java 使用JSqlParser和CCJSqlParser 解析sql

memgLIFE2024-12-07 12:10

maven

java 复制代码

<dependency>
    <groupId>com.github.jsqlparser</groupId>
    <artifactId>jsqlparser</artifactId>
    <version>4.9</version>
</dependency>

解析SQL

java 复制代码

String sql = "select aa,bb from b";
Statement statement=CCJSqlParserUtil.parse(sql)；
Select selectStatement = (Select) statement;
PlainSelect plainSelect = selectStatement.getPlainSelect();
//plainSelect可以获取sql各个部分 如属性集合
List<SelectItem<?>> selectItems0 = plainSelect.getSelectItems();

分析

Statement 被设计成一个接口满足CURD各个处理方式

1、查询PlainSelect继承Select

java 复制代码

        1.1//字段起别名  SELECT aa AS ALIAS1, bb AS ALIAS2 FROM b
        AddAliasesVisitor instance = new AddAliasesVisitor();
        instance.setPrefix("alias");
        selectStatement.accept(instance);
        1.2//加字段SELECT aa AS ALIAS1, bb AS ALIAS2, field FROM b
        SelectUtils.addExpression(selectStatement, new Column("field"));
        1.3//加字段表达式 SELECT aa AS ALIAS1, bb AS ALIAS2, field, 5 + 6 FROM b
                Addition add = new Addition();
        add.setLeftExpression(new LongValue(5));
        add.setRightExpression(new LongValue(6));
        SelectUtils.addExpression(selectStatement, add);
        1.4//加join  
        //SELECT aa AS ALIAS1, bb AS ALIAS2, field, 5 + 6 FROM b LEFT JOIN mytable2 ON a = b
        
        EqualsTo equalsTo = new EqualsTo();
        Statement select = (PlainSelect) test(sql);
        equalsTo.setLeftExpression(new Column("a"));
        equalsTo.setRightExpression(new Column("b"));
        Join addJoin = SelectUtils.addJoin(selectStatement, new Table("mytable2"), equalsTo);
        addJoin.setLeft(true);
        //SelectUtils构建一个SQL语句
                Select selectbuild = SelectUtils.buildSelectFromTableAndExpressions(new Table("mytable"), new Column("a"), new Column("b"));
       //SELECT a, b, c FROM mytable
       SelectUtils.addExpression(selectbuild, new Column("c"));
        //where 条件设置
        EqualsTo equalsTo1 = new EqualsTo();
        equalsTo1.setLeftExpression(new Column("id"));
        equalsTo1.setRightExpression(new Column("1"));
        PlainSelect plainSelect1 = selectbuild.getPlainSelect();
        plainSelect1.setWhere(equalsTo1);
        更多条件访问 https://blog.csdn.net/a250152/article/details/128610616

2、插入Insert

3、更新Update

4、删除Delete