简介

        JSqlParse是一款很精简的sql解析工具，它可以将常用的sql文本解析成具有层级结构的语法树，我们可以针对解析后的节点进行处理(增加、移除、修改等操作),从而生成符合我们业务要求的sql，比如添加过滤条件等等

     JSqlParse采用访问者模式

项目简介

        

项目结构非常简单，从截图上看就5个包。如果对源码感兴趣的可以直接从github上下载源码包调试。其中expression包包含了所有的sql表达式的抽象对象：

statement包含了所有sql语句的类型，比如：增删改查，ddl语句,rollback语句等等

schema包是对数据库基本单元的抽象：服务器、数据库、表、列等等

parser包是整个解析的核心逻辑，感兴趣的可以自行源码调试

使用示例

        上面已经做了关于该解析工具的简单介绍，对于工具类，最重要的使用。以下举例关于增、删、改、查的sql语句中，均增加一列为例介绍该工具的简单使用

依赖引入

<dependency><groupId>com.github.jsqlparser</groupId><artifactId>jsqlparser</artifactId><version>4.5</version>
</dependency>

新增add

原始sql：insert into t_user_info(id,user_name,address) values('123','zhangsan','龙华')

期望在执行该sql时，能增加一列STATUS作为插入

都是一些api的运用，相关代码如下：

package com.lyc.boot.client.test.insert;import com.lyc.boot.client.test.insert.visitor.InsertStatementVisitor;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.RowConstructor;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.relational.ExpressionList;
import net.sf.jsqlparser.expression.operators.relational.ItemsList;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.statement.Statement;
import net.sf.jsqlparser.statement.insert.Insert;
import net.sf.jsqlparser.statement.select.Select;
import net.sf.jsqlparser.statement.select.SelectBody;
import net.sf.jsqlparser.statement.select.SetOperationList;
import net.sf.jsqlparser.statement.values.ValuesStatement;import java.util.List;import static com.lyc.boot.client.test.CommonUtil.printStatement;
import static com.lyc.boot.client.test.CommonUtil.printTableName;@Slf4j
public class InsertCommonTest {private static final String INSERT_COMMON = "insert into t_user_info(id,user_name,address) values('123','zhangsan','龙华')";public static void main(String[] args) throws JSQLParserException {useCommonAddColumn();
//        useVisitorAddColumn();}private static void useCommonAddColumn() throws JSQLParserException {Statement statement = CCJSqlParserUtil.parse(INSERT_COMMON);printStatement(statement);if (statement instanceof Insert) {Insert insert = (Insert)statement;printTableName(insert.getTable());List<Column> columns = insert.getColumns();columns.add(new Column("STATUS"));Select select = insert.getSelect();SelectBody selectBody = select.getSelectBody();if (selectBody instanceof SetOperationList) {SetOperationList operationList = (SetOperationList)selectBody;List<SelectBody> selects = operationList.getSelects();for (SelectBody body : selects) {if (body instanceof ValuesStatement) {ValuesStatement valuesStatement = (ValuesStatement)body;ItemsList itemsList = valuesStatement.getExpressions();if(itemsList instanceof ExpressionList) {ExpressionList expressionList = (ExpressionList)itemsList;List<Expression> expressions = expressionList.getExpressions();for (Expression expression : expressions) {if(expression instanceof RowConstructor) {RowConstructor rowConstructor = (RowConstructor)expression;ExpressionList exprList = rowConstructor.getExprList();List<Expression> rowConstructorExList = exprList.getExpressions();rowConstructorExList.add(new StringValue("0"));}}}}}}}printStatement(statement);}/*** 使用访问者方式增加insert的column** @throws JSQLParserException*/private static void useVisitorAddColumn() throws JSQLParserException {Statement statement = CCJSqlParserUtil.parse(INSERT_COMMON);printStatement(statement);statement.accept(new InsertStatementVisitor());printStatement(statement);}}

