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http断点续传简单实现(java)

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/* u_8Z^T  
**SiteFileFetch.java tbfwgK  
*/ Gq%,'am f  
package NetFox; PIoBKCJ  
import java.io.*; 8.7lc2aX  
import java.net.*; }KNBqPo4B  
2p58_^l  
m,}GP^<1i  
public class SiteFileFetch extends Thread { pTncx%!W5  
b?, =|H  
QR<<O  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3BF3$_u)o  
long[] nStartPos; //开始位置 $ERiBALN:  
long[] nEndPos; //结束位置 Wd ga(8t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I%B\Wy/j^  
long nFileLength; //文件长度 dOKe}?}==  
boolean bFirst = true; //是否第一次取文件 mHH>qW{`  
boolean bStop = false; //停止标志 Lzcea+*uw  
File tmpFile; //文件下载的临时信息 VtGZB3  
DataOutputStream output; //输出到文件的输出流 wLvM<p7OX  
M~+DxnJ=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) hZ "Sqm]  
public SiteFileFetch(SiteInfoBean bean) throws IOException !;${2Q  
{ fP$rOJ)P  
siteInfoBean = bean; 1 (e64w@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Oq)7XL4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PSyUC#;  
if(tmpFile.exists ()) #%V+- b(  
{ k]2_vk^  
bFirst = false; 10bv%ZX7  
read_nPos(); *u< ZQq  
} *55unc  
else /a6i`  
{ <|w(Sn  
nStartPos = new long[bean.getNSplitter()]; Nx E=^ v  
nEndPos = new long[bean.getNSplitter()]; Q^* 3 3  
} >gz8,&  
Dt iM}=:  
|t~>Xs  
Tk `|{Ph0  
} _6g(C_m'T?  
?I\,RiZkz^  
Lg|d[*;'7  
public void run() $R:Q R?   
{ m1xR uj]  
//获得文件长度 T8yMaC  
//分割文件 QV4FA&f&  
//实例FileSplitterFetch M|{NC`fa  
//启动FileSplitterFetch线程 ) t CNp  
//等待子线程返回 :H+8E5  
try{ oArJ%Y>  
if(bFirst) )lq+Gv[%F  
{ w"? RbA  
nFileLength = getFileSize(); & x_ #zN]  
if(nFileLength == -1) tf[)| /M  
{ G&"O)$h  
System.err.println("File Length is not known!"); {faIyKtW  
} &:1q3 gDm  
else if(nFileLength == -2) +d(|Jid  
{ S0}=uL#dt  
System.err.println("File is not access!"); 15r=d  
} ? PpS4Rd  
else II Amx[ b  
{ ;uzLa%JQ  
for(int i=0;i<nStartPos.length;i++) \k^ojzJ  
{ Wrh$`JC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [+!&iN  
} qB&Je$_uh  
for(int i=0;i<nEndPos.length-1;i++) |.L_c"Bc  
{ !Lw]aHb  
nEndPos = nStartPos[i+1]; @PctBS<s  
} d`~~Ww1  
nEndPos[nEndPos.length-1] = nFileLength; Iga#,k+%  
} nd7g8P9p  
} M>}_2G]#F  
PC|ul{[*}  
D3%2O`9  
//启动子线程 M |f V7g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1vtC4`  
for(int i=0;i<nStartPos.length;i++) \O\q1 s~  
{ n9n)eI)R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EdkIT|c{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }r!hm?e  
nStartPos,nEndPos,i); Ps{vN ~}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ={+8jQqi1  
fileSplitterFetch.start(); kX8NRPW  
} F\|4zM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E+#<WK-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ivyaGAF}+o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T[#q0bv  
nEndPos = " + nFileLength); R<(xWH  
// fileSplitterFetch[nPos.length-1].start(); To5hVL<Ex"  
H Ix%c5^  
;BYuNQr  
//等待子线程结束 ]5Dh<QY&.  
//int count = 0; qZ&~&f|>e  
//是否结束while循环 aB?usVoS  
boolean breakWhile = false; egURRC!  
