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http断点续传简单实现(java)

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/* hR b k-b  
**SiteFileFetch.java @iB**zR/  
*/ ju0]~,  
package NetFox; //@_`.  
import java.io.*; S#0y\  
import java.net.*; q_HC68YF,  
 s=#IoNh  
[?Y u3E\  
public class SiteFileFetch extends Thread { U@yrqT@;AU  
i_g="^  
QNFA#`H  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1pXAPTV  
long[] nStartPos; //开始位置 FMY r6/I  
long[] nEndPos; //结束位置 W6'+#Fp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N;A1e@bP  
long nFileLength; //文件长度 9Q=g]int u  
boolean bFirst = true; //是否第一次取文件 L6BHh_*E  
boolean bStop = false; //停止标志 SAs'u"EB  
File tmpFile; //文件下载的临时信息 7qon:]b4  
DataOutputStream output; //输出到文件的输出流 H:U1#bQQ:  
RTA9CR)JP4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 598 xV|TON  
public SiteFileFetch(SiteInfoBean bean) throws IOException :*t v`:;p  
{ vtR<(tOu@  
siteInfoBean = bean; OW)8Z 60  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E1 *\)q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gtJ^8khME  
if(tmpFile.exists ()) Z T8. r0  
{ z-[Jbjhd  
bFirst = false; '7>Vmr 6  
read_nPos(); wX#\\Jgi  
} v{H23Cfh:  
else )~d2`1zGS  
{ "$0f.FO:i  
nStartPos = new long[bean.getNSplitter()]; ;oh88,*'  
nEndPos = new long[bean.getNSplitter()]; FD|R4 V*3  
}  i+(`"8W  
XIBw&mWf  
\Zoo9Wy  
U@& <5'  
} 2_r}4)z  
2yq.<Wz<  
=AgY8cF!sl  
public void run() pe,c  
{ Syp|s3u;  
//获得文件长度 pKEMp&geo  
//分割文件 U45/%?kE)  
//实例FileSplitterFetch JB%6G|Z  
//启动FileSplitterFetch线程 G#dpSNV3|  
//等待子线程返回 GmAE!+"  
try{ J)jiI>  
if(bFirst) ^~BJu#uVyy  
{ v{% /aw  
nFileLength = getFileSize(); !+>yCy$~_  
if(nFileLength == -1)  }O1F.5I1  
{ +bRL.xY  
System.err.println("File Length is not known!"); DN^ln%#  
} `=-}S+  
else if(nFileLength == -2) RtqW!ZZ:H  
{ T7W+K7kbI  
System.err.println("File is not access!"); W_sDF; JP  
} u'32nf?  
else -\NB*|9m|  
{ ^<% w'*gR  
for(int i=0;i<nStartPos.length;i++) /itO xrA  
{ TfZO0GL$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B;K{Vo:C  
} ![vc/wuf  
for(int i=0;i<nEndPos.length-1;i++) G&uj}rj  
{ YF:NRY[i  
nEndPos = nStartPos[i+1]; zkd#vAY(A  
} 10[~ki-1;  
nEndPos[nEndPos.length-1] = nFileLength; MfL q h  
} "lz!'~im  
} T|{BT! W1E  
4a3f!G$  
!Uj !Oy  
//启动子线程 6iC}%eU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yRgo1ow]  
for(int i=0;i<nStartPos.length;i++) 9J|YP}%  
{ yNDyh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vy/g;ZPU1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C8t+-p  
nStartPos,nEndPos,i); H@ w6.[#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aIfog+Lp  
fileSplitterFetch.start(); Hou{tUm{xC  
} O]PfQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dT|z)-Z`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >`NM?KP s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", PO}Q8Q3  
nEndPos = " + nFileLength); )5&m:R9  
// fileSplitterFetch[nPos.length-1].start(); RB\WttI  
E"" /dC:B  
9|e"n|[  
//等待子线程结束 &U,f~KJ  
//int count = 0; I{Kc{MXn  
//是否结束while循环 b%_QL3 m6  
boolean breakWhile = false; i5wA=K_  
34?yQX{  
)RkU='lB "  
while(!bStop) qB=pp!zQ  
{ Q72wg~%w  
write_nPos(); b\+|g9Tm  
Utility.sleep(500); yf8UfB#a  
