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http断点续传简单实现(java)

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/* fQa*>**j;  
**SiteFileFetch.java JPqd} :u3  
*/ '|SO7}`;Q  
package NetFox; :Ph>\aG  
import java.io.*; =Pl@+RgK+  
import java.net.*; !#)t<9]fv  
]!/U9"_e"B  
6]?%1HSi  
public class SiteFileFetch extends Thread { ~-zTY&c_  
k\#;  
RJWO h  
SiteInfoBean siteInfoBean = null; //文件信息Bean H:c5 q0O^x  
long[] nStartPos; //开始位置 9i5?J]o^  
long[] nEndPos; //结束位置 (lM,'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F<I*?${[  
long nFileLength; //文件长度 ;98&5X\u<  
boolean bFirst = true; //是否第一次取文件 [nO3%7t@  
boolean bStop = false; //停止标志 l)[|wPf  
File tmpFile; //文件下载的临时信息 L?[m$l!T}  
DataOutputStream output; //输出到文件的输出流 (kLaXayn  
@-)?uYw:r  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) UN.;w3`Oc  
public SiteFileFetch(SiteInfoBean bean) throws IOException {1Ra |,;  
{  B(;MI`  
siteInfoBean = bean; ?@G s7'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /^.S nqk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  8${n}}  
if(tmpFile.exists ())  1c0' i  
{ X,v.1#[  
bFirst = false; U.<j2K um  
read_nPos(); +^Xf:r` G  
} bZYayjxZ5i  
else ZG^<<V$h  
{ ] ]U)wg  
nStartPos = new long[bean.getNSplitter()]; .#QE*<T)]  
nEndPos = new long[bean.getNSplitter()]; @A1f#Ed<  
} ^L2d%d\5  
Hx gC*-A$/  
r1r$y2v~  
?wB_fDb}  
} 3}H{4]*%_  
;_bRq:!j;  
oVpZR$  
public void run() WoZU} T-  
{ G]ek-[-  
//获得文件长度 j?N<40z  
//分割文件 S oeoUI]m  
//实例FileSplitterFetch k9x[( #  
//启动FileSplitterFetch线程 @ 8H$   
//等待子线程返回 Fe0M2%e;|  
try{ *-9i<@|(U^  
if(bFirst) OvX&5Q5  
{ {nKw<F2  
nFileLength = getFileSize(); ' 4FH9J  
if(nFileLength == -1) z}MxMx c4h  
{ M1/d7d  
System.err.println("File Length is not known!"); iM<$ n2t  
} B5z'Tq1  
else if(nFileLength == -2) ?sk>Mzr  
{ fmuh 9Z  
System.err.println("File is not access!"); "A}sD7xy9  
} '.bf88D  
else TTVmm{6  
{ ,&UKsrs_  
for(int i=0;i<nStartPos.length;i++) a dqS.xs  
{ ,->K)Rs;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UDG1F_&h  
} 9)oi_U.  
for(int i=0;i<nEndPos.length-1;i++) r%=-maPL[  
{ ^`kwSC  
nEndPos = nStartPos[i+1]; b-<0\@`Z#  
} =5\*Zh1  
nEndPos[nEndPos.length-1] = nFileLength; %'iJVFF  
} V5K/)\#  
} 0>od1/`  
kGV:=h  
MrR`jXz  
//启动子线程 i3w~&y-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^{uHph9ny  
for(int i=0;i<nStartPos.length;i++) QJ XP -  
{ <<0sv9qw1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \\k=N(n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <Z%=lwtX  
nStartPos,nEndPos,i); ,\6Vb*G|E>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 712nD ?>  
fileSplitterFetch.start(); P2'N4?2  
} (mIjG)4t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R/oi6EKv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j0e,>X8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kkjugm{D7  
nEndPos = " + nFileLength); E2dM0r<]  
// fileSplitterFetch[nPos.length-1].start(); Z^|N]Ej  
s\;/U|P_  
Tgz=I4g  
//等待子线程结束 $2a"Ec!7  
//int count = 0; e\V -L_  
//是否结束while循环 2Xe1qzvo  
boolean breakWhile = false; v[Q)L!J1  
i#la'ICwJ  
O>h`  
while(!bStop) I0+6p8,  
{ ]Ucw&B* @  
write_nPos(); CGi;M=xr  
Utility.sleep(500); v@=qVwX  
breakWhile = true; @-sWXz*W  
S9Sgd&a9  
P P J^;s  
for(int i=0;i<nStartPos.length;i++) Yj@ Sy  
{ Xfk DMh  
if(!fileSplitterFetch.bDownOver) T`E0_ZU;  
{ ,m{R m0  
breakWhile = false; ,ucRQ&P  
break; ^sf,mM~D  
} (xb2H~WrN  
} _f^6F<!  
