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http断点续传简单实现(java)

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/* #sTEQjJ,J  
**SiteFileFetch.java VIC0}LT0R  
*/ Y4E/?37j  
package NetFox; > @_im6  
import java.io.*; +vW)vS[  
import java.net.*; :w`3cw Q  
l.`u5D  
g:7,~}_}^  
public class SiteFileFetch extends Thread { j~E",7Q'  
K<4Kk3  
}lP;U$  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~ Vw9  
long[] nStartPos; //开始位置 RBwO+J53y  
long[] nEndPos; //结束位置 LJFG0 W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ST5V!jz  
long nFileLength; //文件长度 -#In;~  
boolean bFirst = true; //是否第一次取文件 'm3t|:nMU  
boolean bStop = false; //停止标志 X T[zj <&_  
File tmpFile; //文件下载的临时信息 .B72C[' c  
DataOutputStream output; //输出到文件的输出流 R\mR$\cS  
 x}TS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) =PkO!Mm8  
public SiteFileFetch(SiteInfoBean bean) throws IOException POAw M  
{ H#i{?RM@l  
siteInfoBean = bean; 2o3EHZ+]cm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )@gZ;`n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7j$Pt8$  
if(tmpFile.exists ()) :O-iykXyI  
{ iD`d99f8O  
bFirst = false; {2&m`D bm  
read_nPos(); 2 PqS%`XiS  
} T!RT<&  
else 1PH: \0}  
{ g7\,{Bw#E  
nStartPos = new long[bean.getNSplitter()]; gU&%J4O  
nEndPos = new long[bean.getNSplitter()]; 5%zXAQD=<  
} r%@Lej5+  
\f:z+F!6R  
P 1XK*GZ  
m<rhIq  
} NGC,lv  
Wy .IcWK  
&;i "P  
public void run() WWKvh  
{ ,Lpixnm]  
//获得文件长度 l<g5yYyf  
//分割文件 0 B@n{PvR0  
//实例FileSplitterFetch 80b;I|-T,  
//启动FileSplitterFetch线程 \1"'E@+  
//等待子线程返回 /E;y,o75  
try{ ~y HU^5D  
if(bFirst) DdQ;Q5|  
{ ^y!;xc$(Qs  
nFileLength = getFileSize(); (*p , T  
if(nFileLength == -1) +Hvc_Av''  
{ 7c|bc6?  
System.err.println("File Length is not known!"); T9W`?A  
} rxn Frx  
else if(nFileLength == -2) fKH7xu!V4+  
{ \Ig68dFf%  
System.err.println("File is not access!"); #:jb*d?  
} >Fio;cn?  
else 54lu2gD'  
{ XfPFo6  
for(int i=0;i<nStartPos.length;i++) 7?j;7.i s(  
{ d^03"t0O]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N`@NiJ(O;  
} :W#rhuzC  
for(int i=0;i<nEndPos.length-1;i++) >F1kR\!  
{ (jjTK'0[  
nEndPos = nStartPos[i+1]; zGKyN@o  
} j#r6b]k(Hv  
nEndPos[nEndPos.length-1] = nFileLength; vo>d!rVCV  
} `?T#Hl>j  
} `Z: R Ce^  
N6K* d` o  
Hnknly  
//启动子线程 7SDFz}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :y*NM,s  
for(int i=0;i<nStartPos.length;i++) m>USD? i  
{ >~%e$a7}+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +#U|skl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &Z(K6U#.  
nStartPos,nEndPos,i); **9x?s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n0Y+b[ +wj  
fileSplitterFetch.start(); ^;!0j9"* :  
} $mf u:tbP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,.eWQK~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); FZjHw_pP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lC:k7<0Ji  
nEndPos = " + nFileLength); |4$M]Mf0  
// fileSplitterFetch[nPos.length-1].start(); ]Chj T}  
`&\Q +W  
X%z }VA  
//等待子线程结束 +$4(zP s@  
//int count = 0; L,y6^J!  
