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http断点续传简单实现(java)

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/* &?QKWxN  
**SiteFileFetch.java Pl'lmUR  
*/ E.m2- P;4  
package NetFox; >wqWIw.w>  
import java.io.*; +76ao7d.  
import java.net.*; ?H_@/?  
D]iyr>V6'  
8~,zv_Pl  
public class SiteFileFetch extends Thread { 4>d]0=x  
8u)>o* :  
k8n9zJ8  
SiteInfoBean siteInfoBean = null; //文件信息Bean sSKD"  
long[] nStartPos; //开始位置 )UU`uzU;u  
long[] nEndPos; //结束位置 B=W#eu <1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]]r ;}$  
long nFileLength; //文件长度 j-/$e,xX  
boolean bFirst = true; //是否第一次取文件 uYlyU~M:D  
boolean bStop = false; //停止标志 m=h/A xW  
File tmpFile; //文件下载的临时信息 !sI^Lh,Y  
DataOutputStream output; //输出到文件的输出流 jt6_1^  
1 Lg{l  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &k*oG: J3  
public SiteFileFetch(SiteInfoBean bean) throws IOException ImB5F'HI$  
{ )g8Kicox5  
siteInfoBean = bean; $HOe){G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q$p3cepsK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;8MQ'#  
if(tmpFile.exists ()) )Dhx6xM[a  
{ ~FAk4z=Ed  
bFirst = false; = YO<.(Lu  
read_nPos(); NoF|j57?u'  
} B)DuikV.D  
else nvQX)Xf  
{ R!"`Po  
nStartPos = new long[bean.getNSplitter()]; I+Yq",{%  
nEndPos = new long[bean.getNSplitter()]; c]k+ Sx&}  
} HI:1Voy  
N6BOUU]  
WS4DzuZZ  
*7*cWO=  
} *=O3kUoL  
UnVa`@P^:G  
>u0XV"g$  
public void run() 4yTgH0(T  
{ R9-mq; u+  
//获得文件长度 p {. 6  
//分割文件 fbdpDVmpU  
//实例FileSplitterFetch I4qS8~+#  
//启动FileSplitterFetch线程 H^o_B1  
//等待子线程返回 @>ys,dy  
try{ k&[6Ld0~56  
if(bFirst) W"\`UzOLQ  
{ T%"wz3~  
nFileLength = getFileSize(); 5sEk rT '  
if(nFileLength == -1) ep5`&g]3  
{ ^(T~Qp  
System.err.println("File Length is not known!"); [q0^Bn}h  
} ,bM):  
else if(nFileLength == -2) <h+UC# .x  
{ ntPX?/  
System.err.println("File is not access!"); N2j^fZd_  
} WCqa[=v)t  
else _ A{F2M  
{ !%(kMN  
for(int i=0;i<nStartPos.length;i++) 9RS viIi$  
{ EcytNYn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I%Z=O=  
} b!J?>du  
for(int i=0;i<nEndPos.length-1;i++) i& \ >/ 1  
{ inq {" 6  
nEndPos = nStartPos[i+1]; eq"Xwq*  
} vqoK9  
nEndPos[nEndPos.length-1] = nFileLength; 8ZjRMr}  
} `{IL.9M!f  
} ' qT\I8%  
9zx9t  
p74Nd4U$s  
//启动子线程  |#xBC+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3H>\hZ  
for(int i=0;i<nStartPos.length;i++) G<rAM+B*g  
{ dqgr98  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &+hk5?c /  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F4V) 0)G  
nStartPos,nEndPos,i); +_*iF5\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M= 3w  
fileSplitterFetch.start(); iW9  
} 6h&t%T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \v{HjqVkC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QAl4w)F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6N Ogi  
nEndPos = " + nFileLength); bQN3\mvY  
// fileSplitterFetch[nPos.length-1].start();  )L":I  
&Wdi 5T8  
!"E/6z2&(k  
//等待子线程结束 9G7Brs:  
//int count = 0; Bz%wV-  
//是否结束while循环 Wi\k&V.mE  
boolean breakWhile = false; \fvm6$ rZ^  
^rY18?XC+:  
OYmutq  
while(!bStop) ]70ZerQ~L  
{ &VCg`r-{~  
write_nPos(); EK Q>hww8  
Utility.sleep(500); )@tHS-Jf  
breakWhile = true; -~_|ZnuM9  
y>T>  
s`v$r,N0  
for(int i=0;i<nStartPos.length;i++) y La E]  
{ Be\@n xV[  
if(!fileSplitterFetch.bDownOver) Jko=E   
{  Bw+ ?MdS  
breakWhile = false; :7Uv)@iUk  
break; fceO|mSz_  
} qf@P9M  
} vwa*'C  
if(breakWhile) j`Ek:  
break; ]|K6Z>V  
&?xtmg<d  
f4f)9n  
//count++; f?16%Rk<  
//if(count>4) (m2_Eh;  
// siteStop(); ?h| DeD!s  
} [yc7F0Aw  
=C|^C3HK  
xwwL  
System.err.println("文件下载结束!"); (KPD`l8.  
