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http断点续传简单实现(java)

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/* |[)t4A"}  
**SiteFileFetch.java `_N8A A  
*/ c5+oP j  
package NetFox; v[q2OWcL  
import java.io.*; hHm &u^xY  
import java.net.*; \f}S Hh  
.DMeW i  
}5z6b>EI9a  
public class SiteFileFetch extends Thread { /QZnN?k  
4L85~l  
bN`oQ.Z 4  
SiteInfoBean siteInfoBean = null; //文件信息Bean :_~UO^*h  
long[] nStartPos; //开始位置 . p^='Kz?  
long[] nEndPos; //结束位置 (wdE@/V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L=O,OS+  
long nFileLength; //文件长度 (`5No:?v<  
boolean bFirst = true; //是否第一次取文件 lbZ,?wm  
boolean bStop = false; //停止标志  ?}e8g  
File tmpFile; //文件下载的临时信息 UeIu -[R  
DataOutputStream output; //输出到文件的输出流 2asA]sY  
bae .?+0[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) dQVV0)z  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZSuUmCm  
{ E{[c8l2B  
siteInfoBean = bean; QXY-?0RO#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (YVl5}V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QZ$94XLI  
if(tmpFile.exists ()) qAUqlSP5  
{ 1&\_|2  
bFirst = false; 7Vr .&`l  
read_nPos(); &PI}o  
} {+r pMUs#  
else ^W5rL@h_  
{ yH#zyO4fD-  
nStartPos = new long[bean.getNSplitter()]; i[`nu#n/  
nEndPos = new long[bean.getNSplitter()]; b#(SDNo6  
} g dT3,8`#[  
C '4u+raq  
.;ml[DXH  
"#z4  
} Dq/[ g,(  
S}gUz9ks  
%H75u 6  
public void run() RXh0hD  
{ $)\%i=  
//获得文件长度 \j !JRD+j  
//分割文件 5gARGA  
//实例FileSplitterFetch QMea2q|3$  
//启动FileSplitterFetch线程 5Al 59]  
//等待子线程返回 m8,P-m  
try{ zYO+;;*@  
if(bFirst) W Y_}D!O  
{ _m;0%]+  
nFileLength = getFileSize(); pXL_`=3Q  
if(nFileLength == -1) 1fM= >Z  
{ IE.JIi^w  
System.err.println("File Length is not known!"); ks< gSCB  
} 5|f[evQj<S  
else if(nFileLength == -2) -U)6o"O_CV  
{ `=Pn{JaD  
System.err.println("File is not access!"); } R!-*Wk  
} hAi50q;z  
else (2(I|O#  
{ zk=5uKcPE  
for(int i=0;i<nStartPos.length;i++) ]^$&Ejpe#  
{ !31v@v:)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ke_Dd?  
} dy N`9  
for(int i=0;i<nEndPos.length-1;i++) 3ddH@Y|  
{ Zm& X $U  
nEndPos = nStartPos[i+1]; li;Np5P  
} GV#"2{t j  
nEndPos[nEndPos.length-1] = nFileLength; (.4mX t  
} W4Rs9NA}  
} :"7V,UP @  
T5?@'b8F6  
SjV;& 1Z/  
//启动子线程 fC+<n{"C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'hfQ4EN  
for(int i=0;i<nStartPos.length;i++) hd1(q33  
{ x~C%Hp*#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sx?IpcPSm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^+tAgK2   
nStartPos,nEndPos,i); L^uO.eI"m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cp=DdmR  
fileSplitterFetch.start(); -:b0fKn  