if(breakWhile) +cH>'OXoB  
break; iAz0 A  
fmixWL7.Zg  
?0; 2ct  
//count++; TaRPMKk  
//if(count>4) Z[nHo'  
// siteStop(); p}QDX*/sSu  
} w1tM !4r  
zP44 Xhz  
3Z?ornS  
System.err.println("文件下载结束!"); 5mZ2CDV  
} ;].X;Ky <  
catch(Exception e){e.printStackTrace ();} NA0nF8ek  
} $9X+dvu*  
6.)ug7aF  
1D 'r;`z  
//获得文件长度 2K9X (th1  
public long getFileSize() !'N@ZZ  
{ m54>}  
int nFileLength = -1; #4Z e2T|  
try{ 1b~21n  
URL url = new URL(siteInfoBean.getSSiteURL()); #+ch  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @S@VsgQ%3Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); !.'D"Me>  
xqX3uq  
1'o[9-  
int responseCode=httpConnection.getResponseCode(); C][$0  
if(responseCode>=400) ?>B?*IK!  
{ -~]H5er`  
processErrorCode(responseCode); Mc,|C)  
return -2; //-2 represent access is error F-s{#V1=  
} y$%oR6 K7-  
7Y8~ ")f  
%C/p+Tg  
String sHeader; #%[;v K  
on 7 n4  
v":q_w<k  
for(int i=1;;i++) K%dQ; C*?  
{ ],weqs  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a<&K^M&  
//Utility.log(in.readLine()); Oo :Dt~Ib  
sHeader=httpConnection.getHeaderFieldKey(i); d3c.lD)L9  
if(sHeader!=null) A&M_ J  
{ _3aE]\O[  
if(sHeader.equals("Content-Length")) A1prYD  
{ s6~;)(r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W/,bz",v3  
break; vQ}ZfP  
} x#`p.sfVo  
} Z9DfwWI2nu  
else N)"8CvQL  
break; :Dt y([  
} n0lOq  
} 84WD R?  
catch(IOException e){e.printStackTrace ();} O z6$u  
catch(Exception e){e.printStackTrace ();} 9I/l+IS"X  
+g g_C'"  
!CU-5bpu  
Utility.log(nFileLength); D U\ytD`u  
KyNu8s k  
K[icVT2v~  
return nFileLength; Q/SO%E`E  
} )Dz]Pv]H'  
VZt%cq  
Wo "s;Z  
//保存下载信息(文件指针位置) e8<}{N0,n  
private void write_nPos() HF*0  
{ C7dq=(p&  
try{ Q#3}AO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @4y?XL(n  
output.writeInt(nStartPos.length); Aars\   
for(int i=0;i<nStartPos.length;i++) ',R%Q0Q  
{ s;I @En  
// output.writeLong(nPos); C$[iduS  
output.writeLong(fileSplitterFetch.nStartPos); `o{ Z;-OF  
output.writeLong(fileSplitterFetch.nEndPos); 7"'RE95  
} >UCg3uFj  
output.close(); TnN yth wZ  
} nook/7]  
catch(IOException e){e.printStackTrace ();} :k_&Zd j,B  
catch(Exception e){e.printStackTrace ();} i(|u g_^  
} a(vt"MQ_  
IVPN=jg?  
