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http断点续传简单实现(java)

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/* +9fQ YJBA  
**SiteFileFetch.java T=W;k<P\k  
*/ .Xm?tC<   
package NetFox; K'@lXA:  
import java.io.*; hN"cXz"/  
import java.net.*; *K'_"2J  
L8{4>,  
.Xcf *$.;s  
public class SiteFileFetch extends Thread { RF|r@/S  
%s;=H)8  
wV{jJyRl  
SiteInfoBean siteInfoBean = null; //文件信息Bean ;i>(r;ZM  
long[] nStartPos; //开始位置 @?/>$  
long[] nEndPos; //结束位置 ]IM/R@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &`LR{7m  
long nFileLength; //文件长度 \b6vu^;p  
boolean bFirst = true; //是否第一次取文件 l2h1CtAU  
boolean bStop = false; //停止标志 j0.E!8Ae{  
File tmpFile; //文件下载的临时信息 t4H*&U  
DataOutputStream output; //输出到文件的输出流 Sa 8T'%W  
t wr-+rm2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6$5?%ZLJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException xWuvT,^  
{ p\G1O*Z  
siteInfoBean = bean; WMXxP gik  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h~r&7G@[}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~R*01AnZ  
if(tmpFile.exists ()) e9p!Caf~I-  
{ Wi"3kps q  
bFirst = false; tW[dJKw  
read_nPos(); MD+e!A#o  
} HbZFL*2x3  
else y8Oz4|  
{ T$&vk#qr  
nStartPos = new long[bean.getNSplitter()]; KfkU_0R+~v  
nEndPos = new long[bean.getNSplitter()]; vo!QJ  
} 9 .3?$(  
6Q~(ibKx  
3:mZ1+  
mhv ;pM6  
} j G^f_w  
 Uip-qWI  
]z#9)i_l3  
public void run() "wj~KbT}&  
{ H9Dw#.em  
//获得文件长度 CYn56eRK  
//分割文件 1F]jy  
//实例FileSplitterFetch 4V7=VZ, @3  
//启动FileSplitterFetch线程 iw=~j  
//等待子线程返回 l<8+>W`_  
try{ -Crm#Ib~  
if(bFirst) `s|^  
{ ~(P\'H&(h  
nFileLength = getFileSize(); \]Y=*+{  
if(nFileLength == -1) Qk?J4 B  
{ K]H [A,  
System.err.println("File Length is not known!"); SpA-E/el  
} *OU&`\bmE  
else if(nFileLength == -2) fI"OzIJV  
{ VxqoE]Dh  
System.err.println("File is not access!"); +&*Ybbhb  
} D^<5gRK?  
else I/k/5  
{ V: P   
for(int i=0;i<nStartPos.length;i++) mXJ`t5v^l  
{ _`d=0l*8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D`hg+64}  
} 8\BYm|%aa  
for(int i=0;i<nEndPos.length-1;i++) _BPp=(|  
{ ,wB)hp  
nEndPos = nStartPos[i+1]; L 4Sa,ZL  
} @E%f AC  
nEndPos[nEndPos.length-1] = nFileLength; -Zfq:Kr  
} ~aL&,0  
} +T8]R7b9  
B"3uuk8  
0fAo&B  
//启动子线程 [{-5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wCw_aXqq  
for(int i=0;i<nStartPos.length;i++) ^<`uyY))Q  
{ 5]F4.sa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HzZ.q2Zz%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kB]?95>Wx  
nStartPos,nEndPos,i); `^'0__<M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3!Cab/T  
fileSplitterFetch.start(); &2//\Qz  
} }@<Ru  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L',7@W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TFYp=xK(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sL4+O P-  
nEndPos = " + nFileLength); flS_rY5  
// fileSplitterFetch[nPos.length-1].start(); :BVYS|%  
J"?jaa2~  
7z9[\]tt  
//等待子线程结束 V\P .uOI  
//int count = 0; 5z@QAQ  
//是否结束while循环 }c ,:uN  
boolean breakWhile = false; ;wF)!d  
~=/.ZUQNX  
!I+F8p   
while(!bStop) ]>oI3&6s  
{ v])R6-T-  
write_nPos(); JVq`v#8  
Utility.sleep(500); hO..j  
breakWhile = true; B/gI~e0  
:r+F95e  
J  7]LMw7  
for(int i=0;i<nStartPos.length;i++) K?gO ]T{6  
{ #|;;>YnZ   
if(!fileSplitterFetch.bDownOver) y2:Bv2}  
{ Igb%bO_  
breakWhile = false; ^^kL.C Ym  
break; Dy^A??A[E}  
} .v[!_bk8C  
} (Z#j^}G_l  
if(breakWhile) {9|S,<9  
break; Q'c[yu  
/[=U$=uH  
m?]= =9  
//count++; '=1@,Skj-  
//if(count>4) uYMH5Om+i  
// siteStop(); =aCd,4B}  
} 4ad-'  
Tk:%YS;=  
~NB lJULS  
System.err.println("文件下载结束!"); Oz4yUR  
} u=& $Z  
catch(Exception e){e.printStackTrace ();} =:(<lKf,<F  
} Azag*M?  
