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http断点续传简单实现(java)

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/* :j? MEeu  
**SiteFileFetch.java Uy|Tu~  
*/ \Hw*q|  
package NetFox; juI)Do2_  
import java.io.*; 0mNL!"  
import java.net.*; $/ g<h  
DOOF--ua  
AH?[K,3  
public class SiteFileFetch extends Thread { Z3U%Afl2{  
3WpQzuHPT  
h]vEXWpG]  
SiteInfoBean siteInfoBean = null; //文件信息Bean J%lrXm(l{  
long[] nStartPos; //开始位置 ^r,0aNzAs  
long[] nEndPos; //结束位置 }0sLeGJ!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |;\pAZ2  
long nFileLength; //文件长度 y&/bp<Z  
boolean bFirst = true; //是否第一次取文件 [hV}$0#E[O  
boolean bStop = false; //停止标志 ]WK~`-3C^  
File tmpFile; //文件下载的临时信息 J50n E~  
DataOutputStream output; //输出到文件的输出流 {|'NpV  
M9G?^mW1sT  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) % K,cGgp^)  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4I9Yr  
{ nzZs2  
siteInfoBean = bean; Ly z8DwZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _2{2Xb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,& wd  
if(tmpFile.exists ()) ]^8CtgC  
{ 9Vl}f^Gn  
bFirst = false; ! ?>I  
read_nPos(); SAdo9m'  
} #=)!\   
else dc0&*/`:  
{ V5p^]To!  
nStartPos = new long[bean.getNSplitter()]; W>qu~ak?x  
nEndPos = new long[bean.getNSplitter()]; j3H_g ^  
} yo8mfH_,  
s>W :vV@  
\4>w17qng  
1CR\!?  
} YkE_7r(1  
#^yOW^  
m WHyk"l  
public void run() B`||4*  
{ `+0dz,  
//获得文件长度 R"l6|9tmP  
//分割文件 lEw;X78+  
//实例FileSplitterFetch |~#A?mK-  
//启动FileSplitterFetch线程 +43~4_Oj  
//等待子线程返回 ^ cE{Uv  
try{ E;9J7Q 4  
if(bFirst) VLVDi>0i  
{ 5<e{)$C  
nFileLength = getFileSize();  U ^nv)  
if(nFileLength == -1) g7^|(!Y%  
{ +o'xyR'(  
System.err.println("File Length is not known!"); |KZX_4   
} +SE\c  
else if(nFileLength == -2) @.c[z D  
{ ?JTTl;  
System.err.println("File is not access!"); Mlr'h}:H  
} &,3s2,1U(  
else cLRzm9  
{ u+ hRaI;v  
for(int i=0;i<nStartPos.length;i++) .C &kWM&j  
{ <lNNT6[/r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $|7=$~y  
} X|/RV4x@Cq  
for(int i=0;i<nEndPos.length-1;i++) Pt cq/f  
{ fmJK+  
nEndPos = nStartPos[i+1]; w^=(:`  
} 54B`T/>R:E  
nEndPos[nEndPos.length-1] = nFileLength; ZJ~0o2xZ'  
} .z=%3p8+  
} uc}tTmB|  
U&{w:P  
8aC=k@YE  
//启动子线程 CBNt _y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mIp> ~  
for(int i=0;i<nStartPos.length;i++) s diWQv  
{ mq:WBSsV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), US=K}B=g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K :kb&W  
nStartPos,nEndPos,i); dG8mE&$g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c5uC?b].  
fileSplitterFetch.start(); *4LRdLMn  
} /Oi(5?Jn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z {:;LC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XT*/aa-1'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |z"$^|@d?  
