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http断点续传简单实现(java)

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/* -7lJ  
**SiteFileFetch.java 4aGHks8Z,\  
*/ #fwG~Q(  
package NetFox; c=7L)w:I  
import java.io.*; yjr!8L:m  
import java.net.*; _3`{wzMA  
y- g5`@  
&u8BGMl2  
public class SiteFileFetch extends Thread { <yeG0`}t  
Qf"gH <vT  
[!v:fj  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3ZC[H'|  
long[] nStartPos; //开始位置 7;Wj ^#  
long[] nEndPos; //结束位置 Hkpn/,D5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U,/>p=s  
long nFileLength; //文件长度 q4VOK 'N  
boolean bFirst = true; //是否第一次取文件 LJT+tb?K  
boolean bStop = false; //停止标志 >%xJ e'  
File tmpFile; //文件下载的临时信息 QkA79%;j  
DataOutputStream output; //输出到文件的输出流 @o8\`G  
Lq yY??\@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _m@QeO'yh  
public SiteFileFetch(SiteInfoBean bean) throws IOException K'y;j~`-  
{ :.@gd7T  
siteInfoBean = bean; z}Xn>-N-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?g!py[CrE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l( "_JI  
if(tmpFile.exists ()) h!$W^Tm2g  
{ :?&N/ 7  
bFirst = false; x3]es"4Q  
read_nPos(); aRR*<dY  
} -\LB>\;qn  
else ~v2_vEu}JX  
{ D=e&"V a  
nStartPos = new long[bean.getNSplitter()]; 2 3 P7~S  
nEndPos = new long[bean.getNSplitter()]; WJ=^r@Sf  
} @>JO &,od  
R}*e%EG/  
m"`&FA  
#lNi\Lw+j  
} <s  $~h  
d!8`}L:=M  
]XU?Wg  
public void run() ;/$zBr`'  
{ Cdc6<8  
//获得文件长度 1}9@aKM  
//分割文件 D guAeK  
//实例FileSplitterFetch S=2-<R  
//启动FileSplitterFetch线程 fk9FR^u  
//等待子线程返回 9"oc.ue.2D  
try{ >lRX+?  
if(bFirst) Q4C28-#  
{ u3Ua>A-  
nFileLength = getFileSize();  &+u$96  
if(nFileLength == -1) ? %F*{3IP  
{ (`xhh  
System.err.println("File Length is not known!"); m@)K]0g<f  
} 59IxY ?  
else if(nFileLength == -2) J'|qFS  
{ Rm{S,  
System.err.println("File is not access!"); EG2NE,,r  
} MWu67">"  
else 4$@)yZ  
{ UV$v:>K#  
for(int i=0;i<nStartPos.length;i++) 0d~>zKho  
{ 2vT>hC?oHz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @MS;qoc  
} V`=#j[gX)=  
for(int i=0;i<nEndPos.length-1;i++) 6I"Q9(  
{ |lrLTI^a  
nEndPos = nStartPos[i+1]; $s$z"<  
} Y;4nIWe JL  
nEndPos[nEndPos.length-1] = nFileLength; fHdPav f,S  
} )EcE{!H6+  
} 8" XbW7^o  
_m#M^<0n  
ul1#_xp  
//启动子线程 ng^`s}?o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z[s{   
for(int i=0;i<nStartPos.length;i++) Y]Td+ Zi  
{ +2 !F6"hP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~bhesWk8!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XTyJ*`>  
nStartPos,nEndPos,i); }hv>LL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 22)2o lU  
fileSplitterFetch.start(); s `U.h^V  
} q0,Diouq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7'k+/rAO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T]Pp\6ff  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ORD@+ {  
nEndPos = " + nFileLength); +h.$ <=  
// fileSplitterFetch[nPos.length-1].start(); )=8MO-{  
I6ffp!^}Y  
a 39Kl_\  
//等待子线程结束 "WV]| TS"]  
//int count = 0; 615, P/  
//是否结束while循环 |9$K'+'  
boolean breakWhile = false; )<nr;n  
LzEs_B=9  
nJ<h}*[  
while(!bStop) Yh\ } i  
{ dq?{?~3  
write_nPos(); T.]+T[}!  
