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http断点续传简单实现(java)

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/* :JV= Kt  
**SiteFileFetch.java QPg QM6  
*/ yS@c2I602  
package NetFox; q$(aMO&J  
import java.io.*; Ra%RcUf~sh  
import java.net.*; [ZZ~^U5  
W[AX?  
8jMw7ti  
public class SiteFileFetch extends Thread { %qV=PC  
4sP0oe[h  
Xg^`fRg =T  
SiteInfoBean siteInfoBean = null; //文件信息Bean UP58Cln*  
long[] nStartPos; //开始位置 )c^Rc9e/  
long[] nEndPos; //结束位置 8uP,#D<wZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GXr9J rs.e  
long nFileLength; //文件长度 K#%L6=t$<  
boolean bFirst = true; //是否第一次取文件 4;<?ec(dc  
boolean bStop = false; //停止标志 W.r0W2))(  
File tmpFile; //文件下载的临时信息 <ZSH1~<{6  
DataOutputStream output; //输出到文件的输出流 V\W?@V9g-  
Xjw> Qws  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) d/v{I  
public SiteFileFetch(SiteInfoBean bean) throws IOException WUvrC  
{ Mi%i_T^i  
siteInfoBean = bean; r? nvJHP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @mSdksB/L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X#EMmB!  
if(tmpFile.exists ()) T&oY:1D,g  
{ [ %cW ?@  
bFirst = false; a:r8Jzr  
read_nPos(); f-F+Y`P  
} V: fz  
else =ps3=D  
{ yH|[K=?S[  
nStartPos = new long[bean.getNSplitter()]; 9E'fM  
nEndPos = new long[bean.getNSplitter()]; P(l$5x]g,  
} GPONCL8(0  
E2 Q[  
{pH{SRM)B  
/x c<&  
} 0M7Or)qN  
$5yH(Z[[  
",!#7h  
public void run() H!?Av$h`  
{ x4r8^,K3Zn  
//获得文件长度 5=WzKM  
//分割文件 !_ZknZTT  
//实例FileSplitterFetch 'W(+rTFf!  
//启动FileSplitterFetch线程 %PRG;kR  
//等待子线程返回 AyKvh  
try{ 0"ksNnxK  
if(bFirst) E (  
{ X;lL$  
nFileLength = getFileSize(); V(I!HT5.W  
if(nFileLength == -1) x$Y44v'>  
{ 2BZYC5jy  
System.err.println("File Length is not known!"); sD H^l)4h  
} VG0Ty;bV  
else if(nFileLength == -2) O-J;iX}  
{ GvSSi'q~B  
System.err.println("File is not access!"); <o@&I " o  
} 5\gL+ qM0  
else c7UmR?m  
{ 4[m})X2(  
for(int i=0;i<nStartPos.length;i++) !~Gx@Ro  
{ UF0W%Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O=~8+sa  
} ZKy)F-yX  
for(int i=0;i<nEndPos.length-1;i++) s~ ||Vv!  
{ cyrVz4_a  
nEndPos = nStartPos[i+1]; me:~q#k  
} Q&+Jeji  
nEndPos[nEndPos.length-1] = nFileLength; BmR++?L  
} a~ q_2S]h  
} fFDI qX  
O'm><a>8  
O<7Q>m  
//启动子线程 t"x 8]Gy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,I6jfXI4  
for(int i=0;i<nStartPos.length;i++) M8dv y!D  
{ <Hd8Jd4f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jr[(g:L   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )[fjZG[  
nStartPos,nEndPos,i); 'NJGez'b ,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j5Kw0Wy7  
fileSplitterFetch.start(); '!eg9}<  
} !"1}zeve  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B7 PkCS&X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KYE)#<V}@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1 aWzd[i  
nEndPos = " + nFileLength); $J6Pv   
// fileSplitterFetch[nPos.length-1].start(); PD #9Z=Hj  
Dl=9<:6FW  
= og>& K  
//等待子线程结束 8T6LD  
//int count = 0; ^*s DJ #  
//是否结束while循环 s%M#  
boolean breakWhile = false; $HgBzZ7A2  
x }\x3U  
I(^pIe-  
while(!bStop) {1?94rz  
{ e&~vO| 3w%  
write_nPos(); LGnb"ZN  
Utility.sleep(500); )/HbmtXqI  
breakWhile = true; n/W@H Im#  
[|iWLPO1&k  
0s9-`nHen|  
for(int i=0;i<nStartPos.length;i++) y7CC5S ?  
