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• Part 1. Separate software concerns with aspect-oriented programming
• Part 2. Learn AspectJ to better understand aspect-oriented programming
• Part 3. Use AspectJ to modularize crosscutting concerns in real-world problems

response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition","inline" );

Those 2 lines make the instant translation of the HTML I put in the page go to excel.  Now something massive to remember here: The formatting is pretty unpredictable if you use css or any fruity styles.  Luckally in my case I didn't need to use either; just output the data.

In either case you simply draw the HTML as you would to output a basic page with the response lines telling your browser that excel owns the page.

http://java.sun.com/docs/books/tutorial/reflect/

Reflection is powerful, but should not be used indiscriminately. If it is possible to perform an operation without using reflection, then it is preferable to avoid using it. The following concerns should be kept in mind when accessing code via reflection.

Performance Overhead

Because reflection involves types that are dynamically resolved, certain Java virtual machine optimizations can not be performed. Consequently, reflective operations have slower performance than their non-reflective counterparts, and should be avoided in sections of code which are called frequently in performance-sensitive applications.

Security Restrictions

Reflection requires a runtime permission which may not be present when running under a security manager. This is in an important consideration for code which has to run in a restricted security context, such as in an Applet.

Exposure of Internals

Since reflection allows code to perform operations that would be illegal in non-reflective code, such as accessing private fields and methods, the use of reflection can result in unexpected side-effects, which may render code dysfunctional and may destroy portability. Reflective code breaks abstractions and therefore may change behavior with upgrades of the platform.

@OneToMany -> @ManyToOne
A class_1 can have many class_2

@OneToMany(targetEntity=com.class_2.class, cascade=ALL, fetch=FetchType.EAGER)
@JoinColumn(name="class_2_id")
private Set<class_2> c2s = new HashSet();

<flip side>

@ManyToOne(targetEntity=com.class_1.class, cascade=ALL, fetch=FetchType.EAGER)
@JoinColumn(name="class_2_id", updatable=false, insertable=false)
private class_1 c1; 

@OneToOne
A class_1 can have one class_2

private class_2 c2;

<flip side>

@OneToOne (targetEntity=struts.hibernate.model.class_1.class, fetch=FetchType.EAGER, mappedBy="c2")
private class_1 c1; 

@ManyToMany
A class_1 can have many class_2 and a class_2 can have many class_1
*Note - This configuration uses a join table

@ManyToMany
@JoinTable(name="class_1_to_class_2"
 joinColumns=
@JoinColumn(name="class_1_id", referencedColumnName="ID"),
inverseJoinColumns=
@JoinColumn(name="class_2_id", referencedColumnName="ID"))
private Set<class_2> c2s = new HashSet();

<flip side>

 

@ManyToMany
@JoinTable(name="class_1_to_class_2"
 joinColumns=
@JoinColumn(name="class_2_id", referencedColumnName="ID"),
inverseJoinColumns=
@JoinColumn(name="class_1_id", referencedColumnName="ID"))
private Set<class_1> c1s = new HashSet();