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http断点续传简单实现(java)

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/* ^"9* 'vTtc  
**SiteFileFetch.java ?c]n^GvG  
*/ v?%LQKO  
package NetFox; 44\cI]!{  
import java.io.*; Mo D?2J  
import java.net.*; pj0fM{E  
>O#grDXb  
qj!eLA-aD  
public class SiteFileFetch extends Thread { ^rL_C}YBj-  
*FK`&(B+}  
y7: tr  
SiteInfoBean siteInfoBean = null; //文件信息Bean {hQ6K)s  
long[] nStartPos; //开始位置 PFM' & ;V  
long[] nEndPos; //结束位置 6BocGo({  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `S3>3  
long nFileLength; //文件长度 nPN?kO=]  
boolean bFirst = true; //是否第一次取文件 6?qDdVR~]  
boolean bStop = false; //停止标志 S|em[D[Y^  
File tmpFile; //文件下载的临时信息 ?<U{{ C  
DataOutputStream output; //输出到文件的输出流 ";x+1R.d  
y<- _(^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) QJn`WSw$_-  
public SiteFileFetch(SiteInfoBean bean) throws IOException w8Vw1wW  
{ 2&Jd f  
siteInfoBean = bean; UG;Y^?Ppe5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Wht(O~F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); At6qtoPRA  
if(tmpFile.exists ()) p`F9Amb  
{ ~+G#n"Pn  
bFirst = false; a|4~NL  
read_nPos(); id^sr Mw  
} vUA0FoOp  
else 71fk.16  
{ #]]Su91BA  
nStartPos = new long[bean.getNSplitter()]; ]Mi.f3QlO6  
nEndPos = new long[bean.getNSplitter()]; "*z_O  
} B@y(.  
3;[DJ5  
F {+`uG  
Ge+0-I6Ju  
} $((6=39s  
N587(wZ  
#A7jyg":  
public void run() 5O/i3m26  
{ 3+Qxg+<  
//获得文件长度 D*PYr{z'  
//分割文件 w|[RDaAb  
//实例FileSplitterFetch Pmg)v!"  
//启动FileSplitterFetch线程 ~EzaC?fQ  
//等待子线程返回 .|qK +Hnc  
try{ 8eBOr9l+j  
if(bFirst) ~PWSo%W8  
{ MPgS!V1  
nFileLength = getFileSize(); l_tw<`Ep  
if(nFileLength == -1) g*UMG>  
{ # ]?bLm<!  
System.err.println("File Length is not known!"); WE6a'  
} A - YBQPE  
else if(nFileLength == -2) |'O[7uT  
{ ltB .Q  
System.err.println("File is not access!"); X?:o;wB  
} m([(:.X/IX  
else OLGBt  
{ LVJI_O{fH  
for(int i=0;i<nStartPos.length;i++) 6VP`evan  
{ [H<bh%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aNn"X y\ k  
} w]b,7QuNz  
for(int i=0;i<nEndPos.length-1;i++) 9E2j!  
{ i,A#&YDl  
nEndPos = nStartPos[i+1]; `p b5*h6r!  
} %J:SO_6  
nEndPos[nEndPos.length-1] = nFileLength; {rfF'@[  
} \<Sv3xy&O  
} uwf 5!Z:>  
@vL20O.  
&AVpLf:?  
