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http断点续传简单实现(java)

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/* yTEuf@  
**SiteFileFetch.java rfZA21y{?  
*/ KIS.4nt#d"  
package NetFox; ]uZH  0  
import java.io.*; u-W=~EO5#  
import java.net.*; $D89|sy  
HaSH0eTw  
UOY1^wY  
public class SiteFileFetch extends Thread { UWnH2  
&A9+%kOk>  
^?A+`1-  
SiteInfoBean siteInfoBean = null; //文件信息Bean 94R+S-|P  
long[] nStartPos; //开始位置 $DVy$)a!u  
long[] nEndPos; //结束位置 D9Z5g3s7R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _&M>f?l  
long nFileLength; //文件长度 `+6HHtF  
boolean bFirst = true; //是否第一次取文件 A gPg0(G  
boolean bStop = false; //停止标志 V+8+ 17^  
File tmpFile; //文件下载的临时信息 w;_Ds  
DataOutputStream output; //输出到文件的输出流 WS(c0c  
&zT~3 >2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h;lnc| Hw  
public SiteFileFetch(SiteInfoBean bean) throws IOException @X#m]ou  
{ e`oc#Od&x]  
siteInfoBean = bean; KV6S-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `7j,njCX.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gu/Yc`S[  
if(tmpFile.exists ()) aJF`rLm  
{ |WX4L7yrhK  
bFirst = false; i!iODt3k  
read_nPos(); v!uLd.(  
} BE2{qO{  
else N3?d?+A$  
{ vfm-K;,#  
nStartPos = new long[bean.getNSplitter()]; G9i#_  
nEndPos = new long[bean.getNSplitter()];  l gC  
} |( V3  
-bE|FFU  
>"[u.1J_'I  
YU`{  
} fP|\1Y?CS  
26**tB<  
BpCSf.zZ  
public void run() 5J;c;PF  
{ 'UyL%h;nJ  
//获得文件长度 _H,RcpyJ  
//分割文件 )t4C*+9<U  
//实例FileSplitterFetch phdN9<Z  
//启动FileSplitterFetch线程  fwEi//1  
//等待子线程返回 $CmTsnR1#y  
try{ (07d0<<[  
if(bFirst) " duJl-  
{ {x: IsQZ  
nFileLength = getFileSize(); K+\hv~+@  
if(nFileLength == -1) r$7rYxFR  
{ P#xn!fMi  
System.err.println("File Length is not known!"); B]vj1m`9  
} 6PH*]#PfoD  
else if(nFileLength == -2) j;3o9!.s:  
{ 7Tbkti;  
System.err.println("File is not access!"); |2# Ro*  
} bo2Od  
else v^tKT&  
{ */)gk=x8  
for(int i=0;i<nStartPos.length;i++) U`Zn*O~/  
{ q~3&f  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lySaJ d  
} NSq"\A\  
for(int i=0;i<nEndPos.length-1;i++) -AE/,@\P  
{ DXt^Ym5Cv  
nEndPos = nStartPos[i+1]; 1<83MO;  
} 2XtQ"`)  
nEndPos[nEndPos.length-1] = nFileLength; eG v"&kr  
} zN1;v6;  
} "DpQnhvbB  
JF gN  
#t O!3=0  
//启动子线程 Pz 'Hqvd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?<;<#JN  
for(int i=0;i<nStartPos.length;i++) H #BgE29  
{ =X*E(.6Ip  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fo#*_y5\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bhmjH(.t  
nStartPos,nEndPos,i); .kIf1-(<U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xh0A2bw'OP  
fileSplitterFetch.start(); s__g*%@B b  