{ g)?Ol  
if(!fileSplitterFetch.bDownOver) D5Zgi!  
{ yS#)F.  
breakWhile = false;  NOY`1i  
break; k=]#)A(#C  
} "PgVvm#w'  
} &10l80vj  
if(breakWhile) M3XG s|gw  
break; ?^Gi;d5  
,+w9_Gy2H  
w8=&rzr8  
//count++; Vn&{yCm3  
//if(count>4) r]q;>\T'  
// siteStop(); f^JiaU4 [  
} ),{v  
r ^=rs!f@  
7 bV(eV  
System.err.println("文件下载结束!"); @jL](Mq|]  
} l7h6R$7; 0  
catch(Exception e){e.printStackTrace ();} B":9C'tip  
} 26M:D&|ZB  
sNa Lz  
^bM\:z"M  
//获得文件长度 Borr  
public long getFileSize() TWzlF>4N  
{ FOPfo b[  
int nFileLength = -1; F u>  
try{ vYFtw L`  
URL url = new URL(siteInfoBean.getSSiteURL()); &}'FC7}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $>JfLSyC  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5)5$h]Nz>  
7MWd(n-  
J.E Bt3  
int responseCode=httpConnection.getResponseCode(); 4nsc`Hu  
if(responseCode>=400) ]ilQq~X  
{ 1.9bU/X  
processErrorCode(responseCode); GLO%>&  
return -2; //-2 represent access is error y+\kZIqX  
} C/$bgK[ev  
s5bqS'%  
r'J="^k{  
String sHeader; O]4v\~@-j  
SND@#?hiO  
@V?T'@W7D  
for(int i=1;;i++) Vu`5/QDq  
{ ?rm3Iac0S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,.kJF4s&  
//Utility.log(in.readLine()); U[0x\~[$K  
sHeader=httpConnection.getHeaderFieldKey(i); |,bP` Z  
if(sHeader!=null) 4s s 4O  
{ ) $`}~  
if(sHeader.equals("Content-Length")) a(J@]X>'  
{ @m5c<(bkfp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N \~}`({  
break;  /!#A'#Z  
} <ni_78  
} c;?J  
else X-=4Z9  
break; 3F?7oMNIh  
} 0BwxPD#6bv  
} |(%=zb=?X  
catch(IOException e){e.printStackTrace ();} (*M*muk  
catch(Exception e){e.printStackTrace ();} ~6"=d  
 Vp7d  
MY60%  
Utility.log(nFileLength); eRqPZb"6MR  
pCf9"LLer  
"ejsz&n  
return nFileLength; kwXUjn p  
} $>8O2p7W  
>\!G43Q=  
3PjX;U|  
//保存下载信息(文件指针位置) "{S6iH)]8  
private void write_nPos() BTzBT%mP  
{ 1{ H=The  
try{ b'ZzDYN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s{Og3qUy  
output.writeInt(nStartPos.length); /F$E)qN7n  
for(int i=0;i<nStartPos.length;i++) P BVF'~f@j  
{ vM@8&,;  
// output.writeLong(nPos); vX7U|zy  
output.writeLong(fileSplitterFetch.nStartPos); fN1b+ d~*6  
output.writeLong(fileSplitterFetch.nEndPos); Vx}e,(i  
} 6HguZ_jC  
output.close(); soRY M  
} DfU]+;AE  
catch(IOException e){e.printStackTrace ();} x5Ue"RMl+  
catch(Exception e){e.printStackTrace ();} :GN++\ 1pw  
} Z2L7US -  
MQQQaD:v  
v.- r %j{I  
//读取保存的下载信息(文件指针位置) D^QL.Du,  
private void read_nPos() hx*4xF  
{ 04WxV(fo'  
try{ ~ulcLvm:i  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q:j~ kutS|  
int nCount = input.readInt(); Ma'#5)D  
nStartPos = new long[nCount]; Gshy$'_e  
nEndPos = new long[nCount]; EJP]E)  
for(int i=0;i<nStartPos.length;i++) a/v]E]=qI  
{ E/hT/BOPK  