G[s/M\l  
n*y@3.  
//获得文件长度 WS2@; 8.N  
public long getFileSize() UjcKvF  
{ z]n&,q,5g  
int nFileLength = -1; 9B2`FJ  
try{ s,]z6L0  
URL url = new URL(siteInfoBean.getSSiteURL()); +9]CGYj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /A>1TPb09"  
httpConnection.setRequestProperty("User-Agent","NetFox"); s p&g  
XE?,)8  
;-d2~1$  
int responseCode=httpConnection.getResponseCode(); z.0!FUd  
if(responseCode>=400) ydf;g5OZ  
{ cBDOA<]r,  
processErrorCode(responseCode); != u S  
return -2; //-2 represent access is error e*hCf5=-  
} 1SY3  
3y]rhB  
+Q&CIo  
String sHeader;  H;Cv] -  
k*o>ZpjNH  
g<5G#  
for(int i=1;;i++) QI{<q<  
{ R\:t 73  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <:I]0|[  
//Utility.log(in.readLine()); 8npjQ;%4>  
sHeader=httpConnection.getHeaderFieldKey(i); A S]jJc^  
if(sHeader!=null) L0>w|LpRc  
{ 0=c:O  
if(sHeader.equals("Content-Length")) :my@Oxx4@  
{ k{ibD5B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0]MI*s>&  
break; p5 )+R/  
} n%I9l]  
} x(bM   
else B6"pw0  
break; )`-vN^1S-  
} of>}fJ_p  
} H'wh0K(  
catch(IOException e){e.printStackTrace ();} jWJ/gv~ $  
catch(Exception e){e.printStackTrace ();} u,),kj<  
k=JT%  
F>co#  
Utility.log(nFileLength); (*dJ   
HQtUNtZ  
o!}/& '(  
return nFileLength; {p M3f  
} Uiu9o]n  
V SUz+W  
2~q(?wY  
//保存下载信息(文件指针位置) R4Si{J*O  
private void write_nPos() O>sE~~g]?  
{ Ll'!aar,  
try{ \'Ewn8Qv8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iWMgU:T  
output.writeInt(nStartPos.length); dX ;G [\  
for(int i=0;i<nStartPos.length;i++) Jej-b<HmQ  
{ q<!Kt I4  
// output.writeLong(nPos); 2-.%WhE/  
output.writeLong(fileSplitterFetch.nStartPos); }*3#*y "  
output.writeLong(fileSplitterFetch.nEndPos); wVY;)1?  