} oe<@mz/  
catch(Exception e){e.printStackTrace ();} X(#8EY}X  
} yVKl%GO  
GlC(uhCpV  
*L Y6hph"  
//获得文件长度 OOABn*  
public long getFileSize() Fs=)*6}&  
{ <{YzmN\Z  
int nFileLength = -1; Ty7 `&  
try{ FKhgUnw  
URL url = new URL(siteInfoBean.getSSiteURL()); @FF{lK?[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ofI,[z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); sint":1FC  
'w<^4/L Q  
^LXsU] R  
int responseCode=httpConnection.getResponseCode(); 3Tw9Uc\vT  
if(responseCode>=400) cT&lkS  
{ O69TU[Vn  
processErrorCode(responseCode); ~*^o[~x]\  
return -2; //-2 represent access is error 0 xvSi9  
} %uiCC>cC  
,R7j9#D  
Fo~q35uB  
String sHeader; MJH>rsTQ  
 <pD  
?s)6 YF  
for(int i=1;;i++) -QBM^L  
{ ;K4uu<e \  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6o(.zk`d  
//Utility.log(in.readLine()); /t2H%#v{  
sHeader=httpConnection.getHeaderFieldKey(i); *Utx0Me  
if(sHeader!=null) 2FO<Z %Y  
{  (wxi!  
if(sHeader.equals("Content-Length")) n!Y}D:6c6  
{ xbHI 4A"Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X%B$*y5  
break; e5; YY  
} +br' 2Pn  
} JP^x]t:  
else $GhL-sqm  
break; 1 >2 /1>  
} S&'s/jB  
} KilN`?EJ  
catch(IOException e){e.printStackTrace ();} Znh;#%n|  
catch(Exception e){e.printStackTrace ();} Y9st3  
9U )9u["DH  
T@zp'6\H  
Utility.log(nFileLength); )!G 10  
z?UEn#E2  
Q{miI N  
return nFileLength; \.P#QVuQ  
} :w4N*lV-  
m?8o\|i,  
;l < amB  
//保存下载信息(文件指针位置) *o(bB!q"c  
private void write_nPos() g1l:k1\Ht  
{ G$CSZrP.  
try{ \-[ >bsg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lKqFuLHwF  
output.writeInt(nStartPos.length); 4 &:|h  1  
for(int i=0;i<nStartPos.length;i++) =n@\m <  
{ W,!7_nl"u  
// output.writeLong(nPos); i!(5y>I_  
output.writeLong(fileSplitterFetch.nStartPos); x~D8XN{  
output.writeLong(fileSplitterFetch.nEndPos); 2<'ol65/c  
} :eevc7  
output.close(); R 4DfqX  
} NMrf I0tbG  
catch(IOException e){e.printStackTrace ();} "st+2#{  
catch(Exception e){e.printStackTrace ();} txX>zR*)  
} Z\n^m^Z =  
EF9Y=(0|  
|;p.!FO  
//读取保存的下载信息(文件指针位置) 4gmlK,a  
private void read_nPos() g2u\gR5  
{ yKm6 8n^  
try{ I58$N+#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IfI:|w}:"r  
int nCount = input.readInt(); 8&qtF.i-6  
nStartPos = new long[nCount]; *Z2Ko5&Y2  
nEndPos = new long[nCount]; x7jFYC  
for(int i=0;i<nStartPos.length;i++) %ca`v;].  
