哪怕对自己的一点小小的克制，也会使人变得强而有力。——高尔基
分享一个开源项目lambda2sql：
https://github.com/ajermakovics/lambda2sql
编写如下的lambda
person -> person.getAge() < 100 && person.getHeight() > 200会被转换为
代码语言：javascript复制age < 100 AND height > 200使用起来非常简单，也非常有意思
代码语言：javascript复制package lambda2sql;
import org.junit.Assert;
import org.junit.Test;
public class Lambda2SqlTest {
@Test
public void testComparisons() {
assertEqual("age = 1", e -> e.getAge() == 1);
assertEqual("age > 1", e -> e.getAge() > 1);
assertEqual("age < 1", e -> e.getAge() < 1);
assertEqual("age >= 1", e -> e.getAge() >= 1);
assertEqual("age <= 1", e -> e.getAge() <= 1);
assertEqual("age != 1", e -> e.getAge() != 1);
}
@Test
public void testLogicalOps() {
assertEqual("!isActive", e -> !e.isActive());
assertEqual("age < 100 AND height > 200", e -> e.getAge() < 100 && e.getHeight() > 200);
assertEqual("age < 100 OR height > 200", e -> e.getAge() < 100 || e.getHeight() > 200);
}
@Test
public void testMultipleLogicalOps() {
assertEqual("isActive AND (age < 100 OR height > 200)", e -> e.isActive() && (e.getAge() < 100 || e.getHeight() > 200));
assertEqual("(age < 100 OR height > 200) AND isActive", e -> (e.getAge() < 100 || e.getHeight() > 200) && e.isActive());
}
@Test
public void testWithVariables() {
String name = "Donald";
int age = 80;
assertEqual("name = 'Donald' AND age > 80", person -> person.getName() == name && person.getAge() > age);
}
private void assertEqual(String expectedSql, SqlPredicate<Person> p) {
String sql = Lambda2Sql.toSql(p);
Assert.assertEquals(expectedSql, sql);
}
}