breakWhile = true; XWvs~Xw@  
JZv]tJWq  
Lhc@*_2  
for(int i=0;i<nStartPos.length;i++) $yc,D=*Isi  
{ s<dD>SU  
if(!fileSplitterFetch.bDownOver) cp2fDn  
{ $e;!nI;z  
breakWhile = false; q+:(@w6  
break; QbNv+Eu5  
} (o:Cxh V  
} >4VU  
if(breakWhile) ,mX|TI<*  
break; m0* B[  
FEZ6X  
mQvKreo~  
//count++; 395o[YZx*  
//if(count>4) X or ,}. w  
// siteStop(); -#o+x Jj  
} 6f>l~$  
v-gT 3kJ  
qB39\j  
System.err.println("文件下载结束!"); h@~X*yLKh  
} :^s7#4%6  
catch(Exception e){e.printStackTrace ();} _l,Z38  
} {UmCn>c  
dbuOiZ  
'f}S ,i +q  
//获得文件长度 *0hiPj:  
public long getFileSize() @r]s9~Lx9  
{ 7gMtnwT  
int nFileLength = -1; iy#OmI>j  
try{ z-gwNE{  
URL url = new URL(siteInfoBean.getSSiteURL()); u`'z~N4}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4@V] zfu^Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); eq+o_R}CS  
Ntn md  
{^kG<v.vV  
int responseCode=httpConnection.getResponseCode(); 0;h1LI)  
if(responseCode>=400) iXm||?Rnx  
{ [4hO3):F  
processErrorCode(responseCode); NslA/"*  
return -2; //-2 represent access is error +.lWck  
} :]^P ^khK  
h3lDDyu  
W^ :/0WR  
String sHeader; B#?2,  
yUW&Wgc=:  
e] K=Nm  
for(int i=1;;i++) M',D  
{ iW}l[g8sw!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8-"5|pNc  
//Utility.log(in.readLine()); y,&M\3A  
sHeader=httpConnection.getHeaderFieldKey(i); icul15'i  
if(sHeader!=null) .G_3blE;  
{ i+[3o@  
if(sHeader.equals("Content-Length")) GeaDaYh#T  
{ b H?qijrC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dl6v <  
break; gc@#O#K~h^  
} ~{vdP=/WP  
} yJ8}*Gj&  
else 3> #mO}\  
break; P"x-7>c>Y  
} ZGpTw[5ql  
} 5g1M_8e'+  
catch(IOException e){e.printStackTrace ();} e4Ox`gLa*p  
catch(Exception e){e.printStackTrace ();} <i'u96  
S[ ~O')  
eq~c  
Utility.log(nFileLength); [Hj'nA^  
@qPyrgy  
A3$aMCwKd  
return nFileLength; 0R}Sw[M.  
} |R;l5ZKvV  
ZSRR lkU  
V`\f+Uu  
//保存下载信息(文件指针位置) l^!A  
private void write_nPos() *?bk?*?s  
{ 6"i{P  
try{ e[QxFg0E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PiQkJ[  
output.writeInt(nStartPos.length); XalJo@%-  
for(int i=0;i<nStartPos.length;i++) tP`G]BCbt  
{ c',:@2R  
// output.writeLong(nPos); `(,*IK a  
output.writeLong(fileSplitterFetch.nStartPos); [2'm`tZL  
output.writeLong(fileSplitterFetch.nEndPos); z,bX.*.-  
} z]c,} Q  
output.close(); +`*qlP;  
}  @yt 2_  
catch(IOException e){e.printStackTrace ();} t0bhXFaiE  
catch(Exception e){e.printStackTrace ();} ;tp]^iB#  
} u`Z0{d  
#P%1{l5m  
H^D 3NuUC  
//读取保存的下载信息(文件指针位置) =_RcoG/^~  
private void read_nPos() ypD<2z^  
{ $_RWd#Q(  
try{ VW9>xVd4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9q1HSJ1)  
int nCount = input.readInt(); 7}ws |4Y  
nStartPos = new long[nCount]; f v E+.{  
nEndPos = new long[nCount]; Fm<jg}>MAd  
for(int i=0;i<nStartPos.length;i++) y9C;T(oi;  
{ QqiJun_m  
nStartPos = input.readLong(); O3kg  
nEndPos = input.readLong(); o_Jn_3=  
} a)!![X?\  
input.close(); uu}`warW  
} ><NI'q*cQ  
catch(IOException e){e.printStackTrace ();} d>%gW*  
catch(Exception e){e.printStackTrace ();} &8<<!#ob  
} =db'#m{$  
7/H^<%;y  
-t8hi+NK  
private void processErrorCode(int nErrorCode) Oj4v#GK]  
{ gjj 93  
System.err.println("Error Code : " + nErrorCode); `$s)X$W?  