//启动子线程 tWTKgbj(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^D^4 YJz  
for(int i=0;i<nStartPos.length;i++) ]5~s "fnG  
{ S##1GOO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4n#ov=)-~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Xs&TJ8a  
nStartPos,nEndPos,i); 2?m.45`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "mL++>ZSQ  
fileSplitterFetch.start(); iwz  
} ^ -FX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iGB_{F~t4}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g%F"l2M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l`kWz5[~  
nEndPos = " + nFileLength); J q{7R  
// fileSplitterFetch[nPos.length-1].start(); -jgysBw+Xb  
q~CA0AR  
26X+ }^52  
//等待子线程结束 DeR='7n  
//int count = 0; ]E  =Iu  
//是否结束while循环 ?USQlnr:R/  
boolean breakWhile = false; !fBF|*/  
%Qg+R26U  
9/+Nj/  
while(!bStop) m}>F<;hQ  
{ vR0 ];{  
write_nPos(); 2G$SpfeIu  
Utility.sleep(500); m<L;  
breakWhile = true; OD' ]:  
1&fc1uYB4  
%uv?we7  
for(int i=0;i<nStartPos.length;i++) "V{yi!D{<  
{ .jy]8S8[|%  
if(!fileSplitterFetch.bDownOver) %|G"-%_E  
{ hhoEb(BA  
breakWhile = false; Ltjbxw"Qd  
break; iNwqF0  
} wP"dZagpj  
} NBb6T V}j  
if(breakWhile) Mi~(aah  
break; %e*@CbO$  
=2w4C_  
|yo\R{&6  
//count++; gWY "w!f  
//if(count>4) A.UUW  
// siteStop(); p&VU0[LIC0  
} jD7NblX  
9W5onn  
wf1lyS  
System.err.println("文件下载结束!"); =)|-?\[w  
} >vo=]c w  
catch(Exception e){e.printStackTrace ();} tE7[Smzuf  
} :x_'i_w  
&S{RGXj_  
bhTb[r  
//获得文件长度 &gVN&  
public long getFileSize() we~[] \  
{ +%zAQeb  
int nFileLength = -1; 7 E r23Q  
try{ V+* P2|  
URL url = new URL(siteInfoBean.getSSiteURL()); 4ni<E*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #C~+JL  
httpConnection.setRequestProperty("User-Agent","NetFox"); rq8K_zp  
aktU$Wbwl  
AF;)#T<  
int responseCode=httpConnection.getResponseCode(); B8.Pn  
if(responseCode>=400) ] bM)t<  
{ 6}gls}[0{e  
processErrorCode(responseCode); 1L%CJ+Q#0i  
return -2; //-2 represent access is error 8 ##-EN;ag  
} #a/5SZP Z\  
wa<MRt W=  
E ]A#Uy  
String sHeader; lGV0 *Cji  
/f:dv?!km  
=)M/@T  
for(int i=1;;i++) Hu\B"fdS  
{ R0P iv:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nOt&pq7  
//Utility.log(in.readLine()); zvYq@Mhr  
sHeader=httpConnection.getHeaderFieldKey(i); yh Yb'GK  
if(sHeader!=null) s>B5l2Q4  
{ j`JMeCG=Ee  
if(sHeader.equals("Content-Length")) V, Z|tB^  
{ s1M Erd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,~aQL  
break; [;r)9mh7  
} 1t:Q_j0Ym  
} ;kFDMuuO  
else *;l]8.  
break; H7z,j}l  
} p#01gB  
} 09X01X[  
catch(IOException e){e.printStackTrace ();}  ,V,`Jf  
catch(Exception e){e.printStackTrace ();} ^!<U_;+  
l7XUXbYp&=  
03|PYk 6EW  
Utility.log(nFileLength); \l'm[jy>  
eV 2W{vuI  
#+:9T /*>0  
return nFileLength; %}SGl${-  
} 0ZT5bg_M  
MuYk};f  
;+e}aER&9  
//保存下载信息(文件指针位置) O!m vJD  
private void write_nPos() 5QW=&zI`=  
{ `_BNy=`s*  
try{ fL_4uC i\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wg7V-+@i  
output.writeInt(nStartPos.length); zcel|oz)  
for(int i=0;i<nStartPos.length;i++) @G BxL*e  
{ Sc>,lIM  
// output.writeLong(nPos); S'|,oUWDb  
output.writeLong(fileSplitterFetch.nStartPos); ?zeJ#i  
output.writeLong(fileSplitterFetch.nEndPos); ^WHE$4U`  
} o>).Cj  
output.close(); @E;=*9ek{u  
} 4iqoR$3Fc  
catch(IOException e){e.printStackTrace ();} LIS)(X<]?  
catch(Exception e){e.printStackTrace ();} 9%8"e>~  
} *EOdEFsR/  
?^H `M|S  
_g+JA3sIJ  
//读取保存的下载信息(文件指针位置) Vu)4dD!  
