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http断点续传简单实现(java)

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/* +Z7:(o<  
**SiteFileFetch.java ,azBk`$iQr  
*/ ;X;q8J^_K_  
package NetFox; {J~VB~('  
import java.io.*; 0+{CN|0  
import java.net.*; 8.WZC1N  
$ VTk0J-W  
;)Fc@OXN>  
public class SiteFileFetch extends Thread { W @ ?*~  
Fswr @du  
Qo\+FkhYq  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1[:tiTG|C  
long[] nStartPos; //开始位置 &*j# [6  
long[] nEndPos; //结束位置  Q'~3Ik  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  -^ceTzW+  
long nFileLength; //文件长度 +?9. &<?  
boolean bFirst = true; //是否第一次取文件 7 MZ(tOR  
boolean bStop = false; //停止标志 328gTP1  
File tmpFile; //文件下载的临时信息 G0h/]%I  
DataOutputStream output; //输出到文件的输出流 qw<~v?{|C  
qxbGUyH==  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T/$hN hQK  
public SiteFileFetch(SiteInfoBean bean) throws IOException FKWL{"y  
{ 2 Q}^<^r  
siteInfoBean = bean; '5etZ!:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8[rZRc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D}T+X ;u)K  
if(tmpFile.exists ()) It#T\fU  
{ =wquFA!c  
bFirst = false; pq +~|  
read_nPos(); ;&9wG`  
} %X -G(Z  
else FR^(1+lx&  
{ *f-8egt-  
nStartPos = new long[bean.getNSplitter()]; ]k)h<)nY  
nEndPos = new long[bean.getNSplitter()]; v43FU3  
} (|dN6M-.K  
\5DOp-2  
 ovsI2  
K<E|29t^k  
} -'Oq.$Qq  
N$! Vm(S  
z8JdA%YBM  
public void run()  j|owU  
{ \O=t5yS  
//获得文件长度 1X-fiQJe  
//分割文件 @+&QNI06S  
//实例FileSplitterFetch C ^ 1;r9  
//启动FileSplitterFetch线程 <IwfiI3y  
//等待子线程返回  % Z-B{I(  
try{ |5g1D^b]s^  
if(bFirst) o 2_mcJ  
{ +Z/aB*aVa^  
nFileLength = getFileSize(); iM_Zn!|@\  
if(nFileLength == -1) :O9i:Xq[QW  
{ mvXIh";  
System.err.println("File Length is not known!"); 'Ivr =-  
} Yq0jw&v  
else if(nFileLength == -2) $.KD nl^  
{ 4fL/,j/^  
System.err.println("File is not access!"); n-x%<j(Xf  
} 7-j=he/  
else Om5+j:YM  
{ ZIp"X  
for(int i=0;i<nStartPos.length;i++) z;1qYW[-A  
{ 8)V6yKGO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ss'`[QhR2  
} js F96X{  
for(int i=0;i<nEndPos.length-1;i++) &XZS}n  
{ bR}=bp4K  
nEndPos = nStartPos[i+1]; f0ME$:2  
} VQ/Jz5^  
nEndPos[nEndPos.length-1] = nFileLength; LWIPq"  
} `kM:5f+>W  
} dPb@[k  
~9JLqN"  
HOb0\X  
//启动子线程 %y[ t+)!E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ByivV2qd{  
for(int i=0;i<nStartPos.length;i++) ~@ML>z 7  
{ 'eg;)e:`b+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w ;]~2$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2>'/!/+R  
nStartPos,nEndPos,i); p -wEPC0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BkJNu_{m?  
fileSplitterFetch.start(); 0Q5fX}  
} {Ax{N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;To][J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XHYVcwmDz-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 57rH`UFXH  
nEndPos = " + nFileLength); ]}A3Pm- t*  
// fileSplitterFetch[nPos.length-1].start(); ES9|eo6  
'Ej&zh  
TW!>~|U)y  
//等待子线程结束 wJ>2}  
//int count = 0; Hmv@7$9s\  
//是否结束while循环 ~]C m  
boolean breakWhile = false; qV7nF }V{  
H-'~c \)  
@ZtDjxN &  
while(!bStop) #n6<jF1G  
{ ]`u_d}`  
write_nPos(); #9 u2LK  
Utility.sleep(500); !fK9YW(Im  
breakWhile = true; :uQ~?amM  
MtXTh*4  
+@jX|  
for(int i=0;i<nStartPos.length;i++) sY@x(qkIOc  
{ b5Vn_;V*  
if(!fileSplitterFetch.bDownOver) ;6/dFOZn  
{ D>m!R[!o  
breakWhile = false; \Ss6F]K]  
break; i5CBLv  
} f) @-X!  