} "U%jG`q  
output.close(); 7T@"2WYat  
} ~AG."<}  
catch(IOException e){e.printStackTrace ();} kU$M 8J.  
catch(Exception e){e.printStackTrace ();} ljRR{HOl  
} v}-jls  
{GM8}M~D&  
SWM6+i p  
//读取保存的下载信息(文件指针位置) ]#Q'~X W  
private void read_nPos() FAP1Bm  
{ Ax"I$6n>  
try{ h2#S ?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W(&9S[2  
int nCount = input.readInt(); rkC6 -9V  
nStartPos = new long[nCount]; P g1EE"N@  
nEndPos = new long[nCount]; ]z_C7Y"4BR  
for(int i=0;i<nStartPos.length;i++) {_5PN^J  
{ DC8,ns]!y  
nStartPos = input.readLong(); >5}jM5$  
nEndPos = input.readLong(); Dt8wd,B  
} C*fSPdg?  
input.close(); I\peO/w  
} |? l6S  
catch(IOException e){e.printStackTrace ();} n*U+jc  
catch(Exception e){e.printStackTrace ();} _I}rQfPJ  
} xtP=/B/  
5Pu F]5  
hg=BXe4:  
private void processErrorCode(int nErrorCode) 1O]27"9  
{ uSi/|  
System.err.println("Error Code : " + nErrorCode); Je~d/,^WU  
} ~ E|L4E  
MX#MDA-4  
Z`lCS o;  
//停止文件下载 *^5..0du  
public void siteStop()  %Jc>joU  
{ 4yu ^cix(  
bStop = true; Q8 r 7  
for(int i=0;i<nStartPos.length;i++) |xQq+e}l<  
fileSplitterFetch.splitterStop(); "3Z<V8xB  
6X.lncE@p  
!rMl" Y[  
} =#c?g Wb56  
} 34P5[j!h  
//负责部分文件的抓取 !^*I?9P  
**FileSplitterFetch.java <r{ )*]#l  
*/ k(v8zDq*  
package NetFox; ET7(n0*P}]  
4?a!6  
2 !^[x~t  
import java.io.*; `X7ns?  
import java.net.*; (iZE}qf7 g  
X@ Gm:6  
I=3e@aTZ,  
public class FileSplitterFetch extends Thread { uY;2tZldf=  
{%;KkC8=R  
Ck0R%|  
String sURL; //File URL Z 7M%}V%  
long nStartPos; //File Snippet Start Position $&|*v1rH  
long nEndPos; //File Snippet End Position { !C';^  
int nThreadID; //Thread's ID boR&'yX  
boolean bDownOver = false; //Downing is over tT;=l[7%  
boolean bStop = false; //Stop identical p 8q9:Tz  
FileAccessI fileAccessI = null; //File Access interface $N#f)8v  
' 1aU0<  
fuxBoB  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "A_W U|  
{ >cPB:kD'  
this.sURL = sURL; O/(qi8En  
this.nStartPos = nStart; w*Gv#B9G  
this.nEndPos = nEnd; 3 TN?yP)  
nThreadID = id; >Rbgg1^]5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  *YFe  
} r4~Bn7j2  
5M{ DJ/q  
fr0iEO_  
public void run() eiF!yk?2  
{ *eO@<j?  
while(nStartPos < nEndPos && !bStop) &!{wbm@  
{ ~OXC6z  
U$`)|/8  
>_biiW~x:  
try{ qK4E:dD  
URL url = new URL(sURL); %8T:rS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {da Nw>TH  
httpConnection.setRequestProperty("User-Agent","NetFox"); h !~u9  
String sProperty = "bytes="+nStartPos+"-"; 6SMGXy*]^  
httpConnection.setRequestProperty("RANGE",sProperty); e_wz8]K)n  
Utility.log(sProperty); }V3p <  
Qj? G KO  
IA|V^Wmt;  
InputStream input = httpConnection.getInputStream(); pX]*&[X?  
//logResponseHead(httpConnection); {37DrSOa  
*a@pZI0'  
.Jz$)R  
byte[] b = new byte[1024]; "9 -duDg  
int nRead; Y'n TyH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HB4Hz0Fa  
{ [ed%"f  
nStartPos += fileAccessI.write(b,0,nRead); %TUljX K}  
//if(nThreadID == 1) ! G%LYHx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8Us5Oi  
} k})Ag7c  
9BGPq)#  
}B_n}<tjD  
Utility.log("Thread " + nThreadID + " is over!"); ~$f+]7  
bDownOver = true; (9BjZ&ej  
//nPos = fileAccessI.write (b,0,nRead); ?J+[|*'yK  
} u!%]?MSc  
catch(Exception e){e.printStackTrace ();} I'o9.B8%#  
} S zOB{  
} :rb<mg[  
P sD+?  