+jyGRSo  
:7mHPe }(  
while(!bStop) a^pbBDi W  
{ .Y"F3 R  
write_nPos(); 'W yWO^Bdk  
Utility.sleep(500); N5h9){Mx  
breakWhile = true; :O$bsw:3w<  
H-U_  
&i.sSqSI5  
for(int i=0;i<nStartPos.length;i++) x!\q69ndv  
{ nosD1sS.K8  
if(!fileSplitterFetch.bDownOver) zsJermF,O  
{ j49Uj}:j  
breakWhile = false; M +r!63T  
break; $Ery&rX.  
} 7B (%2  
} g\ vT7x  
if(breakWhile) 9 fYNSr  
break; l $"hhI8  
lg~7[=%k#  
=I)43ah d  
//count++; 2wHbhW[  
//if(count>4) +E_yEH7_)  
// siteStop(); ne/JC(  
} XW" 0:}`J  
vIbM@Y4 '?  
kuV7nsXiQ  
System.err.println("文件下载结束!"); 2R.L LE  
} oSC'b%  
catch(Exception e){e.printStackTrace ();} Mjy:k|aY"  
} OmO#} k<  
I4{xQI  
HOF$(86zqA  
//获得文件长度 wz*iwd-  
public long getFileSize() d6YXITL)\>  
{ Qop,~yK  
int nFileLength = -1; ,7]hjf_h  
try{ qul#)HI  
URL url = new URL(siteInfoBean.getSSiteURL()); "+- 'o+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <ak[`]  
httpConnection.setRequestProperty("User-Agent","NetFox"); YAOfuas]j  
L ,dh$F  
Y(.e e%;,  
int responseCode=httpConnection.getResponseCode(); : ~vodh  
if(responseCode>=400) Y \-W`  
{ ehr-o7](  
processErrorCode(responseCode); 6FA+q YSV  
return -2; //-2 represent access is error 'Oue 1[  
} zVq!M-e  
?K>)bA&l'  
30! DraW8  
String sHeader; yx :^*/  
-AdDPWn  
}kqh[`:  
for(int i=1;;i++) ,X4+i8Yc  
{ W2 -%/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); oS fr5 i  
//Utility.log(in.readLine()); (Xh <F  
sHeader=httpConnection.getHeaderFieldKey(i); g Ed A hfx  
if(sHeader!=null) $nO~A7  
{  $3^M-w  
if(sHeader.equals("Content-Length")) Q[biy{(b8  
{ XB7Aa)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CUu Owx6%  
break; &zdS9e-fF  
} 1;ttwF>G7  
} H5}61JC/z  
else ca g5w~Px  
break; Zv;nY7B  
} ]F4QZV( M  
} /iU<\+ H  
catch(IOException e){e.printStackTrace ();} .SD-6GVD  
catch(Exception e){e.printStackTrace ();} z1mB Hz6  
o5o myMN  
Vp/XVyL}R  
Utility.log(nFileLength); >Ku4Il+36  
vB8$Qx\J  
K81X32Lm'  
return nFileLength; -V/y~/]J  
} L|CdTRgRCB  
<=M5)#  
I%YwG3uR  
//保存下载信息(文件指针位置) 1<r!9x9G  
private void write_nPos() 5whW>T  
{ |>;PV4])(  
try{ 8z`ZHn3=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ieZ$@3#&z  
output.writeInt(nStartPos.length); 0= $/  
for(int i=0;i<nStartPos.length;i++) ):$KM{X  
{ .-Lrrk)R+  
// output.writeLong(nPos); "ko*-FrQ  
output.writeLong(fileSplitterFetch.nStartPos); \l GD8@,x  
output.writeLong(fileSplitterFetch.nEndPos); zZCl]cql  
} x%viCkq  
output.close(); jY=y<R_oK  
} m!FuC=e  
catch(IOException e){e.printStackTrace ();} rN}pi@  
catch(Exception e){e.printStackTrace ();} MQoA\  
} /vSGmW-*  
&-=~8  
>(RkoExO/  
//读取保存的下载信息(文件指针位置) ojM'8z 0Hn  
private void read_nPos() EO!,rB7I  
{ W.j^L;  
try{ }yT/UlU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cW%)C.M  
int nCount = input.readInt(); 6Z_V,LD9L  
nStartPos = new long[nCount]; L$PbC!1  
nEndPos = new long[nCount]; PuN L%D  
for(int i=0;i<nStartPos.length;i++) $s7U |F,I  
{ syX?O'xJ  
nStartPos = input.readLong(); v9f+ {Y%-  
nEndPos = input.readLong(); s5*4<VxQN.  