} ^gd[UC-"w  
if(breakWhile) 2Pic4Z  
break; Mhiz{Td  
~-zch=+u  
V^E.9fs,  
//count++; wC>Xu.Z:  
//if(count>4) HRF;qR9v  
// siteStop(); Hribk[99  
} s2;b-0  
vY'E+M"+@  
qgk6 \&K[  
System.err.println("文件下载结束!"); |n q}#  
} V>:ubl8j0l  
catch(Exception e){e.printStackTrace ();} -Gn0TA2/C  
} mrId`<L5l{  
6ujePi <U  
#P5tTCM  
//获得文件长度 ^E= w3g&  
public long getFileSize() JsyLWv@6xa  
{ (|_N2R!  
int nFileLength = -1; }RN&w ]<  
try{ uwhb-.w  
URL url = new URL(siteInfoBean.getSSiteURL()); :Miri_l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Netnzv%  
httpConnection.setRequestProperty("User-Agent","NetFox"); @-G^Jm9~\m  
.7v .DR>  
PA<<{\dp  
int responseCode=httpConnection.getResponseCode(); zpM%L:S  
if(responseCode>=400) _7Rp.)[&  
{ t182&gpd`  
processErrorCode(responseCode); C3z#A3&J  
return -2; //-2 represent access is error zcE[wM  
} w;4FN'  
\'.#of  
e9@7GaL`"S  
String sHeader; 8nQjD<-  
bj`mQMC  
3gNVnmZG  
for(int i=1;;i++) N;.}g*_+}  
{ i{5,mS&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r'~^BLT`#  
//Utility.log(in.readLine()); Kt\#|-{CH-  
sHeader=httpConnection.getHeaderFieldKey(i); ~.L\f%<  
if(sHeader!=null) WC *e#QP  
{ \g<=n&S?  
if(sHeader.equals("Content-Length")) W*/0[|n*  
{ J8:f9a:|M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xIb^x=|h  
break; zf}X%tp  
} W&Pp5KR  
} ,sln0  
else <Zn -P  
break; Qkq9oZ  
} 568qdD`PS  
} 2c4x=%  
catch(IOException e){e.printStackTrace ();}  mZ^ev;  
catch(Exception e){e.printStackTrace ();} WZ]f \S  
dzn[4  
C=uYX"  
Utility.log(nFileLength); Uth H  
'I8K1Q=/  
\.,qAc\[  
return nFileLength; '&n4W7  
} ^;=L|{Xl  
Ln C5"  
w!N?:}P<N  
//保存下载信息(文件指针位置) F,'rW:{HMt  
private void write_nPos() M9scZuj  
{ ERQc1G]3Dd  
try{ mf\eg`'4?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GfMCHs   
output.writeInt(nStartPos.length); H(WRm1i"G  
for(int i=0;i<nStartPos.length;i++) daakawn+  
{ TE!+G\@  
// output.writeLong(nPos); PGaYYc3X  
output.writeLong(fileSplitterFetch.nStartPos); g7r_jj%ow  
output.writeLong(fileSplitterFetch.nEndPos); : ZWKrnG  
} cTQ]0<9:e  
output.close(); \WN ,.  