} hZf0q 2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lg FA}p@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W- 5Z"m1I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'AU(WHf  
nEndPos = " + nFileLength); p9rnhqH6  
// fileSplitterFetch[nPos.length-1].start(); ce-5XqzY@  
`K37&b;`[  
8gWifx #N  
//等待子线程结束 XoEiW R  
//int count = 0; hi4#8W  
//是否结束while循环 l\< *9m<  
boolean breakWhile = false; 6=A   
D_er(  
1uBnU2E  
while(!bStop) m[7@l  
{ 89ivyv;]U  
write_nPos(); qE?*:$  
Utility.sleep(500); vpu20?E>5z  
breakWhile = true; `7$0H]*6  
5/4N  Y  
l2Z!;Wm(  
for(int i=0;i<nStartPos.length;i++) ^x(BZolkm  
{ &6 .r=,BO  
if(!fileSplitterFetch.bDownOver) e<o{3*%p)  
{ tmEF7e`(o  
breakWhile = false; YLs%u=e($  
break; S_?{ <{  
} |35"V3bs  
} @9S3u#vP  
if(breakWhile) 'jh9n7mH  
break; .: gZ*ks~  
GBnf]A,^ @  
8U}BSM_<2  
//count++; @vzv9c[  
//if(count>4) +Y;/10p  
// siteStop(); pIcvsd  
} trD-qi  
*b#00)d  
j"g[qF/*  
System.err.println("文件下载结束!"); 2MS-e}mi  
} Q'-g+aN  
catch(Exception e){e.printStackTrace ();} 9w\ yWxl  
} i2$7nSQ9  
cb|cYCo5  
qy@v, a  
//获得文件长度 .3Ex=aQcX  
public long getFileSize() kB~KC-&O  
{ ig G8L  
int nFileLength = -1; `-Yo$b;:  
try{ G&ZpQ)  
URL url = new URL(siteInfoBean.getSSiteURL()); ]M2<b:yo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6,Aj5jG  
httpConnection.setRequestProperty("User-Agent","NetFox"); #a7 Wx}  
4rX jso|  
j;%RV)e  
int responseCode=httpConnection.getResponseCode(); E(t:F^z&D  
if(responseCode>=400) "h.-qQGU%  
{ bWp40&vx  
processErrorCode(responseCode); E1'| ;}/  
return -2; //-2 represent access is error }M_Yn0(3  
} {zGM[A  
N0U6N< w  
^)-* Ubzz  
String sHeader; s^O>PEX&<I  
.4I "[$?Q  
M? 7CBqZ  
for(int i=1;;i++) ]*fiLYe9  
{ +[W_J z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @C\>P49  
//Utility.log(in.readLine()); UC@ &! kM  
sHeader=httpConnection.getHeaderFieldKey(i); <\0+*`">g  
if(sHeader!=null) H~fX >6>  
{ i;+]Y   
if(sHeader.equals("Content-Length")) wXj!bh8\r  
{ E]Wnl\Be  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AfQ?jKk&{'  
break; ChVur{jR  
} %M? A>7b  
} e-@=QI^,  
else &RSUB;y mL  
break; s]=bg+v?j  
} Nd b_|  
} ,gdf7&r  
catch(IOException e){e.printStackTrace ();}  D I` M  
catch(Exception e){e.printStackTrace ();} :Ng4? +@r  
KDt@Xi 6||  
drv"I[}{A  
Utility.log(nFileLength); IiX`l6L~W  
ZH@BHg|}H  
gOk<pRcTb=  
return nFileLength; A4kYE A  
} g 0=Q>TzY  
HTpoYxn(  
RU r0K#]  
//保存下载信息(文件指针位置) jg,oGtRz  
private void write_nPos() cwe@W PE2  
{ f;Cu@z{b  
try{ ^N{Lau  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T(n<@Ac]V  
output.writeInt(nStartPos.length); WKHEU)'!  
for(int i=0;i<nStartPos.length;i++) ,{KjVv<  
{ NZj_7j|o9  
// output.writeLong(nPos); rSGt`#E-s.  