{ 6J$I8b#/  
nStartPos = input.readLong(); ]Qp-$)N  
nEndPos = input.readLong(); P /q] u  
} g$/7km{TP  
input.close(); pRjrMS  
} wMCgL h\wi  
catch(IOException e){e.printStackTrace ();} ;W\?lGOs{  
catch(Exception e){e.printStackTrace ();} 6UqDpL7^U  
} 13Q87i5B  
RfCu5Kn  
=xSf-\F  
private void processErrorCode(int nErrorCode) G}}Lp~  
{ sEL0h4  
System.err.println("Error Code : " + nErrorCode); |fgh ryI,  
} #hXvGon$?  
TDy$Mv=y  
WWOjck #  
//停止文件下载 :j/sTO=  
public void siteStop() (>lH=&%zj  
{ OcC|7s" ,  
bStop = true; u6MU @?  
for(int i=0;i<nStartPos.length;i++) MvaX>n !o  
fileSplitterFetch.splitterStop(); >m%7dU  
\uJ+~db=  
Fp]ErDan  
} cXYE !(  
} GR 1%(,  
//负责部分文件的抓取 Cyo:Da  A  
**FileSplitterFetch.java Y'+K U/H  
*/ x>T+k8[n  
package NetFox; i]qxF&1  
E7/i_Xkk  
VAqZ`y  
import java.io.*; .}(X19R  
import java.net.*; 3h A5"G+7  
#n|eq{fkK  
h$%h w+"4  
public class FileSplitterFetch extends Thread { n+2>jY  
z*cKH$':  
)gAqWbkB  
String sURL; //File URL Kt/:caD  
long nStartPos; //File Snippet Start Position RfT)dS+rAh  
long nEndPos; //File Snippet End Position y,qn9  
int nThreadID; //Thread's ID LIyb+rH#yg  
boolean bDownOver = false; //Downing is over wk1/&  
boolean bStop = false; //Stop identical WB `h)  
FileAccessI fileAccessI = null; //File Access interface zp``e;gY  
vM:c70=  
t=jG$A  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^U,Dx  
{ gplrJaH@  
this.sURL = sURL; Ev3,p`zS._  
this.nStartPos = nStart; 7m:TY>{  
this.nEndPos = nEnd; nXjSf  
nThreadID = id; }n"gX>e~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BhiOV_}Hn  
} :" JEC'  
PM&NY8|Zy  
^ _W] @m2  
public void run() j^h:*rw  
{ {*<%6?  
while(nStartPos < nEndPos && !bStop) 82o|(pw  
{ sNMF(TY  
S?c<Lf~W  
f=7[GZoDn  
try{ ,8!'jE[d  
URL url = new URL(sURL); z&jASL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `-?`H>+OG  
httpConnection.setRequestProperty("User-Agent","NetFox"); '#Do( U'  
String sProperty = "bytes="+nStartPos+"-"; J\ J3 'u  
httpConnection.setRequestProperty("RANGE",sProperty); P=s3&NDD  
Utility.log(sProperty); 4`Jf_C  
J]Rh+@r.  
lfr^NxOU  
InputStream input = httpConnection.getInputStream(); E;q+u[$  
//logResponseHead(httpConnection); >T{TE"XyO|  
JE<h  
Fw#1?/K~  
byte[] b = new byte[1024]; DV)NY!  
int nRead; 8~BLTZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |A+,M"F?  