} y+g01z  
catch(IOException e){e.printStackTrace ();} QFYO_$1 Y)  
catch(Exception e){e.printStackTrace ();} F#^<t$5t  
} 1YxG<K]  
{} gr\  
"x P2GZ  
//读取保存的下载信息(文件指针位置) wSwDhOX=  
private void read_nPos() YN>k5\M_v  
{ MrGq{,6C  
try{ -=)Al^V4T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @;K-@*k3  
int nCount = input.readInt(); h.ln%6:d  
nStartPos = new long[nCount]; U81--'@y  
nEndPos = new long[nCount]; r(Vz(  
for(int i=0;i<nStartPos.length;i++) m}oqs0xx  
{ GZ@`}7b}  
nStartPos = input.readLong(); A;\1`_i0  
nEndPos = input.readLong(); W-UMX',0zS  
} IVblS iFF  
input.close(); -4IHs=`;I  
} /suW{8A(E  
catch(IOException e){e.printStackTrace ();} 2S^:fm}  
catch(Exception e){e.printStackTrace ();} rrL gBeQa  
} Un[ 0or  
9KgGK cy%  
Gi=s|vt  
private void processErrorCode(int nErrorCode) Jv+N/+M47  
{ yy*8Aw}  
System.err.println("Error Code : " + nErrorCode); jFr[T  
} d%wy@h  
bh&Wy<Y  
fKYR DGn  
//停止文件下载 _b)=ERBbCo  
public void siteStop() O7of9F~"  
{ {#o0vWS>  
bStop = true; RL|d-A+;  
for(int i=0;i<nStartPos.length;i++) do$+ Eh  
fileSplitterFetch.splitterStop(); a?dUJt  
]QbT%0  
fC7rs5  
} 4 [K"e{W3  
} 'Jl |-RUd  
//负责部分文件的抓取 <jwQ&fm)/R  
**FileSplitterFetch.java "7X[@xX@  
*/ {k"t`uo_  
package NetFox; 9>I&Z8J$M  
(O@fgBM  
<Mq vGXI  
import java.io.*; 2^;zj0]Rt  
import java.net.*; DY(pU/q  
h%*@82DKK  
3)6&)7`*  
public class FileSplitterFetch extends Thread { G3wkqd  
}8e_  
9z9\pXFQ  
String sURL; //File URL N R0"yJV>  
long nStartPos; //File Snippet Start Position i] I{7k  
long nEndPos; //File Snippet End Position }gR!]Cs)^  
int nThreadID; //Thread's ID !CGpE=V  
boolean bDownOver = false; //Downing is over `:>N.9'o  
boolean bStop = false; //Stop identical A6Vb'Gqv{  
FileAccessI fileAccessI = null; //File Access interface S8Ec.]T   
9(AY7]6  
`$oy4lDKQ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p`I[3/$3  
{ ^1mnw@04  
this.sURL = sURL; N}\%r&KR=  
this.nStartPos = nStart; 5"WI^"6b:  
this.nEndPos = nEnd; f]C`]qg  
nThreadID = id; @yj$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,%X"Caz  
} LuE0Hb"S8  
9 7Ua,  
qe<xH#6  
public void run() >.o<}!FW  
{ &rbkw<=j  
while(nStartPos < nEndPos && !bStop) %5yP^BL0  
{ ;Zt N9l  
j' }4ZwEh  
4Wk`P]?^  
try{ #9e2+5s  
URL url = new URL(sURL); /:.p{y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r"&uW !~0  
httpConnection.setRequestProperty("User-Agent","NetFox"); b'1m 9T780  
String sProperty = "bytes="+nStartPos+"-"; #6F|}E  
httpConnection.setRequestProperty("RANGE",sProperty); 8c3/n   
Utility.log(sProperty); N# <X"&-_#  
o5;|14O  
O/b1^ Y   
InputStream input = httpConnection.getInputStream(); ?[#4WH-G  
//logResponseHead(httpConnection); Memb`3  
\f-@L;8#  
<Eu/f`8  
byte[] b = new byte[1024]; uGU-MC *  
int nRead; >v'@p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j^)=<+Q;=  
{ %$6?em_  
nStartPos += fileAccessI.write(b,0,nRead); u/.# zn@9h  
//if(nThreadID == 1) +k{l]-)1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ov~vK\  
} "UUoT  
&ev#C%Nu  
CsX@u#  
Utility.log("Thread " + nThreadID + " is over!"); @ QfbIP9  
bDownOver = true; l[Ko>  
//nPos = fileAccessI.write (b,0,nRead); u$rSM0CJ  
} %{B4M#~  
catch(Exception e){e.printStackTrace ();} 1deK}5'  
} [5;_XMj%  
} 5h [<!f=  
/:ju/ ~R}  
f64}#E|w  
//打印回应的头信息 4K0Fc^-  
public void logResponseHead(HttpURLConnection con) ?W\KIp \Kn  
{ <~hx ~"c  
for(int i=1;;i++) _+ERX[i  
{ #}+_Hy  
String header=con.getHeaderFieldKey(i); ?.g="{5X  
if(header!=null) RV>n Op}R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :4x&B^,53  
Utility.log(header+" : "+con.getHeaderField(header)); ow4|GLU^;  
else MUi#3o\f  
break; 9/PX~j9O?  
