMF  
} GgA =EdJn  
else S31 :}   
{ `*}#Bks!  
for(int i=0;i<nStartPos.length;i++) Bq R;d  
{ jf/;`br  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {:6VJ0s\  
} q n=6>wP  
for(int i=0;i<nEndPos.length-1;i++) =C`v+NPM)|  
{ qf)]!w U9  
nEndPos = nStartPos[i+1]; eDaVoc3  
} 2$\1v*:  
nEndPos[nEndPos.length-1] = nFileLength; ocdXzk`  
} /^#} \<;  
} QREIr |q'  
wfo}TGhC  
mXhr: e  
//启动子线程 y;<jE.7>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <LBMth  
for(int i=0;i<nStartPos.length;i++) ]t(g7lc}U  
{ *:\QD 8^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !vImmhI!I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9oc[}k-M  
nStartPos,nEndPos,i); P Cw.NJd$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )j6S<mn  
fileSplitterFetch.start();  zKT \i  
} ;y HA.}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m{b(^K9}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  4jG@ #  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vtL)  
nEndPos = " + nFileLength); G4g },p!  
// fileSplitterFetch[nPos.length-1].start(); Bljh'Qp>C  
uidE/7  
m1+DeXR_g  
//等待子线程结束 c!kbHZ<Z  
//int count = 0; bZ3CJ f&mE  
//是否结束while循环 &=02.E@  
boolean breakWhile = false; s[xdID^3.  
60`y=!?f  
Qz<v. _  
while(!bStop) N4HnW0  
{ B623B HwS  
write_nPos(); Dhef|E<  
Utility.sleep(500); `^_.E:f  
breakWhile = true; "h:xdaIE/p  
?+5K2Zk  
{BKI8vy  
for(int i=0;i<nStartPos.length;i++) zH|!O!3"4  
{ 9KAXc(-  
if(!fileSplitterFetch.bDownOver) { 0Leua  
{ "]JS,g {m  
breakWhile = false; )ZiJl5l@  
break; B&.XGo)  
} a<vCAFQ  
} Gia_B6*Y[  
if(breakWhile) Qz/=+A/4  
break; ;PLby]=O  
bLf }U9  
{},G xrQm  
//count++; Bd\p!f<  
//if(count>4) F;MFw2G  
// siteStop(); (?J&Ar0  
} _jnH!Mw  
@-u/('vpB  
,T1 t`  
System.err.println("文件下载结束!"); (<3'LhFII  
} V1"+4&R^T_  
catch(Exception e){e.printStackTrace ();} UHR)]5Lt  
} WH'[~O  
\UN7lDH  
4'_uN$${$  
//获得文件长度 nP_s+k  
public long getFileSize() Y{2\==~  
{ ^*Rrx  
int nFileLength = -1; Vl'|l)b4W  
try{ \Dr@n^hk@[  
URL url = new URL(siteInfoBean.getSSiteURL()); o1kLT@VCl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W~DY-;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9~u1fk{  
~":?})  
rF 7EO%,  
int responseCode=httpConnection.getResponseCode(); Af*^u|#  
if(responseCode>=400) {]|};E[}m  
{ kS+*@o  
processErrorCode(responseCode); ^$yr-p%-  
return -2; //-2 represent access is error ##yi^;3Y  
} (wvDiW5  
.cle^P  
%'EOFv]  
String sHeader; @KNp?2a  
K3 "co1]u  
/t ,ujTK  
for(int i=1;;i++) 9<-AukK m  
{ SAXjB;VH6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [O(78n$$  
//Utility.log(in.readLine()); H VG'v>s@  
sHeader=httpConnection.getHeaderFieldKey(i); nvpdu)q<  
if(sHeader!=null) tQ] R@i  
{  :E'38~  
if(sHeader.equals("Content-Length")) sx(yG9  
{ -Z]?v3 9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Gl}=Q7  
break; #p*OLQ3~  
} I)DLnnQQ  
} Px'%5TKN  
else vNi7=3  
break; TZPWMCN4  
} C6O1ype  
} F]SexP4:A  
catch(IOException e){e.printStackTrace ();} hRGK W  
catch(Exception e){e.printStackTrace ();} S 8h/AW6l  
Q)HVh[4  
u`K+0^)T`  
Utility.log(nFileLength); %E~4Ur  
,Ea.ts>  
Vx-H W;,  
return nFileLength; . |KxQn}  
} CI$F#j  
QQ1+uY  
<k}>eGn  
//保存下载信息(文件指针位置) T" 8>6a@}E  
private void write_nPos() 4$d|}ajH  
{ $U"/.Mh\  
try{ %+FM$xyJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8uS1HE\%  
output.writeInt(nStartPos.length); d<(1^Rto  
for(int i=0;i<nStartPos.length;i++) HC}D<FX |  
{ 8~\Fpz|Og  
// output.writeLong(nPos); @+B .<@V  
output.writeLong(fileSplitterFetch.nStartPos);  +6uun  
output.writeLong(fileSplitterFetch.nEndPos); hG&RGN_<6+  
} $* 8c0.{U  
output.close(); 3 +BPqhzf  
} qmOGsj`#  
catch(IOException e){e.printStackTrace ();} 8p>%}LX/  
catch(Exception e){e.printStackTrace ();} htlsU*x  
} ,N <;!6e  
~$!eB/6ty  
!);}zW!  