}  0xJ7M.  
k"xGA*B|  
2+?T66 g  
//停止文件下载 8Y2xW`  
public void siteStop() pheE^jUr  
{ #`W=m N(+k  
bStop = true; *cbeyB{E  
for(int i=0;i<nStartPos.length;i++) P$Z}  
fileSplitterFetch.splitterStop(); ,E\h!/X  
lVPOYl%  
w8O" =},  
} T~BA)![  
} *7ZGq(O  
//负责部分文件的抓取 4/S=5r}  
**FileSplitterFetch.java sI_7U^"[  
*/ [r)e P({  
package NetFox; !p9)CjQ"  
N0i!l|G6  
>F1G!#$0  
import java.io.*; /~De2mq1   
import java.net.*; 9lf*O0Z&n  
BZK2$0  
HPrq1QpK  
public class FileSplitterFetch extends Thread { uG!:Z6%p  
{7*>Cv}  
$ a?  
String sURL; //File URL >M]6uf  
long nStartPos; //File Snippet Start Position  qve ./  
long nEndPos; //File Snippet End Position "#yJHsu]  
int nThreadID; //Thread's ID j~;;l!({i  
boolean bDownOver = false; //Downing is over  MJ`N,E[  
boolean bStop = false; //Stop identical ^W~p..DF  
FileAccessI fileAccessI = null; //File Access interface A /(lKq  
T*?s@$)m4  
Lxv6!?v|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException } bH$O%  
{ UiH!Dl}<  
this.sURL = sURL; J'b<z.OW  
this.nStartPos = nStart; $&{ti.l  
this.nEndPos = nEnd; =pcF:D#+  
nThreadID = id; !gF9k8\Yr$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xa," 'r  
} qFco3  
j%L&jH 6@  
t 42ub  
public void run() Z&Y=`GOI  
{ \\06T `  
while(nStartPos < nEndPos && !bStop) \8S ~c8Z~  
{ D-2.fjo9!  
gn8 |/ev  
eujK4s  
try{ LJFG0 W  
URL url = new URL(sURL); P?LlJ 5hn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QzOkpewf  
httpConnection.setRequestProperty("User-Agent","NetFox"); MP^ d}FL  
String sProperty = "bytes="+nStartPos+"-"; ,HB2 hHD  
httpConnection.setRequestProperty("RANGE",sProperty); ujFzJdp3k  
Utility.log(sProperty); zce`\ /:  
oR .cSGh  
)w h%|  
InputStream input = httpConnection.getInputStream(); cc}Key@D  
//logResponseHead(httpConnection); DC+b=IOz  
GsQ*4=C  
G(iJi  
byte[] b = new byte[1024]; >j*;vG5T  
int nRead; 'sh~,+g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r%@Lej5+  
{ s 5WqR 8  
nStartPos += fileAccessI.write(b,0,nRead); urBc=3Rz  
//if(nThreadID == 1) tZyo`[La  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^qGb%! l  
} Fmyj*)J[Z  
*\}}Bv+9  
g{IF_ 1  
Utility.log("Thread " + nThreadID + " is over!"); hR#-u1C  
bDownOver = true; d}'U?6 ob  
//nPos = fileAccessI.write (b,0,nRead); = ?D(g  
} V7d) S&*V  
catch(Exception e){e.printStackTrace ();} $ _j[2EU  
} cD*}..-/4  
} fKH7xu!V4+  
<%.5hCTp97  
3`E=#ff%  
//打印回应的头信息 /X"/ha!=&D  
public void logResponseHead(HttpURLConnection con) E>b2+;Jv  
{ N`@NiJ(O;  
for(int i=1;;i++) e^p +1-B  
{ $YxBE`)d-  
String header=con.getHeaderFieldKey(i); KWAb-yB  
if(header!=null) )J]9 lW&y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @ "a6fn  
Utility.log(header+" : "+con.getHeaderField(header)); N`iwC!  