#r#[&b  
//读取保存的下载信息(文件指针位置) ]jD\4\M}  
private void read_nPos() 1Rd|P<y  
{ -rU_bnm  
try{ \OVFZ D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;D~#|CB  
int nCount = input.readInt(); NWn*_@7;  
nStartPos = new long[nCount]; QQW}.>N  
nEndPos = new long[nCount]; :6(\:  
for(int i=0;i<nStartPos.length;i++) )G)6D"5,+G  
{ dE"_gwtX  
nStartPos = input.readLong(); uaO.7QSwN  
nEndPos = input.readLong(); "Vq= Ph  
} J>v[5FX+  
input.close(); Md~SzrU  
} aM $2lR])J  
catch(IOException e){e.printStackTrace ();} ')v,<{  
catch(Exception e){e.printStackTrace ();} O4X03fUx  
} gbzBweWF  
c ?CD;Pk  
r x9*/Q0F  
private void processErrorCode(int nErrorCode) p(pfJ^/:(  
{ 8vuTF*{yZ  
System.err.println("Error Code : " + nErrorCode); o6A$)m5V  
} HVus\s\&y%  
MU$tX  
u~OlJ1V  
//停止文件下载 T!,5dt8L  
public void siteStop() ,;t:x|{%  
{ ntH`\ )xi  
bStop = true; B}TY+@  
for(int i=0;i<nStartPos.length;i++) i6HRG\9nU  
fileSplitterFetch.splitterStop(); ~qqxHymc  
<<LLEdB  
bRu 9*4t  
} Z5v_- +K  
} r\"R?P$y|  
//负责部分文件的抓取 FXo.f<U  
**FileSplitterFetch.java KNmU2-%l  
*/ z6U'"T"a  
package NetFox; DyqqY$ vH(  
In1{&sS  
RVA ku  
import java.io.*; SY5}Bu#  
import java.net.*; (xW+* %  
=u}~\ 'd  
nT> v  
public class FileSplitterFetch extends Thread { ke2dQ^kc4  
9xbT?$^  
:jv(-RTI  
String sURL; //File URL L'Cd` .yVO  
long nStartPos; //File Snippet Start Position 6qDt 6uB  
long nEndPos; //File Snippet End Position %!t9)pNc  
int nThreadID; //Thread's ID #~'d Y\&  
boolean bDownOver = false; //Downing is over #qVTB@d  
boolean bStop = false; //Stop identical 9@CRL=  
FileAccessI fileAccessI = null; //File Access interface h rSH)LbJ  
J\@g3oGw  
B{=DnB6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SWw!s&lP&  
{ J.JD8o9sa  
this.sURL = sURL; bz>\n"'  
this.nStartPos = nStart; K W&muD  
this.nEndPos = nEnd; C5^WJx[  
nThreadID = id; q>(?Z#sB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ((`\i=-o5  
} )&T 5 /+  
?u#s?$Y?  
K9ia|2f  
public void run() |9XoRGgXU  
{ v_Vw!u  
while(nStartPos < nEndPos && !bStop) YD[AgToo0  
{ ]*=!lfrV  
=iB[sLEJ  
kk`K;`[tB  
try{ lwfS$7^P  
URL url = new URL(sURL); 4*Hzys[{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +JYb)rn$^  
httpConnection.setRequestProperty("User-Agent","NetFox"); tRI<K  
String sProperty = "bytes="+nStartPos+"-"; "y~*1kBu  
httpConnection.setRequestProperty("RANGE",sProperty); ^Lb\k|U ,\  
Utility.log(sProperty); 2'=)ese  
Fk49~z   
cEa8l~GC<  
InputStream input = httpConnection.getInputStream(); Fy\q>(v.  
//logResponseHead(httpConnection); Jvc<j:{^w  
vWmp ?m  
tW~kn9glZ  
byte[] b = new byte[1024]; pNd`fV#jX  
int nRead; #C } +  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  \xp0n  
{ "0%K3d+  
nStartPos += fileAccessI.write(b,0,nRead); )U|V|yem'  
//if(nThreadID == 1) W5'6L =WG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .WKJ37od  
} 9nVb$pfe#  
 ;@k=9o]A  
1c QF(j_  
Utility.log("Thread " + nThreadID + " is over!"); .aO6Y+Y  
bDownOver = true; y@v)kN)Y9\  
//nPos = fileAccessI.write (b,0,nRead); {HY3E}YJL  
} <ot`0  
catch(Exception e){e.printStackTrace ();} 'y!qrmMRr  
} 5|0/$ SWd*  
} 6p }a!  