nEndPos = " + nFileLength); [b&V^41W  
// fileSplitterFetch[nPos.length-1].start(); J7C?Z  
x!vyjp  
<L11s%5-  
//等待子线程结束 /hmDeP o}  
//int count = 0; ~-y&C%  
//是否结束while循环 sa _J6~  
boolean breakWhile = false; MX?UmQ'  
AAW] Y#UwW  
s;E(51V<>  
while(!bStop) Xit@.:a;  
{ Nd_A8H,&B  
write_nPos(); ~c] q:pU2  
Utility.sleep(500); r[T(R9k  
breakWhile = true; ){z#Y#]dP  
Fw{68ggk  
8SL E*c^8  
for(int i=0;i<nStartPos.length;i++) 8DMqjt3B  
{ $G6kS@A  
if(!fileSplitterFetch.bDownOver) %'=2Jy6h  
{ 2{Dnfl'k  
breakWhile = false; LFqY2,#i  
break; [s\8@5?E  
} #_`p 0wY  
} %Y0BPTt$  
if(breakWhile) avM8-&h  
break; )4-!]NsV  
#H<}xC2  
 LAM{ ,?~  
//count++; W(Md0*   
//if(count>4) K'e,9P{  
// siteStop(); tZm`(2S  
} l:bbc!3  
e==/+  
8B-mZFXpK  
System.err.println("文件下载结束!"); 'p\&Mc_Gu  
} Cg%Owe/E?0  
catch(Exception e){e.printStackTrace ();} $T:;Kc W)  
} [` }w7  
PFx.uqp  
2L[!~h2  
//获得文件长度 0VNpd~G$  
public long getFileSize() gR gB= C{  
{ c`hENPhW  
int nFileLength = -1; zHg=K /  
try{ 7HY8 F5Brx  
URL url = new URL(siteInfoBean.getSSiteURL()); tS5J{j>T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZR%$f-  
httpConnection.setRequestProperty("User-Agent","NetFox"); :xq{\"r  
[\ Sd*-  
+4Wl  
int responseCode=httpConnection.getResponseCode(); 1JdMw$H  
if(responseCode>=400) \CE+P5  
{ s]`6u yW"  
processErrorCode(responseCode); 2 M\7j  
return -2; //-2 represent access is error #`= >Mza  
} 6/Yo0D>M$  
\ZhkOl  
0S4Y3bac&  
String sHeader; n[qnrk*3 %  
/.rj\,  
5D?{dA:Rq  
for(int i=1;;i++) 0bJT0_  
{ X(17ESQ/Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \6.dGKK  
//Utility.log(in.readLine()); ,' t&L]  
sHeader=httpConnection.getHeaderFieldKey(i); F Pjc;zNA  
if(sHeader!=null) (fr=[m$`  
{ iRcac[uV  
if(sHeader.equals("Content-Length")) z.\\m;s  
{ y!:vX6l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zFipuG02  
break; TOgH~R=  
} 8tf>G(I{  
} N+5f.c+S-  
else VKu_ l  
break; <0hVDk~  
} ubsv\[:C  
} 7bE`P[  
catch(IOException e){e.printStackTrace ();} =B'Yx  
catch(Exception e){e.printStackTrace ();} i$}G[v<4  
)+hJi/g  
aO?KRn  
Utility.log(nFileLength); B-L@ 0gH  
Q>;Aq!mr=  
W>Pcj EI  
return nFileLength; %}-ogi/c  
} wv\"(e7(  
qK@,O \  
y?3u6q++  
//保存下载信息(文件指针位置) OVgak>$  
private void write_nPos() EG &me  
{ <nV3`L&]  
try{ mr_NArF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wt'"<UN  
output.writeInt(nStartPos.length); [I'q"yRu]i  
for(int i=0;i<nStartPos.length;i++) 1|G5 W:  
{ p14$XV  
// output.writeLong(nPos); k%-UW%  
output.writeLong(fileSplitterFetch.nStartPos); H15!QxD#  
output.writeLong(fileSplitterFetch.nEndPos); &`>dY /Y  
} ts@ e ,  
output.close(); XgKYL<k?S  
} DIvxut  
catch(IOException e){e.printStackTrace ();} s2 aFme  
catch(Exception e){e.printStackTrace ();} i?#U>0!  