Utility.sleep(500); x|&A^hQ  
breakWhile = true; <E[X-S%&  
s~W:N .}*  
s>~ h<B  
for(int i=0;i<nStartPos.length;i++) +}@1X&v:  
{ yS%IE>?  
if(!fileSplitterFetch.bDownOver) BrcT`MM[(=  
{ I"eXoqh  
breakWhile = false; Ze[ezu  
break; (sSMH6iCif  
} GSj04-T"  
} sN.h>bd  
if(breakWhile) S7vT=  
break;  df;-E  
u2,V34b-  
 Gqvj  
//count++; }%Dsy2:y  
//if(count>4) BuII|j  
// siteStop(); Nz %{T  
} |}P4Gr}6  
`'H"|WsT  
$$_aHkI j  
System.err.println("文件下载结束!");  K6d9[;F  
} ?]+{2&&$  
catch(Exception e){e.printStackTrace ();} v0&E!4q*'  
} O:3LA-vA  
~OO&%\$k  
 [R:\  
//获得文件长度 {L^b['h@  
public long getFileSize() K"B2 SsC  
{ #&a-m,Y$sx  
int nFileLength = -1; 9 &a&O Z{  
try{ |7KW'=O  
URL url = new URL(siteInfoBean.getSSiteURL()); PZmg7N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /2Q@M>  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vw0cf;  
u?6L.^Op  
J-yj&2  
int responseCode=httpConnection.getResponseCode(); {U/a h2*  
if(responseCode>=400) 0 UdAF  
{ # Un>g4>Rh  
processErrorCode(responseCode); :I*G tq   
return -2; //-2 represent access is error |d =1|C%,  
} o\6A]T=R  
*Y(v!x \L  
uH 1%diL^  
String sHeader; X~wkqI#d%E  
 JsAl;w  
hqOy*!8'@  
for(int i=1;;i++) w],+lN;  
{ %v 0 I;t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {YnR]|0&  
//Utility.log(in.readLine()); =g| e- XC  
sHeader=httpConnection.getHeaderFieldKey(i); p(dJf&D  
if(sHeader!=null) |eH >55 b  
{ e%. Xya#\  
if(sHeader.equals("Content-Length")) IO3`/R-  
{ NGZEUtj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #'m&<g,  
break; } m5AO4:  
} k1Cx~Q)XC  
} ernZfd{H  
else ')ZxWYT O^  
break; v|r\kr k  
} (s`oJLW>  
} r,F~Vwa}  
catch(IOException e){e.printStackTrace ();} yM}b  
catch(Exception e){e.printStackTrace ();} R(_UR)G0 @  
WrWJ!   
ZuF"GNUC  
Utility.log(nFileLength); J?4aSssE  
Ws2SD6!4`  
V}<Hx3!  
return nFileLength; P>q"P1&{  
}  "";[U  
W+N9~.q\^  
#lDf8G|ST~  
//保存下载信息(文件指针位置) "o" ujQ(v  
private void write_nPos() 4wfT8CL  
{ TTB1}j+V6  
try{ a|aRUxa0"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H{}0- 0o  
output.writeInt(nStartPos.length); f`Km ctI  
for(int i=0;i<nStartPos.length;i++) lFvRXV^+f  
{ :6R0=oz  
// output.writeLong(nPos); mY[s2t  
output.writeLong(fileSplitterFetch.nStartPos); g+shz{3zvz  
output.writeLong(fileSplitterFetch.nEndPos); ACQbw)tiv}  
} OT-!n  
output.close(); ` @.  