output.writeLong(fileSplitterFetch.nStartPos); a.oZ}R7'Y  
output.writeLong(fileSplitterFetch.nEndPos); DA0{s  
} {e>E4(  
output.close(); FN-j@  
} WJB/X"J  
catch(IOException e){e.printStackTrace ();} 8ec6J*b  
catch(Exception e){e.printStackTrace ();} ZO^Y9\L  
} %`o3YR  
C>1fL6ct  
M*& tVG   
//读取保存的下载信息(文件指针位置) X={n9*Sd8  
private void read_nPos() kX\\t.nH  
{ !W^b:qjJ  
try{ |~6X: M61  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z / YF7wrx  
int nCount = input.readInt(); =z=$S]qN  
nStartPos = new long[nCount]; }w,^]fC:  
nEndPos = new long[nCount]; w Ud6xR  
for(int i=0;i<nStartPos.length;i++) !jV}sp<Xp  
{ R0 g-  
nStartPos = input.readLong(); jK#[r[q{  
nEndPos = input.readLong(); `L-GI{EJ  
} wEMh !jAbv  
input.close(); p@/i e@DX  
} }s0?RH  
catch(IOException e){e.printStackTrace ();} ` 0YI?$G1  
catch(Exception e){e.printStackTrace ();} jz\LI  
} ~"oxytJ  
L_3undy,  
~|LlT^C  
private void processErrorCode(int nErrorCode) 5<?O S &B  
{ aNqhxvwf  
System.err.println("Error Code : " + nErrorCode); Z#n!=k TTm  
} **zh>Y}6  
qk Cj33v  
tkN5 |95  
//停止文件下载 [Rqv49n*V  
public void siteStop() r%*UU4xvB  
{ `M "O #  
bStop = true; sj)$o94=  
for(int i=0;i<nStartPos.length;i++) rv(Qz|K@  
fileSplitterFetch.splitterStop(); ^,Paih 2  
JN9 W:X.  
&&N]u e@>  
} xB1Oh+@i  
} l7{Xy_66  
//负责部分文件的抓取 sC8C><y  
**FileSplitterFetch.java 9~6FWBt  
*/ IX!Q X  
package NetFox; G8m:]!  
"Qf X&'09  
CJ*8x7-t  
import java.io.*; g\ r%A  
import java.net.*; 7$ vs X  
g]^@bxdg  
:iWW2fY  
public class FileSplitterFetch extends Thread { &E0d{ 2  
b' 1%g}  
$wL zaZL|  
String sURL; //File URL 2}Ga   
long nStartPos; //File Snippet Start Position }O_kbPNw  
long nEndPos; //File Snippet End Position [P5+}@t  
int nThreadID; //Thread's ID h J*2q"  
boolean bDownOver = false; //Downing is over by 'P}  
boolean bStop = false; //Stop identical 0n5{Wr$  
FileAccessI fileAccessI = null; //File Access interface J{W<6AK\S  
MP5 vc5[  
dQD YN_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p 8,wr )  
{ ~x:\xQti  
this.sURL = sURL; .>4Zt'gCt  
this.nStartPos = nStart; [If%+mHdU  
this.nEndPos = nEnd; Z`L-UQJ .  
nThreadID = id; gq[|>Rs75  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D6cqON0a.  
} clE_a?  
)bJS*#  
jH+ddBVA  
public void run() 2g>4fZ  
{ G}!dm0s$  
while(nStartPos < nEndPos && !bStop) V)[ta`9  
{ ,(h:0L2v7d  
J2rw4L  
y|sU-O2}Dl  
try{ ~RlsgtX"  
URL url = new URL(sURL); }.j<kmd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A 9 I5  
httpConnection.setRequestProperty("User-Agent","NetFox"); CC Z'(Tkq  
String sProperty = "bytes="+nStartPos+"-"; B=E<</i  
httpConnection.setRequestProperty("RANGE",sProperty); (o+(YV^  
Utility.log(sProperty); L>4!@L5)  
S;pKL,d>r  
^[]q/v'3m!  
InputStream input = httpConnection.getInputStream(); 1}O&q6\"J  
//logResponseHead(httpConnection); ${(c `X  
 y5"b(nb  
2vb{PQ  
byte[] b = new byte[1024]; \Y37wy4  
int nRead; Dt)O60X3>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) An cka  
{ *{_WM}G  
nStartPos += fileAccessI.write(b,0,nRead); 7w}PYp1Z'~  
//if(nThreadID == 1) 0A]+9@W;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BKd03s=  
} WA~PE` U  
Z/ Vb_  
fdU`+[_  
Utility.log("Thread " + nThreadID + " is over!"); Y~FN` =O  
bDownOver = true; I.C,y\  
//nPos = fileAccessI.write (b,0,nRead); mmN!=mf*  
} n'WhCrW  
catch(Exception e){e.printStackTrace ();} U|[+M@F_L  
} xN^ngRg0  
} `5J`<BPs  
l"T{!Oq  
p#k>BHgnF  
//打印回应的头信息 )GbVgYkk  
public void logResponseHead(HttpURLConnection con) UW!*=?h  
{ Ub>Pl,~'  
for(int i=1;;i++) fga{ b7  
{ Cf~H9  
String header=con.getHeaderFieldKey(i); bcVzl]9  
if(header!=null) oRp;9   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Cob<N'.  