package com.lyc.boot.client.test.insert.visitor;import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.statement.StatementVisitorAdapter;
import net.sf.jsqlparser.statement.insert.Insert;
import net.sf.jsqlparser.statement.select.Select;
import net.sf.jsqlparser.statement.select.SelectBody;import java.util.List;import static com.lyc.boot.client.test.CommonUtil.printTableName;public class InsertStatementVisitor extends StatementVisitorAdapter {@Overridepublic void visit(Insert insert) {printTableName(insert.getTable());List<Column> columns = insert.getColumns();columns.add(new Column("status"));Select select = insert.getSelect();SelectBody selectBody = select.getSelectBody();selectBody.accept(new InsertSelectVisitor());}
}

package com.lyc.boot.client.test.insert.visitor;import net.sf.jsqlparser.expression.operators.relational.ItemsList;
import net.sf.jsqlparser.statement.select.SelectBody;
import net.sf.jsqlparser.statement.select.SelectVisitorAdapter;
import net.sf.jsqlparser.statement.select.SetOperationList;
import net.sf.jsqlparser.statement.values.ValuesStatement;import java.util.List;public class InsertSelectVisitor extends SelectVisitorAdapter {@Overridepublic void visit(SetOperationList setOpList) {List<SelectBody> selects = setOpList.getSelects();for (SelectBody body : selects) {body.accept(this);}}@Overridepublic void visit(ValuesStatement valuesStatement) {ItemsList itemsList = valuesStatement.getExpressions();itemsList.accept(new InsertItemsListVisitor());}
}

package com.lyc.boot.client.test.insert.visitor;import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.operators.relational.ExpressionList;
import net.sf.jsqlparser.util.validation.validator.ItemsListValidator;import java.util.List;public class InsertItemsListVisitor extends ItemsListValidator {@Overridepublic void visit(ExpressionList expressionList) {List<Expression> expressions = expressionList.getExpressions();for (Expression expression : expressions) {expression.accept(new InsertExpressionVisitor());}}
}

package com.lyc.boot.client.test.insert.visitor;import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.ExpressionVisitorAdapter;
import net.sf.jsqlparser.expression.RowConstructor;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.relational.ExpressionList;import java.util.List;public class InsertExpressionVisitor extends ExpressionVisitorAdapter {@Overridepublic void visit(RowConstructor rowConstructor) {ExpressionList exprList = rowConstructor.getExprList();List<Expression> expressions = exprList.getExpressions();expressions.add(new StringValue("0"));}
}

      以上是关于新增sql增加一列作为插入的简单运用，其中有通过类型判断处理和通过访问者模式处理(基于java多态实现)，最终打印的结果如下：

删除delete

原sql：delete from t_user_info where user_name = ? and addres = ?

期望在删除时增加过滤条件STATUS='0'

相关代码如下：

package com.lyc.boot.client.test.delete;import com.lyc.boot.client.test.delete.visitor.DeleteStatementVisitor;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.statement.Statement;
import net.sf.jsqlparser.statement.delete.Delete;import static com.lyc.boot.client.test.CommonUtil.printStatement;@Slf4j
public class DeleteCommonTest {private static final String DELETE_COMMON = "delete from t_user_info where user_name = ? and addres = ?";public static void main(String[] args) throws JSQLParserException {
//        commonAddColumn();visitorAddColumn();}private static void visitorAddColumn() throws JSQLParserException{Statement statement = CCJSqlParserUtil.parse(DELETE_COMMON);printStatement(statement);statement.accept(new DeleteStatementVisitor());printStatement(statement);}private static void commonAddColumn() throws JSQLParserException {Statement statement = CCJSqlParserUtil.parse(DELETE_COMMON);printStatement(statement);if(statement instanceof Delete) {Delete delete = (Delete)statement;DeleteStatementVisitor.addColumn(delete);}printStatement(statement);}
}

package com.lyc.boot.client.test.delete.visitor;import com.lyc.boot.client.test.CommonUtil;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.Parenthesis;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.conditional.AndExpression;
import net.sf.jsqlparser.expression.operators.relational.EqualsTo;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.statement.StatementVisitorAdapter;
import net.sf.jsqlparser.statement.delete.Delete;import java.util.Objects;@Slf4j
public class DeleteStatementVisitor extends StatementVisitorAdapter {@Overridepublic void visit(Delete delete) {addColumn(delete);}public static void addColumn(Delete delete) {CommonUtil.printTableName(delete.getTable());Expression where = delete.getWhere();Parenthesis parenthesis = new Parenthesis(new EqualsTo(new Column("STATUS"), new StringValue("1")));if (Objects.isNull(where)) {delete.setWhere(parenthesis);} else {delete.setWhere(new AndExpression(where,parenthesis));}}
}

执行结果如下图：

修改update

原sql为：update t_user_info set user_name = ?,address = ? where id = ? and score = ?