{ J-5kvQi8  
nStartPos += fileAccessI.write(b,0,nRead); e-VGJxR  
//if(nThreadID == 1) 7=&+0@R#/d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;*=7>"o'`  
} %CUwD  
v`p@djM  
+Z]}ce u"  
Utility.log("Thread " + nThreadID + " is over!"); DUg[L  
bDownOver = true; 9`KFJx6D  
//nPos = fileAccessI.write (b,0,nRead); b S'dXP  
} $0+&xJVn  
catch(Exception e){e.printStackTrace ();} }U%T6~_wR  
} c}H}fyu%n  
} QC6QqcOX  
]!s@FKC{;  
b tbuE  
//打印回应的头信息 z<J2e^j  
public void logResponseHead(HttpURLConnection con) [lu+"V,<LJ  
{ X}ihYM3y/  
for(int i=1;;i++) U_Q;WPJ  
{ cxx8I  
String header=con.getHeaderFieldKey(i); '+c@U~d*7  
if(header!=null) lAo4)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y3 -f68*(  
Utility.log(header+" : "+con.getHeaderField(header)); aEun *V^,  
else . K_Jg$3  
break; 1{1mL-I;  
} 9Sl5jn  
} bkrl>Im<n  
. +,{|){c  
CdtCxy5  
public void splitterStop() +6^hp-G7  
{ 6 B7 F  
bStop = true; mXyg\5  
} q%,y66pFr  
!Y/S2J  
APCE }%1U  
} C^:{y  
~4xn^.w  
J*AYZS-tSE  
/* v] m`rV8S[  
**FileAccess.java EiyHZ  
*//文件访问(定位,写) <q&i"[^M  
package NetFox; %_~1(Glz  
import java.io.*; {!!8 *ix  
(`R heEg@f  
~B7<Yg  
public class FileAccessI implements Serializable{ VZ7E#z+nM#  
*?>52 -&b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3T[zieX  
RandomAccessFile oSavedFile; czB),vooz  
long nPos; b'vIX< g  
_ D"S  
Vl'rO_?t  
public FileAccessI() throws IOException /J(~NGT  
{ ;1>V7+/  
this("",0); ZmJ<FF4  
} OM`Ws5W}f  
~D`  
U99Uny9  
public FileAccessI(String sName,long nPos) throws IOException Cm0K-~ U  
{ FV/lBWiQQ  
oSavedFile = new RandomAccessFile(sName,"rw"); _<l)4A3rS  
this.nPos = nPos; o  WAy[  
oSavedFile.seek(nPos); FtDF}   
} 3FMYs&0r4  
^Cj3\G4,  
9V;A +d,  
public synchronized int write(byte[] b,int nStart,int nLen) E 0@u|  
{ ]Y$jc  
int n = -1; m';4`Y5-  
try{ AtqsrYj  
oSavedFile.write(b,nStart,nLen); :4LWm<P  
n = nLen; l7Wdbx5x0  
} M<SVH_  
catch(IOException e) =NWzsRl,  
{ tJm1Q#||  
e.printStackTrace (); ):n'B` f}z  
} Dv4 H^  
-a'D~EGB^  
Lzx/9PPYn  
return n; N9u {)u  
} 4E$d"D5]>p  
Zm+GH^f'  
9S<V5$}  
} K?yMy,9%Yw  
7Jpq7;  
AE Abny q  
/* V@\u<LO0G  
**SiteInfoBean.java c<{~j~+  
*/ cs[nFfM  
package NetFox; *q@3yB}  
$8Z4jo  
S7@/d HN  
public class SiteInfoBean { R_vK^Da  
oq,*@5xV2  
&gI*[5v  
private String sSiteURL; //Site's URL vtc%MG1  
private String sFilePath; //Saved File's Path Ga pM~~  
private String sFileName; //Saved File's Name /!60oV4p0  
private int nSplitter; //Count of Splited Downloading File Q@*9|6-  
?!3u ?Kd  
O8-Z >;  
public SiteInfoBean() a%QgL&_5  
{//nSplitter的缺省值为5 lXD=uRCI  
//default value of nSplitter is 5 .sb0|3&  
this("","","",5); M[e^Z}w.V  
} b27t-p8  
+;bZ(_ohG  
:*cd$s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'CRjd~L  
{ []?*}o5&>T  
sSiteURL= sURL; G\(*z4@Gz  
sFilePath = sPath; dki3(  
sFileName = sName; V|<'o<h8  
this.nSplitter = nSpiltter; lQ4$d{m`  
Q,};O$h  
g+xcKfN{  
} $- Y8@bw  
XG5"u  
}}Gkipp  
public String getSSiteURL() \vuWypo  
{ .s|5AC[  
return sSiteURL; q77Iq0VR  
} Pu'lp O  
6H0aHCM  
V8Z@y&ny  
public void setSSiteURL(String value) ZbH_h]1$D  
{ ('.I)n  
sSiteURL = value; 51ILR9 Bc_  
} (.b!kfC  
_j~y;R)  
Of eM;)  
public String getSFilePath() rY$ wC%  
{ ppeF,Q  
return sFilePath; V2g"5nYT  
} \\Z?v,XsS  
}$* z:E  
Q_*.1L  
public void setSFilePath(String value) &0{&4,  
{ BT f  
sFilePath = value; |Vp ?  
