http断点续传简单实现（java)

/* kH G"XTL  
**SiteFileFetch.java Gz,i~XX  
*/ {?:X8&Sf  
package NetFox; Hl{S]]z  
import java.io.*; iT2B'QI=<  
import java.net.*;  J4fi'  
,[P{HrHx  
Z$/xy"  
public class SiteFileFetch extends Thread { o!kbK#k  
CEX"D`  
t.xxSU5~%  
SiteInfoBean siteInfoBean = null; //文件信息Bean n[lJLm^(_C  
long[] nStartPos; //开始位置 ^
\4h<M  
long[] nEndPos; //结束位置 {y=j?lD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iO|se:LY<  
long nFileLength; //文件长度 iOW#>66d  
boolean bFirst = true; //是否第一次取文件 Ab{ K<:l  
boolean bStop = false; //停止标志 9_Be0xgJ3^  
File tmpFile; //文件下载的临时信息 2AT5  
DataOutputStream output; //输出到文件的输出流 < t,zaIi  
leTf&W  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @~^5l  
public SiteFileFetch(SiteInfoBean bean) throws IOException J  IUx  
{ j+$rj  
siteInfoBean = bean; ]:XoRyIZ1[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (|klSz_4LM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9\_eK,*B  
if(tmpFile.exists ()) ;$.J3!  
{ '>-gi}z7  
bFirst = false; m qMHL2~  
read_nPos(); nn@-W]  
} =8AO:  
else K,+LG7ec  
{ ~*z% e*EL  
nStartPos = new long[bean.getNSplitter()]; RtTJ5@V(  
nEndPos = new long[bean.getNSplitter()]; ME46V6[LX]  
} =P't(<  
 zv0l,-o  
VVac:  
d3ZdB4L  
} 1w@(5 ^V  
O}-jCW;K  
6jE|  
public void run() &Sw%<N*r  
{ u0|8Tgf  
//获得文件长度 IzikDc10  
//分割文件 )dbB=OZ  
//实例FileSplitterFetch ;oW6 NJ  
//启动FileSplitterFetch线程 mF*2#]%dx  
//等待子线程返回 >3_jWFq  
try{ [ 9 {*94M  
if(bFirst) $rv8K j
+  
{ [uC]*G]  
nFileLength = getFileSize(); I&}L*Z?`  
if(nFileLength == -1) e!N:,`R 5  
{ ]zE;Tw.S  
System.err.println("File Length is not known!");
[^Os kJ4  
} x@P y>f2  
else if(nFileLength == -2) $PTP/^  
{ :61Tun  
System.err.println("File is not access!"); EMwS1~3dD  
} 3er nTD*`  
else $HHs^tW  
{ :W!7mna  
for(int i=0;i<nStartPos.length;i++) ]m g)Q:d,  
{ _}lZ,L(w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qE&v ;  
} ] o*#t  
for(int i=0;i<nEndPos.length-1;i++) BLfTsNzmt  
{ 0^I|ut4  
nEndPos = nStartPos[i+1]; C7lH]`W|/  
} i2E)P x  
nEndPos[nEndPos.length-1] = nFileLength; ehzM)uK  
} "c3Grfoz  
} ]R h#g5X  
|=Eo?Q_  
i UCXAWP  
//启动子线程 7Ri46Tkt  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Xe6w|  
for(int i=0;i<nStartPos.length;i++) ~ {E'@MU  
{ 1O/+
8yw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R;s?$;I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &]"  
nStartPos,nEndPos,i); ")O%86_Q:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [Y|8\Ph`&  
fileSplitterFetch.start(); %HGD;_bhI  
} (D#B_`;-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Oft-w)cYz,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -I*^-+>H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y2a5bc P  
nEndPos = " + nFileLength); zKw`Md  
// fileSplitterFetch[nPos.length-1].start(); qaiNz S@q  
&+Z,hs9%  
|L%Z,:yO  
//等待子线程结束 ?5C!<3gM)  
//int count = 0; LPZF)@|`  
//是否结束while循环 *7CV^mDm  
boolean breakWhile = false; :[wsKFaV+  
Lm*e5JnV  
aZ2!i  
while(!bStop) ]NUl9t*N4  
{ /1"(cQ%?  
