Java Mysql 简明教程
Java & MySQL - Batching with Statement Object
以下是有关如何对语句对象使用批量处理的典型步骤序列:
-
使用 createStatement() 方法创建语句对象。
-
使用 setAutoCommit() 将自动提交设置为 false。
-
使用所创建的语句对象上的 addBatch() 方法向批处理中添加任意数量的 SQL 语句。
-
使用 executeStatement() 方法对已创建的语句对象执行所有 SQL 语句。
-
最后,使用 commit() 方法提交所有更改。
此示例代码基于先前章节中完成的环境和数据库设置编写。
将以下示例复制并粘贴到 TestApplication.java 中,如下进行编译和运行:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestApplication {
static final String DB_URL = "jdbc:mysql://localhost/TUTORIALSPOINT";
static final String USER = "guest";
static final String PASS = "guest123";
public static void printResultSet(ResultSet rs) throws SQLException{
// Ensure we start with first row
rs.beforeFirst();
while(rs.next()){
// Display values
System.out.print("ID: " + rs.getInt("id"));
System.out.print(", Age: " + rs.getInt("age"));
System.out.print(", First: " + rs.getString("first"));
System.out.println(", Last: " + rs.getString("last"));
}
System.out.println();
}
public static void main(String[] args) {
// Open a connection
try(Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
Statement stmt = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE)
) {
conn.setAutoCommit(false);
ResultSet rs = stmt.executeQuery("Select * from Employees");
printResultSet(rs);
// Create SQL statement
String SQL = "INSERT INTO Employees (first, last, age) " +
"VALUES('Zia', 'Ali', 30)";
// Add above SQL statement in the batch.
stmt.addBatch(SQL);
// Create one more SQL statement
SQL = "INSERT INTO Employees (first, last, age) " +
"VALUES('Raj', 'Kumar', 35)";
// Add above SQL statement in the batch.
stmt.addBatch(SQL);
// Create one more SQL statement
SQL = "UPDATE Employees SET age = 35 " +
"WHERE id = 7";
// Add above SQL statement in the batch.
stmt.addBatch(SQL);
// Create an int[] to hold returned values
int[] count = stmt.executeBatch();
//Explicitly commit statements to apply changes
conn.commit();
rs = stmt.executeQuery("Select * from Employees");
printResultSet(rs);
stmt.close();
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
现在让我们如下编译上述示例:
C:\>javac TestApplication.java
C:\>
运行 TestApplication 时,它会生成以下结果:
C:\>java TestApplication
ID: 1, Age: 23, First: Zara, Last: Ali
ID: 2, Age: 30, First: Mahnaz, Last: Fatma
ID: 3, Age: 35, First: Zaid, Last: Khan
ID: 4, Age: 33, First: Sumit, Last: Mittal
ID: 5, Age: 40, First: John, Last: Paul
ID: 7, Age: 20, First: Sita, Last: Singh
ID: 8, Age: 20, First: Rita, Last: Tez
ID: 9, Age: 20, First: Sita, Last: Singh
ID: 1, Age: 23, First: Zara, Last: Ali
ID: 2, Age: 30, First: Mahnaz, Last: Fatma
ID: 3, Age: 35, First: Zaid, Last: Khan
ID: 4, Age: 33, First: Sumit, Last: Mittal
ID: 5, Age: 40, First: John, Last: Paul
ID: 7, Age: 35, First: Sita, Last: Singh
ID: 8, Age: 20, First: Rita, Last: Tez
ID: 9, Age: 20, First: Sita, Last: Singh
ID: 10, Age: 30, First: Zia, Last: Ali
ID: 11, Age: 35, First: Raj, Last: Kumar
C:\>