} `*]r+J2  
zY].ZS=7  
.m xc~  
public String getSFileName() YDgG2hT/2  
{ 2Ic)]6z R  
return sFileName; CYM>4C~>JW  
} e'fo^XQn[  
6 I43a1[s  
cq/@ng*o  
public void setSFileName(String value) R0F&!y!B  
{ *~.'lE%[U  
sFileName = value; ~ x J#NC+  
} Xod/GY G  
Q{ { =  
A^4#6],%v  
public int getNSplitter() s1X?]A  
{ ^xr & E  
return nSplitter; m,F4N$  
} 59V8cO+qH  
U?EXPi61Z  
~b[5}_L=>  
public void setNSplitter(int nCount) hl8oE5MU  
{ >&T J  
nSplitter = nCount; semTAoqH  
} %xC}#RDf  
} 6f+@@=Xc  
!)`m mr  
hl,x|.f}4Y  
/* `J;g~#/k  
**Utility.java 1TgD;qX  
*/ |w>d]eA5  
package NetFox; '1Ex{$Yk  
$`L |  
^ JU#_  
public class Utility { G}nj 71=H  
mw83pU6  
'"6*C*XS  
public Utility() gj }Vnv1[  
{ xk^`4;  
/8/N  
]Bz.6OR  
} Z/OERO   
V\AF%=6}  
//线程睡眠 Z0M|Bv9_  
public static void sleep(int nSecond) fyq %-Tj  
{ .RbPO#(  
try{ O81'i2M J9  
Thread.sleep(nSecond); "~"=e  
} <V|\yH9  
catch(Exception e) 9zpOp-K6  
{ f2ck=3  
e.printStackTrace (); m-Se-aF  
} bc2S?u{  
} 6dRvx;d  
OZe`>Q6  
//日志 - P4X@s_;  
public static void log(String sMsg) 5&]a8p{  
{ ?VyiR40-Cx  
System.err.println(sMsg); T5_rPz  
} _t6 .9CXl  
mzf^`/NO  
P+rDln {  
public static void log(int sMsg) PE6ZzxR|U<  
{ BD mF+  
System.err.println(sMsg); P[H 4Yp  
} 4u1au1c  
} BD M"";u  
F*y7 4j,  
~Vc`AcWP  
/* Z_Y gV:jc  
**TestMethod.java _ujhD  
*/ hh-sm8  
package NetFox; 9Wdx"g52_D  
r$,Xv+}  
$8Gj9mw4e'  
public class TestMethod { mD,fxm{G  
q oz[x  
gbFHH,@  
public TestMethod() L(HAAqRnJ  
{ ///xx/weblogic60b2_win.exe 5$*=;ls>J  
try{ ~vMJ?P@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zSBR_N51  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2rM/kF >g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IG!(q%Gf  
fileFetch.start();  y`pgJO  
} {7EpljH@  
catch(Exception e){e.printStackTrace ();} w%%*3[--X  
J #;|P-pt  
H9[0-Ur5  
} w|-m*v .  
4@Bl 1b[<  
12}!oS~_  
public static void main(String[] args) j!IkU}*c  
{ &HqBlRo  
new TestMethod(); |zy` ]p9  
} z:A_  
} :VX2&*  
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