} n[v`F  
@Xh8kvc81  
,O^kZ}b  
//读取保存的下载信息(文件指针位置) B=X_c5  
private void read_nPos() l +`CgYo  
{ %4#ChlXB  
try{ ntL%&wY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q'ib7R;V,  
int nCount = input.readInt(); Zw/??Tq b  
nStartPos = new long[nCount]; K7(GdKZe  
nEndPos = new long[nCount]; eISHV.QV  
for(int i=0;i<nStartPos.length;i++) MC B2  
{ _jxysFl=  
nStartPos = input.readLong(); sv "GX< +  
nEndPos = input.readLong(); g&ba]?[A  
} ^Ga_wJP8S  
input.close(); TC:t!:  
} 4zBcq<R7  
catch(IOException e){e.printStackTrace ();} ~aL?{kb+  
catch(Exception e){e.printStackTrace ();} Hb^ovc0   
} mryT%zSlM  
abEdZ)$  
z!~{3M  
private void processErrorCode(int nErrorCode) }y*rO(cu7G  
{ `sRys oW  
System.err.println("Error Code : " + nErrorCode); Q2@yUDd!  
} q^@*k,HG  
{w99~?  
,? &$ c+  
//停止文件下载 1ahb:Mjv  
public void siteStop() [{ A5BE -  
{ IY2f$YV  
bStop = true; 5hAs/i9_  
for(int i=0;i<nStartPos.length;i++) :ZM=P3QZ  
fileSplitterFetch.splitterStop(); @Hp=xC9V  
+ J}h  
wG22ffaki  
} oOQ0f |MGp  
} ]ddL'>$c$  
//负责部分文件的抓取 :?#wWF.  
**FileSplitterFetch.java 0J= $ A  
*/ BT5~MYBl  
package NetFox; *vzj(HGO  
k.H4Mf(4  
K5+ONA<c  
import java.io.*; 5Ak>/QF9  
import java.net.*; ]}_Ohe]X  
Az(J @  
/"1[qT\F  
public class FileSplitterFetch extends Thread { zn\$6'"  
).$kp2IN  
]k.YG!$  
String sURL; //File URL p!K]c D  
long nStartPos; //File Snippet Start Position g8Zf("  
long nEndPos; //File Snippet End Position &=.7-iC|W  
int nThreadID; //Thread's ID + j6^g*  
boolean bDownOver = false; //Downing is over s! sG)AR.J  
boolean bStop = false; //Stop identical k~$}&O  
FileAccessI fileAccessI = null; //File Access interface M:K4o%  
SR9M:%dga  
` B+Pl6l)F  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Pj*"2 LBW#  
{ .ldBl  
this.sURL = sURL; piPV&ytI  
this.nStartPos = nStart; Jqt|' G3  
this.nEndPos = nEnd; ~$ 4!C'0  
nThreadID = id; v%Su#xq/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T@N)BfkB  
} qNbgN{4  
:HN\A4=kc(  
@'?7au ''  
public void run() .[o?qCsw  
{ d1d:5 b  
while(nStartPos < nEndPos && !bStop) ~NO'8 Mr  
{ 1 swqs7rR|  
BOW`{=  
Vdf~rV  
try{ e= _7Q.cn  
URL url = new URL(sURL); xa%2w]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J)=Ts({  
httpConnection.setRequestProperty("User-Agent","NetFox"); =Xb:.  
String sProperty = "bytes="+nStartPos+"-"; RsP^T:M}$  
httpConnection.setRequestProperty("RANGE",sProperty); 95  X6V  
Utility.log(sProperty); KWT[b?  
brt` oR  
Cqw`K P  
InputStream input = httpConnection.getInputStream(); 0J9Ub   
//logResponseHead(httpConnection); YoRD9M~iG~  
G/}nwj\  
7C^W<SUo  
byte[] b = new byte[1024]; '\B!1B>T  
int nRead; 'ewVn1ME[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |f"1I4K g  
{ lO^YAOY  
nStartPos += fileAccessI.write(b,0,nRead); n0'"/zyc  
//if(nThreadID == 1) 0]t7(P"F6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %0Ke4c  
} T9Pu V  
? `#  
Tn\59 (  
Utility.log("Thread " + nThreadID + " is over!"); TZS:(MJ9M  
bDownOver = true; >U[YSsFt6  
//nPos = fileAccessI.write (b,0,nRead); je~gk6}Y  
} VxGR[kq$]  
catch(Exception e){e.printStackTrace ();} T#R*]  
} 4B=@<( H  
} VWE`wan<  
CZ/:(sOJ  
AU H_~SY  
//打印回应的头信息 % KmhR2v  
public void logResponseHead(HttpURLConnection con) L)/^%/!  
