1. 怎么用java备份mysql数据库
首先，设置mysql的环境变量（在path中添加%MYSQL_HOME%\bin），重启电脑。
完整代码：
备份：
public static void main(String[] args) {
backup();
load();
}
public static void backup() {
try {
Runtime rt = Runtime.getRuntime();
// 调用 mysql 的 cmd:
Process child = rt
.exec("mysqlmp -u root --set-charset=utf8 bjse act_obj");// 设置导出编码为utf8。这里必须是utf8
// 把进程执行中的控制台输出信息写入.sql文件，即生成了备份文件。注：如果不对控制台信息进行读出，则会导致进程堵塞无法运行
InputStream in = child.getInputStream();// 控制台的输出信息作为输入流
InputStreamReader xx = new InputStreamReader(in, "utf8");// 设置输出流编码为utf8。这里必须是utf8，否则从流中读入的是乱码
String inStr;
StringBuffer sb = new StringBuffer("");
String outStr;
// 组合控制台输出信息字符串
BufferedReader br = new BufferedReader(xx);
while ((inStr = br.readLine()) != null) {
sb.append(inStr + "\r\n");
}
outStr = sb.toString();
// 要用来做导入用的sql目标文件：
FileOutputStream fout = new FileOutputStream(
"e:/mysql-5.0.27-win32/bin/bjse22.sql");
OutputStreamWriter writer = new OutputStreamWriter(fout, "utf8");
writer.write(outStr);
// 注：这里如果用缓冲方式写入文件的话，会导致中文乱码，用flush()方法则可以避免
writer.flush();
// 别忘记关闭输入输出流
in.close();
xx.close();
br.close();
writer.close();
fout.close();
System.out.println("");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void load() {
try {
String fPath = "e:/mysql-5.0.27-win32/bin/bjse22.sql";
Runtime rt = Runtime.getRuntime();
// 调用 mysql 的 cmd:
Process child = rt.exec("mysql -u root bjse ");
OutputStream out = child.getOutputStream();//控制台的输入信息作为输出流
String inStr;
StringBuffer sb = new StringBuffer("");
String outStr;
BufferedReader br = new BufferedReader(new InputStreamReader(
new FileInputStream(fPath), "utf8"));
while ((inStr = br.readLine()) != null) {
sb.append(inStr + "\r\n");
}
outStr = sb.toString();
OutputStreamWriter writer = new OutputStreamWriter(out, "utf8");
writer.write(outStr);
// 注：这里如果用缓冲方式写入文件的话，会导致中文乱码，用flush()方法则可以避免
writer.flush();
// 别忘记关闭输入输出流
out.close();
br.close();
writer.close();
System.out.println("");
} catch (Exception e) {
e.printStackTrace();
}
}
备份语句：
mysql> SELECT * INTO OUTFILE "D:\\data\\db_testtemp.txt" fields terminated by ',
' from db_testtemp where std_state='1';
Query OK, 1 row affected (0.00 sec)
mysql> SELECT * INTO OUTFILE "D:\\data\\db_testtemp.txt" fields terminated by ',
' from db_testtemp ;
Query OK, 2 rows affected (0.00 sec)
只生成一个只有数据的.txt:SELECT * INTO OUTFILE "D:\\data\\db_testtemp.txt" fields terminated by ',' lines terminated by '\r\n' from db_testtemp ;
只生成一个只有数据的.txt:mysqlmp -uroot -pncae2010 -w "std_state='1'" -T D:\data --no-create-info --fields-terminated-by=, exam db_testtemp
生成一个创建数据库语句的.sql,一个只有数据的.txt:mysqlmp -uroot -pncae2010 -w "std_state='1'" -T D:\data --fields-terminated-by=, exam db_testtemp
只生成insert语句：mysqlmp -uroot -pncae2010 -w "std_state='1'" -t exam db_testtemp > D:\data\a.sql
2. java怎么获得 mysql 当前数据库大小
我倒是有个方法，以前我做个mysql数据库备份，备份的时候也就是赋值数据库的过程，当然能知道大小了，要是想实时获取的话那就就定义一个线程来空值就可以了，代码大概如下：其中赋值的过程楼主可省略，你要的就是一个值，就是sb的大小。。
package com.huagong.backdatabase;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
public class BackmysqlUtil {
/**
*
* mysql数据备份 接收脚本名，并返回此路径
*
* sql为备份的脚本名比如eg.sql
* @throws IOException
*
*/
public static void backup(String sqlname,String readlyPath) throws IOException {
Properties pros = getPprVue("backup.properties");
String username = pros.getProperty("username");
String password = pros.getProperty("password");
// 得到MYSQL的用户名密码后调用 mysql 的 cmd:
String databaseName = pros.getProperty("databaseName");
String address = pros.getProperty("address");
File backupath = new File(readlyPath);
if (!backupath.exists()) {
backupath.mkdir();
}
StringBuffer sb = new StringBuffer();
sb.append(" mysqlmp ");
sb.append("--opt ");
sb.append("-h ");
sb.append(address);
sb.append(" ");
sb.append("--user=");
sb.append(username);
sb.append(" ");
sb.append("--password=");
sb.append(password);
sb.append(" ");
sb.append("--lock-all-tables=true ");
sb.append("--result-file=");
sb.append(readlyPath);
sb.append(sqlname);
sb.append(" ");
sb.append("--default-character-set=utf8 ");
sb.append(databaseName);
Runtime cmd = Runtime.getRuntime();
Process p = cmd.exec(sb.toString());
pros.setProperty("ss", "ss");
}
public static void load(String filename,String readlyPath) throws IOException {
Properties pros = getPprVue("backup.properties");
// 这里是读取的属性文件，也可以直接使用
String root = pros.getProperty("username");
String pass = pros.getProperty("password");
// 得到MYSQL的用户名密码后调用 mysql 的 cmd:
String filepath = readlyPath + filename; // 备份的路径地址
// 新建数据库newdb
String stmt1 = "mysqladmin -u " + root + " -p" + pass
+ " create newdb";
// -p后面加的是你的密码
String stmt2 = "mysql -u " + root + " -p" + pass + " newdb < "
+ filepath;
String[] cmd = { "cmd", "/c", stmt2 };
Runtime.getRuntime().exec(stmt1);
Runtime.getRuntime().exec(cmd);
System.out.println("数据已从 " + filepath + " 导入到数据库中");
}
// 加载配置文件
public static Properties getPprVue(String properName) throws IOException {
InputStream inputStream = BackmysqlUtil.class.getClassLoader()
.getResourceAsStream(properName);
Properties p = new Properties();
p.load(inputStream);
inputStream.close();
return p;
}
//测试
public static void main(String[] args) throws IOException {
backup("eg.sql","e:\\mysql\\");
//load("eg.sql","e:\\mysql\\");
}
}
配置文件：
backup.properties配置文件的内容如下,用户名和密码随便你改。
#mysqlpath = D:\\ProgramFiles\\wamp\\bin\\mysql\\mysql5.1.32\\bin
#sqlpath = E:\\MySQl\\
username = root
password = cool
address=localhost
databaseName=huagongdb
最后你想什么时候调用直接就在程序里用一个线程控制调用就可以了。