else :x.7vZzxs  
break; ]i(-I <`  
} m>USD? i  
} [(X y.L7x  
!+>v[(OzM  
-9N@$+T  
public void splitterStop() =_$Qtq+h  
{ -;f*VM.a  
bStop = true; P-F)%T[  
} |4$M]Mf0  
&'cL%.  
theZ]5_C  
} 8fA_p}wp  
sn7AR88M;  
=q N2Xg/  
/* b0 iSn#$  
**FileAccess.java #/PAA  
*//文件访问(定位,写) R1Sy9x .  
package NetFox; coYij  
import java.io.*; 5F`;yh+e  
RMMd#/A@}  
DN4$Jva  
public class FileAccessI implements Serializable{ d%l{V6  
t78k4?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s4&^D<  
RandomAccessFile oSavedFile; {vAE:W.s  
long nPos; 9x,RvWTb  
 hi g2  
8~5cJPi6  
public FileAccessI() throws IOException C9p"?vX  
{ h iNEJ_f  
this("",0); f~ }H  
} gZ5[ C  
J2uZmEt  
N !TW!  
public FileAccessI(String sName,long nPos) throws IOException =8U&[F  
{ qI^ /"k*5  
oSavedFile = new RandomAccessFile(sName,"rw"); kdGT{2u  
this.nPos = nPos; t&?i m<  
oSavedFile.seek(nPos); $9?cP`hmi  
} R8.CC1Ix  
0uBl>A7qhn  
{Zp\^/  
public synchronized int write(byte[] b,int nStart,int nLen) 5dZ|!  
{ \QmCeB  
int n = -1; ;WldHaZ9r  
try{ qCv20#!"|  
oSavedFile.write(b,nStart,nLen); ,t1abp{A  
n = nLen; }NsUnbxT  
} J,b&XD@m  
catch(IOException e) >[X{LI(_<<  
{ jsNF#yE>  
e.printStackTrace (); "s\L~R.&  
} 28 3 H  
$0arz{Oh  
 ,m,)I  
return n; m*mm\wN5  
} _'#x^D  
NKQOUw:qn  
E= `6-H{  
} ZY:[ekm%4Z  
@^uH`mc  
['ksP-=  
/* =|=.>?t6Z0  
**SiteInfoBean.java s`#(   
*/ p019)X|vx  
package NetFox; [CAR[ g&  
C)cwAU|h#  
$y b4xU  
public class SiteInfoBean { 'g9"Qv?0{`  
@u1zB:  
5aa<qtUjH  
private String sSiteURL; //Site's URL ;U_QvN|  
private String sFilePath; //Saved File's Path )Z %T27r,^  
private String sFileName; //Saved File's Name Kt(-@\)!  