} )g@+ MR  
input.close(); Ey=2 zo^F  
} y0xBNhev  
catch(IOException e){e.printStackTrace ();} =Y2 Rht  
catch(Exception e){e.printStackTrace ();} }097[-g7  
} IWv(G Qx  
cEL:5*cAU}  
$Tbsre\MJ  
private void processErrorCode(int nErrorCode) ._rPM>B?  
{ BE0l2[i?  
System.err.println("Error Code : " + nErrorCode); yJ?=##  
} h .Qk{v  
w9|x{B  
|+Wn5iT  
//停止文件下载 Q:P)g#suc  
public void siteStop() (_pw\zk>  
{ c6:uM1V{  
bStop = true; n-9xfn0U~#  
for(int i=0;i<nStartPos.length;i++) r?DCR\Jq  
fileSplitterFetch.splitterStop(); m"!SyN}&9?  
O\<zQ2m  
y.Z_\@  
} Q/|.=:~FO  
} @rGY9%E  
//负责部分文件的抓取 i]MemM-  
**FileSplitterFetch.java mu\1hKq;B  
*/ daSe0:daJ  
package NetFox; ,b5'<3\  
\c\~k0u  
&PJ;B)b  
import java.io.*; KS*,'hvY  
import java.net.*; W`x.qumN  
GFFwk4n1  
}ktIG|GC  
public class FileSplitterFetch extends Thread { D9+qT<ojN  
Hhtl~2t!0  
y,:WLk~  
String sURL; //File URL |Ahf 01  
long nStartPos; //File Snippet Start Position 1{N+B#*<[X  
long nEndPos; //File Snippet End Position v? ."`,e  
int nThreadID; //Thread's ID 0d+n[Go+S  
boolean bDownOver = false; //Downing is over ChK-L6  
boolean bStop = false; //Stop identical xN*k&!1&  
FileAccessI fileAccessI = null; //File Access interface eWFkUjz  
J$6WUz:?  
Rrh6-]A  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eKOEOm+  
{ +c% jOl  
this.sURL = sURL; nT?+^Ruc  
this.nStartPos = nStart; @aQ:3/  
this.nEndPos = nEnd; 9\EW~OgTu  
nThreadID = id; vb^fx$V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iZG-ca  
} !L.R"8!  
|tAkv  
kTH"" h{  
public void run() _&]7  
{ n#6{K6}k~  
while(nStartPos < nEndPos && !bStop) &pY '  
{ t]SB .ja  
^N^G?{EV/#  
W(]A^C=/  
try{ I/w;4!+)  
URL url = new URL(sURL); {ENd]@N*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8=$XhC  
httpConnection.setRequestProperty("User-Agent","NetFox"); +(= -95qZ  
String sProperty = "bytes="+nStartPos+"-"; <( OHX3~  
httpConnection.setRequestProperty("RANGE",sProperty); =6U5^+|d  
Utility.log(sProperty); CzG[S\{+  
^ ##j {h7  
/Pe xtj<  
InputStream input = httpConnection.getInputStream(); * sldv  
//logResponseHead(httpConnection); $,K@xq5  
oz=V|7,  
ho$}#o  
byte[] b = new byte[1024]; A5j? Yts  
int nRead; EmaS/]X[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LilK6K  
{ +ZbNSN=  
nStartPos += fileAccessI.write(b,0,nRead); bVz<8b6h'-  
//if(nThreadID == 1) JOG- i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2->Lz  
} )Wle CS_  
]A}ZaXd  
D SX%SE)  
Utility.log("Thread " + nThreadID + " is over!"); NxF:s,a6  
bDownOver = true; lD0a<L 3  
//nPos = fileAccessI.write (b,0,nRead); x%s1)\^A  
} 7>z {2D  
catch(Exception e){e.printStackTrace ();} WyOav6/*K^  
} OCu_v%G 0  
} ,Z @I" &H  
rrz([2E2  
Lxv;[2XsW)  
//打印回应的头信息 C)c*s C5N  
public void logResponseHead(HttpURLConnection con) oUn+tu:  
{ a& 0g0n6  
for(int i=1;;i++) 8x- 19#  
{ 3Qd/X&P  
String header=con.getHeaderFieldKey(i); qqo#H O  
if(header!=null) p@O Ip  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QDW,e]A  
Utility.log(header+" : "+con.getHeaderField(header)); }'tJc $!  