} 30{+gYA  
} %*^s%NI  
@@5Ju I-!  
xMA2S*%ca  
public void splitterStop() nn8uFISb  
{ gg&Dej2{  
bStop = true; 7e:7RAX  
} IXU~& 5&J  
}+fBJ$  
,T8fo\a4  
} ow7*HN*  
c8oE,-~  
+:3p*x%1H  
/* 6Tg'9|g  
**FileAccess.java 5 J 7XVe>  
*//文件访问(定位,写) BYZllwxwTE  
package NetFox; g+QNIM>  
import java.io.*; J:dNV <A^  
6.M!WK{+  
$%z M Z  
public class FileAccessI implements Serializable{ BWLeitS/  
',s{N9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6)1xjE#  
RandomAccessFile oSavedFile; .#_g.0<  
long nPos; uz@lz +  
4`p[t;q  
vFK!LeF%  
public FileAccessI() throws IOException ]//D d/L6  
{ oRHWb_$"  
this("",0); cHUj6'neO  
} Tl S 904'  
Z9UNp[  0  
eo<=Q|nI&  
public FileAccessI(String sName,long nPos) throws IOException GC)xQZU)s  
{ P`y 0FKS  
oSavedFile = new RandomAccessFile(sName,"rw"); I{7Hz{  
this.nPos = nPos; Bw4PxJs-  
oSavedFile.seek(nPos); vJg^uf)  
} Q@- h  
H1e^/JD)  
k-8$ 43  
public synchronized int write(byte[] b,int nStart,int nLen) WO+_ |*&  
{ 4p]hY!7  
int n = -1; 7Yly^  
try{ /S`d?AV  
oSavedFile.write(b,nStart,nLen); e[%g'}D:-  
n = nLen; Ew2ksZ>B]&  
} J72 YZrc  
catch(IOException e) o%l|16DR  
{ ^w~Utx4  
e.printStackTrace (); ;mXw4_{  
} |\/V1  
!z_VwZ#,  
PHqIfH [  
return n; ^:]~6p#  
} J0yo@O  
i]IZ0.?Y  
bEl)/z*gy/  
} $qk(yzY  
CDGN}Q2_  
u =|A  
/* fMIKA72>{  
**SiteInfoBean.java qW t 9Tr  
*/ BZRC0^-C@  
package NetFox; r&D&xsbQ  
Gu\lV c  
QW6\~l 4  
public class SiteInfoBean { 6Ej@;]^^-  
xyRZ v]K1  
Z{ b($po  
private String sSiteURL; //Site's URL ?iaD;:'qE  
private String sFilePath; //Saved File's Path gf U!sYZ  
private String sFileName; //Saved File's Name 28d=-s=[  
private int nSplitter; //Count of Splited Downloading File 3&7$N#v  
M\jTeB"Z  
Oz7WtN  
public SiteInfoBean() roE*8:Y  
{//nSplitter的缺省值为5 ?o.Q  
//default value of nSplitter is 5 "P {T]  
this("","","",5); Qh@A7N/L  
} Wo~#R   
Dv[ 35[Yh  
\k)(:[^FY  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Zv)x-48  
{ 9|RR;k[  
sSiteURL= sURL; ]BBL=$*  
sFilePath = sPath; "+:~#&r  
sFileName = sName; ,MdK "Qa>  
this.nSplitter = nSpiltter; K(B|o6[  
gv,8Wo  
:,BKB*a\  
} l*z.20^P  
>6"u{Qmr  
q$ 6Tb  
public String getSSiteURL() -P|st;?#  
{ 6zJfsKf$  
return sSiteURL; 8^%Nl `_2B  
} a5# B&|#q  
U> s$}Y:+Z  
[p# }=&d  
public void setSSiteURL(String value) yZ]u{LJS  
{ JJ$q*  