private int nSplitter; //Count of Splited Downloading File bMU(?hb  
WKSPBT;  
VM0j`bs'K*  
public SiteInfoBean() \cCV6A[  
{//nSplitter的缺省值为5 8| $3OVS  
//default value of nSplitter is 5 /x1MPP>fu  
this("","","",5); 5y?-fT]X  
} ?Mee 6  
$U/YR&vcw  
O2"gj"D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pD&& l!i&[  
{ (#;`"Yu  
sSiteURL= sURL; *cO sv  
sFilePath = sPath; -J^(eog[6  
sFileName = sName; @&}q} D  
this.nSplitter = nSpiltter; {?`al5Sz  
;.bm6(;  
]f1{n  
} n>'Kp T9|  
z'`y,8Y1l  
 ;vb8G$  
public String getSSiteURL() IVW1]y  
{ _FwK-?4E-  
return sSiteURL; TFcT3]R[rL  
} C R|lt  
Q#EP|  
i9=&;_z  
public void setSSiteURL(String value) l|hUw  
{ *x) 8fAr  
sSiteURL = value; gI8Bx]  
} U w4>v:  
IMk'#)  
!|<=ZF2  
public String getSFilePath() R CkaJ3  
{ 95<EN (oUD  
return sFilePath; hTbI -u7BF  
} 4Yl;  
Sc7U |s  
7+hK~  
public void setSFilePath(String value) d`1I".y  
{ HD N9.5 S  
sFilePath = value; =f(cH152T  
} BW,mwq  
( 9]_ HW[  
[V 8{b{  
public String getSFileName() b}Zd)2G  
{ .] `f,^v<c  
return sFileName; `CeJWL5{  
} "YB** Y  
jzK5-;b  
2<hpK!R  
public void setSFileName(String value) 9!><<7TS  
{ &[&r2 >a  
sFileName = value; sN("+ sZ.n  
} ?h!i0Rsm  
H}LS??P  
Z/ Tm)Xd  
public int getNSplitter() DI;DECQl$  
{ 2!Bd2  
return nSplitter; #Oha(mRY  
} pMs AyCAk  
5E0eyW  
xF8}:z0  
public void setNSplitter(int nCount) R1Ye<R!Q  
{ Iyo@r%I  
nSplitter = nCount; =YG _z^'  
} `HuCT6O  
} %okzOKKX  
CU7F5@+  
.`CZUKG  
/* z_ =Bt  
**Utility.java I!wX[4p eg  
*/ KgW:@X7wvM  
package NetFox;  8L*GE  
 mA7m  
DKVT(#@T  
public class Utility { "G:<7oTa  
it2 a  
[j4v]PE  
public Utility() )+H[kiN  
{ +wW@'X  
""svDfy$  
+PK6-c\r  
} _W3Y\cs,-  
IcIOC8WC  
//线程睡眠 *1@:'rJ  
public static void sleep(int nSecond) 8^B;1`#  
{ A>VX*xd  
try{ Dr;iQkGP  
Thread.sleep(nSecond); IHC1G1KW=A  
} =e?$M  
catch(Exception e) /# <pVgN  
{ ~L7:2weV[  
e.printStackTrace (); LEECW_:  
} xLZd!>C  
} wY"o`o Z  
s/Xb^XjS1  
//日志 7< 9L?F2  
public static void log(String sMsg) :c8n[+5  
{ ^zEE6i  
System.err.println(sMsg); (cv!Y=]  
} V[a[i>,Z  
/XS&d%y  
m=qOg>k  
public static void log(int sMsg) 0uCT+-  
{  uIMe  
System.err.println(sMsg); =8=!Yc(>  
} pUl8{YGS  
} +rWZ|&r%  
p4VSm a_(  
*R % wUi  
/* T}7uew\v0<  
**TestMethod.java }%{MPqg  
*/ y33~HsOJ  
package NetFox; q6`G I6  
=neL}Fav56  
y|_Eu:  
public class TestMethod { ep(g`e  
[FQ\I-GNC  
"Mmf6hu  
public TestMethod() t^E hE  
{ ///xx/weblogic60b2_win.exe }gf}eH  
try{ ZEbLL4n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lu UYo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MEwdw3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \)m"3yY  
fileFetch.start(); 6-,m}Ce\  
} Ua*&_~7kJ  
catch(Exception e){e.printStackTrace ();} m(sXk}e;1  
fMK#x\.4  
Gk~l,wV>  
} Qu{c B^Ga*  
8 |h9sn;P  
(&&87(  
public static void main(String[] args) +lO'wa7|3  
{ 3/M.0}e  
new TestMethod(); fAj2LAK  
} 4f1D*id*`#  
} xQt 3[(Z  
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