} 29eg.E  
catch(IOException e){e.printStackTrace ();} |KSd@   
catch(Exception e){e.printStackTrace ();} Fh  t$7V  
} 4-l G{I_S:  
8w,U[aJm  
$x_6 .AOZ,  
//读取保存的下载信息(文件指针位置) * ]uo/g  
private void read_nPos() ch2Qk8  
{ H(f~B<7q  
try{ .-Y3oWV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S<), ,(  
int nCount = input.readInt(); FtBYPSGz  
nStartPos = new long[nCount]; XP#j9CF#.  
nEndPos = new long[nCount]; 7kDX_,i  
for(int i=0;i<nStartPos.length;i++) d V+%x"[:  
{ Cm)_xnv  
nStartPos = input.readLong(); v.Fq.  
nEndPos = input.readLong(); b'i-/l$  
} s-^B)0T!  
input.close(); 0Vu&UD  
} 2 de[ yz  
catch(IOException e){e.printStackTrace ();} 3a#X:?  
catch(Exception e){e.printStackTrace ();} q:Lw!'Z h  
} N^i<A2'6S;  
BN!N_r  
)Rhy^<xH  
private void processErrorCode(int nErrorCode) o)w8 ]H /  
{ _3_d;j#G U  
System.err.println("Error Code : " + nErrorCode); 4 yLC  
} Yr9>ATR  
&=bWXNU.  
j#KL"B_ A  
//停止文件下载 {O\>"2}m'f  
public void siteStop() ?,Z[)5 ZN  
{ t{)Z$ )'  
bStop = true; c;\}R#  
for(int i=0;i<nStartPos.length;i++) N^,@s"g  
fileSplitterFetch.splitterStop(); kz4d"bTb  
Be?b| G!M  
{P'TtlEp  
} B+e$S%HV  
} 'k|?M  
//负责部分文件的抓取 3&*_5<t\X  
**FileSplitterFetch.java "YIrqk  
*/ \;"$Z 9W  
package NetFox; B(}u:[ b^S  
i1ph{;C  
KIt:ytFx  
import java.io.*; dQhh,}  
import java.net.*; UsT+o  
?sF<L/P0 F  
EBF608nWfW  
public class FileSplitterFetch extends Thread { i21ybXA=Z  
S;0,UgB1  
e_Cns&  
String sURL; //File URL HS1Gy/6'  
long nStartPos; //File Snippet Start Position ` oBlv  
long nEndPos; //File Snippet End Position "S$4pj`<  
int nThreadID; //Thread's ID ?QzA;8H  
boolean bDownOver = false; //Downing is over Z#8O)GK  
boolean bStop = false; //Stop identical Y yI4T/0s_  
FileAccessI fileAccessI = null; //File Access interface ZY%]F,Y  
,,*i!%Adw  
>3R%GNw  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XhF7%KR  
{ V{51wnxT  
this.sURL = sURL; lZpa)1.tiC  
this.nStartPos = nStart; Ave{ `YD  
this.nEndPos = nEnd; C[cNwvz  
nThreadID = id; [Xy^M3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Vf Jpiv1  
} gHU/yi!T  
V wj^h  
Qg dHIMY  
public void run()  '%! '1si  
{ EH;w <LvT  
while(nStartPos < nEndPos && !bStop) d,"?tip/SX  
{ \Qp #utC0s  
&<{=  
YuO-a$BP  
try{ }=kf52Am,}  
URL url = new URL(sURL); SG6@Rn*^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D@[Mk"f  
httpConnection.setRequestProperty("User-Agent","NetFox"); _O!)aD  
String sProperty = "bytes="+nStartPos+"-"; xRZ9.Agv_  
httpConnection.setRequestProperty("RANGE",sProperty); ]?<j]u0J  
Utility.log(sProperty); .A;D-"!  
Z,'#=K  
,TuDG*YA  
InputStream input = httpConnection.getInputStream(); nF0V`O \T  
//logResponseHead(httpConnection); 3`9H  
D;@*  
eQBR*@x  
byte[] b = new byte[1024]; I+ZK \?Rs  
int nRead; XY(3!>/eQ[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5w:   
{ -Fcg}\9  
nStartPos += fileAccessI.write(b,0,nRead); Y6(I %hE`  
//if(nThreadID == 1) a<CN2e_Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &@E{0ZD  
} fJ!i%</V  
d8 1u  
x"kc:F  
Utility.log("Thread " + nThreadID + " is over!"); uo`O$k<;  
bDownOver = true; Mx,QgYSu  
//nPos = fileAccessI.write (b,0,nRead); }t4?*:\  
} fFG, ^;7-O  
catch(Exception e){e.printStackTrace ();} Y..   