write_nPos(); {G U&a  
Utility.sleep(500); |jI#"LbF  
breakWhile = true; 3LAIl913  
Bc+w+  
![`Ay4AZ@a  
for(int i=0;i<nStartPos.length;i++) vI:;A
/&  
{ jr)1(**  
if(!fileSplitterFetch.bDownOver) 3.|S  
{ .<jr0,i  
breakWhile = false; YPU*@l>  
break; }#L^!\V}  
} *@Lp`thq  
} iP =V8g?L  
if(breakWhile) d74d/l1*{  
break; 8$")%_1]  
9!6f-K  
]JCv
yz H  
//count++; zz+$=(T:M  
//if(count>4) QqFR\6  
// siteStop(); 0"kbrv2y  
} XRcqhv  
sPr~=,F  

m_
.>C  
System.err.println("文件下载结束！"); oC<.=2]  
} g<l1zo`_  
catch(Exception e){e.printStackTrace ();} f$+,HB  
} 9{RB{<Se!  
S)cLW~=z  
I9/W;# *~  
//获得文件长度 J2::'Hw*s  
public long getFileSize() v4u5yy_;(  
{ NG--6\  
int nFileLength = -1; 2;zb\d  
try{ hlV=qfc  
URL url = new URL(siteInfoBean.getSSiteURL()); igkYX!0#8O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wi*.TWz
3  
httpConnection.setRequestProperty("User-Agent","NetFox"); Gr7=:+0n|P  
tX5"UQA  
g l^<Q  
int responseCode=httpConnection.getResponseCode(); cv?06x{  
if(responseCode>=400) q1z"-~i)E  
{ ZIf  
processErrorCode(responseCode); 48:>NW  
return -2; //-2 represent access is error wLi4G@jJ  
} 3jGWkby0  
@LS@cCC,a  
rX4j*u2u  
String sHeader; kW*f.!  
RX
>xB  
dYG,_ji  
for(int i=1;;i++) v'U{/ ,x  
{ y`\@N"Cf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fa++MNf}3  
//Utility.log(in.readLine()); :Pvzl1  
sHeader=httpConnection.getHeaderFieldKey(i); gYNjzew'  
if(sHeader!=null) ]Y%Vio  
{ 9`1O"R/  
if(sHeader.equals("Content-Length")) ey2S#%DF]  
{ $CY~5A`l9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6N",-c  
break; 43|XSyS  
} 8D>n1b(H  
} j"}*T  
else u])b,9&En  
break; W~zbm]  
} v9:9E|,U+  
} le1}0L  
catch(IOException e){e.printStackTrace ();} 2[Z,J%:0  
catch(Exception e){e.printStackTrace ();} N!ls j \-  
! ='rc-E  
'JCZ]pZ  
Utility.log(nFileLength); VXYK?Qc'  
uEktQ_u[  
+@94;me  
return nFileLength; U@HK+C"M|  
} v16JgycM  
n2]/v{E;/  
3 ^>l\,  
//保存下载信息（文件指针位置） <QA6/Ef7  
private void write_nPos() b:Wm8pp?  
{ xCg52zkH#  
try{ 2^y^q2(r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <}E!w_yi  
output.writeInt(nStartPos.length); pnjXf.g"O  
for(int i=0;i<nStartPos.length;i++) 4(|cG7>9-  
{ ba[1wFmcL  
// output.writeLong(nPos); 5MN8D COF  
output.writeLong(fileSplitterFetch.nStartPos); +?:7O=Y  
output.writeLong(fileSplitterFetch.nEndPos); 
I,0q4  
} JBi*P.79^  
output.close(); J&M o%"[)  
} 7[> 6i  
catch(IOException e){e.printStackTrace ();} F ~^Jmp7Y  
catch(Exception e){e.printStackTrace ();} 1`(tf6op  
} P
K{acen  
jF0jkj1&/[  
|.F$G<  
//读取保存的下载信息（文件指针位置） \MbB#  
private void read_nPos() eM$
sv9?  