private void read_nPos() |*oZ _gI  
{ ))R5(R  
try{ q+Lr"&'Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t|H^`Cv6  
int nCount = input.readInt(); cQ/5qg  
nStartPos = new long[nCount]; R{WE\T'  
nEndPos = new long[nCount]; !Z`j2 e}  
for(int i=0;i<nStartPos.length;i++) aUzBV\Yd}  
{ w&$`cD  
nStartPos = input.readLong(); 1_o],? Q  
nEndPos = input.readLong(); fRrvNj0{ V  
} w:%o?pKet1  
input.close(); hXfQ)$J  
} H(R1o~  
catch(IOException e){e.printStackTrace ();} I CZ4 A{I  
catch(Exception e){e.printStackTrace ();} VYu~26Zr  
} XF Patd  
UM!ENI|  
bHPYp5UwN  
private void processErrorCode(int nErrorCode) CUO+9X-<8  
{ EqyeJq .  
System.err.println("Error Code : " + nErrorCode); K-e9>fmB#  
} sc|_Q/`\.  
o]+z)5zC  
3[\iQ*d }B  
//停止文件下载 J{l1nHQZSu  
public void siteStop() )hd@S9Z.Y  
{ 0@ yXi  
bStop = true; o 4`hY/<t  
for(int i=0;i<nStartPos.length;i++) /mXBvY  
fileSplitterFetch.splitterStop(); , `wXg  
!,l9@eJQ  
m#8m] Y  
} c|lu&}BS  
} ?Y)vGlWDW<  
//负责部分文件的抓取 tkVbo.[8K  
**FileSplitterFetch.java pA`+hQNN  
*/ nA?`BOe(  
package NetFox; hhSy0  
XUM!Qv  
VcAue!MN  
import java.io.*; *YW/_  
import java.net.*; stG~AC  
8;z6=.4xtg  
IYqBQnX}oM  
public class FileSplitterFetch extends Thread { @En^wN  
g3Ec"_>P  
Mx6@$tQ%  
String sURL; //File URL M^MdRu  
long nStartPos; //File Snippet Start Position {n(b{ ibl  
long nEndPos; //File Snippet End Position ;6gDV`Twy  
int nThreadID; //Thread's ID j Yx38_5e  
boolean bDownOver = false; //Downing is over -#0qV:D  
boolean bStop = false; //Stop identical tna .52*/  
FileAccessI fileAccessI = null; //File Access interface ]p*l%(dhY  
V\6=ySx  
VOKZ dC-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p%iGc<vHX  
{ 3Dg,GaRk  
this.sURL = sURL; WzAb|&?  
this.nStartPos = nStart; JCz@s~f\y  
this.nEndPos = nEnd; F ;{n"3<  
nThreadID = id; .EpV;xq}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Cnnh7`  
} E>&n.%  
%dJX-sm@  
7x#Ckep:I  
public void run()  gG uZ8:f  
{ <!L>Exh&r  
while(nStartPos < nEndPos && !bStop) bQE};wM,  
{ k xP-,MD  
uJOJ-5}yt  
(H)2s Y  
try{ 0rh]]kj  
URL url = new URL(sURL); |w_7_J2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WEFlV4/  
httpConnection.setRequestProperty("User-Agent","NetFox"); I{ HN67O  
String sProperty = "bytes="+nStartPos+"-"; r9X?PA0f  
httpConnection.setRequestProperty("RANGE",sProperty); Ae mDJ8Y  
Utility.log(sProperty); J+[_Wd  
"nZ*{uv  
wyp|qIS;  
InputStream input = httpConnection.getInputStream(); ) u3 Zm  
//logResponseHead(httpConnection); 0*%Z's\M"  
iDMJicW!+F  
:r%P.60H X  
byte[] b = new byte[1024]; nNrPHNfqD  
int nRead; #rxVd 7f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  =Qh\D  
{ NXwz$}}Pp  
nStartPos += fileAccessI.write(b,0,nRead); W4hbK9y  
//if(nThreadID == 1) Z&0'a  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N U|d  
} UjaK&K+M?  
Dpvk\t  
#6ri-n  
Utility.log("Thread " + nThreadID + " is over!"); Uh7v@YMC  
bDownOver = true; =.y~fA!  