{ ,[ M^rv  
for(int i=1;;i++) e5.sqft  
{ FKu^{'Y6E0  
String header=con.getHeaderFieldKey(i); 1FmqNf:V7I  
if(header!=null) ST^{?Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o^& nkR  
Utility.log(header+" : "+con.getHeaderField(header)); 6ALUd^  
else AG<TY<nqL  
break; W!WeYV}kb  
} '9q:gFO  
} |t h"ET  
's6hCs&|NV  
*v9 {f?  
public void splitterStop() Eg|C  
{ ZuQ\Pyx  
bStop = true; :l?/]K  
} B"fKv0  
/kK:{  
@ Yzj  
} 91j.%#[v'  
t_ZWd#x+;  
.2:S0=xt<  
/* Z?tw#n[T  
**FileAccess.java F6 c1YI[  
*//文件访问(定位,写)  8&KqrA86  
package NetFox; ]u@`XVEJ  
import java.io.*; pj9s=}1 '  
,O ]AB  
AwO'%+Bv  
public class FileAccessI implements Serializable{ }=JuC+#~n  
05Go*QvV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rA#Ji~  
RandomAccessFile oSavedFile; Y!L<& sl   
long nPos; G .k\N(l  
[I7([l1Wvd  
#^&.*' z%z  
public FileAccessI() throws IOException 66shr  
{ ,2 _!hm /  
this("",0); @jevY81)  
} 5Dlx]_  
aXO|% qX  
/0I=?+QSo  
public FileAccessI(String sName,long nPos) throws IOException ZRo-=/1  
{ 2k3yf_N  
oSavedFile = new RandomAccessFile(sName,"rw"); meNz0ve  
this.nPos = nPos; `d i/nv)  
oSavedFile.seek(nPos); BY^5z<^.  
} 0vm}[a4+i;  
i7(\i2_P  
QHuh=7u)  
public synchronized int write(byte[] b,int nStart,int nLen) E?Ofkc$q  
{ j8"2K^h=  
int n = -1; 1 |zy6  
try{ 5uufpvah  
oSavedFile.write(b,nStart,nLen); !2Q>   
n = nLen; b5Pakz=jNM  
} mMRdnf!Uid  
catch(IOException e) bkfk9P  
{ Rk.GrLp  
e.printStackTrace (); vswBK-w(Z  
} [v$NxmRu  
#[{xEVf  
J=qPc}+  
return n; bP,_H  
} %!e;sL~&  
PC}m.tE  
SQd`xbIuL  
} iNAaTU  
z7P] g C$\  
=q-HR+  
/* Rr>h8Ni <  
**SiteInfoBean.java hPHrq{YZ  
*/ Du2v,n5@  
package NetFox; !HP/`R  
vAMr&[  
j L[ hB  
public class SiteInfoBean { J6Q}a7I#  
DfQD!}=  
aY7.<p*a  
private String sSiteURL; //Site's URL H;O PA8\n  
private String sFilePath; //Saved File's Path f:-dw6a=s  
private String sFileName; //Saved File's Name Ew kZzVuX  
private int nSplitter; //Count of Splited Downloading File t846:Z%[  
a:3f>0_t  
;c_pa0L  
public SiteInfoBean() w+0Ch1$  
{//nSplitter的缺省值为5 XiB]I5(hcc  
//default value of nSplitter is 5 YQ+Kl[ec  
this("","","",5); `b{.K,  
} $q6'VLPo  
=':,oz^|  
}@V ,v[&e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dn1Tu6f;|  
{ pH1 9"=p<  
sSiteURL= sURL; ohA@Zm8O  
sFilePath = sPath; #`0iN+qh  
sFileName = sName; 7o4 vf~  
this.nSplitter = nSpiltter; K{&b "Ba1  
42m}c1R  
/j1p^=ARV  
} CXs i  
h8yv:}XU*  
.ZxH#l _  
public String getSSiteURL() 6GD Uo}.  