Utility.log(header+" : "+con.getHeaderField(header)); 5V"Fy&}:  
else `W& :*  
break; P#gY-k&Nr  
} c8R#=^ DD  
} EWU(Al T  
&Fw8V=Pw  
Or({|S9d2  
public void splitterStop() Cp`>dtCd  
{ W*S !}ZT`  
bStop = true; :J 7p=sX  
} zi7>!#(  
>Rnj6A|Q  
q?9x0L  
} R)[ l 3  
|FR'?y1  
$y2"Q,n+  
/* JGLjx"Y  
**FileAccess.java (Lp$EC&%6  
*//文件访问(定位,写) h 2Kx  
package NetFox; P7X':  
import java.io.*; {6/Yu: ;  
 q#=}T~4j  
! u4'1jd[d  
public class FileAccessI implements Serializable{ W5&;PkhQ6  
CO)BF%?B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /d1 B-I  
RandomAccessFile oSavedFile; CyWaXp65  
long nPos; ljS~>&  
/q3]AVV  
t V]BcDp  
public FileAccessI() throws IOException _&]B  
{ nMBKZ  
this("",0); ;X9nYH  
} zG[GyyAQ  
uyp|Xh,  
SccaX P  
public FileAccessI(String sName,long nPos) throws IOException |q( .j4[i  
{ Zy<gA >  
oSavedFile = new RandomAccessFile(sName,"rw"); V~9s+>  
this.nPos = nPos; DGQGV[9%4C  
oSavedFile.seek(nPos); YNRorE   
} nw)yK%`;M  
R cz;|h8  
2G(RQ\Ro*  
public synchronized int write(byte[] b,int nStart,int nLen) OJ/l}_a  
{ )S,Rx  
int n = -1; o'`:$ (  
try{ ,[Bv\4Ah  
oSavedFile.write(b,nStart,nLen); sfN6ro  
n = nLen; b/yXE)3 X  
} 8 <~E;:  
catch(IOException e) {dbPMx  
{ A<+veqb4  
e.printStackTrace (); #y?iUv  
} 3=)!9;uY  
7M#irCX  
sK&[sN33  
return n; h"/y$  
} 5 wT e?  
j3J\%7^i  
1U/ dc.x5  
} y1FE +EX[  
E&wz0d;gf  
Pf4b/w/  
/* ??7c9l5,  
**SiteInfoBean.java :B(vk3;U!  
*/  3g#  
package NetFox; "s6\l~+9l  
X<j(AAHE  
Q.$|TbVfds  
public class SiteInfoBean { E76#xsyhF  
_T{ "F  
{Y(#<UDM  
private String sSiteURL; //Site's URL Jw b'5[R  
private String sFilePath; //Saved File's Path %+{[%?xh  
private String sFileName; //Saved File's Name Fr,qVYf  
private int nSplitter; //Count of Splited Downloading File m! 3e>cI  
uE]kv  
z+k[HE^S  
public SiteInfoBean() 'Pm.b}p<  
{//nSplitter的缺省值为5 {?zBc E:  
//default value of nSplitter is 5 SFiK_;  
this("","","",5); | k:ecw  
} d<@SRHP(  
G%RL8HU  
[PI!.9H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k\NwH?ppu  
{ qpCNvhi  
sSiteURL= sURL; RXbhuI  
sFilePath = sPath; mk'$ |2O  
sFileName = sName; bh~"LQS1  
this.nSplitter = nSpiltter; GlPd)m`  
zBKfaQI,  
jk\04k  
} \mIm}+!H  
G""L1?  