期望在修改时set增加STATUS = ? where条件增加STATUS = '1'

package com.lyc.boot.client.test.update;import com.lyc.boot.client.test.update.visitor.UpdateStatementVisitor;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.JdbcParameter;
import net.sf.jsqlparser.expression.Parenthesis;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.conditional.AndExpression;
import net.sf.jsqlparser.expression.operators.relational.EqualsTo;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.Statement;
import net.sf.jsqlparser.statement.update.Update;
import net.sf.jsqlparser.statement.update.UpdateSet;import java.util.ArrayList;
import java.util.Objects;import static com.lyc.boot.client.test.CommonUtil.printStatement;/*** update语句修改***/
@Slf4j
public class UpdateCommonTest {private static final String COMMON_UPDATE = "update t_user_info set user_name = ?,address = ? where id = ? and score = ?";public static void main(String[] args) throws JSQLParserException {
//        commonUpdateAddColumn();visitorAddColumn();}private static void visitorAddColumn() throws JSQLParserException{Statement statement = CCJSqlParserUtil.parse(COMMON_UPDATE);printStatement(statement);statement.accept(new UpdateStatementVisitor());printStatement(statement);}private static void commonUpdateAddColumn() throws JSQLParserException {Statement statement = CCJSqlParserUtil.parse(COMMON_UPDATE);printStatement(statement);if(statement instanceof Update) {Update update = (Update)statement;Table table = update.getTable();ArrayList<UpdateSet> updateSets = update.getUpdateSets();Column column = new Column("STATUS");StringValue stringValue = new StringValue("?");JdbcParameter jdbcParameter = new JdbcParameter();UpdateSet updateSet = new UpdateSet(column,jdbcParameter);updateSets.add(updateSet);Expression whereExpression = update.getWhere();EqualsTo equalsTo = new EqualsTo(new Column("STATUS"), new StringValue("1"));Parenthesis parenthesis = new Parenthesis(equalsTo);if (Objects.isNull(whereExpression)) {update.setWhere(parenthesis);} else {update.setWhere(new AndExpression(whereExpression,parenthesis));}}printStatement(statement);}}

package com.lyc.boot.client.test.update.visitor;import com.lyc.boot.client.test.CommonUtil;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.JdbcParameter;
import net.sf.jsqlparser.expression.Parenthesis;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.conditional.AndExpression;
import net.sf.jsqlparser.expression.operators.relational.EqualsTo;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.StatementVisitorAdapter;
import net.sf.jsqlparser.statement.update.Update;
import net.sf.jsqlparser.statement.update.UpdateSet;import java.util.ArrayList;
import java.util.Objects;@Slf4j
public class UpdateStatementVisitor extends StatementVisitorAdapter {@Overridepublic void visit(Update update) {CommonUtil.printTableName(update.getTable());ArrayList<UpdateSet> updateSets = update.getUpdateSets();UpdateSet statusUpdateSet = new UpdateSet(new Column("STATUS"), new JdbcParameter());updateSets.add(statusUpdateSet);Expression where = update.getWhere();Parenthesis parenthesis = new Parenthesis(new EqualsTo(new Column("STATUS"), new StringValue("1")));if (Objects.isNull(where)) {update.setWhere(parenthesis);} else {update.setWhere(new AndExpression(where,parenthesis));}}
}

执行结果如下图所示：

查询select

原sql如下：select id as id,user_name as userName,address as address from t_user_info where id = ? and user_name = ? order by create_time desc