//读取保存的下载信息(文件指针位置) &g.w~KWa  
private void read_nPos() t<}'/ )  
{ ^=E4~22q  
try{ u#la+/   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9%kY8#%SV  
int nCount = input.readInt(); -!(3fO:  
nStartPos = new long[nCount]; \9@*Jgpd6*  
nEndPos = new long[nCount]; KW^s~j  
for(int i=0;i<nStartPos.length;i++) VlXIM,  
{ Z]uN9c  
nStartPos = input.readLong(); $//18+T  
nEndPos = input.readLong(); N, ;'oL+  
} ^7F!>!9Ca  
input.close(); fcD$km  
} u%VO'}Gz  
catch(IOException e){e.printStackTrace ();} p0`Wci  
catch(Exception e){e.printStackTrace ();} \*!g0C 8 o  
} "{qhk{  
p^ 9QYR  
REnRpp$  
private void processErrorCode(int nErrorCode) 7b:oz3?PI  
{ |3Oe2qb  
System.err.println("Error Code : " + nErrorCode); &Mo=V4i>  
} a%*W^R9Ls  
` n@[=l~  
jr" yIC_  
//停止文件下载 &Vvy`JE  
public void siteStop() 4h:Oo  
{ ) 8st  
bStop = true; w v9s{I{P  
for(int i=0;i<nStartPos.length;i++) =h5&\4r=  
fileSplitterFetch.splitterStop(); m\"M`o B  
JWlH(-U4|  
j4ypXPY``!  
} {BY`Wu:w  
} ruB&&C6)v  
//负责部分文件的抓取 hSp[BsF`,  
**FileSplitterFetch.java s3/->1#i  
*/ UyD=x(li  
package NetFox; jWUN~#p!  
6jPaS!E  
R 4E0avt  
import java.io.*; _ nS';48  
import java.net.*; 7s<v06Wo  
oel3H5Nz  
i3rvD ch  
public class FileSplitterFetch extends Thread { I;uZ/cZ|/  
D'|#5>G  
}I; =IYrN  
String sURL; //File URL >fdS$,`A  
long nStartPos; //File Snippet Start Position %}+j4n  
long nEndPos; //File Snippet End Position , $78\B^  
int nThreadID; //Thread's ID ',*I=JW;  
boolean bDownOver = false; //Downing is over h"#^0$f  
boolean bStop = false; //Stop identical YPf&y"E&H  
FileAccessI fileAccessI = null; //File Access interface (aiE!c  
eZI&d;i  
 5t:4%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JQQD~J1)E  
{ {LR?#.   
this.sURL = sURL; |+x;18  
this.nStartPos = nStart; Ju)2J?Xs5  
this.nEndPos = nEnd; 31Zl"-<#-  
nThreadID = id;  6.KR(V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?!Rl p/  
} &q``CCOF&  
`"A\8)6-  
g9GE0DbT`  
public void run() y9Yh%M(  
{ !_l W#feR  
while(nStartPos < nEndPos && !bStop) c6E@+xU  
{ r\ ` R$  
/_26D0}UuF  
:Oa|&.0l?  
try{ _9\ ayR>d  
URL url = new URL(sURL); +)L 'qbCSM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q4CxtY  
httpConnection.setRequestProperty("User-Agent","NetFox"); SZK~<@q5  
String sProperty = "bytes="+nStartPos+"-"; 5c3 )p^ ]g  
httpConnection.setRequestProperty("RANGE",sProperty); 1 /7H` O?  