+x{o  
> }f!. i  
//打印回应的头信息 gdD|'h  
public void logResponseHead(HttpURLConnection con) W8QP6^lY  
{ R\ 8[6H  
for(int i=1;;i++) EGI$=Y  
{ _R(ZvsOZ  
String header=con.getHeaderFieldKey(i); .lj5pmD  
if(header!=null) Y[)mHs2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nHeJ20  
Utility.log(header+" : "+con.getHeaderField(header)); xO:h[  
else ?8kFAf~  
break; XK\nOHLS  
} l'4<^q  
} >Z*b0j  
ZDaHR-%Y  
d)U(XiK'  
public void splitterStop() | eCVq(R  
{ UTE6U6  
bStop = true; j~Fd8]@  
} [Y!HQ9^LEp  
XM5)|D  
':}9>B3 S  
} h/A\QW8Sd  
;]xc}4@=mg  
C3^3<  
/* } *) l  
**FileAccess.java &Y@),S9  
*//文件访问(定位,写) SVwxK/Fci  
package NetFox; ]r!|@AWrQ\  
import java.io.*; bBML +0a  
!BW!!/U  
b=BNbmX  
public class FileAccessI implements Serializable{ 8J&9}@y  
h #gI1(uL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +C;;4s)  
RandomAccessFile oSavedFile; [4C_iaE  
long nPos; d , g~.iS~  
%pWJ2J@  
}R}M>^(R4  
public FileAccessI() throws IOException 6oQ7u90z*  
{ y`$qcEw  
this("",0); n~ $S  
} aC=2v7*  
!Z>,dN  
#t Uhul/O  
public FileAccessI(String sName,long nPos) throws IOException TD floDxA  
{ `qd5+~c  
oSavedFile = new RandomAccessFile(sName,"rw"); 9$U>St  
this.nPos = nPos; .<%q9Jy#  
oSavedFile.seek(nPos); 7hx^U90K  
} F$4=7Njv  
h&i(Kfv*  
FZU1WBNL%t  
public synchronized int write(byte[] b,int nStart,int nLen) X&aQR[X  
{ FTEC=j$ln  
int n = -1; /g*_dH)=  
try{ 6(?@B^S>2  
oSavedFile.write(b,nStart,nLen);  ^F?B_'  
n = nLen; x&u@!# d]  
} 7>@0nHec  
catch(IOException e) 20 $Tky_  
{ ik?IC$*n3i  
e.printStackTrace (); .e5@9G.jb  
} B!`.,3  
B QUYT/$(  
a'-xCV|^  
return n; jxW/"Q   
} )IK%Dg(v  
E)Qg^DHP/  
 h8p{  
} Xo(W\Pes  
JcP<@bb>B  
HL[V}m  
/* S.iUiS"  
**SiteInfoBean.java k}kwr[  
*/ G,Yctv  
package NetFox; Z>w@3$\z  
:-+][ [  
hC{2LLu;n  
public class SiteInfoBean { q4@+Pi)  
Bk.`G)t  
-$%~EY}  
private String sSiteURL; //Site's URL 9\Rk(dd  
private String sFilePath; //Saved File's Path wrCV&2CG  
private String sFileName; //Saved File's Name <MO40MP  
private int nSplitter; //Count of Splited Downloading File ;>>:7rdYt  
z,C>Rh9Id  
b; ;y|H  
public SiteInfoBean() 6,CK1j+tZ  
{//nSplitter的缺省值为5 Yx. t+a-  
//default value of nSplitter is 5 #0*I|gfV  
this("","","",5); n|=yw6aV'  
} b!SIs*  
V^.Z&7+E`_  
2&s(:=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T|oDJ]\J  
{ /YwwG;1  
sSiteURL= sURL; Z^mIGy}  
sFilePath = sPath; %^I 7=  
sFileName = sName; ,-$%>Uv   
this.nSplitter = nSpiltter; P:'y}a-  
}EfRYE$E  
b[n6L5P5m2  
} @ohJ'  