} rx/6x(3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s<b7/;w'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pB./L&h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i`qh|w/b_  
nEndPos = " + nFileLength); =S,<yQJ  
// fileSplitterFetch[nPos.length-1].start(); 9o`3g@6z  
7 SZR#L  
.Dm{mV@*T  
//等待子线程结束 5*$Zfuf  
//int count = 0; KfNXX>'  
//是否结束while循环 :X f3wP=  
boolean breakWhile = false; *$VurqLn  
JyO lVs<T  
%a `dO EO  
while(!bStop) k:Q<Uanc[  
{ %Qq)=J<H ;  
write_nPos(); 6K}=K?3Z  
Utility.sleep(500); iE(grI3  
breakWhile = true; t^hkGYj!2  
@{uc  
#EUgb7  
for(int i=0;i<nStartPos.length;i++) {9 O`/|  
{ +bW|Q>u  
if(!fileSplitterFetch.bDownOver) @_3$(*n$~  
{ x(=x;X$[^  
breakWhile = false; cmI#R1\  
break; ub5hX{uT  
} Hea<!zPH  
} ;kBies>V  
if(breakWhile) `@7tWX0  
break; 03@| dN  
\<**SSN  
<J-Z;r(gQN  
//count++; -::%9D}P|  
//if(count>4) CN(4;-so)  
// siteStop(); 46Nf|~  
}  HU9y{H  
(_ah~VnO  
.Er/t"Qs;  
System.err.println("文件下载结束!"); '.,.F0{x  
} 8 -A7  
catch(Exception e){e.printStackTrace ();} VsEAo  
} JxJntsn  
+_P 2S  
PBtU4)  
//获得文件长度 \DK*> k  
public long getFileSize() &,]+>  
{ @~3c"q;i7  
int nFileLength = -1; (}1f]$V  
try{ {LHe 6#  
URL url = new URL(siteInfoBean.getSSiteURL()); _`>7 Q) ,7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rJp6d :M  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]bb}[#AY  
/g'-*:a  
 <z2mNq  
int responseCode=httpConnection.getResponseCode(); ^1=|(Z/  
if(responseCode>=400) +Q31K7Gr  
{ y$o=\:  
processErrorCode(responseCode); +z0}{,HX  
return -2; //-2 represent access is error : "te-  
} "B3:m-'  
f*{;\n (.t  
Ba|}C(Ws?  
String sHeader; i0Q _f!j  
Eu.qA9,@U  
U^BXCu1km  
for(int i=1;;i++) 2_n*u^X:_  
{ 3Lki7QW`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LoE(W|nj  
//Utility.log(in.readLine()); <Cu?$  
sHeader=httpConnection.getHeaderFieldKey(i); e-3pg?M  
if(sHeader!=null) O&iYGREO  
{ tkqBCKpDa  
if(sHeader.equals("Content-Length")) ZM`P~N1?)g  
{ a9zph2o-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x9A ZS#e)[  
break; zN/~a)  
} `)M\(_  
} % 3-\3qx*  
else IC.<)I  
break; &iy(oM  
} g{)H" 8L  
} nvo1+W(%  
catch(IOException e){e.printStackTrace ();} Ja=70ZI^ 6  
catch(Exception e){e.printStackTrace ();} xWz;5=7a]  
_ZM9 "<M-X  
"4uUI_E9F;  
Utility.log(nFileLength); kjC{Zr  
XW_xNkpL5c  
8t: &#h  
return nFileLength; 0$Y 9>)O  
} w <>6>w@GZ  
?En| _E_C  
<`j[;>O  
//保存下载信息(文件指针位置) 2vdQ&H4  
private void write_nPos() *a,.E6C*  
{ )  v5n "W  
try{ 7h9[-d6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4O_+4yS  
output.writeInt(nStartPos.length); 3r:)\E+Q_  
for(int i=0;i<nStartPos.length;i++) *r,&@UB  
{ U"y'Kd  
// output.writeLong(nPos); _q$LrAT  
output.writeLong(fileSplitterFetch.nStartPos); ca3BJWY}J  
output.writeLong(fileSplitterFetch.nEndPos); yb{{ z@  