h,(f3Ik0O  
public String getSSiteURL() ?e. Ge0&  
{ ,1!~@dhs  
return sSiteURL; \uUd *  
} #j?SdQ  
I/HcIBJ  
A@o:mZ+XN(  
public void setSSiteURL(String value) w9W0j  
{ @|i f^  
sSiteURL = value; q"uP%TN  
} RaBq@r*(  
"{lw;AA5F  
p3L0'rY|+  
public String getSFilePath() mx ]a@tu  
{ *Bj7\8cKC  
return sFilePath; GcpAj9  
} ]5_6m;g  
Ug1[pONk  
?L'4*S]  
public void setSFilePath(String value) D rMG{Yiu  
{ l[cBDNlrC;  
sFilePath = value; bY>JLRQJ-  
} 1;Q>B>6  
n1mqe*Mvs/  
:9=J=G*  
public String getSFileName() [/Figr]  
{ f]*_]J/  
return sFileName; &AS<2hB  
} ]\8{z"  
YcQ3 :i  
CQ( _$  
public void setSFileName(String value) u]Eyb),Gy  
{  -l ?J  
sFileName = value; <.l$jW]  
} \kQ@G  
m K);NvJ!  
cfg_xrW0^  
public int getNSplitter() )RFE< Qcj  
{ 5YQq*$|'+  
return nSplitter; , id`=L=  
} F[65)"^  
jcuC2t  
<r1N6(n  
public void setNSplitter(int nCount) EXrOP]Kl  
{ EA/+~ux  
nSplitter = nCount; _s&sA2r<  
} 'g$a.75/-  
} 2Y2J)5,  
'B$ bGQ  
HVz,liq  
/* :2\H>^u V  
**Utility.java /JOEnQ5X\!  
*/ ZYBK'&J4m  
package NetFox; 7T)J{:+0!|  
N;.cZp2  
j1LL[+G-"_  
public class Utility { R\oas"  
DJF-J#  
wW1E 'Vy{  
public Utility() 7r_Y.  
{ OSvv\3=  
1HBdIWhHv.  
xP1`FSO8=  
} abvA*|  
:h|nV ~  
//线程睡眠 x4HVB  
public static void sleep(int nSecond) I'_.U]An  
{ $jDp ^ -  
try{ A#"AqNVWv  
Thread.sleep(nSecond); 3j2% '$>E^  
} p:,(r{*?  
catch(Exception e) mST/u>'  
{ -9 AI@^q  
e.printStackTrace (); )eFq0+6*)  
} JQ*CF(9  
} NINaOs  
hE-u9i  
//日志 \mt0mv;c  
public static void log(String sMsg) GUe&WW:Sqk  
{ A3UC=z<y  
System.err.println(sMsg); <*Kj7o{Qn  
} d.7pc P  
=9oN#4mWK  
C#5z!z/:%  
public static void log(int sMsg) | Wrf|%p  
{ >Ic)RPO9  
System.err.println(sMsg); (wNL,<%~  
} FS%Xq-c  
} T[iwP~l  
(aX5VB**  
Ny;(1N|&3  
/* B_k[N}|zD  
**TestMethod.java *Mt's[8  
*/ 1RtbQ{2F;  
package NetFox; Ksq{=q-T  
RNyw`>  
)w8h2=l  
public class TestMethod { 4Lx#5}P  
"%aJ 'l2  
C?bq7kD:H  
public TestMethod() "28b&pm  
{ ///xx/weblogic60b2_win.exe p;dH[NW  
try{ \e5bxc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 21$YZlhJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o;XzJ#P  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -d+q+l>0  
fileFetch.start(); -<gGNj.x-  
} A0SEzX({[  
catch(Exception e){e.printStackTrace ();} ~+{OSx<S  
C@` eYi  
V `V Z[  
} #h@/~xr  
?Sj3-*/?  
swvn*xr  
public static void main(String[] args) vMsb@@O\\  
{ F:.rb Ei  
new TestMethod(); 6,sZo!G  
} AF4:v<EN  
} W8Z&J18AU  
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