//是否结束while循环 8n1'x;  
boolean breakWhile = false; ! cKz7?w  
B9p?8.[  
rpeJkG@+  
while(!bStop) 7Q\|=$2  
{ 4tL<q_  
write_nPos(); X%yO5c\l2  
Utility.sleep(500); 8.F~k~srA  
breakWhile = true; COH<Tj  
m/#a0~dB  
mF` B#  
for(int i=0;i<nStartPos.length;i++) UOQEk22  
{ c/c$D;T  
if(!fileSplitterFetch.bDownOver) }Zl&]e  
{ 21k5I #U  
breakWhile = false; r0p w_j  
break; YK|bXSA[  
} [MuEoWrq(}  
} t78k4?  
if(breakWhile) wFG3KzEq ~  
break; 8XbA'% o  
rG,5[/l  
3u%{dGa  
//count++; z-M3  
//if(count>4) 9x,RvWTb  
// siteStop(); ]Q[p@gLd  
} ss;R8:5  
8~5cJPi6  
5 ae2<Y=  
System.err.println("文件下载结束!"); F~A'X  
} [O: !(G je  
catch(Exception e){e.printStackTrace ();} t_mIOm)S%  
} y:v,j42%  
 XL7h}  
lu Q~YjH  
//获得文件长度 Mq';S^  
public long getFileSize() cuOvN"nuNj  
{ %Uz(Vd#K  
int nFileLength = -1; =8U&[F  
try{ Q:J^"  
URL url = new URL(siteInfoBean.getSSiteURL()); >X*Mio8P#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sz9L8f2  
httpConnection.setRequestProperty("User-Agent","NetFox"); CI3XzH\IX*  
Z7 E  
bWOS `5  
int responseCode=httpConnection.getResponseCode(); re> rr4@  
if(responseCode>=400) DTWD |M  
{ _X@v/sAy  
processErrorCode(responseCode); '\jd#Kn'h  
return -2; //-2 represent access is error (b`]M`Fc  
} %YOndIS:  
T|tOTk  
6e7{Iy  
String sHeader; )7_"wD` z  
'Ei;^Y 1e  
fS^!ZPe1  
for(int i=1;;i++) zt^48~ry  
{ 2t $j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @LJpdvb  
//Utility.log(in.readLine()); Ivb 4P`{  
sHeader=httpConnection.getHeaderFieldKey(i); ,t1abp{A  
if(sHeader!=null) #s!'+|2n  
{ TX#m&vh  
if(sHeader.equals("Content-Length")) P./VmY'  
{ {3&|tk!*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QBR=0(giF  
break; kI%%i>Y}  
}  \>Efd  
} (Vo>e =q  
else 7Pa@1']  
break; jsNF#yE>  
} Wh&8pH:  
} "?| > btr  
catch(IOException e){e.printStackTrace ();} o/ui)U_   
catch(Exception e){e.printStackTrace ();} Y#g4$"G9  
([xo9FP;  
u ElAnrm  
Utility.log(nFileLength); '= l[;Q^Q  
m*mm\wN5  
|ae97 5  
return nFileLength; S4=R^];l  
} Q,80Hor#J  
IgC}&  
s|D>-  
//保存下载信息(文件指针位置) W\18{mbuy  
private void write_nPos() 3"rzb]=R  
{ 1h.)#g?{  
try{ wY"Q o7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7.j[a*^  
output.writeInt(nStartPos.length); .; &# )l  
for(int i=0;i<nStartPos.length;i++) '?({;/L  
{ %$TGzK1  
// output.writeLong(nPos); p019)X|vx  
output.writeLong(fileSplitterFetch.nStartPos); 1Z,[|wJ  
output.writeLong(fileSplitterFetch.nEndPos); ^Idle*+  
} NH0qVQ@A  
output.close(); , lJ  v  
} c2K:FdB  
catch(IOException e){e.printStackTrace ();} g (#f:"  
catch(Exception e){e.printStackTrace ();} `SVmQSwO[  
} `)QCn<  
z)uuxNv[R  
uPniLx\t:  
//读取保存的下载信息(文件指针位置) ;U_QvN|  
private void read_nPos() +S=Rn,  
{ vVE7fq3  
try{ UQ4% Xp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nJ" '  
int nCount = input.readInt(); d[;.r  
nStartPos = new long[nCount]; \w'*z&`W9  
nEndPos = new long[nCount]; +kFxi2L6  
for(int i=0;i<nStartPos.length;i++) ,6r{VLN  
{ gkHNRAL  
nStartPos = input.readLong(); cCR+D.F  
nEndPos = input.readLong(); bBY^+c<  
} GLGz 2 ,#  
input.close(); T,$WlK Wj  
} kCXdGhb  
catch(IOException e){e.printStackTrace ();} `l*;t`h  
catch(Exception e){e.printStackTrace ();} I<A6Z&*un  
} ?ByM[E$  
xz:J  
O2"gj"D  
private void processErrorCode(int nErrorCode) 2./ 3 \n2  
{ +Y+Y6Ac[}  
System.err.println("Error Code : " + nErrorCode); r:]1 O*  
} @9&P~mo/  
t3+Py7qv  
SI8%M=P>  
//停止文件下载 \Vl`YYjZ  
public void siteStop() Jnv@.  