} GHC?Tp   
output.close(); k-cIb@+"  
} f@Rpb}zg+C  
catch(IOException e){e.printStackTrace ();} KR+BuL+L  
catch(Exception e){e.printStackTrace ();} 4B8Se  
} Y:!/4GF  
]VG84bFm  
K1/gJ9+(\  
//读取保存的下载信息(文件指针位置) {&}/p-S  
private void read_nPos() 4IP\iw#w  
{ e(=~K@m  
try{ /z)3gsF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @S"pJeP/f  
int nCount = input.readInt(); a3dzok  
nStartPos = new long[nCount]; Hl2f`GZ   
nEndPos = new long[nCount]; CpRu*w{  
for(int i=0;i<nStartPos.length;i++) R!k<l<9q  
{ R-A'v&=  
nStartPos = input.readLong(); 2u*h*/  
nEndPos = input.readLong(); B?lBO V4v4  
} g3~~"`2  
input.close(); lc3S|4  
} 3pTS@  
catch(IOException e){e.printStackTrace ();} kV:FJx0xP  
catch(Exception e){e.printStackTrace ();} ;Ma/b=Y  
} F'>GN}n  
a j@C0  
T5dUJR2k$  
private void processErrorCode(int nErrorCode) $dZ>bXUw:  
{ &.  =}g]  
System.err.println("Error Code : " + nErrorCode); ELrZ8&5G  
} "gbnLKs  
q?Ku}eID3  
UC+7-y,  
//停止文件下载 `mKlv~$1^  
public void siteStop() > 0Twr  
{ BsK|:MM]  
bStop = true; aFr!PQp4{  
for(int i=0;i<nStartPos.length;i++) k99gjL`  
fileSplitterFetch.splitterStop(); b1+hr(kMRM  
9oj e`Ay  
#7~tL23}]  
} I*:qGr+ WJ  
} J|"nwY}a9  
//负责部分文件的抓取 x?f0Hk+  
**FileSplitterFetch.java N(_ .N6  
*/ z>mZT.  
package NetFox; /nY).lSH  
e>,9]{N+$  
9QOr,~~s  
import java.io.*; h8#5vO2  
import java.net.*; dE5 5  
~~xyFT+{F  
4C,kA+P  
public class FileSplitterFetch extends Thread { X"TUe>cM  
Sqdc1zC  
z{`6#  
String sURL; //File URL <;z[+6T  
long nStartPos; //File Snippet Start Position $#G6m`V  
long nEndPos; //File Snippet End Position 'Vm5Cs$  
int nThreadID; //Thread's ID z)&naw.  
boolean bDownOver = false; //Downing is over 4/HY[FT  
boolean bStop = false; //Stop identical D%;wVnU w  
FileAccessI fileAccessI = null; //File Access interface !c4)pMd  
sP6 ):h  
ZTh?^}/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1Nl&4YLO  
{ Q/QQ:t<XUi  
this.sURL = sURL; qab) 1ft  
this.nStartPos = nStart; VBbUl|X\  
this.nEndPos = nEnd; %="~\1y  
nThreadID = id; 5Cc6 , ]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dm|gSv8d,  
} BN\fv,  
` $.X[\*U  
`z3|M#r\;  
public void run() $ DDSN  
{ } g3HoFC  
while(nStartPos < nEndPos && !bStop) /FP~jV!z  
{ d7W%zg\T  
FX|0R#4vm  
J0?$v6S  
try{ Jw:Fj {D  
URL url = new URL(sURL); ub`z7gL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .8T\Nr\~2  
httpConnection.setRequestProperty("User-Agent","NetFox"); IwTr'}XIw  
String sProperty = "bytes="+nStartPos+"-"; gro7*<  
httpConnection.setRequestProperty("RANGE",sProperty); rPiiC/T.`  
Utility.log(sProperty); YW8K $W  
W>p\O9BG  
5E]UI YAkV  
InputStream input = httpConnection.getInputStream(); hi;WFyJTu  
//logResponseHead(httpConnection); wUZQB1$F  