{ S0ct;CS  
return sSiteURL; Y{8L ~U:  
} ^8V cm*  
YTco;5/  
^<e"OV  
public void setSSiteURL(String value) o\luE{H .?  
{ (qP !x 2j  
sSiteURL = value; 0P_Y6w+  
} QJG]z'c+  
4D/mm(2d$  
>)N}V'9  
public String getSFilePath() Lz VvUVk  
{ RhJL`>W`  
return sFilePath; 2,>q(M6,EA  
} Yb|zE   
%V$ujun`  
N!fp;jvG  
public void setSFilePath(String value) TLL.Ch|#Y  
{ e< Ee2pGX  
sFilePath = value; Z6cG<,DQ  
} YSuw V)Y  
^j2:fJOU#  
IpxFME%!  
public String getSFileName() Q#bFW?>y,  
{ )W@H  
return sFileName; o4kNDXP#S  
}  5m+:GiI  
/ N@0qQ  
pg~`NN  
public void setSFileName(String value) } V4"-;P  
{ Pc]c8~  
sFileName = value; Kg@9kJB  
} n#N<zC/  
;e0>.7m  
+{/zP{jH  
public int getNSplitter() r,6~?hG]  
{ EMH?z2iGd  
return nSplitter; `.dTkL  
} @T1 >%oi  
p;n)YY$  
U6=m4]~Z  
public void setNSplitter(int nCount) )_EobE\  
{ Ze$:-7Czl  
nSplitter = nCount; Iw"?%k\U  
} }}qR~.[  
} 8IC((  
nm'm*sU\  
t:M({|m Y  
/* sI`i  
**Utility.java #k=!>%+E  
*/ ,`|KN w5  
package NetFox; !9o8v0ZI  
)K2n!Fbd  
RpLm'~N'  
public class Utility { (oJ#`k:&n  
W,agP G\+  
j7-#">YL  
public Utility() ]-.Q9cjc$q  
{ % wRJ"T`Tt  
@V:b Co  
of& vQ  
} nTu"  
kd\yHI9A  
//线程睡眠 Mdwh-Cis/  
public static void sleep(int nSecond) >5 5/@+^  
{ Q)a*bPz  
try{ *pasI.2s#  
Thread.sleep(nSecond); N=+Up\h  
} 1*-58N*  
catch(Exception e) vJq`l3&  
{ T  |j^  
e.printStackTrace (); OClY ,@  
} Eun%uah6c  
} q>omCk%h  
|J}~a8o  
//日志 3\@6i'  
public static void log(String sMsg) [1vrv(u>  
{ NM]6  o  
System.err.println(sMsg); I3s}t$`y(  
} _ve7Is`/  
-`?V8OwY]  
d'-^ VxO0  
public static void log(int sMsg) Dkdm~~Rr  
{ <I|ryPU9{X  
System.err.println(sMsg); jA]xpf6}  
} v5$zz w  
} A`r&"i OKA  
Y2$ % %@  
jN {ED_  
/*  b'{D4/  
**TestMethod.java P7Y[?='v  
*/ .HtDcGp  
package NetFox; 2C8M1^0:Z  
$K G?d>wx  
zR<jZwo]#  
public class TestMethod { :e9E#o  
oL6_Ya  
3> fuH'=  
public TestMethod() ja>Tnfu  
{ ///xx/weblogic60b2_win.exe [D?E\Nkk  
try{ er<~dqZ}]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (Pu*[STTT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G/`_$ c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XnG!T$  
fileFetch.start(); da<1,hF  
} H5aUZ=  
catch(Exception e){e.printStackTrace ();} D>1Dao  
!9N%=6\  
L'6zs:i  
} >3Y&jsh<  
Je*gMq:D  
*LhR$(F(  
public static void main(String[] args) )i>KYg w  
{ 4i19HD_  
new TestMethod(); 5y~[2jB:  
} UmJg-~  
} HU'E}8%t6  
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