'@hnqcqXq  
A-\n"}4  
public String getSSiteURL() JZyEyN  
{ [sPLu)q2  
return sSiteURL; 75Bn p9  
} =5pwNi_S  
)d {8Cu6  
Y'6P ~C;v  
public void setSSiteURL(String value) u4=ulgi  
{ hoPh#? G  
sSiteURL = value; .b*-GWx  
} JK XIxw>q  
_#P5j#  
eBECY(QMQ  
public String getSFilePath() g2r8J0v  
{ =o"sBVj  
return sFilePath; %HZ!s `w_  
} \=W t{  
{2|sk9?W  
lQ.3_{"s  
public void setSFilePath(String value) /KJWo0zo  
{ Tc;BE  
sFilePath = value; 9fSX=PVRmQ  
} uTrGb:^  
rPW 9lG  
%%O_:@9x,  
public String getSFileName() c$hoqi |tD  
{ y3V47J2o  
return sFileName; c%n%,R>  
} #0qMYe>Y  
exm*p/  
C\[g>_J  
public void setSFileName(String value) Q},uM_" +  
{ fV/  
sFileName = value; LTD;  
} <8Q?kj  
!%C&hH\  
*UG=dl#F#  
public int getNSplitter() ZcN%F)htm  
{ O >&,h^  
return nSplitter; WgV[,(  
} +7)/SQM5  
w\.z-6G  
<J1$s_^`  
public void setNSplitter(int nCount) !3at(+4  
{ dNs<`2m  
nSplitter = nCount; KI<Vvc m  
} BtWm ZaKi  
} j\@|oW0  
~hA;ji|I  
oakm{I|k}  
/* L@5g#mSl  
**Utility.java Zo(QU5m0  
*/ Uefw  
package NetFox; obIYC  
!}uev  
;,_c1x/F  
public class Utility { J 9k~cz  
! XNTk]!  
9o5_QnGE  
public Utility() le`_    
{ gI~jf- w  
G9\@&=  
lhV'Q]s@6  
} .7GAGMNS  
R_DZJV O  
//线程睡眠 oG;;='*  
public static void sleep(int nSecond) V$ss[fX  
{ b<rJ@1qtJ  
try{ _52BIrAO2  
Thread.sleep(nSecond); thSo,uGlW  
} )wY bcH  
catch(Exception e) 80ms7 B  
{ M}6? |ir  
e.printStackTrace (); B\!.o=<h  
} u>-!5=D8  
} 'xp&)g L  
r*l:F{  
//日志 Aa/lKiiz  
public static void log(String sMsg) lN^} qg><  
{ ! =c&U.B  
System.err.println(sMsg); #(NkbJ5ka  
} BK:S:  
_-I0f##.  
3F0:v,+;  
public static void log(int sMsg) \TBY)_[ {  
{ "&/&v  
System.err.println(sMsg); I806I@ix  
} $.@)4Nu!_  
} @v,qfT*k7  
MoP 0qNk  
M9b_Q  
/* V<!E9/4rS  
**TestMethod.java fOyLBixR  
*/ l;g8_uyjv7  
package NetFox; .<`Rq'  
L~jKx)S%  
IZ6[|Ach6  
public class TestMethod { V+l>wMeo  
Et+N4w  
.ZrQ{~t  
public TestMethod() ^dR5fAS  
{ ///xx/weblogic60b2_win.exe z_J"Qk  
try{ d98ZC+q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }A"%YDrNbG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )xQA+$H#4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }0Q6iHX@  
fileFetch.start(); 1vQj` F  
} [Hww3+~+  
catch(Exception e){e.printStackTrace ();} ukSi9| 1-,  
8W"~>7/>D  
eS jXaZh  
} *lIK?"mo  
`_'I 9,.a  
d(L u|/~  
public static void main(String[] args) { LJRdV  
{ YDyi6x,  
new TestMethod(); BjR:#*<qD  
} bgm$<;`U  
} ?8X+)nU@  
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