{ >+JqA7K  
try{ ?\t#1"d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }q $5ig  
int nCount = input.readInt(); eO?p*"p"F  
nStartPos = new long[nCount]; oXb;w@:  
nEndPos = new long[nCount]; N>XS=2tzN  
for(int i=0;i<nStartPos.length;i++) $})g?Q  
{ P!H_1RwXKC  
nStartPos = input.readLong(); *1v[kWa?  
nEndPos = input.readLong(); Y"~gw~7OD  
} ^lA=* jY(  
input.close(); ~F4fFQ-yy  
} E~]R2!9  
catch(IOException e){e.printStackTrace ();} qAn!RkA  
catch(Exception e){e.printStackTrace ();} pi Z[Y 5OE  
} OW3sS+y  
cki81bOT  
43mP]*=A  
private void processErrorCode(int nErrorCode) te3}d'9&|  
{ .!f$ \1l  
System.err.println("Error Code : " + nErrorCode); (-ufBYO6  
} MUTj-1H6)  
iPd[l{85Z  
BQ=PW|[  
//停止文件下载 yzerOL  
public void siteStop() *M:B\D  
{ <kGU,@6PF  
bStop = true; 3QG7C{  
for(int i=0;i<nStartPos.length;i++) K_RjX>q%N  
fileSplitterFetch.splitterStop(); +
89*)pk   
sE:M@`2L  
`%+Wz0(K  
} _H j!2 '  
} QR%mj*@Wle  
//负责部分文件的抓取 2w["aVr =  
**FileSplitterFetch.java \.-}adKg  
*/ Nv(9N-9r  
package NetFox; -I&m:A$4*  
)%`^xR  
D|e uX7b  
import java.io.*; l|kSsP:GO  
import java.net.*; FFu9&8Y  
d-k%{eBV  
{]:7bV#JP  
public class FileSplitterFetch extends Thread { nEJY5Bz$  
n2)@S0{  
tasUZ#\6  
String sURL; //File URL BW 4%l  
long nStartPos; //File Snippet Start Position a-=8xs'
 
long nEndPos; //File Snippet End Position ^pQCNKLBY  
int nThreadID; //Thread's ID @\f^0^G  
boolean bDownOver = false; //Downing is over S/9DtXQ  
boolean bStop = false; //Stop identical {]
%0lf:  
FileAccessI fileAccessI = null; //File Access interface \l9qt5rS  
@cFJeOC|  
czS+< w  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I@yCTluV$  
{  K i'Fn"  
this.sURL = sURL; !bN*\c  
this.nStartPos = nStart; X*{2[+<o  
this.nEndPos = nEnd; _$ +^q-  
nThreadID = id; VXR>]HUF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "#{4d),r  
} CF?1R  
(O.d>  
C~o7X^[R\  
public void run() j)<IRD^  
{ 6YGubH7%_  
while(nStartPos < nEndPos && !bStop) 6]W=nAD  
{ BYVY)<v/  
uBNn6j  
23RN}LUi  
try{ ^eo|P~w g  
URL url = new URL(sURL); P:k>aHnW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  ?zw|kl  
httpConnection.setRequestProperty("User-Agent","NetFox"); C|}iCB  
String sProperty = "bytes="+nStartPos+"-"; -"=U?>(  
httpConnection.setRequestProperty("RANGE",sProperty); '}B+r@YCN  
Utility.log(sProperty); Q9Kve3u-i  
Gn ~6X-l  
G!>z;5KuS  
InputStream input = httpConnection.getInputStream(); @ycDCB(D}  
//logResponseHead(httpConnection); ??M"6k  
j4|N-:  
8~J(](QA  
byte[] b = new byte[1024]; @zU6t|mhz  
int nRead; .J)I | '  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6W]9$n\"?  
{ M%2+y5  
nStartPos += fileAccessI.write(b,0,nRead); i36eBjT  
//if(nThreadID == 1) B0dQ@Hq*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a&c6.#E{y  
} +l9!Fl{MK\  

Mxyb
5h  
H!5\v
"]WB  
Utility.log("Thread " + nThreadID + " is over!"); 4^WpS/#4  
bDownOver = true; E\as@pqo\p  
//nPos = fileAccessI.write (b,0,nRead); YjxF}VI~<  
} 3%E }JU?MM  
catch(Exception e){e.printStackTrace ();} +a^nlW9g  
} }o(zj=7  
} MvK !u  
PIu1+k.r?  