} 'n> ,+,&  
} L4th 7#  
Fv n:V\eb  
oObm5e*Z  
//打印回应的头信息 x,W)qv  
public void logResponseHead(HttpURLConnection con) _I;+p eq  
{ L,Jl# S  
for(int i=1;;i++) /I2RU2|B  
{ #bX~.jKW  
String header=con.getHeaderFieldKey(i); TV$Pl[m   
if(header!=null) (<?6X9F:N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m>4jRr6sF  
Utility.log(header+" : "+con.getHeaderField(header)); Y)@mL~){  
else I>k >^  
break; S1Q2<<[  
} \79KU   
} voRr9E*n  
cP[3p :  
b2OVg +3  
public void splitterStop() }wmn v  
{ 4_3O?IY  
bStop = true; 2mVcT3  
} x <^vJ1  
iV X12  
,#G>&  
} K-Bf=7F,  
J(*QtF  
v J*IUy  
/* !,}W|(P)  
**FileAccess.java Ux_tHyc/  
*//文件访问(定位,写) :+;AXnDM~  
package NetFox; l?CUd7P(a  
import java.io.*; b>|3?G  
bH}6N>Fp  
+^% y&8e  
public class FileAccessI implements Serializable{ ns_5|*'  
!6_lD 0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G_EU/p<Q  
RandomAccessFile oSavedFile; ~.qzQ_O/  
long nPos; H"PnX-fGN  
a\an  
1(C3;qlVD  
public FileAccessI() throws IOException  V"n0"\k,  
{ I(fq4$  
this("",0); 41luFtE9  
} @DgJxY|  
6Q]c]cCu  
a`5ODW+  
public FileAccessI(String sName,long nPos) throws IOException D`]Lm24_]  
{ %OWLM  
oSavedFile = new RandomAccessFile(sName,"rw"); k)D:lpxv  
this.nPos = nPos; uLV@D r   
oSavedFile.seek(nPos); ~@ZdO+n?  
} jbQ2G|:Q  
fu|N{$h%X  
J%']t$ AR  
public synchronized int write(byte[] b,int nStart,int nLen) jRN*W2]V  
{ 0ra VC=[  
int n = -1; UkrqHHpy  
try{ ]_NN,m>z  
oSavedFile.write(b,nStart,nLen); "oZ]/(  
n = nLen; %FnaS u  
} 55xv+|k  
catch(IOException e) 4`@]jm  
{ 82F q}N <  
e.printStackTrace (); K @3 yS8F  
} 1aKYxjYM  
*<*{gO?Q4  
0'!v-`.  
return n; m#SDB6l  
} hQ&S*f&='  
Dt,b\6  
& f7{3BK  
} [.DSY[!8U  
 (A 2x  
@xR7>-$0p  
/* )e.Y"5My  
**SiteInfoBean.java v)@EK6Nty  
*/ fr S1<+  
package NetFox; <VV./W8e9  
IuDg-M[  
0T2h3,  
public class SiteInfoBean { -o\$.Q3  
%zE_Q  
lcgT9 m#  
private String sSiteURL; //Site's URL c;_GZ}8  
private String sFilePath; //Saved File's Path :+ksmyW  
private String sFileName; //Saved File's Name Tj@}O:q7:  
private int nSplitter; //Count of Splited Downloading File GF5WR e(E  
!=C4=xv  
dw,Nlf~*0  
public SiteInfoBean() 2SU G/-P#  
{//nSplitter的缺省值为5 Q\G8R^9j p  
//default value of nSplitter is 5 Izq]nR  
this("","","",5); BQWEC,*N  
} !}wJ+R ^2  
0S@O]k)  
d;&'uiS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P_+S;(QQ~d  
{ 24{!j[,q@  
sSiteURL= sURL; f !t2a//  
sFilePath = sPath; ty]JUvR@  
sFileName = sName; \Ku=a{Ne  
this.nSplitter = nSpiltter; hGi"=Oud2  
MfUG@  
xkR--/f  
} "- xm+7  
S/-[OA>N  
TkhbnO g6  
public String getSSiteURL() >T{9-_#P  
{ Tz.!  