sSiteURL = value; dS m; e_s  
} ULIpb  
'vUx4s  
^z\*; f  
public String getSFilePath() %wuD4PRK  
{ smN |r  
return sFilePath; #DFfySH)A  
} OFe?T\dQn  
`@07n]KB  
o7;#B)jWS  
public void setSFilePath(String value) jsOid5bs  
{ =vZF/r  
sFilePath = value; jjrhl  
} sHQ82uX  
%\2w 1  
26Jb{o9Z<  
public String getSFileName() .y~vn[qN  
{ ;VAHgIpx;  
return sFileName; .#[==  
} uWE :3  
 }L.&@P<  
 *c6o#[l  
public void setSFileName(String value) ).b,KSi  
{ #N'W+M /  
sFileName = value; 1fzHmD  
} l4+Bs!i`  
qoXncdDHZ  
c$ skLz  
public int getNSplitter() n6Qsug$z  
{ fyE#8h_>4  
return nSplitter; X|w[:[P  
} mWPA]g(  
l@OY8z-_  
wfXm(RYM  
public void setNSplitter(int nCount)  nW*D  
{ E'O[E=  
nSplitter = nCount; zZax![Z  
} bYKe5y=  
} n$oHr  
9Oe~e  
q/lQEfR  
/* ?' :v): J}  
**Utility.java awic9 uMH  
*/ jJK`+J,i}X  
package NetFox; Q'B2!9=LB  
%P2l@}?a  
= olmBXn/  
public class Utility { yxx'g+D*  
GF=rGn@,)`  
h vO  
public Utility() lEWF~L5=:  
{ NB|yLkoDyI  
Oe/\@f0bLT  
' M'k$G@Z  
} -FGQn |h4  
n+XLZf#  
//线程睡眠 F?B`rw@xr  
public static void sleep(int nSecond) Qmg2lP.)  
{ ^f%hhpV@  
try{ Sb& $xWL  
Thread.sleep(nSecond); y9xvGr[l  
} >3Mzs AH\  
catch(Exception e) y`|86` Y  
{ ,&5\`  
e.printStackTrace (); R#^.8g)t  
} [PW\l+i  
} %A^V@0K3  
ac%6eW0#  
//日志 7B)m/%>3s  
public static void log(String sMsg) 1z5Oi u  
{ ;#Y'SK  
System.err.println(sMsg); ?;0w1  
} dz>2/'  
D,l&^diz  
QK`5KB(k'  
public static void log(int sMsg) nR(v~_y[V  
{ EIrAq!CA  
System.err.println(sMsg); ~Bi>T15e  
} S[ln||{  
} 1XpG7  
nUy.gAb  
o#~Lb9`@U  
/* fR$_=WWN>h  
**TestMethod.java ' %&gER  
*/ js..k*j  
package NetFox; ^P}jn`4  
d^(7\lw|  
`i:DmIoz  
public class TestMethod { @?vC4+'  
PptVneujI  
@$aGVEcU$  
public TestMethod() LGdM40  
{ ///xx/weblogic60b2_win.exe 9Gc4mwu  
try{ X;&Iu{&=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |Fi{]9(G2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =f/CBYNw@V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0;Oe&Y  
fileFetch.start(); yCvP-?2  
} srCpgs]h  
catch(Exception e){e.printStackTrace ();} 77b^d9! ~  
xMs!FMn[  
b$;qtfJG  
} _@5|r|P>  
vk0b b3){D  
|ns B'Q  
public static void main(String[] args) ,` 64t'g  
{ tP][o494\&  
new TestMethod(); B%^W$7 q  
} bt{b%r  
} Ls` [7w  
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