nStartPos = input.readLong(); QH,Fw$1  
nEndPos = input.readLong(); x=Aq5*A0  
} .l hS  
input.close(); ,1g_{dMx  
} |ZM>UJ  
catch(IOException e){e.printStackTrace ();} aX~Jk >a0  
catch(Exception e){e.printStackTrace ();} V.9p4k`  
} !7f,gvk  
mrq,kwM  
33 S CHQ  
private void processErrorCode(int nErrorCode) cV"Ov@_.k  
{ 3GNcnb  
System.err.println("Error Code : " + nErrorCode); z9:yt5ar  
} jXVvVv  
L|Xg4Z  
M}j[{wW3  
//停止文件下载 JljCI@  
public void siteStop() q9H\ $  
{ 8f<y~L_(`  
bStop = true; t 9t '9  
for(int i=0;i<nStartPos.length;i++) !MrQ-B(  
fileSplitterFetch.splitterStop(); :.tL~% q  
Qcks:|5  
Y]_$+Si:NK  
} 1{5t.  
} )+"5($~  
//负责部分文件的抓取 aM xd"cTzx  
**FileSplitterFetch.java C(9"59>{]y  
*/ Y]*&\Ex"\  
package NetFox; j /_&]6!  
C0K: ffv;<  
Fg 8lX9L  
import java.io.*; ^Vhl@  
import java.net.*; CPL,QVO9  
&S`g&  
pGfGGY>i%  
public class FileSplitterFetch extends Thread { #?k</~s6M`  
|d z2Drc  
>&Oql9_  
String sURL; //File URL BzzZ.AH~  
long nStartPos; //File Snippet Start Position `a:3S@n(}  
long nEndPos; //File Snippet End Position k$ T  
int nThreadID; //Thread's ID ;X a N  
boolean bDownOver = false; //Downing is over AAs&P+;  
boolean bStop = false; //Stop identical zRa2iCi  
FileAccessI fileAccessI = null; //File Access interface ar\ K8mj  
*7-rm  
@e&0Wk  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }zS5o [OE  
{ H] g=( %ok  
this.sURL = sURL; %.D!J",\/K  
this.nStartPos = nStart; /D1Lh_,2  
this.nEndPos = nEnd;  sa&`CEa  
nThreadID = id; O_ZYm{T[7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 : 8j7}'  
} !Vg=l[  
3z, Ci$[  
K,JK9)T  
public void run() \EU^`o+  
{ Ssuz%*  
while(nStartPos < nEndPos && !bStop) /M::x+/T  
{ w[\rS`J  
w3"L5;oH  
`Oi#`lC\  
try{ AC'_#nPL#  
URL url = new URL(sURL); ^a`3)WBv8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1og+(m`BL  
httpConnection.setRequestProperty("User-Agent","NetFox"); G&Dl($  
String sProperty = "bytes="+nStartPos+"-"; 5 2 Qr  
httpConnection.setRequestProperty("RANGE",sProperty); (hdu+^Qj=  
Utility.log(sProperty); SASLeGaV  
jI0gf&v8  
'e' p`*  
InputStream input = httpConnection.getInputStream(); 7i{(,:  
//logResponseHead(httpConnection); 8!cHRtqK  
'<YBoU{ e*  
Z\Ur F0  
byte[] b = new byte[1024];  T&MhSJf#  
int nRead; me{u~9&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R|'W#"{@  
{ Z~QLjv&$/r  
nStartPos += fileAccessI.write(b,0,nRead); xp'Q>%v  
//if(nThreadID == 1) .4U*.Rf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n}[S  
} ;1PJS_@rX  
j)Ak:l%a  
4bp})>}jB  
Utility.log("Thread " + nThreadID + " is over!"); '2i !RT-  
bDownOver = true; rm9>gKN;#  
//nPos = fileAccessI.write (b,0,nRead); A7%/sMv  
} 'Etq;^H  
catch(Exception e){e.printStackTrace ();} (xN1?qXB.  