return sSiteURL; )#[?pYd  
} ]xQPSs_  
,Iq+v  
kvs^*X''Ep  
public void setSSiteURL(String value) \&]M \  
{ Db\.D/ 76  
sSiteURL = value; NL&(/72V  
} Hno@  
N'R^S98x  
~/1kCZB  
public String getSFilePath() Z"#ysC  
{ tr"iluwGc  
return sFilePath; >XP]NY}Po[  
} i'J.c4  
[7B:{sH  
$wU.GM$t~  
public void setSFilePath(String value) c38RE,4U  
{ & Sy0Of  
sFilePath = value; +]H9:ARI  
} A<^IG+Q,B7  
/ 3:R{9S%  
x<60=f[O2R  
public String getSFileName() r/=v;4.W  
{ !q~s-~d^  
return sFileName; W"4E0!r  
} {EbR =  
STu!v5XY}-  
~PaD _W#xP  
public void setSFileName(String value) 'qQ 5K o  
{ e/lfT?J\  
sFileName = value; @& #df  
} {U(-cdU{e`  
r=4'6!  
qdh;zAMx  
public int getNSplitter() "L.)ML  
{ .6SdSB ^M  
return nSplitter; 5%D:w S1  
} h>= e<H?f  
 bW<_K9"  
L?&+*|VxI  
public void setNSplitter(int nCount) .Tt \U  
{ x3T)/'(  
nSplitter = nCount; ,eOOV@3C  
} :bwdEni1P  
} {g\Yy(r  
sLK J<=0i  
1B= vrGq  
/* Da1BxbDeI  
**Utility.java =[(1u|H 9  
*/ X;flA*6V  
package NetFox; .g DWv  
4][m!dsU  
_z\oDd`'  
public class Utility { @i&LKr8  
B1c`(mHl  
62rTGbDbx  
public Utility() 2NAGXWE  
{ aUSxy8%  
!uLAW_~  
}!\NdQs  
} E4[ |=<  
Xhtc0\0"(  
//线程睡眠 *c7kB}/  
public static void sleep(int nSecond) [&t3xC,  
{ @=`Dw/13  
try{ CCfuz&  
Thread.sleep(nSecond); z*ZEw  
} }$#e&&)n  
catch(Exception e) G U~?S'{  
{ { ,.1KtrSN  
e.printStackTrace (); ,)'!E^n  
} pSkP8'  ?  
} im9 B=D  
/XS6X  
//日志 pBiC  
public static void log(String sMsg) [J\5DctX;c  
{ 9_ JK.  
System.err.println(sMsg); 'VFxg,  
} ]Rohf WHX  
[Ua4{3#  
 dKDtj:  
public static void log(int sMsg) -liVYI2s  
{ EAxg>}'1j  
System.err.println(sMsg); ?H eC+=/Z  
} SPOg'  
} ~!meO;|W  
+e<P7}ZQ  
Fzh%#z0  
/* 9vCn^G%B  
**TestMethod.java w_@N T}  
*/ VE4!=4  
package NetFox; ,=B "%=S  
'cy35M  
WRZi^B8 @  
public class TestMethod { `GC7o DL  
ir qlU  
J)A1`(x&T  
public TestMethod() 'e02rqip{  
{ ///xx/weblogic60b2_win.exe 78#je=MDg  
try{ #6fp "  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H&E c *MT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dm,7OQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); | ctGxS9  
fileFetch.start(); "p.MJxH  
} .x$+R%5U  
catch(Exception e){e.printStackTrace ();} J6Hw05%0=  
 rmUT l  
5Ft bZ1L  
} zCL/^^#  
[%YA42_`LD  
yeKzI~  
public static void main(String[] args) Un^QNd>  
{ !jMa%;/  
new TestMethod(); 8HX(1nNj}  
} )+wBS3BC  
} 4LtFv)i  
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