else k9oi8G'g~  
break; c*B< - l<5  
} Y=|p}>.}  
} V|@bITJ?7  
*lA+ -gkK*  
D N)o|p  
public void splitterStop() C-S>'\ |8  
{ |pS]zD  
bStop = true; EpO2%|@  
} m8PS84."]M  
N$Ad9W?T  
=PY{Elf  
} UUDHknm"  
. s>@@m-  
1OExa<Zq  
/* 5qH*"i+|s  
**FileAccess.java Z[w}PN,xV  
*//文件访问(定位,写) ?7V~>i8[  
package NetFox; l!XCYg@67  
import java.io.*; )EB+(c~E  
)bih>>H  
/0qbRk i  
public class FileAccessI implements Serializable{ B<L7`xL  
niCK(&z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +kd1q  
RandomAccessFile oSavedFile; O'IU1sU  
long nPos; ms5?^kS2O  
[u!n=ev  
zMA;1Na  
public FileAccessI() throws IOException \~A qA!)6  
{ n"RV!{&  
this("",0); g(tVghHxt$  
} 8Yk*$RR9  
17?YN<  
.Ja].hP  
public FileAccessI(String sName,long nPos) throws IOException ^wWbW&<Tg  
{ ;6``t+]q   
oSavedFile = new RandomAccessFile(sName,"rw"); 1|4,jm$  
this.nPos = nPos; 8cOft ;|qB  
oSavedFile.seek(nPos); 'I/_vqp@  
} DFWO5Y_  
%gO/mj3*  
2kDY+AN;  
public synchronized int write(byte[] b,int nStart,int nLen) 04dz ?`HuB  
{ -O\i^?lD;  
int n = -1; =3(Auchl$Y  
try{ #at`7#K@  
oSavedFile.write(b,nStart,nLen); tgG*k$8z  
n = nLen; R`c[ ?U  
} {rR(K"M  
catch(IOException e) :Q"|%#P  
{ Gqd|F>  
e.printStackTrace (); V($V8P/  
}  "&k(lQ4  
Dj96t5R  
<$e|'}>A  
return n; exhU!p8  
} .+u b\  
T#-;>@a}  
h*l$!nEN  
} SdYf^@%}F  
` 'Qb?F6  
[ -$ Do  
/* ?'P}ZC8P  
**SiteInfoBean.java .c-a$39  
*/ dW4jkjap  
package NetFox; ;9k>; g3m  
HCN/|z1Xq  
T3P9  
public class SiteInfoBean { #_35bg4h{  
JnsJ]_<  
RJ3oI+gI  
private String sSiteURL; //Site's URL '3672wF/  
private String sFilePath; //Saved File's Path 4`#Q  
private String sFileName; //Saved File's Name 2g{tzR_j  
private int nSplitter; //Count of Splited Downloading File x>[]Qk^?q  
W\kli';jyC  
^MvuFA ,C  
public SiteInfoBean() EpAgKzVpJ  
{//nSplitter的缺省值为5 h) Wp  
//default value of nSplitter is 5 ^-Od*DTL  
this("","","",5); hU#e\L 7  
} \A[l(aB  
TsTc3  
}'x;J   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 06pvI}   
{ O6;"cUv  
sSiteURL= sURL; Tsg9,/vXM  
sFilePath = sPath; (P)G|2=  
sFileName = sName; q ;'f3Y  
this.nSplitter = nSpiltter; 5^Qa8yA>7  
YqX$a~  
nzflUR{`-  
} O{LCHtN  
'{d@Gc6.  