//nPos = fileAccessI.write (b,0,nRead); D<|qaHB=  
} e "/;7:J5\  
catch(Exception e){e.printStackTrace ();} ]x\-$~E  
} eK.e| z|  
} j2Tr $gx<  
>"gf3rioW  
W4[V}s5u  
//打印回应的头信息 )A!>=2M `  
public void logResponseHead(HttpURLConnection con) (EK"V';   
{ ZaeqOVp/j  
for(int i=1;;i++) *_R]*o!W'  
{ [E+$?a=  
String header=con.getHeaderFieldKey(i); HHiT]S9  
if(header!=null) W- i&sUgy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RMd[Yr2e  
Utility.log(header+" : "+con.getHeaderField(header)); ?dD&p8{  
else h]og*(  
break; 4$qWiG~  
} ELBa}h;  
} i7ISX>%  
, FhekaA  
'6Ay&A3N]  
public void splitterStop() >2~+.WePu  
{ uvtF_P/  
bStop = true; .{ 44a$)  
} *F ? 8c  
U"q/rcA  
)E6;-rD0^+  
} b`)){LR  
m_=$0m J$  
^dP KDrKxh  
/* *:>"q ej  
**FileAccess.java =:DaS`~V  
*//文件访问(定位,写)  -QOw8vm  
package NetFox; {LX.iH9}l  
import java.io.*;  Mu2  
Sl-v W  
Ul2R'"FB  
public class FileAccessI implements Serializable{ ._8KsuJG  
A]YV s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \]P!.}nX#  
RandomAccessFile oSavedFile; _Dym{!t  
long nPos; ^&bRX4pYo  
vr0WS3  
, #U .j  
public FileAccessI() throws IOException @?=|Y  
{ 1U^A56CN  
this("",0); YhOlxON  
} WA]c=4S  
]Tkc-ez  
N-I5X2  
public FileAccessI(String sName,long nPos) throws IOException 2R=DB`3  
{ bhkUKxd  
oSavedFile = new RandomAccessFile(sName,"rw"); SG-'R1 J  
this.nPos = nPos; }:u~K;O87  
oSavedFile.seek(nPos); FL(6?8zK  
} (S xR`QP?,  
Mu{;vf|j  
Nc+,&R13m  
public synchronized int write(byte[] b,int nStart,int nLen) o4*+T8[|5  
{ ;3\3q1oX  
int n = -1; w;k):; $  
try{ >Y_*%QGH_  
oSavedFile.write(b,nStart,nLen); c6nflk.l  
n = nLen; tj Gd )  
} OR}c)|1  
catch(IOException e) H|R T?Q  
{  PZ{Dv'C  
e.printStackTrace (); KN7^:cC  
} K$M^gh0  
qw@puw@D  
U+)xu>I  
return n; 3 dht!7/  
} _<a7CCg  
9uRF nzJVx  
BT)X8>ct  
} D[_|*9BC  
-8r  
~><^'j[  
/* T:/,2.l  
**SiteInfoBean.java 3 n'V\H vz  
*/ SfJ./ny  
package NetFox; }?z@rt^  
0Z0:,!  