{ |c`w'W?C6  
bStop = true; >,DbNmi  
for(int i=0;i<nStartPos.length;i++) ;.bm6(;  
fileSplitterFetch.splitterStop(); WMj}kq)SY)  
CSCN['x  
B7"PIkk;  
} 7-BvFEM;  
} RW P<B0)  
//负责部分文件的抓取 4WB-Ec  
**FileSplitterFetch.java AdWq Q  
*/ b pv= %  
package NetFox; m:hY`[ f6  
''|#cEc)  
$2%f 8&  
import java.io.*; KOwOIDt  
import java.net.*; yOvm`9  
lq"f[-8a2q  
U#1bp}y  
public class FileSplitterFetch extends Thread { 0T>H)c6:\  
3su78et}  
x1ztfJd  
String sURL; //File URL %r+vSGt;5  
long nStartPos; //File Snippet Start Position |$7vI&m  
long nEndPos; //File Snippet End Position p7H3J?`w1+  
int nThreadID; //Thread's ID 5cWw7V<m  
boolean bDownOver = false; //Downing is over =v*.p=r  
boolean bStop = false; //Stop identical PH{_ ,X  
FileAccessI fileAccessI = null; //File Access interface rL5z]RY  
t5lO'Ll*Q]  
Zec <m8~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6b!F1  
{ OnWx#84  
this.sURL = sURL; w4LScvBg  
this.nStartPos = nStart; 'L{8@gq i  
this.nEndPos = nEnd; 5 Qoew9rA  
nThreadID = id; !u]1 dxa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 NuU9~gSQ  
} X(7qZ P~  
98.>e  
KeNL0_ Pw  
public void run() sFBneBub  
{ 1[ ]&(Pa  
while(nStartPos < nEndPos && !bStop) vp(;W,ba:|  
{ #b7$TV  
*kIc9}  
=f(cH152T  
try{ $TI5vhQ  
URL url = new URL(sURL); U8(Nk\"X\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jg&E94}+  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;us%/kOR  
String sProperty = "bytes="+nStartPos+"-"; ",)Qc!^P$  
httpConnection.setRequestProperty("RANGE",sProperty); aTzjm`F0  
Utility.log(sProperty); hkO sm6  
jP~Z`y f  
4Bl{WyMJ|  
InputStream input = httpConnection.getInputStream(); 1bw{q.cmD  
//logResponseHead(httpConnection); yAN=2fZm  
G"T',~  
eznypY=  
byte[] b = new byte[1024]; 2<hpK!R  
int nRead; D/=5tOy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mR;qMX)0h  
{ +x1eJug4  
nStartPos += fileAccessI.write(b,0,nRead); Tz9`uW~Mf  
//if(nThreadID == 1) \(">K  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j:w{;(1=W  
} >><.3  
]QuM<ms  
=~I-]4  
Utility.log("Thread " + nThreadID + " is over!"); !d&C>7nb  
bDownOver = true; .SWt3|Pi5  
//nPos = fileAccessI.write (b,0,nRead); 2y%,p{="  
} mYc.x  
catch(Exception e){e.printStackTrace ();} #Oha(mRY  
} zm,@]!wI  
} 'Z`$n8  
~8m=1)A{(  
jLJ1u/l>;  
//打印回应的头信息 (5Sivw*mP  
public void logResponseHead(HttpURLConnection con) IG3,XW  
{ $x6$*K(F  
for(int i=1;;i++) %AN/>\#p  
{ &P,^.'  
