MyBatis - how to create w dynamic WHERE Clause

Question

The service gets an unknown object containing a list of three values ​​[column, operator, value] For example, EMAIL - like - \"TEST\"

Based on the resulting list to

Answer 1

I have been rediscovering MyBatis after a long absence myself (I was familiar with iBatis at one time). Rolf's example looks like it might be the .Net implementation, I may be wrong but I don't think the Java notation looks like that now. Rolf's tip about the literal strings is very useful.

I've created a little class to hold your columns, operators and value and pass these into MyBatis to do the processing. The columns and operators are string literals but I have left the values as sql parameters (I imagine MyBatis would be able to do any necessary type conversion).

public class TestAnswer {
    public static void main(String[] args) {
            ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
            SqlSessionFactory sqlFactory = (SqlSessionFactory) ctx.getBean("sqlSessionFactory");            
            MappedStatement statement = sqlFactory.getConfiguration().getMappedStatement("testAnswer");                        

            ArrayList params1 = new ArrayList();
            params1.add(new Clause("email","like","test"));
            params1.add(new Clause("user","<>",5));

            ArrayList params2 = new ArrayList();
            params2.add(new Clause("trans_id","<",100));
            params2.add(new Clause("session_id",">",500));

            HashMap params = new HashMap();
            params.put("params1", params1);
            params.put("params2", params2);

            BoundSql boundSql = statement.getBoundSql(params);
            System.out.println(boundSql.getSql());             
    }

    static class Clause{        
        private String column;
        private String operator;
        private Object value;

        public Clause(String column, String operator, Object value){
            this.column = column;
            this.operator = operator;
            this.value = value;
        }

        public void setColumn(String column) {this.column = column;}
        public void setOperator(String operator) {this.operator = operator;}
        public void setValue(Object value) {this.value = value;}
        public String getColumn() {return column;}
        public String getOperator() {return operator;}
        public Object getValue() {return value;}        
    }    
}

As you can see, I use Spring but I expect something similar would probably work outside of the Spring environment.

    

    
      select *
    FROM somewhere
        
             
                ${clause.column} ${clause.operator} #{clause.value} 
                        
            OR
             
                ${clause.column} ${clause.operator} #{clause.value}