Utility.log(sProperty); i,<TaW*I  
L$i&>cF\_>  
l_>^LFOA  
InputStream input = httpConnection.getInputStream(); w KXKc\r  
//logResponseHead(httpConnection); wEQV"I  
f{^C+t{r  
|DwI%%0(F  
byte[] b = new byte[1024]; :T5l0h-eC  
int nRead; TP'EdzAT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ol{)U;, `  
{ vZhN% DfY  
nStartPos += fileAccessI.write(b,0,nRead); $-jj%x\}  
//if(nThreadID == 1) `:-{8Vo7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^qS[2Dy  
} ?9OiF-:n  
9~ K 1+%!  
"9&6bBa  
Utility.log("Thread " + nThreadID + " is over!"); [0Z r z+q  
bDownOver = true; cqRIi~`  
//nPos = fileAccessI.write (b,0,nRead); &]16Hb~  
} W*}q;ub;  
catch(Exception e){e.printStackTrace ();} 8e[kE>tS._  
} %fJ*Ql4M  
} k .KN9=o  
xzz[!yJjG  
)+u|qT3%  
//打印回应的头信息 A_CEpG]  
public void logResponseHead(HttpURLConnection con) =5[}&W  
{ FC.y%P,  
for(int i=1;;i++) a%Q.8  
{ ?h<I:[oZ  
String header=con.getHeaderFieldKey(i); hz>&E,<8q  
if(header!=null) b_W0tiyv%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o'D{ql  
Utility.log(header+" : "+con.getHeaderField(header)); (`<l" @:_*  
else (SkI9[1\@3  
break; O<)"k j 7  
} <6Y o%xt  
} A+iQH1C0h  
:@`Ll;G  
I,_wt+O&j  
public void splitterStop() &g\D-At  
{ >C*q  
bStop = true; gk>A  
} i(a2FKLy  
Yih^ZTf]O?  
n,wLk./`  
} Fm#4;'x5E  
G!ty@ Fx  
:cnH@:  
/* "e&S*8QhM  
**FileAccess.java |FS79Bv  
*//文件访问(定位,写) 3R !Mfz*  
package NetFox; c#<v:b  
import java.io.*; w3:Y]F.ot  
JcvWE $  
17a'C  
public class FileAccessI implements Serializable{ isLIfE>  
VuN= JX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RnE=T/VZJ  
RandomAccessFile oSavedFile; Q$iYhR  
long nPos; $A`D p{e"  
]uI#4t~  
q=M!YWz  
public FileAccessI() throws IOException Hq?-e?Nc  
{  5%mc|  
this("",0); ;[R{oW Nw  
} C&^"]-t  
ZxlQyr`~a(  
9fp1*d  
public FileAccessI(String sName,long nPos) throws IOException EJ`JN|,M  
{ @/@#,+  
oSavedFile = new RandomAccessFile(sName,"rw"); 6 D_3Hwrs  
this.nPos = nPos; 2j9Mr  
oSavedFile.seek(nPos); iq)4/3"6  
} {9q~bt  
IP~*_R"bM  
8%S5Fc #am  
public synchronized int write(byte[] b,int nStart,int nLen) y*0bHzJ  
{  /~yk  
int n = -1; +@ga  
try{ I,OEor6%R(  
oSavedFile.write(b,nStart,nLen); J+r\EN^9  
n = nLen; Z& e_yl  
} :8cp]v dW  
catch(IOException e) Oz<{B]pEul  
{ N2[EdOJT_  
e.printStackTrace (); KP `{ UD)  
} 4loG$l+a1  
[1K\ _  
f'` QW@U  
return n; G[z!;Zuf  
} FJDx80J  
r8x<- u4  
T2|dFKeWG  
} 6}zargu(;  
'yd<<BM`  
lcR53X  
/* 4n_f7'GZg  
**SiteInfoBean.java b2]1Dfw  
*/ {WfZE&B  
package NetFox; ?*lpu  
;K]6/Wt  
%2>ya>/M  
public class SiteInfoBean { b3]QH h/  
Wm_:1~  
',`GdfAsH  
private String sSiteURL; //Site's URL ?Ho~6q8O@  
private String sFilePath; //Saved File's Path yzJ VU0s  
private String sFileName; //Saved File's Name  d(!W  
private int nSplitter; //Count of Splited Downloading File d/oxRzk'L  
Qv=F'  
&cy @Be}|T  
public SiteInfoBean() }@JPvI E  
{//nSplitter的缺省值为5 KtH-QQDluj  
//default value of nSplitter is 5 t<~$?tuZ  
this("","","",5); !U,W; R  
} ?VVtEmIN  
:2^j/  
<Sw>5M!j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &,~0*&r0  
{ lU6?p")F1  
sSiteURL= sURL; q=Cc2|Ve  
sFilePath = sPath; , H$1iJ?  