NK+FQ^m[  
'^Pq(b~  
byte[] b = new byte[1024]; (j8GiJ]{L,  
int nRead; u;+%Qh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?G4iOiyt  
{ c&Gz> L  
nStartPos += fileAccessI.write(b,0,nRead); kF(Ce{;z  
//if(nThreadID == 1) K,x$c %  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tr}KPdE  
} K[Y c<Q  
z3^RUoGU  
7XUhJN3n  
Utility.log("Thread " + nThreadID + " is over!"); eZ!yPdgy|  
bDownOver = true; f![xn2T  
//nPos = fileAccessI.write (b,0,nRead); y!7B,  
} ?-pxte8  
catch(Exception e){e.printStackTrace ();} P<>[e9|  
} I6K7!+;2  
} ,pDp>-vI%  
3 R5%N ~  
?gd'M_-J,  
//打印回应的头信息 z6p#fsD  
public void logResponseHead(HttpURLConnection con) -]Q3/"Q  
{ %$/=4f.j  
for(int i=1;;i++) D-Bv(/Pz]$  
{ 51&|t#8h  
String header=con.getHeaderFieldKey(i); vn|TiZ  
if(header!=null) }7iUagN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3xBN10R#  
Utility.log(header+" : "+con.getHeaderField(header)); 5c<b|  
else MS{Hz,I,  
break; m3U+ du  
} ^D9 /  
} e ZynF<i  
:6 Uk)   
! (B_EM  
public void splitterStop() !aQIh  
{ d>^~9X  
bStop = true; 5>'?:jY  
} fkW3~b  
nURvy}<r  
2#'rk'X,K  
} | d~B]65t  
d>YmKTk"  
G{ F6  
/* !c\7  
**FileAccess.java X"kXNKV/n  
*//文件访问(定位,写) >ysriPnQ  
package NetFox; .KFA218h*x  
import java.io.*; l!\1,J:}Z  
` !zQ  
n)tU9@4Np  
public class FileAccessI implements Serializable{ B:e.gtM5  
i B%XBR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 dj3|f{kg{  
RandomAccessFile oSavedFile; &K06}[J  
long nPos; +*n] tlk  
USE   
ah 4kA LO  
public FileAccessI() throws IOException P\.WXe#j  
{ .H Fc9^.*  
this("",0); c L?\^K)  
} D._{E*vg  
U%Dit  
Dz,uS nnm  
public FileAccessI(String sName,long nPos) throws IOException \^yXc*C  
{ D=2~37CzQ1  
oSavedFile = new RandomAccessFile(sName,"rw"); =nLO?qoe  
this.nPos = nPos; \.5F](:  
oSavedFile.seek(nPos); k - FB  
} Z#CxQ D%\  
\$'R+k-57;  
M#`{>R|  
public synchronized int write(byte[] b,int nStart,int nLen) <sa #|Y$  
{ yU*u  
int n = -1; % =y;L:S\p  
try{ YFG-U-t3  
oSavedFile.write(b,nStart,nLen); T]^?l  
n = nLen; N"S3N)wgd  
} ,cLH*@  
catch(IOException e) g&Z"_7L~  
{ N A8 sN  
e.printStackTrace (); _jW>dU^B  
} 9p5= _  
yGRR8F5>(  
M/*Bh,M`  
return n; *K`x;r  
} (m6EQoW^s+  
^#2xQ5h  
Umij!=GPG^  
} nZ~kZ |VS  
</,.K`''W  
cxgE\4_u"  
/* 1^S'sWwe  
**SiteInfoBean.java l@xWQj9  
*/ =`JW1dM  
package NetFox; cbfD B^_  
U4=]#=R~o  
]7*kWc2  
public class SiteInfoBean { ;3mL^  
Is ot4HLM  
iZC>)&ax  
private String sSiteURL; //Site's URL KVg[#~3  
private String sFilePath; //Saved File's Path ?gU}[]  
private String sFileName; //Saved File's Name Z A[)  
private int nSplitter; //Count of Splited Downloading File 00"CC  
/\d(c/,4  
rjXnDh]MC  
public SiteInfoBean() *u}'}jC1X  
{//nSplitter的缺省值为5 3\1#eK'TK.  