期望在查询时增加where的过滤条件STATUS = '1'

package com.lyc.boot.client.test.select;import com.lyc.boot.client.test.select.visitor.SelectSelectVisitor;
import com.lyc.boot.client.test.select.visitor.SelectStatementVisitor;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import net.sf.jsqlparser.statement.Statement;
import net.sf.jsqlparser.statement.select.*;import static com.lyc.boot.client.test.CommonUtil.printStatement;@Slf4j
/*** 给查询条件添加更多的过滤条件** and status = '1'*/
public class SelectCommonTest {private static final String SELECT_COMMON = "select id as id,user_name as userName,address as address from t_user_info where id = ? and user_name = ? order by create_time desc";public static void main(String[] args) throws JSQLParserException {
//        commonSelectAddWhere();visitorSelectAddWhere();}private static void visitorSelectAddWhere() throws JSQLParserException{Statement statement = CCJSqlParserUtil.parse(SELECT_COMMON);printStatement(statement);statement.accept(new SelectStatementVisitor());printStatement(statement);}private static void commonSelectAddWhere() throws JSQLParserException {Statement statement = CCJSqlParserUtil.parse(SELECT_COMMON);printStatement(statement);if (statement instanceof Select) {Select select = (Select)statement;SelectBody selectBody = select.getSelectBody();if (selectBody instanceof PlainSelect) {PlainSelect plainSelect = (PlainSelect)selectBody;SelectSelectVisitor.setWhereExpression(plainSelect);}}printStatement(statement);}}

package com.lyc.boot.client.test.select.visitor;import net.sf.jsqlparser.statement.StatementVisitorAdapter;
import net.sf.jsqlparser.statement.select.Select;
import net.sf.jsqlparser.statement.select.SelectBody;public class SelectStatementVisitor extends StatementVisitorAdapter {@Overridepublic void visit(Select select) {SelectBody selectBody = select.getSelectBody();selectBody.accept(new SelectSelectVisitor());}
}

package com.lyc.boot.client.test.select.visitor;import com.lyc.boot.client.test.CommonUtil;
import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.Parenthesis;
import net.sf.jsqlparser.expression.StringValue;
import net.sf.jsqlparser.expression.operators.conditional.AndExpression;
import net.sf.jsqlparser.expression.operators.relational.EqualsTo;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.select.PlainSelect;
import net.sf.jsqlparser.statement.select.SelectVisitorAdapter;import java.util.List;
import java.util.Objects;@Slf4j
public class SelectSelectVisitor extends SelectVisitorAdapter {@Overridepublic void visit(PlainSelect plainSelect) {setWhereExpression(plainSelect);}public static void setWhereExpression(PlainSelect plainSelect) {Expression where = plainSelect.getWhere();EqualsTo equalsTo = new EqualsTo(new Column("STATUS"), new StringValue("1"));Parenthesis parenthesis = new Parenthesis(equalsTo);if (Objects.isNull(where)) {plainSelect.setWhere(parenthesis);} else {AndExpression andExpression = new AndExpression(where, parenthesis);plainSelect.setWhere(andExpression);}}
}

执行结果如下图：

扩展简析

jsqlParser的实际之一就是在mybaits-plus中的各种插件，比如：多租户插件com.baomidou.mybatisplus.extension.plugins.inner.TenantLineInnerInterceptor

该插件的作用是：在执行sql时在where条件处增加了过滤条件(默认是tenant_id = ?,具体的字段可以自己配置实现)

当配置了MybatisPlusInterceptor，并且添加了TenantLineInnerInterceptor时，在执行sql时会被该拦截器拦截，具体的源码流程如下：

当执行查询语句时，sql会被MybatisPlusInterceptor插件拦截，插件调TenantLineInnerInterceptor的beforeQuery方法触发

其中BaseMultiTableInnerInterceptor是JsqlParserSupport的子类，提供了模板方法用于修改sql

图上，生成的sql由com.baomidou.mybatisplus.extension.parser.JsqlParserSupport#parserSingle方法决定

最终执行sql解析完成添加过滤条件的操作：

在TenantLineInnerInterceptor插件中，最终是在where结尾出添加了(默认)tenant_id = xxxx的过滤条件，完成多租户数据隔离处理的。具体的源码逻辑可以调试根据