ML0o :8Bd\  
//打印回应的头信息 [S":~3^B6  
public void logResponseHead(HttpURLConnection con) d>  Y9g  
{ !5 %c`4  
for(int i=1;;i++) _p7c<$ ;  
{ p[&'*"o!/  
String header=con.getHeaderFieldKey(i); IQdiVj  
if(header!=null) D<}KTyG]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Cdiu*#f  
Utility.log(header+" : "+con.getHeaderField(header)); m$A|Sx&sG$  
else f6^H Q1SSt  
break; (I,PC*:  
} j0o_``  
} 8;.WX  
g!D?Yj4  
Bfaj4i ;_  
public void splitterStop() zp"sM z]  
{ kwK<?\D  
bStop = true; R#Id"O  
} a)4.[+wnRf  
bWwc2##7jo  
A[;R_  
}  F[115/  
;hmy7M1%  
fT/;TK>z>  
/* 2M= gpy  
**FileAccess.java ,/|"0$p2x  
*//文件访问(定位,写) Q9X_aB0  
package NetFox; GKtG#jZ&  
import java.io.*; $~50M5&K#  
Oh~J yrZy  
W:b8m Xx  
public class FileAccessI implements Serializable{ # o)a`,f  
[Pby  d  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pb}QP  
RandomAccessFile oSavedFile; e!ar:>T  
long nPos; vz,l{0 v  
.'p_j(uv  
+l2{EiQw  
public FileAccessI() throws IOException 1>4'YMdZi  
{ S!2M?}LU  
this("",0); *xM4nUu<~  
} CP'?Om2  
br>"96A1l  
E*.D_F  
public FileAccessI(String sName,long nPos) throws IOException _%;$y5]v  
{ OYgD9T.8^  
oSavedFile = new RandomAccessFile(sName,"rw"); 3F[z]B  
this.nPos = nPos; 1N1MD@C?P  
oSavedFile.seek(nPos); 4{X5ZS?CkI  
} 5)2lZ(5.A#  
:Y0*P  
U=QV^I Qm  
public synchronized int write(byte[] b,int nStart,int nLen) =5oE|F%  
{ ,S2D/Y^>  
int n = -1; H{E223  
try{ d5\w'@Di  
oSavedFile.write(b,nStart,nLen); c@~\ FUr  
n = nLen; W7S`+Pq  
} BE:HO^-.1  
catch(IOException e) ; GRSe  
{ #)tt}GX  
e.printStackTrace (); 7*M+bZ`x  
} ckBcwIXlP&  
8U*}D~%!  
siZw-.  
return n; cMsm[D{b  
} cc*A/lD  
%/CCh;N#  
't{~#0d=  
} 1xar L))  
e54wAypPOl  
BYyR-m  
/* p./zW )7+  
**SiteInfoBean.java x/#* M  
*/ >pbO\=j]X  
package NetFox; LS+ _y <v=  
mMS%O]m,|  
kTT!gZP$  
public class SiteInfoBean { /G9wW+1  
7;) T;X  
'mp@!@_  
private String sSiteURL; //Site's URL kKr7c4q  
private String sFilePath; //Saved File's Path 'mXf8   
private String sFileName; //Saved File's Name A/|To!R  
private int nSplitter; //Count of Splited Downloading File c]v $C&FX  
(xBS~}e  
(Gp/^[.%&  
public SiteInfoBean() TIbiw  
{//nSplitter的缺省值为5 t4/d1qW0  
//default value of nSplitter is 5 3J32W@}.K  
this("","","",5); Ya<S/9c  
} G<#9`  
}Ry:})  
S4aN7.'Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [ p$f)'  
{ $d3al%Uo  
sSiteURL= sURL; GF*8(2h2  
sFilePath = sPath; X9K@mX  
sFileName = sName; C}<j8a?  
this.nSplitter = nSpiltter; 3vfm$sx@  
uPr'by  
@#hd8_)A.  