} 2_)UHTwsK  
} 9M3"'^ {$  
DpvHIE:W  
d"miPR  
//打印回应的头信息 %7}j|eS)G  
public void logResponseHead(HttpURLConnection con) 9]w?mHslE  
{ NU?<bIQ  
for(int i=1;;i++) p%&$%yz$  
{ knYp"<qj  
String header=con.getHeaderFieldKey(i); 'sH_^{V2  
if(header!=null) S4 Uu/EX6S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Dol{y=(3e  
Utility.log(header+" : "+con.getHeaderField(header)); DBB&6~;?  
else UWqD)6  
break; mICEJ\`x  
} ni%)a  
} d6'G 7'9  
pvUV5^B(M  
jq*`| m;Q  
public void splitterStop() #"rK1Z  
{ ;m#4Q6k)V?  
bStop = true; prN+{N8YC  
} Ikf[K%NKn  
w-# f^#  
L;$>SLl,  
} isd-b]@:Lc  
1w(3!Ps+  
j|wN7@Zc  
/* [8IO0lul+  
**FileAccess.java WEe7\bWF  
*//文件访问(定位,写) 4F G0'J&hw  
package NetFox; o.A:29KoU  
import java.io.*; SU4i'o  
]#^v754X^T  
@WS77d~S  
public class FileAccessI implements Serializable{ CN:T$ f|)  
^ex\S8j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -yc YQ~R  
RandomAccessFile oSavedFile; mc8Q2eQat}  
long nPos; e }?.3,?  
QJ4$) Fr(  
`3i>e<m~  
public FileAccessI() throws IOException <MkvlLu((o  
{ ~Ay)kv;  
this("",0); HrvyI)4{  
} WIf.;B)L  
2{63:f1c`'  
0jlM~H  
public FileAccessI(String sName,long nPos) throws IOException n.2:fk  
{ j\~,Gtn>Z  
oSavedFile = new RandomAccessFile(sName,"rw"); =FhP$r*  
this.nPos = nPos; \8QOZjy  
oSavedFile.seek(nPos); ?l?l<`sTO  
} =3-?$  
{<gv1Yht  
>x;\H(g  
public synchronized int write(byte[] b,int nStart,int nLen) aF^N  Ye  
{ 94ruQ/  
int n = -1; k Alx m{  
try{ }rfikm  
oSavedFile.write(b,nStart,nLen); "Mj#P9  
n = nLen; Ge-Bk)6  
} !Z:XSF[T  
catch(IOException e) ^wd@mWxx  
{ v f{{z%3T  
e.printStackTrace (); ?PMbbqa0  
} +`k30-<P  
[m0X kvd  
3< ?+Yhq  
return n; >bf.T7wy  
} mW%8`$rVEO  
F6[F~^9D  
uW!XzX['  
} MmjZq  
lxL.ztL  
^%9oeT{  
/* vnvpb! @Q  
**SiteInfoBean.java z eT`kZ  
*/ fF0i^E<  
package NetFox; T3z ovnR  
]5f;Kz)  
{V QGfN  
public class SiteInfoBean { f_S$CFa@  
6Bjo9,L  
}OAU5P!rp  
private String sSiteURL; //Site's URL hbx4[Pf  
private String sFilePath; //Saved File's Path Cj8&wz}ez  
private String sFileName; //Saved File's Name `w:kY9  
private int nSplitter; //Count of Splited Downloading File w!20  
49QsT5b)  
F*PhV|XU  
public SiteInfoBean() -/JEKw c  
{//nSplitter的缺省值为5 (^}t  
//default value of nSplitter is 5 !\7`I}:  
this("","","",5); J#Hh4Kc  
} W|>jj$/o  
"frZ%mv  
0AQ4:KV(Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }Kgi!$<aQx  
{ _ f%s]  
sSiteURL= sURL; c]|vg=W  
sFilePath = sPath; n;Oe-+oSC  
sFileName = sName;  lrv-[}}  
this.nSplitter = nSpiltter; 0#J~@1Gf  
1z6aMd6.  