String header=con.getHeaderFieldKey(i); ?X&6M;Zi  
if(header!=null) W>b(Om_%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `HuCT6O  
Utility.log(header+" : "+con.getHeaderField(header)); eyp,y2Tz  
else *. &HD6Qr  
break; x3rlJs`$;  
} 8t=(,^c  
} _ %%Z6x(  
]m#5`zGK1|  
4:9KR[y/  
public void splitterStop() A6oq.I0  
{ G Xt4j  
bStop = true; 0R0{t=VJZ  
} LB/C-n.`  
K 0hu:1l)  
 mA7m  
} m4:^}O-#  
T}3v(6ew4  
>h+349  
/*  9dzdrT  
**FileAccess.java wDwH.~3!  
*//文件访问(定位,写) ?RzDQy D  
package NetFox; `m.eM  
import java.io.*; )+H[kiN  
k0Ek:MjJr  
@t1V o}c  
public class FileAccessI implements Serializable{ 1.q_f<U  
s6o>m*{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  M/z}p  
RandomAccessFile oSavedFile; 8z5# ]u;  
long nPos; $0^P0RAH  
{7Mj P+\  
!,Zp? g)  
public FileAccessI() throws IOException ^h &I H|  
{ C>Is1i^9  
this("",0); %c)[ kAU!  
} saD-D2oj  
pb0E@C/R  
1|8<H~&  
public FileAccessI(String sName,long nPos) throws IOException vKoP|z=m  
{ S-#q~X!yJ  
oSavedFile = new RandomAccessFile(sName,"rw"); 79=45'8  
this.nPos = nPos; /# <pVgN  
oSavedFile.seek(nPos); dC}`IR  
} !AJ]j|@VBd  
Npn=cLC&  
H.G!A6bd  
public synchronized int write(byte[] b,int nStart,int nLen) KLC{7"6e)  
{ TzBzEiANn  
int n = -1; @ d"wAZzD?  
try{ AOrHU M[I  
oSavedFile.write(b,nStart,nLen); 7< 9L?F2  
n = nLen; &6Il(3-^  
} ~Ki`Ze"x  
catch(IOException e) H6aM&r9}  
{ ):EBgg4-N  
e.printStackTrace (); /HZumV?  
} O3V.^_k;  
l.nH?kK<  
F~U!1)  
return n; /(t sb  
} IF*&%pB  
_y .]3JNm  
woq)\;CK  
} 5.tvB  
Tp<k<uKD  
bzi|s5!'<  
/* pUl8{YGS  
**SiteInfoBean.java B pLEPuu30  
*/ TFDm5XJ  
package NetFox; }%n5nLU`  
f=J<*h  
2>em0{e  
public class SiteInfoBean { 6k?`:QK/sl  
GD-&_6a  
/NF#+bx  
private String sSiteURL; //Site's URL P%X-@0)  
private String sFilePath; //Saved File's Path oojiJ~  
private String sFileName; //Saved File's Name 5(&xNT-n8  
private int nSplitter; //Count of Splited Downloading File #ZiT-  
dPjhq(8 zU  
u1K\@jlw  
public SiteInfoBean() 0=v{RQ;W4  
{//nSplitter的缺省值为5 *Dr5O9Y  
//default value of nSplitter is 5 +pqM ^3t|y  
this("","","",5); pJ, @Y>  
} M,:Bl}  
5|$a =UIR  
> 8]j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rn.\tDeA  
{ cy~oPj]j  
sSiteURL= sURL; =FW5Tkw0  
sFilePath = sPath; AW5iV3  
sFileName = sName; y,+[$u7h  
this.nSplitter = nSpiltter; @LLTB(@wR  
e<gx~N9l'  
U=Bn>F}y\  
} >qT'z$  
4}KU>9YRA  
n"aCt%v  
public String getSSiteURL() wX1ig  
{ E@ h y7X  