8zA=;~GHP  
public class SiteInfoBean { ?;vgUO  
uL3Eq>~x  
" R-!(9k^`  
private String sSiteURL; //Site's URL = M]iIWQ@`  
private String sFilePath; //Saved File's Path UB 6mqjPK  
private String sFileName; //Saved File's Name K'X2dG*  
private int nSplitter; //Count of Splited Downloading File A5i:x$ww  
~zSCg|"r  
@+9<O0  
public SiteInfoBean() %^1cyk  
{//nSplitter的缺省值为5 ,WvY$_#xW%  
//default value of nSplitter is 5 v^zu:Z*  
this("","","",5); oP!;\a( SL  
} -O&CI)`;B  
E2cB U{x  
oS7(s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \3'9Uz,OC  
{ aX~%5 mF  
sSiteURL= sURL; AX= 1b,s  
sFilePath = sPath; abJ" [  
sFileName = sName; AJSx%?h:6  
this.nSplitter = nSpiltter; qTAc[Ko  
~mO62(8m  
&g.@u~SI1  
} C4hx@abA  
={5#fgK>  
lW(px^&IN  
public String getSSiteURL() c>/. ;p  
{ ~v'3"k6  
return sSiteURL; ' v\L @"  
} 7zHh@ B:]  
jCrpL~tWT  
H|ER  
public void setSSiteURL(String value) 6I!7c^]t  
{ :=8t"rO=W  
sSiteURL = value; em\ 9'L^  
} Ea?XT&,  
W -  
Mz1G5xcl  
public String getSFilePath() ?V}j`r8|\4  
{ YKE46q;J  
return sFilePath; nK$X[KrV'  
} 7<jZ`qdq_  
/Nr*`l  
E@-KGsdhK  
public void setSFilePath(String value) 1fo U  
{ >0dv+8Mn  
sFilePath = value; @#P,d5^G  
} !!4Qj  
Xe#K{gA  
m! W3Cwz\&  
public String getSFileName() t9Y=m6  
{ u ~3%bJ]  
return sFileName; \=0V uz  
} f)g7 3=  
m85WA # `  
{0;3W7  
public void setSFileName(String value) rz"txN  
{ kl"+YF5/  
sFileName = value; Up:<=Kgci  
} &AlJ "N|  
01T`Flz  
I+!:K|^  
public int getNSplitter() = pI?A^  
{ +3a?` Z  
return nSplitter; :> &fV  
} MwfOy@|N  
avy"r$v_&  
<,AS8^$X[  
public void setNSplitter(int nCount) %0 #XPc("  
{ ATy*^sc&"  
nSplitter = nCount; })w*m  
} gtYAHi  
} >Bs#Xb_B]  
O:{U^K:*  
[w\9as/ E  
/* |A%<Z(  
**Utility.java t6BHGX{o  
*/ DfV~!bY  
package NetFox; ?88`fJ@tk?  
EwS!]h?  
U:MPgtwe  
public class Utility { O$kq`'9  
XyMG.r-,  
>HPdzLY?  
public Utility() j F-v% ?  
{ `xiCm':  
+fx8muz:y  
Mc-)OtmG[  
} k8,?hX:  
341?0 %=  
//线程睡眠 _U{([M>;  
public static void sleep(int nSecond) x f4{r+  
{ 5'w^@Rs5  
try{ hUz[uyt  
Thread.sleep(nSecond); |0{u->+ )  
} 83cW=?UgA  
catch(Exception e) aZKOY  
{ =SD\Q!fA  
e.printStackTrace (); X%bFN  
} YpUp@/"  
} W>M~Sk$v  
* MM[u75  
//日志 $6F)R|  
public static void log(String sMsg) Y${l!+q  
{ V@d )?T  
System.err.println(sMsg); CK_(b"  
} \n9A^v`F/  
;nmM7TZ;  
\Hqc 9&0  
public static void log(int sMsg) >x3ug]Bu  
{ gPzL*6OS A  
System.err.println(sMsg); @c'|Iqy`  
} ~#}Dx :HH  
} <DH*~tLp2  
i`)!X:j  
tvX>{-M  
/* ZyR_6n>L$  
**TestMethod.java z"DkFvA  
*/ A>NsKWf{  
package NetFox; ,jy*1Hjd  
}a&mY^  
R7~Yw*#,  
public class TestMethod { V 'X;jC  
:L0/V~D  
Lc<eRVNd,  
public TestMethod() oUx[+Gnv  
{ ///xx/weblogic60b2_win.exe rZbEvS  
try{ %Y4e9T".  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); OMihXt[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Uz%Z&K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J NC  
fileFetch.start(); n,P5o_^:  
} iy\KzoB  
catch(Exception e){e.printStackTrace ();}  17hTr  
/T0nLp`gi  
K#K\-TR|$  
} Aox3s?  
e=/&(Y  
0;~yZ?6_F  
public static void main(String[] args) dMl+ko  
{ K8^kJSF\  
new TestMethod(); ly4Qg\l  
} 0"xPX#Cvj  
} rFJ[dz  
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