Document Information

Preface

Part I Introduction

1.  Overview

2.  Using the Tutorial Examples

Part II The Web Tier

3.  Getting Started with Web Applications

4.  JavaServer Faces Technology

5.  Introduction to Facelets

6.  Expression Language

7.  Using JavaServer Faces Technology in Web Pages

8.  Using Converters, Listeners, and Validators

9.  Developing with JavaServer Faces Technology

10.  JavaServer Faces Technology: Advanced Concepts

11.  Using Ajax with JavaServer Faces Technology

12.  Composite Components: Advanced Topics and Example

13.  Creating Custom UI Components and Other Custom Objects

14.  Configuring JavaServer Faces Applications

15.  Java Servlet Technology

16.  Uploading Files with Java Servlet Technology

17.  Internationalizing and Localizing Web Applications

Part III Web Services

18.  Introduction to Web Services

19.  Building Web Services with JAX-WS

20.  Building RESTful Web Services with JAX-RS

21.  JAX-RS: Advanced Topics and Example

Part IV Enterprise Beans

22.  Enterprise Beans

23.  Getting Started with Enterprise Beans

24.  Running the Enterprise Bean Examples

25.  A Message-Driven Bean Example

26.  Using the Embedded Enterprise Bean Container

27.  Using Asynchronous Method Invocation in Session Beans

Part V Contexts and Dependency Injection for the Java EE Platform

28.  Introduction to Contexts and Dependency Injection for the Java EE Platform

29.  Running the Basic Contexts and Dependency Injection Examples

30.  Contexts and Dependency Injection for the Java EE Platform: Advanced Topics

31.  Running the Advanced Contexts and Dependency Injection Examples

Part VI Persistence

32.  Introduction to the Java Persistence API

33.  Running the Persistence Examples

34.  The Java Persistence Query Language

Query Language Terminology

Simplified Query Language Syntax

Select Statements

Update and Delete Statements

Example Queries

Simple Queries

A Basic Select Query

Eliminating Duplicate Values

Using Named Parameters

Queries That Navigate to Related Entities

A Simple Query with Relationships

Navigating to Single-Valued Relationship Fields

Traversing Relationships with an Input Parameter

Traversing Multiple Relationships

Navigating According to Related Fields

Queries with Other Conditional Expressions

The LIKE Expression

The IS NULL Expression

The IS EMPTY Expression

The BETWEEN Expression

Comparison Operators

Bulk Updates and Deletes

Update Queries

Delete Queries

Full Query Language Syntax

BNF Symbols

BNF Grammar of the Java Persistence Query Language

FROM Clause

Identifiers

Identification Variables

Range Variable Declarations

Collection Member Declarations

Joins

Path Expressions

Examples of Path Expressions

Expression Types

Navigation

WHERE Clause

Literals

Input Parameters

Conditional Expressions

Operators and Their Precedence

BETWEEN Expressions

IN Expressions

LIKE Expressions

NULL Comparison Expressions

Empty Collection Comparison Expressions

Collection Member Expressions

Subqueries

Functional Expressions

Case Expressions

NULL Values

Equality Semantics

SELECT Clause

Return Types

The DISTINCT Keyword

Constructor Expressions

ORDER BY Clause

GROUP BY and HAVING Clauses

35.  Using the Criteria API to Create Queries

36.  Creating and Using String-Based Criteria Queries

37.  Controlling Concurrent Access to Entity Data with Locking

38.  Using a Second-Level Cache with Java Persistence API Applications

Part VII Security

39.  Introduction to Security in the Java EE Platform

40.  Getting Started Securing Web Applications

41.  Getting Started Securing Enterprise Applications

42.  Java EE Security: Advanced Topics

Part VIII Java EE Supporting Technologies

43.  Introduction to Java EE Supporting Technologies

44.  Transactions

45.  Resources and Resource Adapters

46.  The Resource Adapter Example

47.  Java Message Service Concepts

48.  Java Message Service Examples

49.  Bean Validation: Advanced Topics

50.  Using Java EE Interceptors

Part IX Case Studies

51.  Duke's Bookstore Case Study Example

52.  Duke's Tutoring Case Study Example

53.  Duke's Forest Case Study Example

Index

 

Creating Queries Using the Java Persistence Query Language

The EntityManager.createQuery and EntityManager.createNamedQuery methods are used to query the datastore by using Java Persistence query language queries.

The createQuery method is used to create dynamic queries, which are queries defined directly within an application’s business logic:

public List findWithName(String name) {
return em.createQuery(
    "SELECT c FROM Customer c WHERE c.name LIKE :custName")
    .setParameter("custName", name)
    .setMaxResults(10)
    .getResultList();
}

The createNamedQuery method is used to create static queries, or queries that are defined in metadata by using the javax.persistence.NamedQuery annotation. The name element of @NamedQuery specifies the name of the query that will be used with the createNamedQuery method. The query element of @NamedQuery is the query:

@NamedQuery(
    name="findAllCustomersWithName",
    query="SELECT c FROM Customer c WHERE c.name LIKE :custName"
)

Here’s an example of createNamedQuery, which uses the @NamedQuery:

@PersistenceContext
public EntityManager em;
...
customers = em.createNamedQuery("findAllCustomersWithName")
    .setParameter("custName", "Smith")
    .getResultList();

Named Parameters in Queries

Named parameters are query parameters that are prefixed with a colon (:). Named parameters in a query are bound to an argument by the following method:

javax.persistence.Query.setParameter(String name, Object value)

In the following example, the name argument to the findWithName business method is bound to the :custName named parameter in the query by calling Query.setParameter:

public List findWithName(String name) {
    return em.createQuery(
        "SELECT c FROM Customer c WHERE c.name LIKE :custName")
        .setParameter("custName", name)
        .getResultList();
}

Named parameters are case-sensitive and may be used by both dynamic and static queries.

Positional Parameters in Queries

You may use positional parameters instead of named parameters in queries. Positional parameters are prefixed with a question mark (?) followed the numeric position of the parameter in the query. The Query.setParameter(integer position, Object value) method is used to set the parameter values.

In the following example, the findWithName business method is rewritten to use input parameters:

public List findWithName(String name) {
    return em.createQuery(
        “SELECT c FROM Customer c WHERE c.name LIKE ?1”)
        .setParameter(1, name)
        .getResultList();
}

Input parameters are numbered starting from 1. Input parameters are case-sensitive, and may be used by both dynamic and static queries.