!g5
xq  
//打印回应的头信息 bpH^:fyLU`  
public void logResponseHead(HttpURLConnection con) 62k^KO6Y  
{ x4;"!Kq\  
for(int i=1;;i++) ?[g=F <r  
{ "Zl5<  
String header=con.getHeaderFieldKey(i); fI{&#~f4C  
if(header!=null) 5,_u/5Y4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); IsZHelg  
Utility.log(header+" : "+con.getHeaderField(header)); .1KhBgy^K  
else d1AioQ9  
break; iOU6V  
} YwDbPX  
} lQ"
p !  
++6`sMJ  
pEBM3r!X  
public void splitterStop() (tIo:j  
{ i;/5Y'KZ  
bStop = true;
xJ>fm%{5  
} OBOtuu.  
Fl kcU `j  
9 7GV2]-M  
} YG3J$_?y0  
'gC_)rK*  
/fZeWU0W  
/* o4m\~as)Y  
**FileAccess.java k5:G-BQ:  
*//文件访问(定位，写) H*ow\ Ct  
package NetFox; 'p>Ra/4  
import java.io.*; mZSD(  
sf)EMh3Z  
,l!Ta"  
public class FileAccessI implements Serializable{ NidIVbT.A  
B8f8w)m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `|{-+m  
RandomAccessFile oSavedFile; oW ::h
B  
long nPos; s5CXwM6cx  
C-Q28lD}f  
fI&t]  
public FileAccessI() throws IOException U>]$a71  
{ _I@9HC 4  
this("",0); Fv~20G(O  
} YC++&Nk  
Z/k:~%|E  
kW;+|qs^  
public FileAccessI(String sName,long nPos) throws IOException &,zq%;-f  
{ kD=WO4}  
oSavedFile = new RandomAccessFile(sName,"rw"); ,{M^-3C  
this.nPos = nPos; )'l:K.F  
oSavedFile.seek(nPos); KN<S}3MN  
} /N=b\-]  
6:b!F  
&e @2  
public synchronized int write(byte[] b,int nStart,int nLen) TE3lK(f  
{ d,+Hd2o^X  
int n = -1; B2
>H_dmQ  
try{ &e E=<x  
oSavedFile.write(b,nStart,nLen); ]V^iN=(_5  
n = nLen; Xe$I7iKD  
} RRmz"j>  
catch(IOException e) ULs\+U  
{ rDm~h~u5  
e.printStackTrace (); 1oR7iD^  
} Zq+v6fk_Mn  
>3p\m  
[k.tWA,&  
return n; ZP@ $Q%up  
} >0/i[k-dk  
q!.byrod  
) i;1*jK  
} (SpX w,:  
+"rDT1^V  
zQcL|(N  
/* nV"~-On  
**SiteInfoBean.java BmbyH{4  
*/ t<#TJ>Le  
package NetFox; th  
O#ai)e_uQk  
kVkU)hqR  
public class SiteInfoBean { xN5)  
`, OG7hg  
6HT;#Znn  
private String sSiteURL; //Site's URL .YhA@8nc~l  
private String sFilePath; //Saved File's Path BF\XEm?!  
private String sFileName; //Saved File's Name )(bW#-  
private int nSplitter; //Count of Splited Downloading File h;
p>o75O  
YWe{juXSw  
mk;&yh  
public SiteInfoBean() 4w*Skl=F}  
{//nSplitter的缺省值为5 %RTBV9LIXr  
//default value of nSplitter is 5 <^&ehy:7y  
this("","","",5); z06r6  
} 7I&&bWB  
Bo)3!wO8  
Rw"sJ)/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CS2Bo  
{ (/=f6^}  
sSiteURL= sURL; EAT"pxP  
sFilePath = sPath; N-G1h?e4  
sFileName = sName; fT;s-v[`k  
this.nSplitter = nSpiltter; joFm]3$;  
,f~J`3(&  
"sS}N%!  
