Mybatis的SqlRunner执行流程
java
SqlRunner exec = new SqlRunner(connection);
Map<String, Object> row = exec.selectOne("SELECT * FROM PRODUCT WHERE PRODUCTID = ?", "FI-SW-01");
connection.close();
assertEquals("FI-SW-01", row.get("PRODUCTID"));
TypeHandlerRegistry类中TYPE_HANDLER_MAP 的初始化过程
java
public TypeHandlerRegistry() {
//构造函数里注册系统内置的类型处理器
//以下是为多个类型注册到同一个handler
register(Boolean.class, new BooleanTypeHandler());
register(boolean.class, new BooleanTypeHandler());
register(JdbcType.BOOLEAN, new BooleanTypeHandler());
register(JdbcType.BIT, new BooleanTypeHandler());
register(Byte.class, new ByteTypeHandler());
register(byte.class, new ByteTypeHandler());
register(JdbcType.TINYINT, new ByteTypeHandler());
register(Short.class, new ShortTypeHandler());
register(short.class, new ShortTypeHandler());
register(JdbcType.SMALLINT, new ShortTypeHandler());
register(Integer.class, new IntegerTypeHandler());
register(int.class, new IntegerTypeHandler());
register(JdbcType.INTEGER, new IntegerTypeHandler());
register(Long.class, new LongTypeHandler());
register(long.class, new LongTypeHandler());
register(Float.class, new FloatTypeHandler());
register(float.class, new FloatTypeHandler());
register(JdbcType.FLOAT, new FloatTypeHandler());
register(Double.class, new DoubleTypeHandler());
register(double.class, new DoubleTypeHandler());
register(JdbcType.DOUBLE, new DoubleTypeHandler());
//以下是为同一个类型的多种变种注册到多个不同的handler
register(String.class, new StringTypeHandler());
register(String.class, JdbcType.CHAR, new StringTypeHandler());
register(String.class, JdbcType.CLOB, new ClobTypeHandler());
register(String.class, JdbcType.VARCHAR, new StringTypeHandler());
register(String.class, JdbcType.LONGVARCHAR, new ClobTypeHandler());
register(String.class, JdbcType.NVARCHAR, new NStringTypeHandler());
register(String.class, JdbcType.NCHAR, new NStringTypeHandler());
register(String.class, JdbcType.NCLOB, new NClobTypeHandler());
register(JdbcType.CHAR, new StringTypeHandler());
register(JdbcType.VARCHAR, new StringTypeHandler());
register(JdbcType.CLOB, new ClobTypeHandler());
register(JdbcType.LONGVARCHAR, new ClobTypeHandler());
register(JdbcType.NVARCHAR, new NStringTypeHandler());
register(JdbcType.NCHAR, new NStringTypeHandler());
register(JdbcType.NCLOB, new NClobTypeHandler());
register(Object.class, JdbcType.ARRAY, new ArrayTypeHandler());
register(JdbcType.ARRAY, new ArrayTypeHandler());
register(BigInteger.class, new BigIntegerTypeHandler());
register(JdbcType.BIGINT, new LongTypeHandler());
register(BigDecimal.class, new BigDecimalTypeHandler());
register(JdbcType.REAL, new BigDecimalTypeHandler());
register(JdbcType.DECIMAL, new BigDecimalTypeHandler());
register(JdbcType.NUMERIC, new BigDecimalTypeHandler());
register(Byte[].class, new ByteObjectArrayTypeHandler());
register(Byte[].class, JdbcType.BLOB, new BlobByteObjectArrayTypeHandler());
register(Byte[].class, JdbcType.LONGVARBINARY, new BlobByteObjectArrayTypeHandler());
register(byte[].class, new ByteArrayTypeHandler());
register(byte[].class, JdbcType.BLOB, new BlobTypeHandler());
register(byte[].class, JdbcType.LONGVARBINARY, new BlobTypeHandler());
register(JdbcType.LONGVARBINARY, new BlobTypeHandler());
register(JdbcType.BLOB, new BlobTypeHandler());
register(Object.class, UNKNOWN_TYPE_HANDLER);
register(Object.class, JdbcType.OTHER, UNKNOWN_TYPE_HANDLER);
register(JdbcType.OTHER, UNKNOWN_TYPE_HANDLER);
register(Date.class, new DateTypeHandler());
register(Date.class, JdbcType.DATE, new DateOnlyTypeHandler());
register(Date.class, JdbcType.TIME, new TimeOnlyTypeHandler());
register(JdbcType.TIMESTAMP, new DateTypeHandler());
register(JdbcType.DATE, new DateOnlyTypeHandler());
register(JdbcType.TIME, new TimeOnlyTypeHandler());
register(java.sql.Date.class, new SqlDateTypeHandler());
register(java.sql.Time.class, new SqlTimeTypeHandler());
register(java.sql.Timestamp.class, new SqlTimestampTypeHandler());
// issue #273
register(Character.class, new CharacterTypeHandler());
register(char.class, new CharacterTypeHandler());
}
回到流程中
原始的jdbc代码
java
/*
执行DQL语句
*/
import java.sql.*;
import java.util.*;
public class JDBCTest05 {
public static void main(String[] args) {
// 1、注册驱动
// 2、建立连接
// 3、获取数据库操作对象
// 4、执行sql语句
// 5、获取查询结果集
// 6、释放资源
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
ResourceBundle rb = ResourceBundle.getBundle("jdbc");
String driver = rb.getString("driver");
String url = rb.getString("url");
String user = rb.getString("user");
String password = rb.getString("password");
Class.forName(driver);
conn = DriverManager.getConnection(url,user,password);
stmt = conn.createStatement();
rs = stmt.executeQuery("select empno,ename,sal from emp");
while(rs.next()){
/*
String empno = rs.getString(1);
String ename = rs.getString(2);
String sal = rs.getString(3);
System.out.println(empno + "," + ename + "," + sal);
*/
/*
// 按下标取出，程序不健壮
String empno = rs.getString("empno");
String ename = rs.getString("ename");
String sal = rs.getString("sal");
System.out.println(empno + "," + ename + "," + sal);
*/
/*
// 以指定的格式取出
int empno = rs.getInt(1);
String ename = rs.getString(2);
double sal = rs.getDouble(3);
System.out.println(empno + "," + ename + "," + (sal + 100));
*/
int empno = rs.getInt("empno");
String ename = rs.getString("ename");
double sal = rs.getDouble("sal");
System.out.println(empno + "," + ename + "," + (sal + 200));
}
} catch(Exception e){
e.printStackTrace();
}finally{
if(rs != null){
try{
rs.close();
} catch (Exception e){
e.printStackTrace();
}
}
if(stmt != null){
try{
stmt.close();
} catch (Exception e){
e.printStackTrace();
}
}
if(conn != null){
try{
conn.close();
} catch (Exception e){
e.printStackTrace();
}
}
}
}
}