sFileName = sName; N0`v;4gF$]  
this.nSplitter = nSpiltter; 3@xn<eu  
v 809/c*  
zg)-RCG  
} ,D#ssxV  
`rt?n|*QF  
9a4Xf%!F>z  
public String getSSiteURL() c*iZ6j"iI  
{ jvGGIb"&1  
return sSiteURL; EtVRnI@  
} =2-!ay:  
7&ty!PpD  
>SS YYy  
public void setSSiteURL(String value) hRKAs ]^j  
{ df@r2 /Y  
sSiteURL = value; ~CTe5PX c  
} urM=l5Sx  
frsqnvm;+  
btb$C  
public String getSFilePath() Na6z1&wS  
{ Q[5j5vry  
return sFilePath; yWsJa)e3*@  
} 1^F !X=  
55aJ =T  
os<YfMM<:/  
public void setSFilePath(String value) ="yN4+0-p  
{ ?<_yW#x6  
sFilePath = value; "Q{)H8,E)x  
} (+M]C]  
d#Hl3]wT  
.\/jy]Y  
public String getSFileName() f=$w,^)M  
{ &nJH23h ^  
return sFileName; }@+3QHwYU  
} n+ot. -  
M|HW$8V3_2  
cM'\u~m{  
public void setSFileName(String value) gd#j{yI/Xf  
{ % ~!A,  
sFileName = value; w+,Kpb<x[0  
} Ib8*rL0p<L  
s7789pR  
5#WyI#YNG  
public int getNSplitter() |/YwMBi  
{ j#f7-nHyz8  
return nSplitter; i&di}x  
} '(6 ^O=  
%v"qFYVX"  
bTd94  
public void setNSplitter(int nCount) 17C"@1n-  
{ ^*$lCUv8p  
nSplitter = nCount; vl"{ovoC  
} f|r +qe  
} o4U[;.?c  
_!K@( dl  
Cqra\  
/* `pJWZ:3  
**Utility.java FSNzBN  
*/ gP^p7aYwn  
package NetFox; |bM?Q$>~  
 aj|gt  
a*N<gId  
public class Utility { R)Y*<Na  
v K7J;U+cJ  
a{y"vVQOF  
public Utility() qJZ:\u8oO  
{ h+ggrwg'  
 F<Y>  
:dML+R#Ymh  
} Eo@b)h  
+]*hzWbe  
//线程睡眠 ln&9WF\I  
public static void sleep(int nSecond) VM"z6@  
{ [7+dZL[  
try{ ;p] f5R^  
Thread.sleep(nSecond); IS [&V&.n  
} 6d#:v"^,  
catch(Exception e) QP={b+8  
{ F8En )#  
e.printStackTrace (); JZom#A. dt  
} 5a^b{=#Y  
} 7jtDhsVz  
x/]]~@:  
//日志 O~L/>Ya  
public static void log(String sMsg) \|< 5zL  
{ BSc5@;  
System.err.println(sMsg); Ip&Q'"HYj  
} n1;y"`gHk  
3B6"T;_  
.`5BgX7W  
public static void log(int sMsg) \4FKZ>1+R  
{ W%&'EJ)62  
System.err.println(sMsg); 5IfyD ]<  
} Xb/^n .>  
} NUjo5.7  
=0gfGwD{  
)gb gsQZ  
/* ^a?H "  
**TestMethod.java rZSX fgfr  
*/ Q?7:Xb N  
package NetFox; ~V?3A/]  
"JBTsQDj!  
S-D=-{@  
public class TestMethod { _WeN\F~^  
TexSUtx@$  
mok%TK  
public TestMethod() ;xMieqz  
{ ///xx/weblogic60b2_win.exe @b,&b6V  
try{ 'D1Sm&M2%e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ocbNf'W;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r|!r!V8j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !v`C-1}70  
fileFetch.start(); PR i3=3oF  
} 2B<0|EGtzw  
catch(Exception e){e.printStackTrace ();} hD I}V 1)  
sM0o,l(5  
^,;AM(E  
} /H m), 9NN  
xM6v0Ua  
I X]K "hT  
public static void main(String[] args) 7HkQ|~zGT  
{ 2-#:Y  
new TestMethod(); ,O[Maj/ch  
} nL[ zXl  
} X|3l*FL  
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