Mybatis SqlRunner execution process

Mybatis’ SqlRunner execution process

 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"));

Initialization process of TYPE_HANDLER_MAP in TypeHandlerRegistry class

 public TypeHandlerRegistry() {
    //Register the system's built-in type processor in the constructor
//The following is registered to the same handler for multiple types
    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());

//The following is to register multiple different handlers for multiple variants of the same type
    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());
  }

Back to the process

Original jdbc code

/*
Execute DQL statement
*/

import java.sql.*;
import java.util.*;

public class JDBCTest05 {
public static void main(String[] args) {
// 1. Register driver
// 2. Establish connection
// 3. Get the database operation object
// 4. Execute sql statement
// 5. Get the query result set
// 6. Release resources
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
\t\t
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");
\t
while(rs.next()){
/*
String empno = rs.getString(1);
String ename = rs.getString(2);
String sal = rs.getString(3);
System.out.println(empno + "," + ename + "," + sal);
*/
\t\t\t\t
/*
// Extract by pressing the subscript, the program is not robust
String empno = rs.getString("empno");
String ename = rs.getString("ename");
String sal = rs.getString("sal");
System.out.println(empno + "," + ename + "," + sal);
*/
\t\t\t\t
/*
// Get it in the specified format
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();
}
}
}
}
}

The knowledge points of the article match the official knowledge files, and you can further learn related knowledge. Java Skill TreeHomepageOverview 138072 people are learning the system