return sSiteURL; l54|Q  
} FquFRx  
Sav`%0q?7a  
POU}/e!Ua  
public void setSSiteURL(String value) e&X>F"z2  
{ N b3$4(F  
sSiteURL = value; & 7QH^  
} 8V4V3^_xs  
\+qOO65/+  
; 7G_f  
public String getSFilePath() #\If]w*j  
{ -.vDF?@G  
return sFilePath; 4f1D*id*`#  
} qJ[@:&:  
9EF~l9`'U  
&:?e&  
public void setSFilePath(String value) 9(VRq^Z1  
{ BH:  
sFilePath = value; :_d3//|  
} w!q&  
I6OSC&A`  
<6N_at3  
public String getSFileName() )wf\F6jN  
{ q"aPJ0ni'  
return sFileName; QV,E #(\5  
} E*v]:kok  
tGqCt9;<  
7$b?m6fmK  
public void setSFileName(String value) +p/1x'J  
{ E;-qP)yU  
sFileName = value; xDrV5bg  
} 4u:0n>nJ1  
Q2~5"  
! gp}U#Yv  
public int getNSplitter() K%,$ V,#  
{ )}X5u%woV  
return nSplitter; S6 }QFx  
} =hX[  
Z6=~1'<X  
QdDtvJLf  
public void setNSplitter(int nCount) ,# "(Z  
{ ^Qh-(u`  
nSplitter = nCount; IbdM9qo7  
} A'eAu  
} t;Wotfc[#0  
-gKpL\  
h-'wV${b  
/* 3;BvnD7  
**Utility.java VbxAd 2')  
*/ YQ,tt<CQ  
package NetFox; By)3*<5a_  
]O@"\_}  
Xm[Czd]%  
public class Utility { Hql5oA  
`facFt[\  
{fG|_+tl3o  
public Utility() -Z?Ck!00  
{ Ku%6$C!,  
|>s v8/!  
44C+h    
} )W9_qmYd"  
>rRf9wO1l  
//线程睡眠 H%.zXQ4}n  
public static void sleep(int nSecond) |[w^eg  
{ ^HFo3V }h  
try{ q,,j',8kq/  
Thread.sleep(nSecond); (UW6F4:$  
} ( Yi=v'd  
catch(Exception e) ^]rxhpS  
{ />Jm Rdf  
e.printStackTrace (); jyjQzt >\  
} 91;HiILgT  
} ?Leyz  
?Y!U*& 7  
//日志 2}`R"MeS  
public static void log(String sMsg) }1rvM4{/+f  
{ (n=Aa;  
System.err.println(sMsg); ?Y!^I2Y6  
} @W [{2d  
i_YW;x  
97x%2.\:  
public static void log(int sMsg) )H+h ;U  
{ s-5wbi.C  
System.err.println(sMsg); RO(iHR3cA  
} t,?,F4 j  
} Zi3T~:0p:  
Sf5]=F-w  
Hd*Fc=>"Y  
/* QE6El'S  
**TestMethod.java |B|@GF?:  
*/ pU DO7Q]  
package NetFox; r9 ;`  
UG=I~{L  
#L1>dHhat  
public class TestMethod { FAd``9kRT  
x)\V lR  
'8Qw:fh  
public TestMethod() !Ud:?U  
{ ///xx/weblogic60b2_win.exe >e_%M5 0  
try{ Xv*}1PZH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k1wr/G'H[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9i[4"&K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fn?VNZ`J  
fileFetch.start(); Okoo(dfM  
} X4 Y  
catch(Exception e){e.printStackTrace ();} $/.<z(F  
zg7G^!PU  
NY 4C@@"  
} \AJS,QD  
{0fz9"|U  
=?+w)(*0c  
public static void main(String[] args) xtsL8-u f  
{ 4[(? L{  
new TestMethod(); Lv3XYZgW~  
} :B+Rg cqi  
} Q4 CJ]J`  
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