//default value of nSplitter is 5 h 5Hr[E1  
this("","","",5); Sg_O?.r  
} 9YAM#LBTWi  
*-6?  
iM"asEU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v_.HGG S  
{ 0JK2%%  
sSiteURL= sURL; +N7"EROc  
sFilePath = sPath; w~]T<^fW~  
sFileName = sName; \Y+")  
this.nSplitter = nSpiltter; w=|py>%  
RJ@\W=aZ  
JwB"\&'1ZS  
} cu)U7  
@cPflb  
Vu%n&uF  
public String getSSiteURL() Y KY2Cw  
{ yWNOG 2qAP  
return sSiteURL; &f"T,4Oh  
} 7|Xe&o<n  
L1:nfH&:'  
b;*c:{W)  
public void setSSiteURL(String value) EZ/^nG  
{ W+K.r?G<j  
sSiteURL = value; Xo\S9,s{  
} Ia#"/`||  
<*_o0;h|  
d+0^u(gc!8  
public String getSFilePath() nZxSMN0]  
{ &8n?  
return sFilePath; ?~Pv3'%d  
} Y([d;_#P  
-R:X<eb  
[ZD[a6(94  
public void setSFilePath(String value) hXc}r6<B  
{ AX;c}0g  
sFilePath = value; '$?du~L-  
} 'AWp6L@  
F5U|9<  
sBU_Ft  
public String getSFileName() N}DL(-SQ3  
{ ' Rc#^U*n  
return sFileName; Z%OW5]q  
} b)`pZiQP  
>Mw'eQ0(y  
}vY.EEy!  
public void setSFileName(String value) t!:)L+$3  
{ o0l7 4  
sFileName = value; AuXs B  
} W~yLl%  
`BjR.xMv  
Zw#<E =\  
public int getNSplitter() |mOMRP#'  
{ :v)6gz(p  
return nSplitter; r**f,PDZ  
} Bzw19S6y  
{[P!$ /  
b]i>Bv  
public void setNSplitter(int nCount) vY_eDJ~'  
{ tF%QH[  
nSplitter = nCount; -?z\5 z  
} ,rai%T/rL  
} I0_Ecp  
N571s  
x[x(y{&~  
/* u{Ak:0G7  
**Utility.java l `R KqT+  
*/ /NU103F yt  
package NetFox; 5gshKmt_  
V&iS~V0.  
wDKELQ(y H  
public class Utility { {OP~8e"  
'yr{^Pek  
~b6GrY"vB  
public Utility() NO4Z"3Pd_  
{ S/7l/DFb  
pV=@sz,G  
0>FE%  
} RX>2~^  
&a6,ln:P  
//线程睡眠 ?Oc -aa  
public static void sleep(int nSecond) kP^*h O!%  
{ X!c?CL  
try{ w.^yP7:  
Thread.sleep(nSecond); +?AW>&68y  
} ``4?a7!!  
catch(Exception e) p9iu:MucD<  
{ V;;#/$oU:4  
e.printStackTrace (); N}mh}  
} ~},W8\C>  
} Z0\Iyc G  
t^U^Tr  
//日志 AY88h$a  
public static void log(String sMsg) R6P\T\~E  
{ QC7k~I8  
System.err.println(sMsg); CA*~2|  
} $>r5>6  
:)4*^a/lC  
U&W"Ea=R/  
public static void log(int sMsg) `0@z"D5c  
{ YlKFw|=  
System.err.println(sMsg); Y.-S=Y   
} no&-YktP}  
} YtYy zX5u7  
P=gJAE5  
b-%l-u  
/* f^e&hyC   
**TestMethod.java 8,*3zVk-  
*/ Q0>q:aj\  
package NetFox; 'RLOV  
CXAVGO'xw  
1Es qQz*$u  
public class TestMethod { onnugj3  
-_>.f(1  
r?3Aqi"  
public TestMethod() Yqj+hC6>,  
{ ///xx/weblogic60b2_win.exe B9#;-QO  
try{ ~kb{K;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PeNF+5s/K  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vpLMhf`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R=$Ls6z  
fileFetch.start(); Qxq-Mpx{  
} h<NRE0-  
catch(Exception e){e.printStackTrace ();} 8 Z8Y[p  
e=>% ^F  
G~!C =l  
} (B}+h   
>| m.?{^  
9rcI+q=E  
public static void main(String[] args) Y[G9Vok VX  
{ 6fGK (r  
new TestMethod(); .NnGVxc5*  
} 1;&T^Gdj  
} tX?J@+  
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