} 1Ir21un  
k Z?=AXu  
F^WP<0C  
public String getSSiteURL() F0GxH?  
{ (l\1n;s*B  
return sSiteURL; !\-{D$E?H  
} {x|[p_?  
8m-U){r!U^  
\HqNAE2T  
public void setSSiteURL(String value) t)~"4]{*}D  
{ d(\%Os  
sSiteURL = value; sZjQ3*<-r  
} G? ]
)o5  
<`.X$r*  
o)h_H;  
public String getSFilePath() QX!-B  
{ m,VOx7%n  
return sFilePath; =i$Fl{vH  
} X$HIVxyq2  
( Z619w  
Yrb{ByO&  
public void setSFilePath(String value) C].iCxn  
{ Q8T]\6)m  
sFilePath = value; 1#C4;3i,  
} b,5~b&<h  
(SWYOMo"  
x6BuF_.  
public String getSFileName() YJ^] u}  
{ bn#"?6Z2  
return sFileName; zZ7;jyD  
} b+%f+zz*h  
*F+KqZ.2  
CnU*Jb  
public void setSFileName(String value) uW=k K0E  
{ Tl%`P_J)-S  
sFileName = value; EMh7z7}Rr  
} 4QH3fTv   
!02`t4Zc-  
~Y`ldL  
public int getNSplitter() .7Dtm<K#  
{ lsJSYJG&  
return nSplitter; LzG%Z1`  
} A0/"&Ag]  
&TnS4O  
S*==aftl(  
public void setNSplitter(int nCount) rx'RSo#1O  
{ !`k1:@NZ  
nSplitter = nCount; _Us#\+]_:  
} O@tU.5*$5  
} lsgh#x  
],>@";9u"  
2L:_rR#w  
/* q['Euy  
**Utility.java J28
M@cn  
*/ SOs:]U-T3  
package NetFox; SbND Y{5RO  
!F*5M1Kjd  
7TgOK   
public class Utility { $3W;=Id=+  
ls_'')yp  
cL-[ZvyVX  
public Utility() X@'uy<tI-  
{ (lXGmx8  
TCN8a/@z  
"LHcB]^<  
} Mz9r5
 
g$":D  
//线程睡眠 #9B)Xx!g  
public static void sleep(int nSecond) J; 3{3  
{ O%Scjm-^X  
try{ k|v3.< -  
Thread.sleep(nSecond); p?{Xu4(  
} ED2a}Tt>Z  
catch(Exception e) h2)yq:87  
{ zE336  
e.printStackTrace (); hP=WFD&  
} 1[mXd  
} xj<Rp|7&  
Um}  
//日志 OPetj.C/a  
public static void log(String sMsg) S$f9m  
{ ~De"?  
System.err.println(sMsg); +s"hqm  
} ,QOG!T4  
+cD<:"L'
g  
#=D) j  
public static void log(int sMsg) :<ka3<0%  
{ <vnHz?71c  
System.err.println(sMsg); b1?#81  
} teOe#*  
} }wWKFX  
QgrpBG  
\n"{qfn`r  
/* j>*S5y.{  
**TestMethod.java 3
RiWZN  
*/ iMt:9|yF}8  
package NetFox; pe0F0Ruy
 
v&Ii^?CvO  
f& 0M*o,)  
public class TestMethod { qsF<!'m7`  
f"B3,6m  
)) Zf|86N  
public TestMethod() >lmi@UN|k  
{ ///xx/weblogic60b2_win.exe +ylTGSZS  
try{ !5wIIS:FT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZufR{^W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OGBHos  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "HX<,l8f%  
fileFetch.start(); 3ovWwZ8&  
} ];}Wfl  
catch(Exception e){e.printStackTrace ();} Q;MT"=RW  
t$+?6E  
SIe="YG]<  
} &*sP/z  
68bQ;Dv  

k=2Lo  
public static void main(String[] args) =31"fS@  
{ #:%&x@@c3P  
new TestMethod(); {qDSPo  
} 9 ^o-EC!_  
} VJ84?b{c W  
点击下载更多相关资料