92DM1~ *  
public String getSSiteURL() dgw.OXa  
{ R_PF*q2 '  
return sSiteURL; 9wWBE<}>u  
} ]1!" q40)]  
q7X]kr*qx  
aas.-N T  
public void setSSiteURL(String value) y"JR kJ  
{ Uq  .6h  
sSiteURL = value; [r/zBF-.  
} WkTJ M  
|H5.2P&9-5  
Z4] n<~o  
public String getSFilePath() 2zTi/&K&  
{ @[n#-!i  
return sFilePath; kTvM,<  
} ,'X"(tpu@  
X NJ4T]><  
s\ -,RQ1  
public void setSFilePath(String value) jo`ZuN{  
{ g":[rXvId  
sFilePath = value; c$g@3gL  
} tq3_az ~1  
sl]< A[jR  
Zl9@E;|=  
public String getSFileName() WTvUz.Et  
{ -R`{]7V  
return sFileName; "D(Lp*3hj&  
} {D +mr[ %  
|mb2<!ag{  
>@YefNX6  
public void setSFileName(String value) A lU^ ,X  
{ {7NGfzwp;6  
sFileName = value; A6&*VD  
} `AJ[g>py^|  
<L &EH@T  
:L[>!~YG_n  
public int getNSplitter() #oUNF0L@6  
{ ;P@]7vkff  
return nSplitter; /).{h'^Hq\  
} xnP!P2  
J +6zV m  
~3&{`9Y  
public void setNSplitter(int nCount) rpR${%jc  
{ z|l*5@p  
nSplitter = nCount; P?54"$b  
} '%NglC[J  
} E[H  
G=zWhqieh  
u^80NR  
/* FfoOJzf~o  
**Utility.java ]\$/:f-2  
*/ OmYVJt_  
package NetFox; wKV4-uyr  
"W|A^@r}  
($[wCHU`!  
public class Utility { HgI!q<)  
4fEDg{T  
g)D_  !iz  
public Utility() )9QtnM  
{ UX 1 )((  
c'2d+*[  
1yy?1&88S  
} kB\{1;  
jc} G+|`  
//线程睡眠 &d#R'Z  
public static void sleep(int nSecond) VtreOJ+  
{ A'WR!*Yt  
try{ 7e/+C{3v  
Thread.sleep(nSecond); sDY~jP[Oa  
} G0cG%sIl  
catch(Exception e) -N *L1Zj  
{ cr7MvXF-  
e.printStackTrace (); /7Q|D sa  
} 5j%G7.S\  
} |{jT+  
!3ggQG!e  
//日志 $o^Z$VmL  
public static void log(String sMsg) k9|5TLXq?  
{ /?\3%<vn  
System.err.println(sMsg); P&-o>mM  
} bS.w<V Ew  
+n3I\7G>  
p{FI_6db  
public static void log(int sMsg) v9$!v^U"D  
{ B@,9Cx564  
System.err.println(sMsg); [,%=\%5  
} S}m_XR]  
} ?GhyVXS y.  
FhE{khc#  
G)3I+uxn  
/* 'j1e(wq  
**TestMethod.java >4 OXG7.&f  
*/ O 4 !$  
package NetFox; {K(mfTqm  
a"8[,A3  
9g92eKS  
public class TestMethod { |(7}0]BP0  
6CJMQi,kn  
v gN!9  
public TestMethod() %+7]/_JO&  
{ ///xx/weblogic60b2_win.exe 0p.bmQSH  
try{ _IH" SVub  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c:[k+_Zr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t [QD#;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?KT{H( rU  
fileFetch.start(); 3v* ~CQy9  
} }d$-:l ,w  
catch(Exception e){e.printStackTrace ();} "S#F I  
Vej$|nF  
:<% bAn  
} Iv`IJQH>  
zF&VzNR2  
*Cy54Z#  
public static void main(String[] args) S0$^|/Sr  
{ 6&3,fSP  
new TestMethod(); HL)!p8UHJ  
} jX53 owZ  
} kmB!NxF>)F  
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