} I} m\(TS-"  
W,9. z%  
Q0K2md_%x  
public String getSSiteURL() S}f 3b N  
{ ig5 d-A  
return sSiteURL; :hr% 6K7  
} 3gV 17a  
XZD9vFj1Z  
zePVB -@u  
public void setSSiteURL(String value) 2a|9D \  
{ As }:~Jy|  
sSiteURL = value; FNL[6.!PV  
} ?{[ ISk)  
M{cF14cQ  
d]{wZ#x  
public String getSFilePath() B9^ @d  
{ D!Pv`wm  
return sFilePath; C62:G+W&o  
} &TJMopVn  
X|zQZ<CO  
Hof@,w  
public void setSFilePath(String value) :,Z'/e0&  
{ >-J%=P  
sFilePath = value; _;L%? -2c  
} }Q&zYC]d  
h\| ~Q.kG  
^YG'p?r.s  
public String getSFileName() (k/[/`3ST  
{ U l8G R  
return sFileName; #JMww  
}  kDbDG,O  
m}ZkNWH  
E[q:65xl  
public void setSFileName(String value) E-gI'qG\(  
{ {w:*t)@j  
sFileName = value; U4)x"s[CP  
} :0@R(ct;>  
/e5' YVP  
cq:<,Ke  
public int getNSplitter() zG-pqE6  
{ fy9mS  
return nSplitter; 011 N  
} DQ%bcXs  
Q+@/.qJ  
_=0%3Sh  
public void setNSplitter(int nCount) zwJB.4@  
{ (=&z:-52V  
nSplitter = nCount;  dpG l  
} >=Bl/0YH  
} lw+Y_;  
ASGV3r (  
6d~[j <@2  
/* 8xf]zM"Q  
**Utility.java ^97u0K3$  
*/ t&|M@Ouet  
package NetFox; QguRU|y  
9dS<^E(ZF  
HGycF|]2  
public class Utility { efzS]1Jpz  
X%(1C,C(  
a|}v?z\  
public Utility() L#huTKX}  
{ U$,-F**  
B:mtl?69g  
h]6m+oPW  
} z`]sWi F0  
Oq3aboAt  
//线程睡眠 D[jPz0  
public static void sleep(int nSecond) n[[2<s*YJ  
{ .)(5F45Wg  
try{ Rtywi}VV2  
Thread.sleep(nSecond); Gx)U~L$B  
} =;L44.,g  
catch(Exception e) ,I|3.4z  
{ bi{G :xt  
e.printStackTrace (); o|7ztpr  
} ~K$dQb])  
} TmviYP gb  
(V(8E%<c  
//日志 mETGYkPUa  
public static void log(String sMsg) C[ma!he  
{ hqDnmzG  
System.err.println(sMsg); Mi^/`1  
} m>FP&~2  
4De2m iq  
xaN[ru@  
public static void log(int sMsg) D( \c?X"  
{ kR0/jEz C  
System.err.println(sMsg); }[;{@Zn  
} R1cOUV,y[/  
} )L+>^cJI<  
J;DTh ]z?:  
bVxbQ$  
/* !kW~s_gUb*  
**TestMethod.java ;$.^  
*/ F[q)ME+`)  
package NetFox; N({0"7  
-3GlpC22  
q2+`a;_S  
public class TestMethod { MA1y@  
sq rY<@%  
S7v# `#  
public TestMethod() }'`iJ b\  
{ ///xx/weblogic60b2_win.exe Mg~62u  
try{ V}aZ}m{J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %\f<N1~*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `RlMfd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @f!r"P]  
fileFetch.start(); ]mR!-Fqj  
} mI> =S  
catch(Exception e){e.printStackTrace ();} oUd R,;h9  
)BeB xo7lv  
-|DBO0q  
} %n{ue9  
W0+m A  
ooA%/  
public static void main(String[] args) B<{Yj}..  
{ e;8nujdG"  
new TestMethod(); (jI_Dk;  
} {Gvv^.H7  
} IkP; i_|  
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