Z\IM~-  
} y 9]d{:9  
h(/? 81:  
CXrOb+  
public String getSSiteURL() eA!Z7 '  
{ .A< HM}   
return sSiteURL; Og7yT{h_  
} AhF@  
/ (BS<A  
]\xt[/?{  
public void setSSiteURL(String value) OCx'cSs-=  
{ ]XEyG7D  
sSiteURL = value; ; CCg]hX  
} FLMiW]?x  
F6q=W#~  
VxN#\D i&  
public String getSFilePath() as:l1S   
{ &}p\&4  
return sFilePath; L }*o8l`  
} 71nZi`AR  
vMp=\U-~^  
v8f3B<kj  
public void setSFilePath(String value) #H~55))F  
{ C|&tdh :g  
sFilePath = value; 2X2Ax~d@  
} F|F0#HC ?  
yQrgOdo,w  
< c^'$  
public String getSFileName() 2.Vrh@FNRo  
{ /+92DV  
return sFileName; Cb+sE"x]  
} XS&Pc  
*U1*/Q.  
(10t,n$  
public void setSFileName(String value) QlGK+I>y;  
{ ,'(|,f42  
sFileName = value; X <xM '  
} %0-oZL  
yf:0u_&]  
u<:uL  
public int getNSplitter() \7LL neq  
{ jv~#'=T'  
return nSplitter; 0BC @wV  
} oYw?kxRZ  
R1LirZlzJ  
y ~  K8  
public void setNSplitter(int nCount) mx}5":}  
{ h~#F2#.  
nSplitter = nCount; \ZcI{t'a  
} >k"O3Pc@  
} SdlO]y9E  
O<s7VHj  
. \a+m  
/* R9A:"sJ  
**Utility.java 2@a'n@-  
*/ KJT N"hF   
package NetFox; DIGw4g4Kt  
6Mc&=}bV  
k5\V:P=#  
public class Utility { t[!,puZc#  
.$-;`&0cZ  
9mD dX  
public Utility() -I5]#%eX^  
{ 9\!&c<i=  
,.P]5 lE  
?/&X _O  
} 8 siP  
[ 6VM4l"  
//线程睡眠 )2).kL>  
public static void sleep(int nSecond) <o()14  
{ X{#^O/  
try{ q,fp DNo  
Thread.sleep(nSecond); _(f@b1O~  
} c(hC'Cp  
catch(Exception e) "T5jz#H#/  
{ qOG@MR(5  
e.printStackTrace (); bsu?Q'q  
} eFs5 l  
} |5;,]lbt  
s>G6/TTH6  
//日志 65zwi-  
public static void log(String sMsg) ^iEf"r  
{ |h $Gs2  
System.err.println(sMsg); *=@8t^fa86  
} DH\Ox>b=  
BMAWjEr  
=Jl\^u%H(x  
public static void log(int sMsg) E~q3o*  
{ 9ls1y=M8J  
System.err.println(sMsg); D7pQWlN\  
} 1<@lM8&.kO  
} 'dwsm7Xd  
xqk(id\&  
1N _"Mm{  
/* !m\By%(  
**TestMethod.java E7h@c>IK  
*/ jR1^e$  
package NetFox; BpA7 z/  
# d"M(nt  
d3EN0e+^  
public class TestMethod { im<!JMI  
<8%+-[(  
?z)2\D  
public TestMethod() q#Otp\f  
{ ///xx/weblogic60b2_win.exe d.ywH;  
try{ VKXi*F9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7]u_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9J%O$sF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J8FzQ2  
fileFetch.start(); ,%m~OB #  
} dT1UYG}>j  
catch(Exception e){e.printStackTrace ();} \l(}8;5}  
miBCq l@x  
G8F;fG N  
} e{2Za   
0F!Uai1  
fc:87ZR{K  
public static void main(String[] args) ;N!n06S3  
{ L9hL@  
new TestMethod(); _j$V[=kdM/  
} X%!?\3S  
} ?>=vKU5  
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